Patent Publication Number: US-2023149125-A1

Title: Dental restoration molds

Description:
This application is a continuation of U.S. application Ser. No. 16/318,245, filed Jan. 16, 2019, which is a 371 of PCT/US2017/043721, filed Jul. 25, 2017, which claims the benefit of U.S. Provisional Application No. 62/366,939, filed on Jul. 26, 2016, the entire contents of which are incorporated herein by reference. 
    
    
     TECHNICAL FIELD 
     This disclosure relates to dental restorations. 
     BACKGROUND 
     A dental restoration, or a dental filling, utilizes a restorative dental material to improve function, integrity, and morphology of missing or irregular tooth structure. For example, a dental restoration may be used to restore missing tooth structure due to congenital discrepancies, following external trauma, or as part of a restorative treatment for dental caries, or tooth decay. 
     Restorative dentistry may also be an aesthetic treatment to improve appearance of teeth by, for example, altering their shape and/or optical properties (e.g., shape and/or translucency) by, for example, applying a veneer, enlarging an undersized tooth, managing position or contour of adjacent soft tissues, lessening or removing a gap (diastema), and/or resolving the appearance of malposition. 
     Restorative dentistry may also be used to adjust the biting or chewing function of teeth, to affect tooth function, and/or other aspects of overall oral health such as temporomandibular joint (TMJ) disorders, periodontal involvement, gingival recession or as part of a larger plan to construct a healthy and stable oral environment. 
     Restorative dentistry may include removing tooth structure, such as drilling decay from an infected tooth or reshaping teeth by removing undesired tooth structure (e.g., which may be referred to as “preparing” or “recontouring” the tooth) and then using relatively simple tools and a relatively high level of craftsmanship to isolate, retract, fill and contour the finished restoration. 
     SUMMARY 
     This disclosure describes devices, systems, and techniques for molding (or shaping or contouring) restorative dental material directly on a tooth located within a mouth of a patient. In some examples, a dental restoration tool includes a mold body that, together with a tooth of a particular patient, defines a mold cavity configured to receive restorative dental material. The restorative dental material may be introduced into the mold cavity and cured to define a dental restoration. The dental restoration tool may be custom designed for a particular tooth (or set of teeth) for a particular patient. In some examples, such custom tools may be produced using three-dimensional printing techniques. Tools may also be produced by other methods of creating physical objects from digital data, such as CAD/CAM milling. 
     The details of one or more aspects of the disclosure are set forth in the accompanying drawings and the description below. Other features, objects, and advantages of the techniques described in this disclosure will be apparent from the description and drawings, and from the claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a front view of an example tool for forming a dental restoration, the tool including at least one mold body. 
         FIGS.  2 A and  2 B  are perspective views of an example door body that may be a part of a tool for forming a dental restoration. 
         FIGS.  3 A and  3 B  are perspective views of another example door body, which is similar to the door body shown in  FIGS.  2 A and  2 B , but includes a flanged portion. 
         FIGS.  4 A  is a perspective view of another example door body that may be a part of a tool for forming a dental restoration, where the door body is configured to be mechanically connected to a mold body via a hinge. 
         FIG.  4 B  is a back view of a part of another example tool for forming a dental restoration, where the tool includes the mold body of  FIG.  1    and the door body of  FIG.  4 A  connected together via a hinge. 
         FIG.  5    is a front view of another example tool for forming a dental restoration, where the tool includes the mold bodies of  FIG.  1   , the door body of  FIGS.  2 A and  2 B , and the door body of  FIGS.  3 A and  3 B . 
         FIGS.  6 A,  6 B, and  6 C  are perspective and side cross-sectional views of another example tool for forming a dental restoration. 
         FIGS.  7 A- 7 G  illustrate example steps for using the tool of  FIG.  5    to form a dental restoration. 
         FIGS.  8  and  9    are interior views of another example tool for forming a dental restoration. 
         FIGS.  10  and  11    are bottom views of another example tool for forming a dental restoration. 
         FIGS.  12  and  13    are assembled and expanded cross-sectional views of another example tool for forming a dental restoration. 
         FIGS.  14 A and  14 B  are side and top views of another example tool for forming a dental restoration. 
         FIG.  15    is a top view of another example tool for forming a dental restoration. 
         FIG.  16    is a perspective view of another example tool for forming a dental restoration. 
         FIGS.  17 A and  17 B  are front and top views of an example mold body of an example tool for forming a dental restoration. 
         FIGS.  18 A and  18 B  are front and bottom views of an example tool for forming a dental restoration, where the tool includes the mold body of  FIGS.  17 A and  17 B  and an additional mold body. 
         FIGS.  19 A and  19 B  are top and perspective views of another example tool for forming a dental restoration. 
         FIGS.  20 A- 20 E  illustrate another example mold body for forming a dental restoration. 
         FIGS.  21 A and  21 B  are perspective and front views of another example tool for forming a dental restoration. 
         FIG.  22    is a diagram of an example system that may be used to design any of the tools of  FIGS.  1 - 21 B . 
         FIG.  23    is a flow diagram illustrating an example method of designing any of the tools of  FIGS.  1 - 21 B . 
         FIG.  24    is a flow diagram illustrating an example method for forming any of the tools of  FIGS.  1 - 21 B . 
     
    
    
     DETAILED DESCRIPTION 
     Restorative dentistry may be used to add tooth structure to a patient&#39;s dentition, e.g., to an existing tooth, in order to improve at least one of function, integrity, aesthetics, or morphology of missing or irregular tooth structure. For example, restorative dentistry can be an aesthetic treatment to improve appearance of teeth by, for example, altering their shape and/or optical properties (e.g., shape and/ translucency), which can be achieved using any suitable technique, such as by applying a veneer, managing position or contour of adjacent soft tissues, lessening or removing a gap (diastema), and/or resolving the appearance of malposition. As another example, restorative dentistry may be used to adjust the biting or chewing function of teeth to affect tooth function and/or other aspects of overall oral health such as temporomandibular joint (TMJ) disorders, periodontal involvement, gingival recession or as part of a larger plan to construct a healthy and stable oral environment. 
     In some cases, a dental restoration process includes drilling decay from an infected tooth or reshaping teeth by removing undesired tooth structure (e.g., which may be referred to as “preparing” or “recontouring” the tooth) and then using tools and craftsmanship to manually isolate, retract, fill and contour the finished restoration. 
     Different techniques may be used to isolate the dental restoration site. Quality isolation of the dental restoration site via a rubber dam can be cumbersome and may be skipped for less effective isolation via cotton rolls, which may increase the risk of contamination, reduce longevity of the restoration, or both. Retraction of soft and hard tissue may include manipulation of cords, wedges and matrix bands. Imperfect retraction techniques may result in contamination, difficulty in achieving proper tooth contours and symmetry, finishing and/or polishing in interproximal areas, poorly adapted contacts, or any combination thereof. 
     While “bulk fill” restorative materials and high intensity curing lights may facilitate relatively fast filling of deep cavities (e.g., 4-5 millimeters (mm)), many restorations may be completed in a single shade (of color) as practitioners may be uncertain of the correct layering protocol for multiple shades or types of restorative material. Additionally, with little geometrical guidance available on a prepared tooth, creation of the final filling level and occlusal surface geometry may include overfilling with restorative dental material, followed by an iterative process of grinding and checking tooth contact and biting function on an anesthetized patient. This process may be the most time consuming for dental restorations and errors here may result in tooth sensitivity and return visits for adjustment. 
     Custom molds may be used to facilitate restoration of tooth structure. For example, a mold body may be positioned over a patient&#39;s tooth structure and, alone or together with existing tooth structure, may define a mold cavity configured to receive restorative material. The configuration of the mold cavity may correspond to the desired configuration of the dental restoration. A dental restoration may be formed by positioning the mold body in a patient&#39;s mouth at the desired location for the dental restoration, introducing a restorative material into the mold cavity before or after positioning the mold body in the patient&#39;s mouth, and curing the restorative material while the mold is still in place in the mouth. The cured restorative material may define the dental restoration. However, some such molds may allow a practitioner little control over material placement, including shading, at least in part because the practitioner is unable to see into the mold cavity while it is positioned in the patient&#39;s mouth at the desired location. 
     Additionally, use of molds may result in flashing as restorative material may leak from seams of the mold cavity or the junction of the mold with the tooth and flow into unintended and often undesirable areas. Flashing may be difficult to remove after curing the restoration. In dental applications, this can potentially cause irritation, staining, food particle entrapment, and/or failure of the restoration. Some areas in which flash may occur are interproximally, e.g., due to poor access, at the gingival margin, where attempts to remove or finish can cause irritation to the gums, and incisally. 
     The tools described herein may include one or more features designed to reduce flash and/or to allow increased control of the placement of restorative material by practitioners using more traditional skills and techniques. The tools described herein may further include features to improve functionality of dental restoration tools, and ease of use of the tools. The tools described herein may not be simple molds that simply reflect the shape of desired tooth structure but may instead be designed to include additional features that provide one or more of the foregoing benefits. 
     In some examples, a tool described herein may be digitally designed. For example, a tool may be designed using a three-dimensional (3D) model of the patient&#39;s tooth structure (e.g., obtained from an intraoral scan of all or part of the patient&#39;s dentition or scanning of a conventional impression or model). The tool can be, for example, manufactured from the digital data using an additive technique, such as 3D printing, or a subtractive technique, such as computer-aided design/computer-aided manufacturing (CAD/CAM) milling. 
     In some examples, the tool for a dental restoration may include a mold designed based on the 3D model of the patient&#39;s tooth structure, and may include additional features to provide advantages over molds that are formed based simply on the 3D scan, a wax mold, or other molds based simply on the shape of the anatomy and/or desired tooth structure of the patient. The disclosed mold and techniques may facilitate high quality dental restorations with reduced time and/or skill requirements compared to conventional dental restoration techniques and/or may facilitate high quality dental restorations with improved quality, reduced flash, and/or reduced time and/or skill requirements compared to other molding techniques. 
     Example techniques for forming tools for a dental restoration are described in International Publication No. WO 2016/094272, entitled, “Dental Restoration Molding Techniques,” International Publication No. WO 2017/106431 A1, entitled, “Dental Restoration Molds,” and International Patent Publication No. WO 2017/106419, entitled, “One-Piece Dental Restoration Molds.” 
       FIG.  1    is a front view of an example tool  100  for forming a dental restoration. The tool  100  includes a mold body  102 , which may be configured to provide a customized fit with at least one tooth of a patient. For example, mold body  102  may be specifically designed to fit over, mate with, and/or provide restorative structure to the at least one tooth. In the example shown in  FIG.  1   , mold body  102  defines one or more apertures  104   a,    104   b  (collectively referred to as “apertures  104 ”), which may each be configured to align with a portion of a surface (e.g., a majority of the surface or less than a majority of the surface) of a respective tooth of the patient to be restored, such as, for example, a lingual, a facial, or an incisal/occlusal surface of a respective tooth. For example, apertures  104  may be configured to align with a portion of a lingual and/or a facial surface of a respective tooth of the patient to be restored. The teeth to be restored are a part of the at least one tooth of the patient with which mold body  102  is configured to provide a customized fit. The surface of the tooth to be restored and aligned with the respective apertures  104  may, for example, be defined by existing tooth structure or by the dental restoration formed using mold body  102 . 
     Mold body  102  is configured to combine with the at least one tooth of the patient to define a mold cavity encompassing at least a portion of desired tooth structure of the tooth or teeth to be restored. For example, in the illustrated example, mold body  102  may combine with teeth of the patient to define a mold cavity encompassing at least a portion of desired tooth structure for each of the teeth with facial portions aligning with apertures  104   a  and  104   b.  In some examples, the dental restoration may include a dental veneer restoration on the tooth or teeth to be restored, and apertures  104   a  and  104   b  may allow a practitioner to have better control over the placement of restorative material in the mold cavity than a traditional mold, in which restorative material is injected through a small hole and the practitioner has little or no visibility to the surface of the tooth. For example, apertures  104 , which align with a surface of a tooth may allow a practitioner to have better control over the final appearance of that surface, including the final surface texture and/or shading, and may provide the practitioner to have better control of layering of restorative materials. 
     In some examples, tool  100  may include a second mold body  106 , which may also be configured to provide a customized fit with the at least one tooth of the patient. Mold body  102  and mold body  106  may be configured to combine with the at least one tooth of the patient to form the mold cavity. For example, mold body  102  and mold body  106  may be configured to mate with one another and/or to be attached to the at least one tooth to form the mold cavity. In some examples, mold body  106  is separable from and engageable with the mold body  102 . For example, a clamp  108  may allow mold body  102  and mold body  106  to easily engage with one another and to easily be separated from one another while maintaining the integrity of the respective mold body. In some examples, mold bodies  102 ,  106  include indicia or alignment features (e.g., visual indicators, mechanical mating features, key holes, notches, and the like) to help a practitioner properly align and easily engage mold body  102  and mold body  106  with one another. 
     Each of the apertures  104  has a suitable configuration (e.g., shape and/or size) for introducing restorative material into a mold cavity defined by an interior surface of mold body  102  to cover the portion of the surface of the tooth to be restored, the interior surface being a surface facing the tooth or teeth to be restored. In addition, each of apertures  104  has a configuration that enables a practitioner to view a meaningful part of the dental restoration being formed via the restorative material. This may allow the practitioner to have better control over the appearance of the dental restoration. Instead of blindly relying on mold body  102  to provide the final shape of the dental restoration, apertures  104  may allow the practitioner to view and manipulate the restorative material before it is cured. Manipulation of the restorative material can include, for example, removal of a portion of the restorative material, application of one or more surface features to the restorative material before it is cured, layering of the restorative material colors, and the like. 
     In some examples in which apertures  104  have a configuration that enables a practitioner to view a meaningful part of the dental restoration being formed, at least one of apertures  104  is configured to align with at least about 20% of the portion of the surface of the tooth to be restored, such as about 20%-80% of the portion of the tooth being restored. As an example, at one of apertures  104  may be configured to align with a portion of a tooth surface that is a majority of the surface of the tooth to be restored. Thus, in some examples, aperture  104   a  may be configured to align with a portion comprising a majority of a facial surface of one tooth, and aperture  104   b  may be configured to align with a portion comprising a majority of a facial surface of another tooth. 
     In other examples, apertures  104  may be configured to align with a portion less than the majority of a surface of a tooth, e.g., when smaller areas of the tooth are being restored and/or when expected flow of the restorative dental material from outside mold body  102  and through apertures  104  to the part of the mold cavity defined by mold body  102  proximate the tooth surface needing restoration is deemed to be sufficient. 
     In some examples, the shape of one or more of apertures  104  may be designed to substantially match the shape of the tooth and/or the portion of the tooth to be restored. For example, apertures  104  may be substantially noncircular. In other examples, however, the shape of one or more apertures  104  may be circular. 
     Apertures  104  may be configured to be larger than a tip of a restorative material introduction device that is used to introduce restorative dental material into the mold cavity defined by mold body  102 . The tip of the restorative material introduction device may also be referred to as a capsule or a syringe tip, and may refer to the portion of the device that is introduced into the aperture. Apertures  104  may be sufficiently large to allow placement and flow of restorative material to cover the portion of the surface of the tooth being restored. Additionally, or alternatively, apertures  104  may be sufficiently large to allow movement of the tip of the dental material device within aperture  104   a  or  104   b,  and/or to allow a practitioner to view the dental restoration as it is being formed. For example, apertures  104  may have an area at least about 2 times the greatest cross-sectional area of a tip of a commercially available restorative material introduction device. 
     An area of an aperture  104  may be measured using any suitable technique. In some examples, the area of aperture  104  may be measured using the perimeter of the respective aperture defined by mold body  102  or may be measured digitally, such as, for example, using a software program such as CAD. For example, using software, the area of aperture  104  may be determined using a grid counting method. Using the software, a user may digitally overlay a grid including squares having known dimensions over aperture  104  and determine the number of squares that are within or make up the area of the respective aperture  104 . The known dimensions of the squares may then be used to convert the number of squares determined into the area of the respective aperture. 
     In some examples, the cross-sectional area of a tip of a commercially available restorative material introduction device is determined using the outer diameter of the tip of the device. In one example, the cross-sectional area of a tip of a commercially available restorative material introduction device may be about 7 mm 2  and the area of each of apertures  104   a,    104   b  may be about 16 mm 2 . In some examples, a ratio of the area of aperture  104   a  or  104   b  to the cross-sectional area of a tip of a commercially available restorative material introduction device be greater than or equal to about 2:1, such as greater than or equal to about 3:1, or greater than or equal to about 4:1. 
     Tips of some commercially available restorative material introduction devices have an inner diameter between about 0.6 mm and about 2.3 mm and an outer diameter between about 0.90 mm and about 2.7 mm. For example, a 3M Filtek Supreme Universal capsule, may have an inner diameter of about 2.03 mm and an outer diameter of about 2.41, the 3M Filtek Supreme Flowable syringe tip may have an inner diameter of about 0.60 mm and an outer diameter of about 0.90 mm, and the 3M Filtek Bulk Fill syringe tip may have an inner diameter of about 0.70 mm and an outer diameter of about 1.10 mm. The 3M Filtek products are commercially available by 3M ESPE Dental Products in St. Paul, Minn.. As other examples, commercially available devices used to deliver restorative dental material may have an inner diameter of about 1.85 mm and an outer diameter of about 2.30 mm, an inner diameter of about 2.20 mm and an outer diameter of about 2.70 mm, an inner diameter of about 2.10 mm and an outer diameter of about 2.60 mm, an inner diameter of about 1.10 mm and an outer diameter of about 1.60 mm, an inner diameter of about 1.90 mm and an outer diameter of about 2.50 mm, or an inner diameter of about 2.30 mm and an outer diameter of about 2.60 mm. 
     In some examples, apertures  104  are each defined by a single, continuous piece of mold body  102  or  106 . For example, either mold body  102  or mold body  106  may define an entire aperture  104 . In some examples, defining an aperture  104  within a single piece of mold body  102  or  106  may prevent the aperture from including or being formed using a seam interface between two separate mold body parts. Apertures  104  that are defined by a single piece of mold body  102  or  106  may help prevent the dental restoration formed using the mold body from including seams or artifacts from mold body  102  or  106 . In contrast, a dental restoration formed using apertures that are defined by more than a single piece of mold body  102  or  106 , may include seams or artifacts from the mold bodies  102 ,  106  due to restorative material curing within the seam between the two mold bodies. 
     Additionally, or alternatively, apertures  104  defined by a single piece of a mold body  102  or  106  may help prevent the part of the one or more mold bodies  102 ,  106  defining the aperture from becoming separated during the introduction of the restorative material into the mold cavity defined by mold bodies  102  and/or  106  and one or more teeth of the patient. The introduction of the restorative material into mold cavity may have enough force to separate parts of mold bodies from each other, thereby providing less of an engagement between mold body  102  and mold body  106  and/or less of a customized fit with one or more teeth. This separation of parts of mold bodies may result in additional flash forming, which may adversely affect the quality of the formed dental restoration and/or increase the time and effort required to form the dental restoration because the practitioner may need to remove the cured flash. 
     Tool  100  may allow the practitioner greater control in placing the restorative material in the mold cavity defined by the patient&#39;s tooth structure and mold bodies  102 ,  106 . For example, tool  100  may allow a practitioner to make adjustments to and/or modifications to the placement of the restorative material in the mold cavity, and/or may allow the practitioner to check for bubbles or voids prior to curing, which may not be provided by traditional injection molding. In some examples, apertures  104  of tool  100  may allow the practitioner to apply the restorative material directly to the tooth to be restored, rather than injecting the restorative material, such as through an injection port. However, in other examples, the practitioner may apply the restorative material to the tooth to be restored or to mold body  102 ,  106  before applying mold bodies  102 ,  106  over the teeth of the patient. 
     Apertures  104  may allow the practitioner to visualize the restorative material on the tooth more easily than a smaller hole for injecting restorative material, e.g., an injection port. In contrast to apertures  104 , an injection port may be sized to be equal to or only slightly larger than a tip of a commercially available restorative material introduction device, such as about 100% to about 125%, such as about 100% to about 110% of the cross-sectional area of the tip of the restorative material introduction device. In some examples, an injection port may be about 0.1 mm in diameter (e.g., about 100 microns) in diameter. 
     Further, the injection port may have a shape (e.g., circular) that matches the shape of the commercially available restorative material introduction device. In contrast, as discussed above, apertures  104  may be configured to be larger (e.g., twice as larger or greater than two times the size) than a tip of a restorative material introduction device that is used to introduce restorative dental material into the mold cavity defined by mold body  102 . 
     Apertures  104  may allow a practitioner to utilize traditional methods and techniques for building up a restoration while still providing isolation, wedging and/or shape/contouring guidance. In some examples, the introduction of material via apertures  104   a  and  104   b,  compared to through a relatively small injection port in mold body  102  and/or  106 , may minimize the pressure required to introduce restorative material into the mold cavity, which may help minimize flashing. For example, the introduction of material via apertures  104  that are larger than the size of a tip of a commercially available restorative material introduction device may reduce or even prevent back pressure on the tip of the dental material introduction device from the mold cavity. The reduced or prevented back pressure may help prevent restorative material from flowing back in the direction of the restorative material introduction device. 
     Additionally, layering of restorative material having different shades of color, different translucencies, and/or different mechanical properties may be easier with the open mold cavity design provided by apertures  104 . Further, in some examples, mold bodies  102 ,  106  including apertures  104  may release easier from the dental restoration (compared to traditional molds that do not include apertures  104 , but only include an injection port) due at least in part to a reduced area of surface contact between the mold and the restorative material. 
       FIGS.  2 A and  2 B  are perspective views of an example door body  200  that may be a part of a tool for forming a dental restoration. In some examples, door body  200  may be used in conjunction with a tool such as the tool  100  of  FIG.  1   . Door body  200  may correspond to the portion of the surface of the tooth to be restored and at least a portion of door body  200  may be configured to mate with an aperture defined by tool  100  and aligned with that surface. For example, at least a portion of door body  200 , such as mating portion  202 , may be configured to mate with aperture  104   a  and/or aperture  104   b  to form the mold cavity. Mating portion  202  may be, for example, a bevel edge of door body  200  that helps aid the insertion of door body  200  in an aperture  104   a,    104   b,  such as by guiding door body  200  into the respective aperture. 
     When door body  200  is mated with a respective aperture  104   a  or  104   b,  surface  204  of the door body  200  facing the mold cavity defined by mold body  102  and a tooth structure of a patient may help shape the restorative material that is in the mold cavity, e.g., in order to define the surface of the tooth to be restored. 
     In some examples, door body  200  includes at least one protrusion  206 , which is a structure that aids the use of door  200 . For example, protrusion  206  may be configured to provide a handle or a gripping mechanism for a practitioner, e.g., the hand of the practitioner or a tool manipulated by the practitioner, and/or ease the mating of door body  200  with aperture  104   a,    104   b.  In this way, mating door body  200  with aperture  104   a ,  104   b  may be facilitated by gripping protrusion  206 . Protrusion  206  may include gripping features in some examples, such as ribs  208 . Ribs  208  may ease the handling of door body  200  by the practitioner, e.g., may prevent the hand of the practitioner or a tool manipulated by the practitioner from slipping from protrusion  206 . 
     Integrated grips provided by protrusion  206  may increase the ease of use of any of the door bodies described herein. For example, protrusion  206  may allow a practitioner to easily identify the points on the door body to use for placing and removing the door body, making use of the door bodies more intuitive. Protrusion  206  may also provide securement of the components (e.g., to reduce the possibility that the door body to which the protrusion is attached is not dropped), and may also provide leverage for removing after the restorative material has been cured. 
     In some examples, door body  200  may be physically separate from (unconnected to) mold body  102 . In these examples, a practitioner may freely move door body  200  relative to apertures  104   a,    104   b  and place door body  200  in the respective aperture  104  by bringing door body  104  into alignment with aperture  104  from any suitable angle. In other examples, however, door body  200  and mold body  102  are mechanically connected to each other, such as by using a hinge. For example, door body  200  and mold body  102  may be connected via a snap hinge, a living hinge, a barrel hinge, a pin joint hinge, or any other suitable type of hinge. An example of a hinge connection between a door body and a mold body is described with reference to  FIGS.  4 A and  4 B . 
     In some examples, to reduce the likelihood of trapping air during stamping of the restorative material within the mold cavity with door body  200 , a release film (e.g., polytetrafluorethylene (PTFE), plastic wrap (e.g., Saran Wrap made available by SC Johnson of Racine, Wisconsin), which can be formed from polyvinylidene chloride or another releasable material) may be placed on surface  204  of door body  200 , which may be gently pressed into the respective aperture  104   a  or  104   b  to distribute the restorative material in the mold cavity, resulting in a near-net shaping of the material. Door body  200  may then be released, the liner removed, and door body  200  reapplied to create a final shape. 
       FIGS.  3 A and  3 B  are perspective views of another example door body  300 , which is similar to the door body  200  shown in  FIGS.  2 A and  2 B , but includes a flanged portion  302 . Flanged portion  302  may be configured to overlay at least a portion of mold body  102  adjacent aperture  104   a  or  104   b  and outside the aperture to provide a seal between door body  300  and mold body  102  and to act as a stop to prevent door body  300  from being inserted too far into the respective aperture. In some cases, inserting door body  300  too far into the respective aperture may negatively impact the contour of the restoration. 
       FIG.  4 A  is a perspective view of another example door body  310  and  FIG.  4 B  is a back view of example tool  312  for forming a dental restoration. Tool  312  includes door body  310  and a mold body  314 . In  FIG.  4 B , door body  310  is inserted in aperture  328  defined by mold body  314 . Mold body  314  and aperture  328  may be similar to mold body  102  and aperture  104   a  or  104   b  of  FIG.  1   . However, in the example shown in  FIG.  4 B , mold body  314  and door body  310  are mechanically connected to each other via door hinge  316 . 
     Door body  310  is similar to door body  200  shown in  FIGS.  2 A and  2 B , but includes a chamfered edge  320 , which, when inserted in aperture  328 , is configured to define a predictable location for cured flash to fracture from the dental restoration. Chamfered edge  320  may help prevent chipping or other damage to a surface of the dental restoration formed using door body  310  and mold body  314 , such as by defining a location for the flash to cure. Chamfered edge  320  may result in cured flash fracturing superficially, e.g., away from the cured restorative material. 
     Chamfered edge  320  is a surface of door body  310  positioned between surface  322  and mating portion  324  of door body  310 . In some examples, chamfered edge  320  is a surface of door body  310  that is oriented at a non-perpendicular angle to a major surface of surface  322  and mating portion  324  of door body  310 . For example, chamfered edge  320  may be oriented at an angle to a major surface of surface  322  and/or mating portion  324  of door body  310  of between about 1 degree and about 89 degrees, such as between about 30 degrees and about 60 degrees. Surface  322  is configured to contact the restorative material within the mold cavity defined by mold body  314  when door body  310  is introduced into aperture  328  and mating portion  324  is at least partially engaged with the part of mold body  314  defining aperture  328 . In other examples, chamfered edge  320  may be part of surface  322  and/or mating portion  324  of the door body  310 . 
     As shown in  FIG.  4 B , when door body  310  is mated with and inserted inside of aperture  328  (e.g., fully inserted in aperture  328 , to the extent allowed by the geometry of door body  310  and mold body  314 ), chamfered edge  320  and mold body  314  define a channel  326  between the side of mold body  314  forming aperture  328  and surface  322  of door body  310 . In some examples, cured flash may form in channel  326 . Due to the configuration of channel  326 , such as the relatively shallow depth of channel  326 , the cured flash formed in channel  326  fracture from the formed dental restoration superficially, e.g., away from the cured restorative material. In some examples, door body  310  defining chamfered edge  320  may allow the cured flash to form in a predictable location, e.g., within channel  326 , which in turn may provide a predictable fracture location of the cured flash. Additionally, or alternatively, the formation of cured flash within channel  326  may prevent chipping or damage to the restorative dental material, such as, for example, in comparison to some door bodies that do not define a channel with a mold body when mated with the mold body. 
     Door hinge  316  mechanically connects door body  310  and mold body  314 , as well as helps maintain alignment door body  310  and mold body  314  during use of tool  312 . Door hinge  316  may have any suitable configuration, such as, but not limited to, a snap hinge, a living hinge, a barrel hinge, or a pin joint hinge. Door hinge  316  may help ensure that the correct door body  310  is used with the corresponding aperture  328 . For example, a manufacturer may preconnect door body  310  to mold body  314  via door hinge  316 , such that a practitioner may not need to attach door body  310  to mold body  314 . In other examples, however, the practitioner may attach door body  310  to mold body  314  via door hinge  316 . In some examples in which door hinge  316  is formed by a hinge part connected to door body  310  and another hinge part connected to mold body  314 , door body  310  and mold body  314  may include one or more indicia or alignment features to help match-up and align a door body  310  to the corresponding aperture  328  to connect the corresponding hinge parts to form door hinge  316 . The indicia or alignment features may be, for example, those described above with respect to mold bodies  102 ,  106  of  FIG.  1    and those described with respect to mold bodies  502 ,  506 , and door bodies  508   a,    508   b  of  FIGS.  6 A- 6 C . 
     Door hinge  316  may be formed separate from door body  310  and/or mold body  314 , or door hinge  316  may be formed as an integral part of door body  310  and/or mold body  314 . In some examples, door hinge  316  may increase the ease of use of tool  312  (e.g., reducing the training required to use tool  312 ). For example, rather than a practitioner applying door body  310  to mold body  314  in an idiosynractic manner, door hinge  316  may provide for door body  310  to be placed in a specific location or orientation relative to mold body  314 . In some examples, door hinge  316  may also allow for mold body  314  and door body  310  to be moved and/or placed together, e.g., without door body  310  becoming separated from mold body  314 . 
     Door hinge  316  is configured to allow door body  310  to rotate relative to mold body  314  about an axis of rotation. The axis of rotation is oriented such that door body  310  may rotate (e.g., pivot) to be inserted within aperture  328  (a “closed” position) or to be outside of aperture  328  (an “open” position). In the open position of door body  310 , a practitioner may access the mold cavity defined by mold body  314  and one or more teeth of the patient, such as to manipulate restorative material introduced into the mold cavity by the practitioner. In some such examples, the range of rotation of door hinge  316  about an axis may be limited by the configuration and/or placement of door hinge  316  with respect to door body  310  and mold body  314 . For example, door body  310  attached to mold body  314  via door hinge  316  may not be able to rotate  360 ° about an axis of rotation due to the presence of mold body  314 . 
     In some examples, door hinge  316  may bias door body  310  in the closed position and/or the opened position, or both, depending on the position of door body  310  relative to mold body  314 . For example, door hinge  316  may be a spring-loaded hinge. 
     Door hinge  316  may be used in combination with any of the example tools described herein. For example, some examples any of the tools described herein that include a door body and a mold body configured to mate together may include a hinge for mechanically connecting the door body and the mold body. 
     In addition to or instead of door hinge  316 , one or more other mechanical features can be used to assist in the alignment of mold body  314  and door body  310 , such as, but not limited to, sliders, guides, bevels, chamfers, and the like. For example, mold body  314  and/or door body  310  may include a slider feature that acts a guide for door body  310 , such as to allow door body  310  to slide along an edge of aperture  328  and guide door body  310  along mold body  314  to mate with aperture  328 . 
       FIG.  5    is a front view of another example tool  400  for forming a dental restoration that includes the mold bodies  102  and  106  of  FIG.  1   , the door body  200  of  FIGS.  2 A and  2 B , and the door body  300  of  FIGS.  3 A and  3 B . The door bodies  200  and  300  are each readily separable from and engageable with the mold body  102 . For example, in the illustrated example, each of the door bodies  200  and  300  are shown engaged with mold body  102 . As shown in  FIG.  5   , door bodies having different configurations (e.g., sizes, shapes, and the like) may be used with the same mold body. 
       FIGS.  6 A and  6 B  are a perspective and side cross-sectional views of another example tool  500  for forming a dental restoration. FIG,  6 B is a cross-sectional view of the tool  500  taken along the line “ 6 B” of  FIG.  6 A . The tool  500  may include first mold body  502 , similar to first mold body  102  of  FIGS.  1  and  4   , which may define apertures  504   a  and  504   b,  similar to the apertures  104   a  and  104   b  of  FIG.  1   , a second mold body  506 , similar to the second mold body  106  of  FIGS.  1  and  4   , door bodies  508   a  and  508   b , similar to the example door bodies  200  and  300  of  FIGS.  2 A- 4   . In the illustrated example, door body  508   a  defines a vent  510 , which may be an opening positioned within door body  508   a,  within mold body  502 , partially within the mold body  502  and door body  508   a,  or combinations thereof. In some examples, vent  510  may be configured to allow excess restorative material to flow out of a mold cavity  520 , which may be removed prior to curing (e.g., with a scalar instrument), providing for easier removal of flash. Alternatively, or in addition, vent  510  may be configured to allow air to flow out of the mold cavity. 
     In some examples, vent  510  may be configured such that vent  510  is drafted towards the dental restoration in order to reduce mechanical interlocking between tool  500  and the formed dental restoration (formed by curing the restorative material within mold cavity  520  of mold body  502 ). In some such examples, vent  510  may not be uniform in size. For example, vent  510  may decrease in cross-sectional area in a direction from mold cavity  520  to the outer surface of mold body  502  and/or door body  508 . The decrease in cross-section area of vent  510  in the direction away from mold cavity  520  may help prevent restorative material from remaining in vent  510 . For example, if restorative material enters vent  510 , the restorative material may flow out of vent  510  away from mold cavity  520 . If restorative material remains in vent  510  when curing, the cured material may provide mechanical locking with the formed dental restoration, and tool  500  may become difficult to remove. By drafting vent  510  towards the restoration, e.g., as shown in  FIG.  6 B , such that the vent  510  has a larger cross-section proximate to the dental restoration than the outer surface of mold body  502 , mechanical interlocking may be reduced, the tool  500  may be more easily be removed from a formed dental restoration, and the possibility of adversely affecting the integrity of the restoration may be reduced. 
     Drafting vent  510  towards the formed restoration may also provide a predictable fracture of the cured flash superficially, e.g., in a direction away from the cured restorative material. In this way, drafting the vent  510  towards the restoration may provide easier removal of the cured flash. 
     In some examples, aperture  504   a  and aperture  504   b  may be different shapes and door body  508   a  and door body  508   b  may be different shapes. The shape of door body  508   a  may correspond to the shape of aperture  504   a  and the shape of door body  508   b  may correspond to the shape of aperture  504   b.  In this way, apertures  504   a,    504   b  may be configured to mate with only the door intended to be used with the respective aperture. This may help reduce user error, e.g., if placement of the incorrect door in aperture  504   a ,  504   b  would result in a malformed dental restoration, e.g., because of the way the door body pushes the restorative material in the mold cavity or because door bodies  508   a,    508   b  are configured to provide surface features or the like to the dental restoration. In other examples, the aperture  504   a  and the aperture  504   b  may be the same shape and the door body  508   a  and the door body  508   b  may be the same shape, such that door bodies  508   a ,  508   b  may mate with either aperture  504   a,    504   b.    
     In some examples, one or more of mold body  502 , mold body  506 , door body  508   a,  or door body  508   b,  and/or any of the example mold bodies or door bodies described herein, may include one or more indicia for facilitating one or more of mating door body  508   a  with aperture  504   a  or mating door body  508   b  with aperture  504   b  (or mating the door body with the respective aperture in any of the examples described herein), mating mold body  502  with mold body  506 , and/or positioning one or more of mold body  502 , mold body  506 , door body  508   a,  or door body  508   b  with respect to one any of the other components and/or with respect to the teeth of the patient. For example, the indicia may provide information to aid a practitioner in correctly mating door body  508   a  with aperture  504   a  instead of attempting to mate door body  508   a  with aperture  504   b.  As another example, the indicia may aid the practitioner in correctly orienting door body  508   a  relative to aperture  504   a.  As another example, the indicia may provide information to aid a practitioner in correctly positioning mold body  502  and/or mold body  506  with respect to the teeth and/or with respect to one another. 
     In the illustrated example, the indicia may include one or more key structures, such as key structures  512   a - 512   e  of door body  508   a,  and one or more corresponding keyholes, such as keyholes  514   a - 514   e  defined by mold body  502 . For example, the practitioner may align each of key structures  512   a - 512   e  with a corresponding keyhole  514   a - 514   e  to ensure that door body  508   a  is correctly oriented relative to aperture  504   a . While, in the illustrated example, key structures  512   a - 512   e  and corresponding keyholes  514   a - 514   e  appear to be similarly shaped oriented around about door body  508   a  as those of door body  508   b,  in some examples, door bodies  508   a  and  508   b  may include key structures with different shapes and/or locations such that key structures of one door body  508  will clearly be corresponding with key holes about one aperture or the other such that the key structures and keyholes will help the practitioner to identify which door body  508  corresponds to which aperture  504 . 
     Alternatively, or in addition to key structures and keyholes, other visual or physical indicia may be used to help a practitioner correctly match a door body to a corresponding aperture. Other indicia may include, for example, color coding, symbols, markings, and/or any other suitable indicia or combination thereof. For example, door body  508   a  may include one or more colors or symbols that match the color or symbol associated with corresponding aperture  504   a  (e.g., printed on mold body  502  next to aperture  504   a  and/or lining a portion of mold body  502  proximate aperture  504   a  and/or inside aperture  504   a  and/or indicating orientation relative to aperture  504 , e.g., one color and/or symbol indicating the top and/or another indicating the bottom including, for example, one color printed on a top of door body  508   a  and on mold body  502  next to the top of respective aperture  504   a  and/or lining a portion of mold body  502  proximate the top of respective aperture  504   a  and/or inside the top of aperture  504   a  and another color). As another example, one of more of door body  508   a,  door body  508   b,  or mold body  502  may include other markings indicating which door body  508  corresponds to which aperture  504  and/or the correct orientation of door body  508  with respect to corresponding aperture  504 . For example, similar to key structures and key holes, notches (physical or printed) may be marked at or near the perimeter of door body  508   a  and/or  508   b  as well as about or along an inner surface of apertures  504   a  and/or  504   b  and a practitioner knows to align notches on corresponding door bodies  508  and apertures  504 . 
     As another example, colored lines or other indicia may be formed on or near an interproximal edge mold body  502  and/or mold body  506  to assist the practitioner in placement of the respective mold body on the teeth. For example, the indicia may be used to prevent or provide indication of upside-down placement of the mold body. 
     As another example, an inner surface of either or both of apertures  504  may be distinguished from other portions of mold body  502  by coloring or other indicia that is distinct from adjacent portions of mold body  502 . This may allow a practitioner to more easily see the perimeter of the aperture  504  to aid in correct placement of respective door body  508 . 
     The indicia discussed herein may be integrated into the respective mold components or may be separate from and applied to a mold component. For example, the markings may be 3D components that are an integrated feature of the mold design, the colorings may be a color of the material used to form portions the mold component, and/or the markings and/or coloring may be applied to a surface of the mold component using ink or any suitable material. 
     In some examples, tool  500  may include a release film (e.g., PTFE, Saran Wrap or another releasable material) configured for placement on one or more surfaces of door body  508   a  and/or  508   b,  including, for example, a surface facing mold cavity  520  when respective door body  508   a  or  508   b  is placed in respective aperture  504   a  or  504   b,  to facilitate release of restorative material from the surface of the door body  508   a  and/or  508   b.  For example, a practitioner can apply the release film on one or both door bodies  508   a,    508   b  prior to bringing the door bodies into contact with restorative material in cavity  520  and exposed via apertures  504   a,    504   b.  In addition to, or instead of the release film, tool  500  may include a coating on one or more surfaces of door body  508   a  and/or  508   b  to facilitate release of restorative material from the surface of door body  508   a  and/or  508   b.  The coating can be, for example, a lubricious coating. 
     In some examples, tool  500  may include one or more additional door bodies  508  corresponding to one or more of the apertures  504 . That is, one aperture  504  may be used with multiple doors. For example, multiple door bodies, including door body  508   a,  may correspond to aperture  504   a.  Each door body for a particular aperture  504  may provide a different function. For example, door body  508   a  may be configured for one or more of final shaping or final layering of at least a portion of the dental restoration and tool  500  may include additional door bodies for use in intermediate layering and/or shaping of the dental restoration. At least a portion of each of the additional door bodies may be configured to mate with aperture  504   a.  For example, an additional door body may be configured for shaping an underlying shade layer of at least the portion of the dental restoration. As another example, an additional door body may be configured to form one or more mamelons, one or more grooves, or and/or one or more pits on the dental restoration. For example, the surface of the door body that faces the cavity when the door is applied to the mold body may define one or more physical features (e.g., one or more mamelons, one or more grooves, or and/or one or more pits) for forming in the dental restoration. 
     As an additional example, an additional door body may be configured for near net shaping of at least the portion of the dental restoration. Forming the restorative material in a near net shape may allow a practitioner to determine whether any changes to the color of the dental restoration are desirable before curing. In this way, the door body that provides for near net shaping of a restorative material prior to curing may increase the workability of the restorative material. 
     As another example, an additional door body may be configured for applying an intermediate layer of restorative material. The intermediate layer of restorative material may comprise restorative material that is different than a material applied during final layering using door body  508   a.  Tool  500  may include any suitable number of door bodies according to particular needs. 
     As shown in  FIG.  6 C , in some examples, door body  508   a  or  508   b  may be attached to mold body  502  via a respective door hinge  516 . As with door hinge  316  shown in  FIGS.  4 A and  4 B , door hinge  516  may mechanically connect and align door bodies  508   a ,  508   b  and mold body  502 , thereby reducing the degrees of freedom of door body  508   b  in which door body  508   b  may move with respect to mold body  502 . In addition, door hinge  516  may help ensure that the correct door body  508   a,    508   b  is used with the corresponding aperture  504   a,    504   b,  respectively. Door hinge  516  may be similar to door hinge  316 . For example, door hinge  516  may be formed separate from door body  508   b  and/or mold body  502 , or door hinge  516  may be formed as an integral part of door body  508   b  and/or mold body  502 . In some examples, door hinge  316  may be a snap hinge, a living hinge, a barrel hinge, or a pin joint hinge. 
     In some examples, mold bodies  502  and  506  may engage with one another via a clamp  518 . Clamp  518  includes two or more parts that interlock together in order to engage mold bodies  502  and  506 . For example, mold body  502  may include a first part of clamp  518  and mold body  506  may include a second part of clamp  518  which is configured to mechanically interlock with the first part of clamp  518  to secure mold bodies  502 ,  506  to each other in a tight-fitting relationship, such that seams between mold bodies  502 ,  506  are closed and restorative material may be contained within a mold cavity defined by mold bodies  502 ,  506  and one or more teeth of the patient. The first and second parts of clamp  518  may be separate from each other (e.g., free floating relative to each other) or may be mechanically connected together. 
     In some examples, clamp  518  may be configured to interlock using a hinge-like mechanism. In other examples, first and second parts of clamp  518  may rest against one another without mechanically interlocking. In some examples, clamp  518 , or more specifically, a part of clamp  518 , may be configured to rotate or slightly rotate about an axis of rotation. In some such examples, the range of rotation of clamp  518  about an axis may be limited by the configuration and/or placement of clamp  518  with respect to mold body  502  and/or mold body  506 . For example, mold body  502  attached to mold body  506  via clamp  518  may not be able to fully rotate about an axis of rotation due to the presence of mold body  506 . Additionally, or alternatively, mold bodies  502 ,  506  may engage with each other via a hinge, a clip, or another structure configured to mechanically connect and engage adjacent mold bodies  502  and  506  with each other. In another example, mold bodies  502 ,  506  may be configured to engage with each other via a snap fit or other interlocking mechanism that does not allow for relative rotational movement between mold bodies  502 ,  506 . When the mold bodies  502 ,  506  combine with at least one tooth of the patient to form a mold cavity, clamp  518  is configured to be at least proximate an incisal edge of at least one of the tooth or teeth to be restored. 
     In the example shown in  FIGS.  6 A and  6 C , clamp  518  is located proximate an incisal edge of a tooth or teeth to be restored when mold bodies  502 ,  506  are positioned over one or more teeth of a patient. In cases in which an incisal edge is being formed by a mold tool such as tool  500 , the incisal edge may be a likely place to experience flash formation. Clamp  518  may help ensure a relatively tight fit between the mold bodies  502 ,  506  to help reduce or eliminate the flash that occurs along this edge. Any flash that does occur may be very thin along the incisal edge and may be relatively easily removed with a dental instrument. In other examples, however, clamp  518  may be proximate another surface of a tooth when mold bodies  502 ,  506  are positioned over one or more teeth of the patient, and may help reduce or eliminate the flash at that other location. 
     By providing a relatively tight fit along the incisal edge or another edge of mold bodies  502 ,  506 , clamp  518  may help excess restorative material preferentially flow toward vent  510  where flash may be relatively easily seen and removed during finishing of the restoration. 
     In some examples, clamp  518  may help mold bodies  502 ,  506  self-align with each other and stay fixed relatively to each other. These features may increase the ease of use of tool  500 . For example, clamp  518  may help ensure that the corresponding mold bodies  502 ,  506  are used with each other. Clamp  518  may also allow for mold body  502  and mold body  506  to be moved and/or placed together, e.g., without mold bodies  502 ,  506  becoming separated from each other. Clamp  518  may be formed separate from the mold bodies  502 ,  506  and connected to the mold bodies  502 ,  506 , or clamp  518  may be formed by clamp parts that are integral with each of mold bodies  502 ,  506 . 
     Clamp  518  may be used in combination with any of the example tools described herein. For example, any of the mold bodies described herein may include a clamp for engaging with another mold body, according to particular needs. 
     In some examples, one or more door bodies  508   a,    508   b  may include a protrustion extending in a direcction away from mold body  502  when door bodies  508   a,    508   b  are inserted in respective apertures  504   a,    504   n.  The protrusions may be configured to provide a handle or a gripping mechanism for a practitioner, e.g., the hand of the practitioner or a tool manipulated by the practitioner, to grasp the respective door bodies  508   a,    508   b.  An example protrusion  522   a  is shown in  FIGS.  6 A and  6 C . Door body  508   a  includes protrusion  522   a,  such that mating door body  508   a  with aperture  504   a  may be facilitated by gripping protrusion  522   a.  In some examples, protrusion  522   a  includes gripping features such as ribs  524 . Ribs  524  may increase the friction between a practitioner&#39;s tool or hand and may help prevent the hand of the practitioner or a tool manipulated by the practitioner from slipping from protrusion  522   a.    
     In addition to or instead of some examples, providing a handle or a gripping mechanism for a practitioner, a protrusion extending away from a door body may define a structure configured to mate with at least a portion of a clamp or another dental instrument. For example, as shown in  FIG.  6 A , door body  508   b  may include protrusion  522   b  that defines a structure configured to mate with at least a portion (e.g., the end or end portion) of a clamp that applies clamping pressure to door body  508   b  in a direction towards mold body  502  when door body  508   b  in inserted in aperture  504   b.  Clamping pressure may help excess restorative material preferentially flow toward vent  510  and toward more accessible and less critical areas of the tooth, such as the incisal edge, where flash may be relatively easily seen and removed during finishing of the restoration. In some examples, a clamp in protrusion  522   b  may hold door body  508   b  within aperture  504   b.  Protrusion  522   b  may allow for easy and stable placement of a clamp. 
     Integrated grips provided by protrusion  522   a  and/or clamping mechanisms provided by protrusion  522   b  may increase the ease of use of any of door bodies  508   a ,  508   b.  For example, protrusions  522  may allow a practitioner to easily identify the points on the door body  508   a,    508   b  to use for placing and removing the door body and/or attaching a clamp to door body  508   a,    508   b,  making use of the door bodies more intuitive. Protrusions  522  may also provide securement of the components (e.g., to reduce the possibility that the door body to which the protrusion is attached is not dropped or to secure the door body to the mold body), and may also provide leverage for removing after the restorative material has been cured. 
     In some examples, mold body  502 ,  506  may include one or more protrusions  526  configured to mate with at least a portion of a clamp that also engages with a door body. For example, as shown in  FIG.  6 A , protrusions  526  may each define a structure configured to mate with at least a portion (e.g., the end or end portion) of a clamp or another dental instrument used to place, align, secure, manipulate, or release the mold body. In addition to or instead of a protrusion, in some examples, one or both mold bodies  502 ,  506  (as well as other mold bodies or door bodies described herein) may define recessed features that can be used to locate a clamp, receive a gripper, or provide an alignment feature. 
     The integrated clamping locations provided by protrusions  526  may allow for the easy and stable placement of a clamp, with the ability to optimize the placement of the clamp for desired force distribution. For example, using digital design, a tool designer, manually or with the aid of software, may select the locations of protrusions  526  based on the pressure points that will result from placing the clamp at the particular locations. 
     Further, building in clamping locations in mold bodies  502 ,  506  via protrusions  526  may help reduce variability of the amount of clamping pressure applied to mold bodies  502 ,  506  from practitioner-to-practitioner, and may increase the ease of use of tool  500  (e.g., reducing the training required to use tool  500 ). Rather than a practitioner applying clamps to mold bodies  502 ,  506  in an idiosynractic manner, the integrated clamping locations provided by protrusions  526  may provide for relatively uniform clamping in a known, specific location (e.g., as compared to hand clamping). 
       FIGS.  7 A- 7 G  illustrate steps of an example method of using the tool  400  of  FIG.  5    to form a dental restoration. A practitioner may place mold body  106  over at least one tooth of a patient, the at least one tooth being the site for the desired dental structure to be formed using tool  400 , or being near the site for the desired dental structure to be formed. In the example shown in  FIG.  7 A , the at least one tooth includes two teeth  602   a  and  602   b , but can include one tooth or more than two teeth in other examples. 
     The practitioner may also position mold body  102  over the teeth and attach mold body  102  to teeth  602   a  and  602   b,  such as by engaging mold body  102  with mold body  106 . In some examples, the practitioner may use additional fixation structures to connect mold bodies  102 ,  106 . For example, the practitioner may engage one or more clamps  604   a  and  604   b  with respective portions of mold bodies  102  and  106  ( FIG.  7 B ). These portions of mold bodies  102 ,  106  may, for example, be configured to receive and engage with clamps  604   a,    604   b  in a relatively tight fit such that clamps  604   a,    604   b  stay in place relative to mold bodies  102 ,  106 . 
     The practitioner may introduce restorative material into a mold cavity defined by mold bodies  102 ,  106  and the teeth  602   a,    602   b  around which mold bodies  102 ,  106  are positioned using any suitable technique. In some examples, the practitioner may fill the mold cavity with restorative material by introducing the restorative material through one or more of apertures  104   a  and  104   b  and into the mold cavity ( FIG.  7 C ). For example, the practitioner may use a tool such as restorative material introduction device  606 , to place the restorative material into the mold cavity. As shown in  FIG.  7 C , a tip of the device  606  may be at least partially introduced into aperture  104   a  in order to introduce the restorative material into the mold cavity. In some examples, restorative material  608  may be placed in the mold cavity through multiple apertures, including aperture  104   a  and  104   b  ( FIG.  7 D ). 
     In addition to or instead of using restorative material introduction device  606 , the practitioner may introduce restorative material  608  into the mold cavity by fully or partially prefilling the mold cavity with restorative material  608  before placement of the mold body  102  and/or  106  over teeth  602   a,    602   b  and/or by placing restorative material  608  on teeth  602   a  and  602   b  and then subsequently placing mold bodies  102  and/or  106  over the teeth  602   a  and  602   b  and restorative material  608 . 
     After at least some restorative material  608  is introduced into the mold cavity, the practitioner may place at least a portion of each of door bodies  200 ,  300  within the corresponding apertures  104   a  and  104   b  ( FIG.  7 E ). The door bodies  200 ,  300  may be used to shape one or more layers of restorative material  608  on the surface of the tooth, to compress restorative material  608  within the mold cavity, or any combination thereof. In some examples, the door bodies  200 ,  300  may shape one or more layers of restorative material on the lingual or facial surface of the tooth. 
     In some examples, the practitioner may cure the restorative material  608 , either while the door bodies  300  and  200  are mated in the mold body  102  or after removing one or more of the door bodies  300  and  200 . For example, in examples in which the restorative material is light curable, the practitioner may expose the restorative material to the curing light (e.g., a blue light) through one or both of the mold bodies  102 ,  106 , which may be formed of a material transparent to the curing light. The practitioner may remove the door bodies  300  and  200  and the mold bodies  102  and  106  from the teeth  602   a  and  602   b,  which now have restored structure defined by the restorative material ( FIG.  6 F ). Removing the mold bodies  102  and  106  may include separating the mold body  102  from the mold body  106 , which may include, for example, disengaging one or more clamps  604   a  and  604   b  with portions of each of mold bodies  102  and  106 . In some examples, the one or more of the door bodies  300  or  200  may leave “witness marks” on the lingual or facial surface of the tooth, but such marks may be relatively easily removable because they are relatively thin. In some examples, the practitioner may finish the teeth  602   a  and  602   b,  which now include restored dental structure defined by the restorative material, such as by polishing, to remove flash or other undesired surface imperfections ( FIG.  6 G ). 
     In some examples, the practitioner may place a release film on at least a portion of a surface of door body  200 ,  300  before placing the at least a portion of door body  200 ,  300  within respective aperture  104   a  and/or  104   b.  The release film may reduce the likelihood of trapping air within the mold cavity during stamping of the restorative material with door body  200 ,  300  and/or may facilitate release of restorative material  608  from the surface of door body  200 ,  300 . The practitioner may remove the at least a portion of door body  200 ,  300  from respective aperture  104   a  and/or  104   b,  remove the release film from the at least a portion of the surface or surfaces, place additional restorative material through aperture  104   a  and/or  104   b  and into the mold cavity, and place the at least a portion of door body  200 ,  300  (or, in some examples, a different door body) within respective aperture  104   a  and/or  104   b.  In some examples, door body  200 ,  300  may be removed from respective aperture  104   a  and/or  104   b  and remain connected to mold body  102 . For example, door body  200 ,  300  may be connected to mold body  102  via a door hinge (e.g., door hinge  316  shown in  FIG.  4 B ) and may be removed from the respective aperture  104   a  and/or  104   b  while remaining connected to mold body  102  via the door hinge. 
     In addition to, or instead of, the release film, in some examples, the practitioner may apply a coating on at least a portion of a surface of the door body  200 ,  300  intended to contact the restorative material before placing the at least a portion of door body  200 ,  300  within respective aperture  104   a  and/or  104   b.  The coating may reduce the likelihood of trapping air within the mold cavity during stamping of restorative material  608  with door body  200 ,  300  and/or may facilitate release of restorative material from the surface of door body  200 ,  300 . The practitioner may subsequently remove the at least a portion of door body  200 ,  300  from respective aperture  104   a  and/or  104   b,  place additional restorative material  608  through aperture  104   a  and/or  104   b  and into the mold cavity, and place the at least a portion of door body  200 ,  300  (or, in some examples, a different door body) within respective aperture  104   a  and/or  104   b.  Release coatings may also be applied to any of the mold components during the manufacturing process. The coating may be removable or non-removable from the mold component by the practitioner. For example, in some examples, a practitioner may remove the coating after using door body  200 ,  300  to place restorative material  608 . 
     In some examples, placement of the at least a portion of door body  200 ,  300  within respective aperture  104   a  and/or  104   b  provides one or more of final shaping or layering of at least a portion of the dental restoration. The method shown in  FIGS.  7 A- 7 G  may further include placing one or more additional door bodies within aperture  104   a  and/or  104   b  to shape an underlying shade layer, form one or more structures such as mamelons, grooves, and/or pits, to provide near net shaping, and/or to provide an intermediate layer of restorative material. 
     For example, in the method shown in  FIGS.  7 A- 7 G , a practitioner may introduce a first layer of restorative material through aperture  104   a  and/or  104   b  and into the mold cavity, place a first door body within respective aperture  104   a  and/or  104   b  to form a first layer of the dental restoration, cure the first layer of restorative material, remove the door body from respective aperture  104   a  and/or  104   b,  place a second layer of restorative material through aperture  104   a  and/or  104   b  and into the mold cavity, and then place a second door body within respective aperture  104   a  and/or  104   b,  and cure the second layer of restorative material to form a second layer of the dental restoration. Any suitable number of door bodies may be used to place additional layers of restorative material including, for example, different shade (color and/or translucency) layers and/or different mechanical property layers, to form structures, to provide near-net shaping, and/or to provide final shaping and/or layering. In some examples, two or more of the restorative materials are different materials. In addition, or instead, in some examples, two or more of the restorative materials are the same material. 
     Alternatively, or in addition, the practitioner may introduce a first restorative material through the aperture  104   a  and/or  104   b  and into the mold cavity, place a first door body within respective aperture  104   a  and/or  104   b  to form the dental restoration, cure the first restorative material, remove the door body from respective aperture  104   a  and/or  104   b,  remove mold body  102  and/or  106 , manually adjust or “cut-back” the dental restoration to create an underlying geometry, and then replace mold bodies  102 ,  106  over teeth  602   a,    602   b,  and repeat the molding process (including curing) with additional restorative material over the first restorative material to form the dental restoration. Any suitable number of door bodies, mold bodies, and restorative materials (with appropriate intermittent cure steps for each restorative material) may be used to place additional layers of restorative material including, for example, different shade layers and/or layers having different mechanical properties, to form structures, to provide near-net shaping, and/or to provide final shaping and/or layering. In some examples, two or more of the restorative materials are different materials. 
     In some examples, the same door body may be used to provide multiple functions. For example, the same door body may be used to apply an intermediate layer of restorative material and/or form structures. In other examples, different door bodies may be used for one or more functions, e.g., each function described above or two or more of the functions described above. When different door bodies are used for a particular aperture, the doors may be numbered or otherwise labeled to indicate the sequence in which the doors may be used. Any suitable combination of door bodies, each for providing one or more functions, may be used to achieve the desired dental restoration characteristics. 
     In some examples, at least one of mold body  102 , mold body  106 , door body  200 ,  300  may define at least one protrusion, such as the protrusions  610   a  and  610   b  defined by mold body  102  shown in  FIGS.  7 B- 7 E . In some examples, protrusion  610   a,    610   b  may be configured to provide a gripping mechanism for a practitioner, e.g., the hand of the practitioner or a tool manipulated by the practitioner. At least one of attaching mold body  102  and/or  106  to teeth  602   a  and/or  602   b,  placing at least the portion of door body  200 ,  300  within respective aperture  104   a  and/or  104   b,  or removing door body  200 ,  300 , mold body  102 , and/or  106  from teeth  602   a  and/or  602   b  may be facilitated by gripping the at least one protrusion  610   a,    610   b.    
     For example, a practitioner may grip one or more of protrusion  610   a,    610   b  to attach mold body  102  to teeth  602   a  and/or  602   b  and/or to remove mold body  102  from teeth  602   a  and/or  602   b.  In some examples, protrusion  610   a,    610   b  may define a structure configured to mate with at least a portion of a clamp and the method may further comprise mating at least the portion of the clamp with the structure. For example, as shown in  FIGS.  7 B- 7 E , protrusions  610   a  and  610   b  may each define a structure configured to mate with at least a portion (e.g., the ends or end portions) of clamp  604   a  or  604   b  and the method may further comprise mating portions of clamps  604   a  and  604  with the structures of the respective protrusions  610   a  and  610   b.    
     In some examples, one or more protrusions  610   a,    610   b  may define at least one lever configured to provide a mechanism for use in prying the respective mold body  102  or mold body  106  away from the one or more teeth around which it is positioned. A practitioner may, for example, remove mold body  102  or mold body  106  from the at least one tooth using the lever to apply force to pry mold body  102  or mold body  106  away from the tooth to be restored. In this way, in some examples, a practitioner may use protrusion  610   a  and/or  610   b  to move mold body  102  relative to teeth  602   a  and  602   b.  In addition to, or alternatively to, protrusions  610   a,    610   b,  indentations may provide mating or movability features for mold body  102  and/or  106 . For example, mold body  102  and/or  106  may include indentations configured to mate with at least a portion of a clamp. 
     In addition to the advantages of tool  100  of  FIG.  1   , inclusion of the contoured door bodies of  FIGS.  2 A- 7 E  may allow for shaping/contouring with use of a contoured surface of the door body designed to mate with the respective aperture. The fit between the door body and respective aperture may be close-fit, such that the door body substantially covers (e.g., completely covers or nearly covers) the aperture. The inside surface of the door body may be contoured to match the contour of the restoration design and features, providing for a molded finish while still providing the practitioner greater control. Additionally, as described above, multiple door bodies may be used for different functions. 
     In some examples, when restorative material is introduced into a mold cavity that is defined by a mold body, e.g., described with respect to  FIGS.  1 - 7 G , excess restorative material may flow into unintended areas in the patient&#39;s mouth. This excess restorative material may be referred to as flash material. When cured, the flash material may be difficult to remove. In some examples, a tool used to form a dental restoration, such as a mold body, can include one or more structural features that are configured to help reduce the amount of flash material that may result after restorative material is introduced into a cavity at least partially defined by the tool and/or may result in flash being less in more critical and/or hard to access areas of the tooth while diverting the flow or excess restorative material, and thus flash, to less critical and/or more accessible areas of the tooth where flash may easily be removed. Example structural features are described with respect to  FIGS.  8 - 16   . These structural features can be used in combination with any of the other features of tools described herein, such as, but not limited to, door hinges, mold body clamps, release coatings, and the like. 
       FIGS.  8  and  9    are interior views of another example tool  700  that can be used to form a dental restoration. The tool includes a mold body  702  configured to provide a customized fit with at least one tooth of a patient. Mold body  702  may be configured to combine with at least the at least one tooth of the patient to define a mold cavity  703  encompassing at least a portion of desired tooth structure of the at least one tooth of the patient. Restorative dental material is introduced into mold cavity  703  (partially shown in  FIGS.  8  and  9   ) in order to define a dental restoration. The interior view of mold body  702  shown in  FIGS.  8  and  9    shows the surface of the tool that defines at least part of mold cavity  703  and faces inward into mold cavity  703 . In in the example shown in  FIGS.  8  and  9   , mold body  702  defines a ridge  704  configured to contact at least a portion of a tooth to be restored of the at least one tooth to concentrate sealing pressure at at least a portion of a perimeter of the mold cavity. 
     For example, mold body  702  may be configured to be placed at a surface of a tooth such that ridge  704  is at a perimeter of a mold cavity that is formed by mold body  702  and the tooth when mold body  702  is placed over the surface of the tooth. Ridge  704  may be configured to extend toward the tooth to such an extent such that it creates sealing pressure against the tooth. The sealing pressure may function to reduce or prevent the seepage of restorative material from the mold cavity such that flashing is either prevented altogether, substantially thin such that it is relatively easy to remove even after curing of the restorative material, and/or in more accessible and/or less critical areas of the tooth. 
     For example, a ridge, such as ridge  704 , may concentrate pressure and promote sealing in critical areas of a restoration, such as the gingival margin and/or interproximal contacts, where excess flash can be difficult to see and remove. Left in place, residual flash in these areas may have undesirable effects such as entrapment of food particles and gingival irritation. A ridge such as ridge  704  may assure that excess restorative material may preferentially flow toward vents and toward more accessible and less critical areas of the tooth, such as the incisal edge, where flash may be relatively easily seen and removed during finishing of the restoration. 
     In some examples, the design of sealing ridges may be particularly enabled by CAD tools and the size, shape and/or position can be optimized based on analytical tools such as finite element modeling and/or machine learning based on feedback from practitioners. 
     Although illustrated as being at a perimeter of the mold cavity configured to be near a gingival contour of the tooth, ridge  704  may be at any suitable position at a perimeter of the mold cavity. A ridge such as ridge  704  may be used in combination with any of the example tools described herein. For example, any of the mold bodies described herein may include a ridge to concentrate sealing pressure at a perimeter of a mold cavity. 
     When tool  700  is formed using digital design, e.g., based on a 3D model of at least part of a patient&#39;s tooth structure, the patient&#39;s gingival margin can be determined. Thus, the digital design may permit ridge  704  to be properly positioned on mold body  702 . In contrast, when a mold body is formed using a wax model or other physical model of the patient&#39;s tooth, the gingival margin may not be readily visible or determinable. In this way, digital design may facilitate the design and manufacture of tool  700 . 
       FIGS.  10  and  11    are bottom views of another example tool  900  for forming a dental restoration. The tool includes a mold body  902  configured to provide a customized fit with at least one tooth of a patient. Mold body  902  may be configured to combine with at least the at least one tooth of the patient to define a mold cavity  903  encompassing at least a portion of desired tooth structure of the at least one tooth of the patient. Mold cavity  903  is only partially shown in  FIGS.  10  and  11   . Like mold body  702  of  FIGS.  7  and  8   , mold body  902  may include a ridge  904  configured to contact at least a portion of a tooth to be restored of the at least one tooth to concentrate sealing pressure at at least a portion of a perimeter of the mold cavity. 
     Ridge  904  may be similar to ridge  704  of  FIGS.  8  and  9   . For example, mold body  902  may be configured to be placed at a surface of a tooth such that ridge  904  is at a perimeter of a mold cavity that is formed by mold body  902 , the tooth, and/or any other components when mold body  902  is placed on the surface of the tooth. Ridge  904  may be configured to extend toward the tooth to such an extent such that it creates sealing pressure against the tooth. The sealing pressure may function to reduce or prevent the seepage of restorative material from the mold cavity such that flashing is either prevented altogether, substantially thin such that it is easy to remove even after curing of the restorative material, and/or in more accessible and/or less critical areas of the tooth. 
     For example, a ridge, such as ridge  904 , may concentrate pressure and promote sealing in critical areas of a restoration, such as the gingival margin and/or interproximal contacts, where excess flash can be difficult to see and remove. Left in place, residual flash in these areas may have undesirable effects such as entrapment of food particles and/or gingival irritation. A ridge such as ridge  904  may assure that excess restorative material may preferentially flow toward vents and toward more accessible and less critical areas of the tooth, such as the incisal edge, where flash may be relatively easily seen and removed during finishing of the restoration. 
     Although illustrated as being at a perimeter of an opening  906  of mold body  902 , ridge  904  may be at any suitable position at a perimeter of the mold cavity. Opening  906  is, for example, an opening defined by mold body  902  and configured to receive at least part of a tooth of the patient in order to mate mold body  902  with the at least one tooth in order to define mold cavity  903 . A ridge such as ridge  904  may be used in combination with any of the example tools described herein. For example, any of the mold bodies described herein may include a ridge to concentrate sealing pressure at a perimeter of a mold cavity. 
     Use of a ridge, such as ridge  704  or ridge  904 , may reduce the likelihood of flash by ensuring good sealing at the perimeter of the mold cavity to be filled. For example, these ridges may concentrate clamping pressure at the base of the tooth, sealing the mold cavity against the pressure developed during filling the mold with restorative material via a traditional injection port, during packing of the restorative material through an aperture such as apertures  104  and  504  discussed above, or during placement of the door bodies such as those discussed above with reference to  FIGS.  1 - 7 G . Any flash that does occur may be relatively thin along the ridgeline, making it easy to remove with a dental instrument. 
       FIGS.  12  and  13    are assembled and expanded cross-sectional views of another example tool  1100  for forming a dental restoration. In the example shown in  FIGS.  11  and  12   , tool  1100  includes a mold body  1102  and a mold body  1104 , which are each configured to provide a customized fit with at least one tooth of a patient, such as tooth  1106  (only partially shown in  FIG.  12   ). Mold body  1102 ,  1104  may be configured to combine with tooth  1106  to define a mold cavity  1108  encompassing at least a portion of desired tooth structure of tooth  1106 . A mold cavity  1108  is configured to receive restorative material, e.g., which may be used to form a dental restoration. Mold bodies  1102 ,  1104  may be, for example, examples of mold bodies  102 ,  106  of  FIG.  1    or any of the other mold bodies described herein. 
     When mold bodies  1102  and  1104  combine with tooth  1106  to form mold cavity  1108 , a portion  1110  of mold body  1102  may be configured to abut a portion  1112  of mold body  1104 . Portion  1110  of mold body  1102  includes an overbuilt portion  1114 , as shown in in  FIG.  13   . Thus, when portion  1110  of mold body  1102  abuts portion  1112  of mold body  1104 , overbuilt portion  1114  is configured to provide intimate contact between portion  1110  of mold body  1102  and portion  1112  of mold body  1104 . For example, because overbuilt portion  1114  is not designed to purely mimic the shape (e.g., contour and dimensions) of portion  1112  of mold body  1104  that it abuts, as it would in a simple mold that purely outlines the desired tooth structure, but is instead overbuilt, it may create sealing pressure (e.g., may define a gasket) between portion  1110  of mold body  1102  and portion  1112  of mold body  1104  when mold bodies  1102  and  1104  combine with tooth  1106  to form mold cavity  1108 , as shown in  FIG.  12   . The sealing pressure may function to reduce or prevent the seepage of restorative material from mold cavity  1108  such that flashing is either prevented altogether, relatively thin such that it is easy to remove even after curing of the restorative material, and/or in more accessible and/or less critical areas of the tooth. 
     In some examples, the design of overbuilt portions may be particularly enabled by CAD tools and the size, shape and/or position can be optimized based on analytical tools such as finite element modeling and/or machine learning based on feedback from practitioners. 
     For example, an overbuilt portion, such as overbuilt portion  1114 , may concentrate pressure and promote sealing in critical areas of a restoration, such as the gingival margin and/or interproximal contacts, where excess flash can be difficult to see and remove. Left in place, residual flash in these areas may have undesirable effects such as entrapment of food particles and/or gingival irritation. An overbuilt portion, such as overbuilt portion  1114 , may help excess restorative material preferentially flow toward vents and toward more accessible and less critical areas of the tooth, such as the incisal edge, where flash may be relatively easily seen and removed during finishing of the restoration. 
     In addition, overbuilt portion  1114  may allow for larger manufacturing tolerances when forming mold bodies  1102 ,  1104  that mate together and define a relatively tight seal between mold bodies  1102 ,  1104 . For example, if one or both mold bodies  1102 ,  1104  are underformed during manufacture, mold bodies  1102 ,  1104  may nevertheless still mate together to form a relatively tight seal therebetween due to overbuilt portion  1114 . 
     Although illustrated as being near an incisal edge of mold cavity  1108 , overbuilt portion  1114  may be at any suitable position where intimate contact between two pieces of tool  1100  may be desired. Although portion  1112  may be configured to form a recess, the portion may be substantially flat, form a protrusion, or form any suitable shape according to particular needs. 
     In some examples, overbuilt portion  1114  may be formed from a compressible material and may be configured to be compressed against portion  1112  of mold body  1104  when mold bodies  1102  and  1104  combine with tooth  1106  to form mold cavity  1108 , as shown in  FIG.  12   . In addition, or alternatively, portion  1112  of mold body  1104  configured to abut overbuilt portion  1114  may be formed from a compressible material and may be configured to be compressed against portion  1110  of mold body  1102  when mold bodies  1102  and  1104  combine with tooth  1106  to form mold cavity  1108 . Thus, in some examples, one or both overbuilt portion  1114  and portion  1112  of mold body  1104  configured to abut overbuilt portion  1114  may be formed from a compressible material. 
     An overbuilt portion such as overbuilt portion  1114  may be used in combination with any of the example tools described herein. For example, any of the mold bodies described herein may include an overbuilt portion to concentrate sealing pressure against another mold body, a tooth, or a door body, according to particular needs. 
     Overbuilt portions such as overbuilt portion  1114  that are designed to be between mold components may reduce or even prevent flash in at least some areas of the tooth by ensuring good sealing between different portions of a tool for forming a dental restoration. As with the sealing ridges, the overbuilt portion of a mold body may be a digitally enabled approach that can be designed based on scan data of a patient and may ensure robust and intimate contact of the mold faces at the seams. A designer may tune the amount of overbuild between the mold faces to optimize performance. In contrast, when mold bodies configured to engage one another are manually formed over a physical model of patient&#39;s tooth structure, a practitioner may form a unitary structure over the physical model and then cut the unitary structure to define two mold bodies that are configured to engage one another. The mold bodies formed by cutting the unitary structure results in mold bodies with mating structures that have the same dimensions, rather than an overbuilt mating structure. The mating structures with the same dimensions may not permit the same type of robust and intimate contact resulting from the overbuilt mating portions described with respect to  FIGS.  12 A and  12 B . 
       FIGS.  14 A and  14 B  are side and top views of another example tool  1300  for forming a dental restoration. Tool  1300  includes a mold body  1302  and a mold body  1304 , each configured to provide a customized fit with at least one tooth of a patient. Mold bodies  1302 ,  1304  may be configured to combine with the tooth or teeth of the patient to define a mold cavity encompassing at least a portion of desired tooth structure of the tooth or teeth. Mold bodies  1302 ,  1304  may be, for example, examples of mold bodies  102 ,  106  of  FIG.  1    or any of the other mold bodies described herein. 
     Mold bodies  1302 ,  1304  may be configured to form a clamp  1306  when engaged with one another, as shown in  FIGS.  14 A and  14 B . Clamp  1306  may be an example of clamp  518  shown in  FIGS.  6 A and  6 C . In some examples, clamp  1306  may alternatively be a clip, a hinge, or another structure configured to engage mold bodies  1302 ,  1304  with each other. In another example, mold bodies  1302  and  1304  may be configured to attach to each other via a snap fit or another interlocking mechanism. When mold bodies  1302 ,  1304  combine with the at least one tooth of the patient to form the mold cavity, clamp  1306  is configured to be at least proximate an incisal edge  1308  of at least one of the tooth or teeth to be restored. 
     A clamp, such as clamp  1306 , configured to be proximate an incisal edge of a tooth or teeth to be restored may be used in combination with any of the example tools described herein. For example, any of the mold bodies described herein may form a clamp with another door body, according to particular needs. 
     In cases where an incisal edge is being formed by a mold tool such as tool  1300 , the incisal edge may be a likely place to experience flash formation. An integrated mold clamping feature, such as clamp  1306  may help ensure relatively tight clamping between the mold bodies  1302 ,  1304  to help reduce or eliminate the flash that occurs along this edge. Any flash that does occur may be very thin along incisal edge  1308  and may be relatively easily removed with a dental instrument. 
     In some examples, by providing relatively tight clamping along the incisal edge, a clamp such as clamp  1306  may help excess restorative material preferentially flow toward vents where flash may be relatively easily seen and removed during finishing of the restoration. 
     In addition, in some examples, the integrated mold clamping feature, such as clamp  1306  may help mold bodies  1302 ,  1304  self-align with each other and stay fixed relatively to each other. These features may increase the ease of use of tool  1300 . 
       FIG.  15    is a top view of another example tool  1400  for forming a dental restoration. Tool  1400  includes mold bodies  1402  and  1404 , each configured to provide a customized fit with at least one tooth of a patient and configured to combine with the at least one tooth of the patient to define a mold cavity encompassing at least a portion of desired tooth structure of the at least one tooth. Mold bodies  1402 ,  1404  may be, for example, examples of mold bodies  102 ,  106  of  FIG.  1    or any of the other mold bodies described herein. 
     Mold body  1402  may define a structure  1406  and mold body  1404  may define a structure  1408 . Structure  1406  may be configured to mate with at least a portion of a clamp  1410  and structure  1408  may be configured to mate with at least another portion of clamp  1410 . Clamp  1410  may be configured to secure mold bodies  1402  and  1404  to one another when portions of clamp  1410  mate with structures  1406  and  1408 . In some examples, clamp  1410  may alternatively be a clip, a hinge, or another structure configured to engage mold bodies  1402  and  1404  with one another. 
     Structures  1406  and  1408  may be integrally formed in mold bodies  1402  and  1404  to provide an integral feature by which a clamp, such as clamp  1410  may be attached to both mold bodies  1402  and  1404  to hold mold bodies  1402  and  1404  together. Although structures  1406  and  1406  are illustrated as protrusions, structures  1406  and  1408  may alternatively be indentations or any other structure capable of attaching clamp  1410  to mold bodies  1402  and  1404 . In some examples, clamp  1410  may be integrally formed in mold bodies  1402  and  1404  and/or structures  1406  and  1408 . In some examples, mold bodies  1402  and  1404  may include structures  1406  and  1408  or structures similar to structures  1406  and  1408  configured to mate with another dental instrument other than clamp  1410  that may be used to place, align, secure, manipulate, and/or release mold bodies  1042  and/or  1404 . For example, mold bodies  1402  and/or  1404  may include one or more structures such as, for example, a pry bar, a lever, a handle, an alignment feature, or the like, according to particular needs. 
     Integral structures such as structures  1406  and  1408  configured to mate with portions of a clamp, such as clamp  1410 , may be used in combination with any of the example tools described herein. For example, any of the mold bodies or door bodies described herein may form a structure configured to mate with a clamp to allow the mold body or door body to be held together with another component, according to particular needs. 
     As discussed above with respect to protrusion  522   b  in  FIG.  6 A , clamping pressure that can be placed on the outside of two mold halves, such as mold bodies  1402  and  1404 , may help ensure tight contact while filling the mold cavity defined by mold bodies  1402 ,  1404  with a restorative material, and reduce flash along the gingival margin and in the interproximal areas. This clamping pressure may counteract the application pressure of the restorative as the practitioner is filling. 
     The sealing pressure may function to reduce or prevent the seepage of restorative material from the mold cavity such that flashing is either prevented altogether, relatively thin such that it is easy to remove even after curing of the restorative material, and/or in more accessible and/or less critical areas of the tooth. 
     For example, clamping pressure may concentrate pressure and promote sealing in critical areas of a restoration, such as the gingival margin and/or interproximal contacts, where excess flash can be difficult to see and remove. Left in place, residual flash in these areas may have undesirable effects such as entrapment of food particles and/or gingival irritation. Clamping pressure may help excess restorative material preferentially flow toward vents and toward more accessible and less critical areas of the tooth, such as the incisal edge, where flash may be relatively easily seen and removed during finishing of the restoration. 
     The integrated clamping locations provided by structures  1406 ,  1408  may allow for the easy and stable placement of the clamps, such as clamp  1410 , with the ability to optimize the placement of clamp  1410  for desired force distribution. For example, using digital design, a tool designer, manually or with the aid of software, may select the locations of structures  1406 ,  1408  based on the pressure points that will result from placing the clamp at the particular locations. 
     Further, building in clamping locations in mold bodies  1402 ,  1404  via structures  1406 ,  1408  may help reduce variability of the amount of clamping pressure applied to mold bodies  1402 ,  1404  from practitioner-to-practitioner, and may increase the ease of use of tool  1400  (e.g., reducing the training required to use tool  1400 ). Rather than a practitioner applying clamps to mold bodies  1402 ,  1404  in an idiosynractic manner, the integrated clamping locations provided by structures  1406 ,  1408  may provide for relatively uniform clamping in a known, specific location (e.g., as compared to hand clamping). 
       FIG.  16    is a perspective view of another example tool  1500  for forming a dental restoration. Tool  1500  may include a mold body  1502  configured to provide a customized fit with at least one tooth of a patient and configured to combine with the at least one tooth of the patient to define a mold cavity encompassing at least a portion of desired tooth structure of the tooth to be restored. Mold body  1502  may define an edge  1504  defining a contour configured to match at least a portion of a gingival contour of a tooth to be restored. This may be referred to as gingival contouring in some examples. 
     A mold body with an edge configured to define a contour configured to match at least a portion of a gingival contour of a tooth to be restored may be used in combination with any of the example tools described herein. For example, any of the mold bodies or door bodies described herein may define a contour configured to match at least a portion of a gingival contour of a tooth to be restored, according to particular needs. 
     Contouring edge  1504  of mold body  1502  along the gingival margin may allow a practitioner access to the gingival margin and thus the ability to manage restorative material subgingivally. This may allow the practitioner to remove excess material below the gingiva before curing the composite, which may minimize the amount of flash on the final restoration. 
     The gingival contouring of mold body  1502  may be designed using a digital model of a patient&#39;s tooth structure. In contrast, with manual techniques for forming mold bodies using a physical model of a patient&#39;s tooth structure, the gingival margin may not be readily determinable. 
       FIGS.  17 A and  17 B  are front (e.g., facial) and top (e.g., incisal) views of another example mold body  1602  of an example tool for forming a dental restoration.  FIGS.  18 A and  18 B  are front and bottom views of another example tool  1700  for forming a dental restoration, where the tool  1700  includes mold body  1602  of  FIGS.  17 A and  17 B  and an additional mold body  1702 . 
     Mold body  1602  may be configured to provide a customized fit with at least one tooth of a patient, such as the teeth  1604 . At least a portion of the mold body  1602  may be configured to surround at least a portion of teeth  1604 . Mold body  1602  may be configured to combine with teeth  1604  to define a mold cavity encompassing at least a portion of desired tooth structure of teeth  1604 . 
     At least a portion of mold body  1702  may be configured to surround at least a portion of mold body  1602 . Additionally, mold body  1702  may be stiffer than mold body  1602  such that mold body  1702  provides structural support to mold body  1602  such that the mold cavity does not expand as restorative material is inserted into the mold cavity. 
     In some examples, mold body  1702  may include a material that is more rigid than a material used to compose mold body  1602  such that mold body  1702  is stiffer than mold body  1602 . Alternatively, or in addition, mold body  1702  may include structures that provide stiffness that is greater than that of mold body  1602 . For example, a support structure  1704  may provide structural support to mold body  1702  such that mold body  1702  is stiffer than mold body  1602  along at least a portion of mold body  1702  or along the entire mold body  1702 . As another example, mold body  1702  may define one dimension with a greater thickness than a corresponding dimension of mold body  1602 . For example, mold body  1702  may have a thickness “t 2 ” that is greater than a thickness “t 1 ” of mold body  1602 . As another example, mold body  1702  may include one or more ribs providing structural support to mold body  1702 . Support structure  1704  may also serve as a handle for placement and/or removal of mold body  1702 . 
     In some examples, mold body  1602  may define one or more apertures, such as apertures  1706   a - 1706   d.  Apertures  1706   a  and  1706   b  may be configured to allow placement of restorative material into the mold cavity and apertures  1706   c  and  1706   d  may allow for excess restorative material to flow out of the mold cavity. Outer mold body  1702  may define an aperture  1708  that may be larger than each of apertures  1706   a - 1706   d  and may be configured to allow access to apertures  1706   a - 1706   d  when at least a portion of mold body  1702  is surrounding at least a portion of mold body  1602 . Further, larger aperture  1708  that is larger than apertures  1706   a - 1706   d  of mold body  1602  may allow for access to apertures  1706   a - 1706   d,  even when there may be misalignment between mold bodies  1602 ,  1702 . 
     Additionally, in some examples, aperture  1708  being larger than apertures  1706   a - 1706   d  may prevent or reduce unwanted material flow between mold bodies  1702  and  1602 . In some examples, support structure  1704  may be located proximate larger aperture  1708  to provide additional structural support proximate larger aperture  1708 , where the rigidity of mold body  1702  may otherwise be compromised by larger aperture  1708 . 
     In some examples, a reinforcement structure  1710  may be located around and/or proximate one or more of apertures  1706   a - 1706   d  to provide structural reinforcement to the mold body  1602  such that mold body  1602  retains its shape given that apertures such as apertures  1706   a - 1706   d  may otherwise compromise the structural integrity of mold body  1602 . In some examples, mold body  1602  may be compressible. 
     The described features of mold bodies  1602  and  1702  may be combined with any of the other features described herein. In some examples, one or more of the other features described above, such as apertures, door bodies, ridges or other overbuilt portions configured to abut a tooth and/or another mold body, clamps, integrated clamping locations, and gingival contouring, may be used with mold bodies  1602 ,  1702 . 
     Defining a mold cavity with an inner mold body, such as mold body  1602 , which may be compliant, may allow the inner mold body to adapt around seams of the mold cavity as needed. This may help provide proper sealing between mold components to prevent flash, reduce flash, result in flash that is relatively thin such that it is easy to remove even after curing of the restorative material, and/or preferentially result in flash in more accessible and/or less critical areas of the tooth. 
     For example, a relatively compliant mold body, such as mold body  1602 , may allow for proper sealing in some areas of a restoration, such as the gingival margin and/or interproximal contacts, where excess flash can be difficult to see and remove. Left in place, residual flash in these areas may have undesirable effects such as entrapment of food particles and/or gingival irritation. Allowing for proper sealing may assure that excess restorative material will preferentially flow toward vents and toward more accessible and less critical areas of the tooth, such as the incisal edge, where flash may be relatively easily seen and removed during finishing of the restoration. 
     A more rigid outer mold body  1702  nested around the more compliant mold body  1702  adds structural support to maintain the intended cavity shape. Inner mold body  1602  may intimately nest within rigid mold body  1702 , which may help to increase the uniformity of the counter pressure applied by mold body of tool  1700  during the filling process. 
     In some examples, a mold body similar to mold body  1602  may first be placed on a lingual side of teeth  1604 . Mold body  1602  may be placed on the facial side of teeth  1604  and may abut at least a portion of the mold body that is on the lingual side of the teeth. Mold body  1702  may be placed over the inner components, including mold body  1602 , to help secure them in place. In some examples, a dental restoration (e.g., a veneer) may be formed by introducing a restorative material (e.g., Filtek™ Supreme Universal A2, available from 3M ESPE Dental Products in St. Paul, Minn.) in the mold cavity through apertures  1706   a  and  1706   b,  with excess material able to flow out of apertures  1706   c  and  1706   d.  The excess material may be removed, the restorative material cured, and the tool removed. In other examples, the mold body placed on the lingual side of the teeth may be of similar rigidity as mold body  1602 . 
     In other examples, in addition to or instead of introducing restorative material into a mold cavity via apertures  1706   a,    1706   b,  the restorative material may be applied to teeth  1604  and then mold body  1602  may be placed on teeth  1604 , and/or the restorative material may be applied to mold body  1602  and then placed on teeth  1604 . 
       FIGS.  19 A and  19 B  are top and perspective views of another example tool  1800  for forming a dental restoration. The tool may include a mold body  1802  configured to provide a customized fit with at least one tooth of a patient and configured to combine with the tooth or teeth of the patient to define a mold cavity encompassing at least a portion of desired tooth structure of a tooth. Mold body  1802  may define at least one protrusion, such as protrusions  1804   a - 1804   d  configured to provide a gripping mechanism for a practitioner. The grips may be configured for gripping by fingers and/or by a dental instrument such as a hemostat. In some examples, one or more of protrusions  1804   a - 1804   d,  such as  1804   a  and  1804   d  may define a structure configured to mate with at least a portion of a clamp. For example, the recess  1806  defined by protrusion  1804   d  may be configured to receive a portion of a clamp. In some examples, one or more of protrusions  1804   a - 1804   d  may define one or more ribs, such as ribs  1808   a - 1808   h  defined by protrusion  1804   c.  Ribs  1808   a - 1808   h  may allow a practitioner to better grip protrusion  1804   c.    
     In some examples, one or more of protrusions  1804   a - 1804   d  may define one or more levers configured to provide a mechanism for use in prying mold body  1802  away from the dental restoration after curing of the dental restoration. For example, the shape of each of protrusions  1804   a - 1804   d  may define a lever that may be used in such a manner. 
     Protrusions configured to allow a gripping mechanism to a practitioner and/or configured to mate with a portion of a clamp, such as protrusions  1804   a - 1804   d  may be used in combination with any of the example tools described herein. For example, any of the mold bodies or door bodies described herein may include a protrusion like protrusions  1804   a - 1804   d,  according to particular needs. Protrusions  1804   a - 1804   d  are examples of protrusion  206  of  FIGS.  2 A and  2 B  and protrusion  522 B of  FIG.  6 A . 
     Integrated grips provided by protrusions  1804   a - 1804   d  may increase the ease of use of any of the mold bodies described herein. For example, protrusions  1804   a - 1804   d  may allow a practitioner to easily identify the points on the tool to use for placing and removing the tool, making use of the tools more intuitive. Protrusions  1804   a - 1804   d  may also provide securement of the components (e.g., to reduce the possibility that the mold body to which the protrusion is attached is not dropped), and may also provide leverage for removing after the restorative has been cured. In some examples, protrusions may also include through holes to allow securement with floss threaded through the hole. In some examples, the protrusions may instead or additionally be configured as indentations. 
     In some cases, it may be desirable to form a dental structure between adjacent teeth, such as to reduce or eliminate a diastema. A mold body that is configured to provide a customized fit over one or more teeth to define a mold cavity may facilitate the formation of a dental structure between adjacent teeth. The dental structure between adjacent teeth can be an entire dental restoration or may be a part of a dental restoration, in which case the same mold body may be used to form the other parts of the dental restoration or another mold body, such as the mold bodies described above with respect to  FIGS.  1 - 19 B , may be used to form the other parts of the dental restoration. 
       FIGS.  20 A- 20 E  illustrate example mold body  1902  that can be used to form a dental structure between adjacent teeth.  FIG.  20 A  illustrates mold body  1902  attached to two or more teeth  1904   a,    1904   b,    1904   c,  and/or  1904   d  (collectively, “teeth  1904 ”),  FIG.  20 B  illustrates a cross-sectional view of teeth  1904  and mold body  1902  when it is attached to two or more teeth  1904 , the cross-section being taken in the x-y plane (orthogonal x-y-z axes are shown in  FIG.  20 B  for ease of description),  FIG.  20 C  illustrates a front view of mold body  1902 ,  FIG.  20 D  illustrates a top view of mold body  1902 , and  FIG.  20 E  illustrates a bottom view of mold body  1902 . Mold body  1902  may also be referred to as a wrapping matrix in some examples. 
     Mold body  1902  may be configured to be attached to two or more teeth  1904 , which can be, but do not have to be, adjacent to each other. Mold body  1902  includes a base member  1906  configured to provide a customized fit with the two or more teeth  1904 . For example, base member  1906  may be configured to contact a reference geometry, such as, for example, a lingual surface  1908   a  and  1908   b  of each of two adjacent teeth  1904   a  and  1904   b,  and mate with the reference geometry when mold body  1902  is attached to the two or more teeth  1904 . A side of base member  1906  configured to contact the teeth may have a geometry that corresponds to the reference geometry such that the teeth having the reference geometry nest in base member  1906 . The reference geometry can be, for example, any suitable surface of a tooth, such as, but not limited to, a lingual surface, a facial surface, an incisal surface, or an occlusal surface of the tooth. Although base member  1906  is shown in  FIGS.  20 A- 20 E  as being fit over teeth  1904   a ,  1904   b,  in other examples, base member  1906  may be configured to provide a customized fit over other teeth. For example, the reference geometry may be tooth  1904   c  and/or tooth  1904   d,  where tooth  1904   c  is nonadjacent to tooth  1904   b  to be restored. 
     Mold body  1902  includes an interproximal member  1910  configured to be disposed between two adjacent teeth  1904   a  and  1904   b.  Interproximal member  1910  is mechanically connected to base member  1906  and extends from base member  1906 . Base member  1906  may be configured to help engage mold body  1902  with teeth  1904 , stabilize interproximal member  1910  relative to tooth  1904   b  to be restored, and properly align interproximal member  1910  relative to teeth  1904 . 
     In the example shown in  FIGS.  20 A- 20 E , mold body  1902  is configured to combine with at least two teeth  1904  to define a mold cavity  1912  encompassing at least a first portion of desired tooth structure of tooth  1904   b.  In some examples, the portion of desired tooth structure may define an interproximal surface of tooth  1904   b.  For example, as shown in  FIG.  20 B , interproximal member  1910  of mold body  1902  may extend between adjacent teeth  1904   a,    1904   b  and, together with tooth  1904   b,  defines mold cavity  1912 . The portion of desired tooth structure may, in some cases, also include an expanded region that may include portions of the facial, lingual, and/or incisal surfaces of tooth  1904   b.  In these examples, interproximal member  1910  or another portion of mold body  1902  may wrap around the other surface or surfaces of tooth  1904   b  to be restored. 
     Interproximal member  1910  extends from a back portion  1906   a  of base member  1906  towards the facial surface of tooth  1904   b  when mold body  1902  is positioned on the teeth  1904  of the patient. In the example shown in  FIGS.  20 A- 20 E , back portion  1906   a  is configured to sit adjacent to a lingual surface of tooth  1904   b  when mold body  1902  is fit over teeth  1904 . In some examples, an end  1910   a  of interproximal member  1910  may extend past facial surface of tooth  1904   b  (in a direction away from the lingual surface), although in other examples, end  1910   a  of interproximal member  1910  may remain between adjacent teeth  1904   a,    1904   b,  in an interproximal region or may be positioned at the facial surface of tooth  1904   b,  when mold body  1902  is properly attached to teeth  1904 . 
     Although  FIG.  20 A  illustrates interproximal member  1910  as being primarily positioned between adjacent teeth  1904   a,    1904   b,  in some examples, interproximal member  1910  may also cover a portion of tooth  1904   b  to be restored. For example, in addition to extending between adjacent teeth, interproximal member  1910  may cover a portion of the lingual and/or facial surface of tooth  1904   b  to be restored. This may help close mold cavity  1912  and contain restorative material within mold cavity  1912 , as well as define portions of the facial, lingual and/or incisal surfaces of tooth  1904   b  to be restored. 
     In some examples, a practitioner may attach mold body  1902  to teeth  1904 , fill mold cavity  1912  with restorative material, and, if necessary, remove some or all excess restorative material to define the desired interproximal surface of tooth  1904   b.  For example, the practitioner may remove any restorative material that remains outside of mold cavity  1912 . Thereafter, the practitioner may cure the restorative material and remove mold body  1902  from teeth  1904 . In addition to, or instead of, filling mold cavity  1912  with restorative material after attaching mold body  1902  to teeth  1904 , the practitioner may apply restorative material directly to mold body  1902 , attach mold body  1902  to teeth  1904 , cure the restorative material, and remove mold body  1902  from teeth  1904 . These steps may provide a portion of desired tooth structure defining an interproximal surface of tooth  1904   b.    
     In some examples, after using mold body  1902  to form portion of desired tooth structure defining an interproximal surface of tooth  1904   b,  the practitioner may then use a second mold body, such as one of the mold bodies of the other examples described herein (e.g., mold bodies  102 ,  106  shown in  FIG.  1   ) or any other suitable mold body, to form other tooth structure. The second mold body may be configured to define tooth structure adjacent to the interproximal surface defined by mold body  1902  and/or tooth structure overlapping with the interproximal surface. 
     After forming the tooth structure that defines an interproximal surface of tooth  1904   b  using mold body  1902 , a practitioner may apply the second mold body to one or more teeth including tooth  1904   b  to define a second mold cavity, fill the second mold cavity with restorative material, cure the restorative material, and remove the mold body from tooth  1904   b.  In some examples, in addition to or instead of filling the second mold cavity after the second mold body is attached to the desired teeth  1904 , the practitioner may fill the second mold body with the restorative material prior to attaching the second mold body tooth  1904   b,  and/or the practitioner may apply the restorative material to tooth  1904   b  and then attach the second mold body to tooth  1904   b.  Thus, mold body  1902  may be used to form an interproximal portion of desired tooth structure defining an interproximal surface of tooth  1904   b,  and another mold body may be used to form other portions of desired tooth structure on tooth  1904   b.  In some examples, the use of mold body  1902  without the use of a subsequent mold body may give tooth  1904   b  the desired structure. This technique may be particularly useful in closing diastemas and may be combined with active wedging (such as that described in International Patent Publication No. WO 2016/094272 A1) to create tight, yet flossible contacts between anterior teeth. 
     In some examples, mold body  1902  may include a coating and/or a release film to facilitate release of the restorative material form the surface of mold cavity  1912 . In addition, in some examples, mold body  1902  may include a protrusion or handle or the like to help a practitioner physically grasp mold body  1902  (manually or with the aid of a gripping device). 
     Although mold body  1902  is shown as being attached to adjacent teeth  1904   a ,  1904   b  to define mold cavity  1912  between adjacent teeth  1904   a,    1904   b,  in some examples, mold body  1902  may be configured to attach to one or more teeth that may not be adjacent to each other, as described with respect to  FIGS.  21 A and  21 B . 
       FIGS.  21 A and  21 B  are perspective and front views, respectively, of another example tool  1920  for forming a dental restoration in an interproximal region between adjacent teeth. In the example shown in  FIGS.  21 A and  21 B , mold  1920  is configured to form a dental structure that is an interproximal portion of tooth  1904   b.  In some examples, the dental restoration may also include portions of the facial, lingual and/or incisal surfaces of a tooth. Tool  1920  is similar to tool  1902  shown in  FIGS.  20 A- 20 E , but includes a plurality of base members  1922   a,    1922   b,    1922   c,  as well as interproximal member  1925 . Base members  1922   a,    1922   b,    1922   c  help engage tool  1920  with teeth  1904 , stabilize interproximal member  1925  relative to tooth  1904   b  to be restored, and properly position interproximal member  1925  relative to tooth  1904   b  to be restored. Although three base member  1922   a,    1922   b,    1922   c  are shown in  FIG.  21 A and  21 B , in other examples, mold body  1920  may include any suitable number of base members to provide stability to interproximal member  1925 , such as, but not limited to, two, four, five or more. In some examples, tool  1920  does not include interproximal member  1925 . For example, tool  1920  may be stabilized and aligned with tooth  1904   b  to be restored using base members  1922   a,    1922   b,    1922   c  and without the use of interproximal member  1925 . 
     Base members  1922   a,    1922   b,    1922   c  are configured to provide a customized fit with teeth  1904   c,    1904   d,    1922   b,  respectively. As shown in  FIG.  21 B , base member  1922   a  is configured to contact a reference geometry that is tooth  1904   c  adjacent to tooth  1904   b  to be restored, and base member  1922   b  may contact a reference geometry other than a tooth adjacent to tooth  1904   b  to be restored, such as, for example, tooth  1904   d.  In some examples, base member  1922   a  may be configured to contact a reference geometry other than tooth  1904   c.  For example, base member  1922   a  may be configured to contact a tooth that is not adjacent to tooth  1904   b  to be restored. A base member  1922   a,    1922   b ,  1922   c  may surround or cover a portion of a surface of one or more teeth  1904   c,    1904   d ,  1904   b,  respectively. For example, base members  1922   a  and/or  1922   b  may surround or cover a portion of the incisal surface of teeth  1904   c  and/or  1904   d.    
     As discussed above, in some cases, a mold body, such as tool  1920 , may also include a portion that wraps around another surface of a tooth, such as the facial or lingual surface of the tooth. An example of this is shown in  FIGS.  21 A and  21 B  with respect to wrapping member  1926 , which is configured to extend at least partially over a facial surface of tooth  1904   b  to be restored when mold body  1920  is positioned over teeth  1904  such that interproximal member  1925  is positioned between adjacent teeth  1904   a ,  1904   b.  Wrapping member  1926  is similar to interproximal member  1910  of  FIGS.  20 A- 20 E . Wrapping member  1926  may engage the facial surface of tooth  1904   b  to be restored or may be spaced from the facial surface of tooth  1904   b  and form a mold cavity that is positioned between the facial surface of tooth  1904   b  and wrapping member  1926 . In some examples, wrapping member  1926  may encompass the portion of tooth  1904   b  to be restored. 
     In the example shown in  FIGS.  21 A and  21 B , mold body  1920  includes a handle  1924 , which is a structure with which mold body  1920  may be grasped. Handle  1924  may allow for a practitioner to place mold body  1920  in the mouth of a patient with greater ease, e.g., in comparison to some mold bodies without handle  1924 . 
     In some examples, mold body  1920  may include one or more other features to increase the ease of use of mold body  1920 , as described herein. For example, mold body  1920  may include a protrusion  1927 , which is a structure that aids the use of mold body  1920 . For example, protrusion  1927  may be configured to provide a handle or a gripping mechanism for a practitioner, e.g., the hand of the practitioner or a tool manipulated by the practitioner, and/or ease the mating of mold body  1920  with one or more teeth  1904 . In this way, mating mold body  1920  with one or more teeth  1904  may be facilitated by gripping protrusion  1927 . Protrusion  1927  may ease the handling of mold body  1920  by the practitioner, e.g., may prevent the hand of the practitioner or a tool manipulated by the practitioner from slipping from mold body  1920 . In some examples, protrusion  1927  may prevent the practitioner from having to handle mold body  1920  using interproximal member  1910  or another portion of mold body  1920 , which may be cumbersome and/or awkward to hold or use to place mold body  1920  in contact with teeth  1904 . Protrusion  1927  may also be used to pry tool  1902 , interproximal member  1925 , and/or wrapping member  1926  from tooth  1904   b  after forming the dental restoration. 
     In some examples, mold body  1920  may include one or more of a pry, a lever, or indicia features. In some examples, mold body  1920  may include a coating and/or a release film to facilitate release of the restorative material form the surface of mold body  1920  defining a mold cavity. 
       FIG.  22    is a diagram of an example system  1932  that can be used to design any of the tools described herein. System  1932  includes display device  1934 , user input device  1936 , and processor  1938 . Processor  1938  may include, for example, one or more processors, such as one or more microprocessors, digital signal processors (DSPs), general purpose microprocessors, application specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), programmable logic circuitry, equivalent discrete or integrated logic circuitry, or the like as well as any combination of such components. Accordingly, the term “processor,” as used herein may refer to any of the foregoing structures or any other structure suitable for implementation of the techniques described herein. In addition, in some aspects, the functionality described herein may be provided within dedicated hardware and/or software modules. Also, the techniques could be fully implemented in one or more circuits or logic elements. In general, system  1932  may comprise any suitable arrangement of hardware (e.g., circuitry), alone or in combination with software and/or firmware, to perform the various techniques described herein. Processor  1938  may be housed in a variety of devices including, for example, one or more supercomputers, servers, personal computers, tablets, mobile phones, and/or other mobile devices. 
     Display device  1934  is configured to present information to a user, e.g., under the control of processor  1938 . Input device  1936  may include a button or keypad, a speaker for voice commands, a mouse or touchpad for moving a cursor or providing input, and the like. In some examples display device  1934  may be a touch screen, and may also act as an input device  1936 . 
     Although not shown in  FIG.  22   , system  1932  may also include a memory configured to store instructions required to perform tasks attributed to system  1932 . The memory may comprise any suitable memory, such as random access memory (RAM), read only memory (ROM), programmable read only memory (PROM), erasable programmable read only memory (EPROM), electronically erasable programmable read only memory (EEPROM), flash memory, comprising executable instructions for causing the one or more processors to perform the actions attributed to system  1932  herein. 
     A practitioner may use system  1932  to select and define one or more tools (e.g., mold bodies  102 ,  106  of  FIG.  1   , door body  200  of  FIGS.  2 A and  2 B , as well as the other mold bodies and door bodies described herein) using a digital 3D model based upon intra-oral 3D scans or 3D scans of impressions or models of teeth. Processor  1938  may be configured to receive digital 3D models of teeth ( 1930 ) from intra-oral scans or scans of impressions of teeth. Example systems that can be used to generate digital 3D images or models based upon image sets from multiple views are described in U.S. Pat. Nos. 7,956,862 and 7,605,817. These systems can use an intra-oral scanner to obtain digital images from multiple views of teeth or other intra-oral structures, and those digital images are processed to generate a digital 3D model representing the scanned teeth. 
       FIG.  23    is a flow diagram illustrating an example method of designing any of the tools of  FIGS.  1 - 21 B . Although  FIG.  23    is described with respect to system  1932  shown in  FIG.  22   , the method may be performed by another system, along or in combination with system  1932 , in other examples. The method may include receiving, by processor  1938 , a 3D scan data of a tooth structure of a patient ( 2002 ). The method may further include designing, by processor  1932 , a tool for forming the dental restoration of the tooth based on the D3 scan data of the mouth of the patient ( 2004 ). The tool may be any of the example tools described herein. Designing the tool may include incorporating any the features described herein that are not based solely on the scan data of the tooth structure of the patient such as, for example, apertures, protrusions, door body configurations, or other features that may improve the functionality of the tool. 
     In some examples, the method may further include controlling, by processor  1938 , a 3D printer to define the tool. For example, the tool may be printed from Accura®  60  resin (a clear plastic) on the 3D Systems Viper™ printer, available from 3D Systems of Rock Hill, S.C.. In some examples, the method may further include manufacturing the tool by a CAD/CAM milling processes. 
     In some examples, tool design may be facilitated by creation of a target restoration design. Commercial design software, such as that available from Exocad™ of Darmstadt, Germany, may be used to create a target restoration, optionally review the proposed design with the practitioner, and then use a combination of CAD design, part libraries and/or Boolean operation to create the design of the custom tool. 
     In some examples, the method may further include controlling, by processor  1938 , a device to process at least a portion of a surface of the tool to facilitate removal of the tool from a dental restoration after curing of the dental restoration and/or a smooth finish of at least one surface of the dental restoration. For example, controlling the device to process the portion of the surface of the tool may include controlling the device to polish the portion of the surface to result in the portion of the surface being smoother than before polishing. As another example, controlling the device to process the portion of the surface of the tool comprises controlling the device to coat the portion of the surface with a material, such as methacrylate resin, and curing the portion of the surface to result in the portion of the surface being smoother than before coating. As another example, controlling the device to process the portion of the surface of the tool may include controlling the device to coat the portion of the surface with a material (e.g., Rubber Sep™ Release Agent from Taub Products of Jersey City, N.J.) to result in the portion of the surface having less adhesion force with restorative material than before coating. 
     When leveraging additive manufacturing technologies to fabricate the tools described herein, layer lines may be visible on the surface of the appliance and thus transferred to the restoration created with the appliance. These layer lines may require the practitioner to spend additional time smoothing the final restoration to achieve an acceptable surface finish. Thus, by polishing and/or coating the surface of the appliance, the layer lines can be removed and leave a smoother surface finish to the restoration. 
     Additionally, polishing and/or coating the surface of the tool may increase the visibility through the tool due to the reduced scattering of light from the rough surfaces. Visual feedback and light transmission for curing are increased when the light scattering is reduced. Reducing the surface roughness of the mold cavity also reduces the mechanical interlocking of the restorative to the mold face. This allows for lower release forces to remove the mold, improving reliability of the process. 
       FIG.  24    is a flow diagram illustrating an example method for forming any of the tools of  FIGS.  1 - 21 B . The method may include receiving, from a remote manufacturing facility, a design for a custom tool for forming the dental restoration of the tooth ( 2102 ). The method may further include manufacturing the tool based on the received design ( 2104 ). In some examples, manufacturing the tool comprises manufacturing the tool by a CAD/CAM milling processes. In some examples, manufacturing the tool comprises 3D printing the tool. In some examples, the method may further include processing one or more portions of one or more surfaces of the tool as described with reference to  FIG.  23   . 
     Various examples have been described. Modifications to the described examples may be made within the spirit of this disclosure. For example, custom tools can be fabricated off of initial tooth geometry or digitally optimized tooth geometry (e.g. hole-filling to close gaps in the data, pulling and scaling data from tooth libraries, testing in a virtual articulator). Tools can fit precisely to the existing structure or can be optimized to selectively move or position tissue. Custom tools may be formed to generate a digitally optimized tooth structure that will require the practitioner to remove tooth structure prior to application of the tool. Such plans can be communicated to the practitioner via images, digital models, and/or reduction copings. Tools can be printed or milled. Tools can be made from the full range of 3D printed materials (strength, flexibility, translucency, color). Tools can be coated with a range of agents to enhance sealing, optimize release, surface finish and optical transparency. Tools can contain features to indicate or define fill level of different restorative materials (shade, fill level, physical properties). 
     Physical characteristics (elasticity, roughness, transparency, etc.) of tools can vary across the tool to improve sealing capability, dimensional fidelity, texture imparted to restorative material, degree of cure of material, etc.). Tools and/or mold or door bodies can interlock with each other or with standard components (e.g., matrix bands). Tools can be used inside or outside of the mouth of a patient. Restorative material may be placed or injected through apertures in tools, applied to tooth structure and/or the tool prior to the application of the tool, such that application shapes the material. Tools can be degradable (e.g. by solvent/heat) to release from the restorative material or enable undercut geometries and/or reduce parting lines. Tools could be collapsible (deflated, frangible, etc.). Kits can be created of the patient specific tools and associated products and quantities, (e.g. adhesives, filling, and polishing materials selected for the patient needs and/or doctor preferences). Series of tools may be used sequentially in the direct filling process in order to control the geometries of multiple layers of a dental restoration on a tooth. 
     Dental scans may be taken at any suitable time, such as at diagnostic appointment to facilitate custom tools fabrication prior to a dental restoration appointment. Tools may be manufactured locally or digital scan data may be sent to a remote location for production. Acquisition of patient 3D data, creation of a treatment plan, creation of a tool design, and fabrication of the tool may be completed in any combination of geographic locations including, for example, a dental office, a dental laboratory, and/or an industrial facility. 
     The following examples are within the scope of the disclosure: 
     Clause 1: A tool for forming a dental restoration, the tool comprising a mold body configured to provide a customized fit with at least one tooth of a patient, a single piece of the mold body defining an aperture configured to align with a portion of a surface of a tooth to be restored of the at least one tooth, the mold body being configured to combine with the at least one tooth to define a mold cavity encompassing at least a portion of desired tooth structure of the tooth to be restored, wherein the aperture is larger than a tip of a restorative dental material introduction device and configured to allow placement and flow of a restorative material into the mold cavity to cover the portion of the surface of the tooth to be restored. 
     Clause 2: The tool of clause 1, wherein the dental restoration comprises a layer formed over the surface of a portion of the tooth to be restored. 
     Clause 3: The tool of clause 1 or 2, wherein the mold body comprises a first mold body, the tool further comprising a second mold body configured to provide a customized fit with the at least one tooth of the patient, wherein the first and second mold bodies are configured to combine with the at least one tooth of the patient to form the mold cavity encompassing the at least the portion of desired tooth structure of the tooth to be restored. 
     Clause 4: The tool of clause 3, wherein the second mold body is separable from and engageable with the first mold body. 
     Clause 5: The tool of clause 3 or 4, wherein, when the first and second mold bodies combine with the at least one tooth of the patient to form the mold cavity, at least a portion of the first mold body is configured to abut a portion of the second mold body, wherein at least one of the portion of the first mold body or the portion of the second mold body comprises an overbuilt portion such that, when the portion of the first mold body abuts the portion of the second mold body, the overbuilt portion is configured to provide intimate contact between the portion of the first mold body and the portion of the second mold body. 
     Clause 6: The tool of any of clauses 3-5, wherein the first and second mold bodies are configured to form a clamp when the second mold body is engaged with the first mold body, and wherein, when the first and second mold bodies combine with the at least one tooth of the patient to form the mold cavity, the clamp is configured to be at least proximate an incisal edge of the tooth to be restored. 
     Clause 7: The tool of any of clauses 3-6, wherein the first mold body defines a first structure configured to mate with at least a first portion of a clamp and the second mold body defines a second structure configured to mate with at least a second portion of the clamp, the clamp being configured to secure the first and second mold bodies to one another when the first portion of the clamp mates with the first structure and the second portion of the clamp mates with the second structure. 
     Clause 8: The tool of any of clauses 1-7, wherein the mold body defines a vent configured to at least one of allow excess restorative material to flow out of the mold cavity or allow air to flow out of the mold cavity. 
     Clause 9: The tool of any of clauses 1-8, further comprising a door body corresponding to the portion of the surface of the tooth to be restored, at least a portion of the door body being configured to mate with the aperture, wherein the mold body and the door body are configured to combine with the at least one tooth of the patient to form the mold cavity encompassing the at least the portion of desired tooth structure of the tooth to be restored. 
     Clause 10: The tool of clause 9, wherein the door body is separable from and engageable with the mold body. 
     Clause 11: The tool of clause 9, wherein the door body is attached to the mold body via a hinge. 
     Clause 12: The tool of any of clauses 9-11, wherein a side of the door body configured to mate with the mold body defines a chamfered edge 
     Clause 13: The tool of any of clauses 9-12, wherein at least one of the mold body or the door body defines a vent configured to at least one of allow excess restorative material to flow out of the mold cavity or allow air to flow out of the mold cavity. 
     Clause 14: The tool of any of clauses 9-13, further comprising a release film configured for placement on a surface of the door body to facilitate release of restorative material from the surface of the door body. 
     Clause 15: The tool of any of clauses 9-14, further comprising a coating configured for placement on a surface of the door body to facilitate release of restorative material from the surface of the door body. 
     Clause 16: The tool of any of clauses 9-15, wherein the door body comprises a first door body, the aperture comprises a first aperture, the portion of the lingual or facial surface of the one tooth to be restored of the at least one tooth comprises a first portion of a first lingual or facial surface of a first tooth to be restored of the at least one tooth, the mold body defines a second aperture configured to align with a second portion of a second lingual or facial surface of a second tooth to be restored of the at least one tooth, and the second portion comprises a majority of the second lingual or facial surface of the second tooth to be restored, the tool further comprising a second door body corresponding to the second portion of the second lingual or facial surface of the second tooth to be restored, at least a portion of the second door body being configured to mate with the second aperture, wherein the mold body, the first door body, and the second door body are configured to combine with the at least one tooth of the patient to form the mold cavity encompassing at least the portion of desired tooth structure of the at least one tooth. 
     Clause 17: The tool of clause 16, wherein the first aperture and the second aperture are different shapes and the first and second door bodies are different shapes, the shape of the first door body corresponding to the shape of the first aperture and the shape of the second door body corresponding to the shape of the second aperture. 
     Clause 18: The tool of clause 16, wherein the first aperture and the second aperture are the same shape and the first and second door bodies are the same shape. 
     Clause 19: The tool of any of clauses 16-18, wherein one or more of the mold body, the first door body, or the second door body comprise one or more indicia for facilitating one or more of mating the first door body with the first aperture or mating the second door body with the second aperture. 
     Clause 20: The tool of clause 19, wherein the one or more indicia comprise one or more of: a key structure and a corresponding keyhole; color coding; one or more symbols; or one or more other integrated or applied markings. 
     Clause 21: The tool of any of clauses 9-20, wherein the door body comprises a first door body configured for one or more of final shaping or final layering of at least a portion of the dental restoration, the tool further comprising one or more of: a second door body, at least a portion of the second door body being configured to mate with the aperture, the second door body being configured for shaping an underlying shade layer of at least the portion of the dental restoration; a third door body, at least a portion of the third door body being configured to mate with the aperture, the third door body being configured to form one or more of one or more mamelons, one or more grooves, or one or more pits; a fourth door body, at least a portion of the fourth door body being configured to mate with the aperture, the fourth door body being configured for near net shaping of at least the portion of the dental restoration; or a fifth door body, at least a portion of the fifth door body being configured to mate with the aperture, the fifth door body being configured for applying an intermediate layer of restorative material, the intermediate layer of restorative material comprising a first restorative material that is different than a material applied during final layering by the first door body. 
     Clause 22: The tool of clauses 9-21, wherein at least one of the mold body or the door body defines at least one protrusion configured to provide a gripping mechanism for a practitioner. 
     Clause 23: The tool of clause 22, wherein the at least one protrusion defines one or more ribs. 
     Clause 24: The tool of clauses 22 or 23, wherein the at least one protrusion defines a structure configured to mate with at least a portion of a clamp. 
     Clause 25: The tool of any of clauses 22-24, wherein the at least one protrusion defines at least one lever configured to provide a mechanism for use in prying the mold body away from the tooth to be restored. 
     Clause 26: The tool of any of clauses 1-25, further comprising a coating configured for placement on a surface of the mold body to facilitate release of restorative material from the surface of the mold body. 
     Clause 27: The tool of any of clauses 1-26, wherein the mold body comprises a ridge configured to contact at least a portion of the tooth to be restored of the at least one tooth to concentrate sealing pressure at at least a portion of a perimeter of the mold cavity. 
     Clause 28: The tool of clause 27, wherein the at least the portion of the perimeter of the mold cavity is configured to be located proximate to a gingival contour of the tooth to be restored when the mold body combines with at least the at least one tooth of the patient to form the mold cavity. 
     Clause 29: The tool of any of clauses 1-28, wherein the first mold body defines an edge defining a contour configured to substantially match at least a portion of a gingival contour of the tooth to be restored. 
     Clause 30: The tool of any of clauses 1-29, wherein a ratio of an area of the aperture to a cross-sectional area of the tip is greater than or equal to about 2:1. 
     Clause 31: The tool of any of clauses 1-30, wherein the aperture is configured to align with a majority of the portion of the surface of the tooth to be restored. 
     Clause 32: The tool of any of clauses 1-31, further comprising the restorative dental material introduction device. 
     Clause 33: A tool for forming a dental restoration, the tool comprising a mold body configured to provide a customized fit with at least one tooth of a patient, the mold body defining an aperture configured to align with a portion of a surface of one tooth to be restored of the at least one tooth; and a door body corresponding to the portion of the surface of the tooth to be restored, at least a portion of the door body being configured to mate with the aperture, wherein the mold body and the door body are configured to combine with the at least one tooth of the patient to form the mold cavity encompassing the at least the portion of desired tooth structure of the tooth to be restored. 
     Clause 34: The tool of clause 33, wherein the surface of the tooth to be restored is a lingual surface, a facial surface, an incisal surface, or an interproximal surface. 
     Clause 35: The tool of clause 33 or 34, wherein the dental restoration comprises a layer formed over the surface of a portion of the tooth to be restored. 
     Clause 36: The tool of any of clauses 33-35, wherein the mold body comprises a first mold body, the tool further comprising a second mold body configured to provide a customized fit with the at least one tooth of the patient, wherein the first and second mold bodies are the door body are configured to combine with the at least one tooth of the patient to form the mold cavity encompassing the at least the portion of desired tooth structure of the tooth to be restored. 
     Clause 37: The tool of clause 36, wherein the second mold body is separable from and engageable with the first mold body. 
     Clause 38: The tool of clause 36 or 37, wherein, when the first and second mold bodies combine with the at least one tooth of the patient to form the mold cavity, at least a portion of the first mold body is configured to abut a portion of the second mold body, wherein at least one of the portion of the first mold body or the portion of the second mold body comprises an overbuilt portion such that, when the portion of the first mold body abuts the portion of the second mold body, the overbuilt portion is configured to provide intimate contact between the portion of the first mold body and the portion of the second mold body. 
     Clause 39: The tool of any of clause 36-38, wherein the first and second mold bodies are configured to form a clamp when the second mold body is engaged with the first mold body, and wherein, when the first and second mold bodies combine with the at least one tooth of the patient to form the mold cavity, the clamp is configured to be at least proximate an incisal edge of the tooth to be restored. 
     Clause 40: The tool of any of clauses 36-39, wherein the first mold body defines a first structure configured to mate with at least a first portion of a clamp, and the second mold body defines a second structure configured to mate with at least a second portion of the clamp, the clamp being configured to secure the first and second mold bodies to one another when the first portion of the clamp mates with the first structure and the second portion of the clamp mates with the second structure. 
     Clause 41: The tool of any of clauses 33-40, wherein the door body is separable from and engageable with the mold body. 
     Clause 42: The tool of any of clauses 33-41, wherein at least one of the door body or the mold body defines a vent configured to at least one of allow excess restorative material to flow out of the mold cavity or allow air to flow out of the mold cavity. 
     Clause 43: The tool of any of clauses 33-42, further comprising a release film configured for placement on a surface of the door body to facilitate release of restorative material from the surface of the door body. 
     Clause 44: The tool of any of clauses 33-43, further comprising one or more of a coating configured for placement on a surface of the door body to facilitate release of restorative material from the surface of the door body or a coating configured for placement on a surface of the mold body to facilitate release of restorative material from the surface of the mold body. 
     Clause 45: The tool of any of clauses 33-44, wherein the door body comprises a first door body, the aperture comprises a first aperture, the portion of the surface of the one tooth to be restored of the at least one tooth comprises a first portion of a first surface of a first tooth to be restored of the at least one tooth, and the mold body defines a second aperture configured to align with a second portion of a surface of a second tooth to be restored of the at least one tooth, the tool further comprising a second door body corresponding to the second portion of the second surface of the second tooth to be restored, at least a portion of the second door body being configured to mate with the second aperture; the mold body, the first door body, and the second door body being configured to combine with the at least one tooth of the patient to form the mold cavity encompassing at least the portion of desired tooth structure of the at least one tooth. 
     Clause 46: The tool of clause 45, wherein the first aperture and the second aperture are different shapes and the first and second door bodies are different shapes, the shape of the first door body corresponding to the shape of the first aperture and the shape of the second door body corresponding to the shape of the second aperture. 
     Clause 47: The tool of clause 45, wherein the first aperture and the second aperture are the same shape. 
     Clause 48: The tool of any of clauses 45-47, wherein one or more of the mold body, the first door body, or the second door body comprise one or more indicia for facilitating one or more of mating the first door body with the first aperture or mating the second door body with the second aperture. 
     Clause 49: The tool of clause 48, wherein the one or more indicia comprise one or more of: a key structure and a corresponding keyhole; color coding; one or more symbols; or one or more other integrated or applied markings. 
     Clause 50: The tool of any of clauses 33-49, wherein the door body comprises a first door body configured for one or more of final shaping or final layering of at least a portion of the dental restoration, the tool further comprising one or more of: a second door body, at least a portion of the second door body being configured to mate with the aperture; the second door body being configured for shaping an underlying shade layer of at least the portion of the dental restoration; a third door body, at least a portion of the third door body being configured to mate with the aperture; the third door body being configured to form one or more of one or more mamelons, one or more grooves, or one or more pits; a fourth door body, at least a portion of the fourth door body being configured to mate with the aperture; the fourth door body being configured for near net shaping of at least the portion of the dental restoration; or a fifth door body, at least a portion of the fifth door body being configured to mate with the aperture, the fifth door body being configured for applying an intermediate layer of restorative material, the intermediate layer of restorative material comprising a first restorative material that is different than a material applied during final layering by the first door body. 
     Clause 51: The tool of any of clauses 33-50, wherein the mold body comprises a ridge configured to contact at least a portion of the tooth to be restored of the at least one tooth to concentrate sealing pressure at at least a portion of a perimeter of the mold cavity. 
     Clause 52: The tool of clause 51, wherein the at least the portion of the perimeter of the mold cavity is configured to be located proximate to a gingival contour of the tooth to be restored when the mold body combines with at least the at least one tooth of the patient to form the mold cavity. 
     Clause 53: The tool of any of clauses 33-52, wherein the mold body defines an edge configured to substantially overlay at least a portion of a gingival contour of the tooth to be restored. 
     Clause 54: The tool of any of clauses 33-53, wherein at least one of the mold body or the door body defines at least one protrusion configured to provide a gripping mechanism for a practitioner. 
     Clause 55: The tool of clause 54, wherein the at least one protrusion defines one or more ribs. 
     Clause 56: The tool of clause 54 or 55, wherein the at least one protrusion defines a structure configured to mate with at least a portion of a clamp. 
     Clause 57: The tool of any of clauses 54-56, wherein the at least one protrusion defines at least one lever configured to provide a mechanism for use in prying the mold body away from the tooth to be restored. 
     Clause 58: A tool for forming a dental restoration, the tool comprising a mold body configured to provide a customized fit with at least one tooth of a patient, the mold body being configured to combine with at least the at least one tooth of the patient to define a mold cavity encompassing at least a portion of desired tooth structure of the at least one tooth of the patient, the mold body comprising a ridge configured to contact at least a portion of a tooth to be restored of the at least one tooth to concentrate sealing pressure at at least a portion of a perimeter of the mold cavity. 
     Clause 59: The tool of clause 58, wherein the at least the portion of the perimeter of the mold cavity is configured to be located proximate to a gingival contour of the tooth to be restored when the mold body combines with at least the at least one tooth of the patient to form the mold cavity. 
     Clause 60: The tool of clause 58 or 59, wherein the dental restoration is a layer formed over the surface of a portion of the tooth to be restored. 
     Clause 61: A tool for forming a dental restoration, the tool comprising a first mold body configured to provide a customized fit with at least one tooth of a patient; and a second mold body configured to provide a customized fit with the at least one tooth of the patient, wherein the first and second mold bodies are configured to combine with the at least one tooth of the patient to define a mold cavity encompassing at least a portion of desired tooth structure of the at least one tooth wherein, when the first and second mold bodies combine with the at least one tooth of the patient to form the mold cavity, at least a portion of the first mold body is configured to abut a portion of the second mold body, wherein the portion of the first mold body comprises an overbuilt portion such that, when the portion of the first mold body abuts the portion of the second mold body, the overbuilt portion is configured to provide intimate contact between the portion of the first mold body and the portion of the second mold body. 
     Clause 62: The tool of clause 61, wherein the dental restoration is layer formed over the surface of a portion of the tooth. 
     Clause 63: The tool of clause 61 or 62, wherein the overbuilt portion of the first mold body is formed from a compressible material, the overbuilt portion being configured to be compressed against the portion of the second mold body when the first and second mold bodies combine with the at least one tooth of the patient to form the mold cavity. 
     Clause 64: A tool for forming a dental restoration, the tool comprising a first mold body configured to provide a customized fit with at least one tooth of a patient and a second mold body configured to provide a customized fit with the at least one tooth of the patient, wherein the first and second mold bodies are configured to combine with the at least one tooth of the patient to define a mold cavity encompassing at least a portion of desired tooth structure of the at least one tooth, and wherein the first and second mold bodies are configured to form a clamp when the second mold body is engaged with the first mold body, wherein, when the first and second mold bodies combine with the at least one tooth of the patient to form the mold cavity, the clamp is configured to be at least proximate an incisal edge of at least one tooth to be restored of the at least one tooth. 
     Clause 65: The tool of clause 64 wherein the dental restoration is a layer formed over the surface of a portion of the tooth to be restored. 
     Clause 66: A tool for forming a dental restoration, the tool comprising a first mold body configured to provide a customized fit with at least one tooth of a patient, the first mold body defining a first structure configured to mate with at least a first portion of a clamp; and a second mold body configured to provide a customized fit with the at least one tooth of the patient, the second mold body defining a second structure configured to mate with at least a second portion of the clamp, the clamp being configured to secure the first and second mold bodies to one another when the first portion of the clamp mates with the first structure and the second portion of the clamp mates with the second structure, wherein the first and second mold bodies are configured to combine with the at least one tooth of the patient to define a mold cavity encompassing at least a portion of desired tooth structure of the at least one tooth. 
     Clause 67: The tool of clause 66, wherein the dental restoration is a layer formed over the surface of a portion of the at least one tooth. 
     Claim 68: The tool of clause 66 or 67, wherein at least one of the first structure or the second structure extends away from the first mold body or the second mold body, respectively. 
     Claim 69: The tool of clause 66 or 67, wherein at least one of the first structure or the second structure is recessed in the first mold body or the second mold body, respectively. 
     Clause 70: A tool for forming a dental restoration, the tool comprising a mold body configured to provide a customized fit with at least one tooth of a patient, the mold body defining an edge defining a contour configured to match at least a portion of a gingival contour of a tooth to be restored of the at least one tooth; wherein the mold body is configured to combine with the at least one tooth of the patient to define a mold cavity encompassing at least a portion of desired tooth structure of the tooth to be restored. 
     Clause 71: The tool of clause 70, wherein the dental restoration is a layer formed over the surface of a portion of the tooth to be restored. 
     Clause 72: A tool for forming a dental restoration, the tool comprising: a first mold body configured to provide a customized fit with at least one tooth of a patient, the first mold body having a first stiffness, at least a first portion of the first mold body being configured to surround at least a portion of the at least one tooth, the first mold body being configured to combine with the at least one tooth to define a mold cavity encompassing at least a portion of desired tooth structure of the at least one tooth; and a second mold body having a second stiffness that is greater than the first stiffness, at least a portion of the second mold body being configured to surround at least a second portion of the first mold body. 
     Clause 73: The tool of clause 72, wherein the first mold body comprises a first material and the second mold body comprises a second material that is more rigid that the first material. 
     Clause 74: The tool of clause 72, wherein the first and second mold bodies are formed from the same material. 
     Clause 75: The tool of any of clauses 72-74, wherein the second stiffness is greater than the first stiffness due to the structures of the second and first mold bodies, respectively. 
     Clause 76: The tool of clause 75, wherein the second mold body defines one or more of at least one dimension with a greater thickness that a corresponding dimension of the first mold body or one or more support ribs. 
     Clause 77: The tool of clause any of clauses 72-76, wherein the first mold body defines a first aperture configured to allow placement of restorative material into the mold cavity, the second mold body defines a second aperture, and the second aperture is larger than the first aperture and is configured to allow access to the first aperture when the at least the portion of the second mold body is surrounding the at least the second portion of the first mold body. 
     Clause 78: The tool of clause 77, wherein the second mold body comprises a reinforcement structure proximate the second aperture and configured to provide reinforcement to the second mold body. 
     Clause 79: The tool of any of clauses 72-79, wherein the dental restoration is a layer formed over the surface of a portion of the at least one tooth. 
     Clause 80: The tool of any of clauses 72-80, wherein the first mold body is compressible. 
     Clause 81: A tool for forming a dental restoration, the tool comprising a mold body configured to provide a customized fit with at least one tooth of a patient, the mold body being configured to combine with the at least one tooth of the patient to define a mold cavity encompassing at least a portion of desired tooth structure of a tooth of the at least one tooth, the mold body defining at least one protrusion configured to provide a gripping mechanism for a practitioner, the protrusion defining a structure configured to mate with at least a portion of a clamp. 
     Clause 82: The tool of clause 81, wherein the protrusion defines one or more ribs. 
     Clause 83: The tool of clause 81 or 82, wherein the at least one protrusion defines at least one lever configured to provide a mechanism for use in prying the mold body away from the dental restoration after curing of the dental restoration. 
     Clause 84: The tool of any of clauses 81-83, wherein the dental restoration is a layer formed over the surface of a portion of the at least one tooth. 
     Clause 85: A method of designing a tool for forming a dental restoration of a tooth, the method comprising receiving, by one or more processors, a three-dimensional scan data of a tooth structure of a patient; and designing, by the one or more processors, a tool for forming the dental restoration of the tooth based on the three-dimensional scan data of the mouth of the patient; wherein the tool is the tool of any of clauses 1-84. 
     Clause 86: The method of clause 85, further comprising controlling, by the one or more processors, a three-dimensional printer to define the tool. 
     Clause 87: The method of clause 85, further comprising manufacturing the tool by a CAD/CAM milling processes. 
     Clause 88: The method of any of clauses 85-87, further comprising controlling, by the one or more processors, a device to process at least a portion of a surface of the tool to facilitate at least one of: removal of the tool from a dental restoration prior to curing of the dental restoration; removal of the tool from a dental restoration after curing of the dental restoration; or a smooth finish of at least one surface of the dental restoration. 
     Clause 89: The method of clause 88, wherein controlling the device to process the at least the portion of the surface of the tool comprises controlling the device to polish the at least the portion of the surface to result in the at least the portion of the surface being smoother than before polishing. 
     Clause 90: The method of clause 88 or 89, wherein controlling the device to process the at least the portion of the surface of the tool comprises controlling the device to coat the at least the portion of the surface with a material to result in the at least the portion of the surface being smoother than before coating. 
     Clause 91: The method of any of clauses 88-90, wherein controlling the device to process the at least the portion of the surface of the tool comprises controlling the device to coat the at least the portion of the surface with a material to result in the at least the portion of the surface having less adhesion force with restorative material than before coating. 
     Clause 92: A method for forming a tool for forming a dental restoration of a tooth, the method comprising receiving, from a remote manufacturing facility, a design for a custom tool for forming the dental restoration of the tooth; and manufacturing the tool for forming the dental restoration of the tooth based on the received design, wherein the tool is the tool of any of clauses 1-81. 
     Clause 93: The method of clause 92, wherein manufacturing the tool comprises manufacturing the tool by a CAD/CAM milling processes. 
     Clause 94: The method of clause 92, wherein manufacturing the tool comprises 3D printing the tool. 
     Clause 95: The method of any of clauses 92-94, wherein manufacturing the tool comprises processing at least a portion of a surface of the tool to facilitate at least one of removal of the tool from a dental restoration prior to curing of the dental restoration; removal of the tool from a dental restoration after curing of the dental restoration; or a smooth finish of at least one surface of the dental restoration. 
     Clause 96: The method of clause 95, wherein processing the at least the portion of the surface of the tool comprises polishing the at least the portion of the surface to result in the at least the portion of the surface being smoother than before polishing. 
     Clause 97: The method of clause 95 or 96, wherein processing the at least the portion of the surface of the tool comprises coating the at least the portion of the surface with a material to result in the at least the portion of the surface being smoother than before coating. 
     Clause 98: The method of any of clauses 95-97, wherein processing the at least the portion of the surface of the tool comprises coating the at least the portion of the surface with a material to result in the at least the portion of the surface having less adhesion force with restorative material than before coating. 
     Clause 99: A method of forming a dental restoration, the method comprising: attaching a mold body to at least one tooth of a patient, the mold body configured to provide a customized fit with at least one tooth of a patient, a single piece of the mold body defining an aperture configured to align with a portion of a surface of a tooth to be restored of the at least one tooth, the mold body being configured to combine with the at least one tooth to define a mold cavity encompassing at least a portion of desired tooth structure of the tooth to be restored, wherein the aperture is larger than a tip of a restorative dental material introduction device and configured to allow placement and flow of a restorative material into the mold cavity to cover the portion of the surface of the tooth to be restored; filling the mold cavity with restorative material; curing the restorative material; and removing the mold body from the at least one tooth. 
     Clause 100: The method of clause 99, further comprising, after filling the mold cavity with restorative material, placing at least a portion of a door body within the aperture, the door body corresponding to the portion of the surface of the at least one tooth to be restored, at least the portion of the door body being configured to mate with the aperture. 
     Clause 101: The method of clause 99 or 100, wherein filling the mold cavity with restorative material comprises aligning a tip of a restorative dental material introduction device with the aperture and introducing the restorative material into the mold cavity via the restorative dental material introduction device, wherein a ratio of an area of the aperture to a cross-sectional area of the tip is greater than or equal to about 2:1. 
     Clause 102: The method of any of clauses 99-101, wherein the mold body comprises a first mold body, the method further comprising attaching a second mold body to the at least one tooth, the second mold body being configured to provide a customized fit with the at least one tooth, the first and second mold bodies being configured to combine with the at least one tooth of the patient to form the mold cavity encompassing at least the portion of desired dental structure of the tooth to be restored. 
     Clause 103: The method of any of clauses 102, further comprising engaging the second mold body with the first mold body; and separating the second mold body from the first mold body. 
     Clause 104: The method of clause 102 or 103, wherein when the first and second mold bodies combine with the at least one tooth of the patient to form the mold cavity, at least a portion of the first mold body abuts a portion of the second mold body, wherein at least one of the portion of the first mold body or the portion of the second mold body comprises an overbuilt portion such that, when the portion of the first mold body abuts the portion of the second mold body, the overbuilt portion provides intimate contact between the portion of the first mold body and the portion of the second mold body. 
     Clause 105: The method of any of clauses 102-104, wherein the first and second mold bodies are configured to form a clamp when the first and second mold bodies are engaged together, wherein, when the first and second mold bodies combine with the at least one tooth of the patient to form the mold cavity, the clamp is configured to be at least proximate an incisal edge of the tooth to be restored. 
     Clause 106: The method of any of clauses 102-105, wherein the first mold body defines a first structure configured to mate with at least a first portion of a clamp, and the second mold body defines a second structure configured to mate with at least a second portion of the clamp, the clamp being configured to secure the first and second mold bodies to one another when the first portion of the clamp mates with the first structure and the second portion of the clamp mates with the second structure, the method further comprising mating the first portion of the clamp with the first structure; and mating the second portion of the clamp with the second structure. 
     Clause 107: The method of any of clauses 99-106, further comprising placing at least a portion of a door body within the aperture, the door body corresponding to the portion of the surface of the tooth to be restored, at least the portion of the door body being configured to mate with the aperture. 
     Clause 108: The method of any of clause 107, wherein the door body is separable from and engageable with the mold body. 
     Clause 109: The method of clause 107 or 108, wherein at least one of the mold body or the door body defines a vent configured to allow excess restorative material to flow out of the mold cavity. 
     Clause 110: The method of any of clauses 107-109, further comprising placing a release film on at least a portion of a surface of the door body before placing the at least a portion of the door body within the aperture; removing the at least a portion of the door body from the aperture; removing the release film from the at least a portion of the surface; and placing the at least a portion of the door body within the aperture. 
     Clause 111: The method of any of clauses 107-110, further comprising placing a coating on at least a portion of a surface of the door body before placing the at least a portion of the door body within the aperture; removing the at least a portion of the door body from the aperture; and placing the at least a portion of the door body within the aperture. 
     Clause 112: The method of any of clauses 107-111, wherein the door body comprises a first door body, the aperture comprises a first aperture, the portion of the lingual or facial surface of the one tooth of the at least one tooth comprises a first portion of a first lingual or facial surface of a first tooth of the at least one tooth, and the mold body defines a second aperture configured to align with a second portion of a second lingual or facial surface of a second tooth of the at least one tooth, the method further comprising placing at least a portion of a second door body within the second aperture, the second door body corresponding to the second portion of the lingual or facial surface of the second tooth of the at least one tooth, at least the portion of the second door body being configured to mate with the second aperture. 
     Clause 113: The method of clause 112, wherein the first aperture and the second aperture are different shapes and the first and second door bodies are different shapes, the shape of the first door body corresponding to the shape of the first aperture and the shape of the second door body corresponding to the shape of the second aperture. 
     Clause 114: The tool of clause 112, wherein the first aperture and the second aperture are the same shape and the first and second door bodies are the same shape. 
     Clause 115: The tool of any of clauses 112-114, wherein one or more of the mold body, the first door body, or the second door body comprise one or more indicia for facilitating one or more of mating the first door body with the first aperture or mating the second door body with the second aperture. 
     Clause 116: The tool of clause 115, wherein the one or more indicia comprise one or more of: a key structure and a corresponding keyhole; color coding; one or more symbols; or one or more other integrated or applied markings. 
     Clause 117: The method of any of clauses 107-116, wherein placing the at least a portion of the door body within the aperture provides one or more of final shaping of at least a portion of the dental restoration, and the door body comprises a first door body, the method further comprising: placing additional restorative material into the mold cavity and at least one of: placing at least a portion of a second door body within the aperture to shape an underlying shade layer of the at least the portion of the dental restoration, the at least the portion of the second door body being configured to mate with the aperture; placing at least a portion of a third door body within the aperture to form one or more of one or more mamelons; one or more grooves; or one or more pits, the at least the portion of the third door body being configured to mate with the aperture; placing at least a portion of a fourth door body within the aperture to provide near net shaping of the at least the portion of the dental restoration, the at least the portion of the fourth door body being configured to mate with the aperture, or placing at least a portion of a fifth door body within the aperture to apply an intermediate layer of restorative material, the intermediate layer of restorative material comprising a first restorative material that is different than a material applied during final layering by the first door body. 
     Clause 118: The method of clause 117, wherein the additional restorative material comprises first additional restorative material, further comprising, after placing the first additional restorative material and at least one of the at least the portion of the second door body, the third door body, the fourth door body, or the fifth door body within the aperture, curing the first additional restorative material with the door within the aperture, adjusting the cured composite (e.g., by cutting back the composite to create an underlying geometry), placing second additional restorative material in the mold cavity, placing at least one of the at least the portion of the second door body, the third door body, the fourth door body, or the fifth door body within the aperture, and curing the second additional restorative material. 
     Clause 119: The method of claim 118, wherein the first and additional restorative materials are the same. 
     Clause 120 The method of claim 118, wherein the first and additional restorative materials are different. 
     Clause 121: The method of any of clauses 107-120, wherein at least one of the mold body or the door body defines at least one protrusion configured to provide a gripping mechanism for a practitioner, wherein one or more of attaching the mold body to at least one tooth, placing at least the portion of the door body within the aperture, or removing the door body and the mold body from the at least one tooth comprises gripping at least one protrusion of the at least one protrusion. 
     Clause 122: The method of clause 121, wherein the at least one protrusion defines one or more ribs. 
     Clause 123: The method of clause 121 or 122, wherein the at least one protrusion defines a structure configured to mate with at least a portion of a clamp, the method further comprising mating at least the portion of the clamp with the structure. 
     Clause 124: The method of any of clauses 121-123, wherein the at least one protrusion defines at least one lever configured to provide a mechanism for use in prying the mold body away from the tooth to be restored, and wherein removing the mold body from the at least one tooth comprises using the lever to pry the mold body away from the tooth to be restored. 
     Clause 125: The method of any of clauses 99-124, wherein the mold body comprises a ridge configured to contact at least a portion of a tooth to be restored of the at least one tooth to concentrate sealing pressure at at least a portion of a perimeter of the mold cavity. 
     Clause 126: The method of clause 125, wherein the at least the portion of the perimeter of the mold cavity is configured to be located proximate to a gingival contour of the tooth when the mold body combines with at least the at least one tooth of the patient to form the mold cavity. 
     Clause 127: The method of any of clauses 99-126, wherein the mold body defines an edge defining a contour configured to substantially match at least a portion of a gingival margin of the tooth. 
     Clause 128: The method of any of clauses 99-127, wherein filling the mold cavity comprises placing the restorative material through the aperture and into the mold cavity. 
     Clause 129: The method of any of clauses 99-128, wherein filling the mold cavity comprises filling the mold body with restorative material before attaching the mold body to the at least one tooth. 
     Clause 130: The method of any of clauses 99-129, wherein filling the mold cavity comprises placing the restorative material on the tooth to be restored before attaching the mold body to the at least one tooth. 
     Clause 131: A method of designing a tool for forming a dental restoration of a tooth, the method comprising: receiving, by one or more processors, a three dimensional scan data of a tooth structure of a patient; and designing, by the one or more processors, a tool for forming the dental restoration of the tooth based on the three dimensional scan data of the mouth of the patient, wherein the tool comprises a mold body configured to provide a customized fit with at least one tooth of a patient, the mold body defining an aperture configured to align with a portion of a surface of the at least one tooth, the aperture being sufficiently large to allow placement and flow of a restorative material to cover the portion of the at least one tooth being restored, the mold body being configured to combine with the at least one tooth to define a mold cavity encompassing at least a portion of desired tooth structure of the at least one tooth to be restored. 
     Clause 132: A tool for forming a dental restoration, the tool comprising a mold body configured to combine with a tooth of a patient to define a mold cavity encompassing at least a portion of desired tooth structure of the tooth, the portion of desired tooth structure defining an interproximal surface of the tooth, the mold body comprising a base member configured to provide a customized fit with at least one tooth of the patient to attach the mold body to the at least one tooth, and an interproximal member extending from the base member and configured to be disposed between adjacent teeth of the patient when the base member is fit over the at least one tooth, the interproximal member defining a surface of the mold cavity. 
     Clause 133: The tool of clause 132, wherein the base member is configured to provide a customized fit with a lingual surface of adjacent teeth of the patient and the interproximal member is configured to be disposed between the adjacent teeth when the mold body is positioned over the at least one tooth. 
     Clause 134: The tool of clause 132 or clause 133, wherein the base member comprises a first base member and a second base member, and the tooth is a first tooth, the first base member being configured to provide a customized fit with an incisal or occlusal surface of the first tooth, and the second base member being configured to provide a customized fit with an incisal or occlusal surface of a second tooth. 
     Clause 135: The tool of clause 134, wherein the first and second teeth are directly adjacent to each other and the interproximal surface of the first tooth is between the first and second teeth. 
     Clause 136: The tool of clause 134, wherein the first and second teeth are not directly adjacent to each other and the interproximal surface of the first tooth is between the first tooth and a third tooth. 
     Clause 137: The tool of any of clauses 132-136, wherein the interproximal member extends around one or more of a lingual surface, a facial surface, an incisal surface, or an occlusal surface of the tooth. 
     Clause 138: The tool of any of clauses 132-137, where the mold body comprises a first mold body and the mold cavity comprises a first mold cavity, the tool further comprising a second mold body defining an aperture configured to align with a portion of another surface of the tooth to be restored, the second mold body being configured to combine with at least one tooth of the patient to define a second mold cavity encompassing at least the portion of the tooth to be restored, wherein the aperture is larger than a tip of a restorative dental material introduction device and configured to allow placement and flow of a restorative material into the second mold cavity to cover the portion of the tooth to be restored. 
     Clause 139: The tool of clause 138, wherein a ratio of an area of the aperture to a cross-sectional area of the tip is greater than or equal to about 2:1. 
     Clause 140: The tool of clause 138, wherein the aperture is configured to align with a majority of the portion of the other surface of the tooth. 
     Clause 141: The tool of any of clauses 138-140, further comprising a door body corresponding to the portion of the other surface of the tooth to be restored, at least a portion of the door body being configured to mate with the aperture, wherein the second mold body and the door body are configured to combine with the at least one tooth to define the second mold cavity. 
     Clause 142: A method of designing a tool for forming a dental restoration of a tooth, the method comprising receiving, by one or more processors, a three dimensional scan data of a tooth structure of a patient, and designing, by the one or more processors, a tool for forming the dental restoration of the tooth based on the three dimensional scan data of the mouth of the patient, wherein the tool comprises a mold body configured to combine with a tooth of a patient to define a mold cavity encompassing at least a portion of desired tooth structure of the tooth, the portion of desired tooth structure defining an interproximal surface of the tooth, the mold body comprising a base member configured to provide a customized fit with at least one tooth of the patient to attach the mold body to the at least one tooth, and an interproximal member extending from the base member and configured to be disposed between adjacent teeth of the patient when the base member, the interproximal member defining a surface of the mold cavity. 
     Clause 143: The method of clause 142, further comprising at least one of controlling, by the one or more processors, a three-dimensional printer to define the tool or manufacturing the tool by a CAD/CAM milling processes. 
     Clause 144: A method for forming a dental restoration, the method comprising: attaching a mold body to at least one tooth of a patient, the mold body configured to combine with a tooth of the patient to define a mold cavity encompassing at least a portion of desired tooth structure of the tooth, the portion of desired tooth structure defining an interproximal surface of the tooth, the mold body comprising a base member configured to provide a customized fit with at least one tooth of the patient to attach the mold body to the at least one tooth, and an interproximal member extending from the base member and configured to be disposed between adjacent teeth of the patient when the base member, the interproximal member defining a surface of the mold cavity, filling the mold cavity with a restorative material, curing the restorative material, and removing the mold body from the at least one tooth. 
     Clause 145: The method of clause 144, wherein the mold body comprises a first mold body, and the mold cavity comprises a first mold cavity, the method further comprising after removing the first mold body from the at least one tooth, attaching a second mold body to the at least one tooth, the second mold body defining an aperture configured to align with a portion of another surface of the tooth to be restored, the second mold body being configured to combine with at least one tooth of the patient to define a second mold cavity encompassing at least the portion of the tooth to be restored, wherein the aperture is larger than a tip of a restorative dental material introduction device and configured to allow placement and flow of a restorative material into the second mold cavity to cover the portion of the tooth to be restored, filling the second mold cavity with restorative material, curing the restorative material in the second mold cavity, and removing the second mold body from the at least one tooth. 
     Clause 146: The method of clause 145, wherein filling the first mold cavity or the second mold cavity comprises at least one of introducing the restorative material into the respective mold cavity after attaching the respective mold body to the at least one tooth, introducing the restorative material into the respective mold body before attaching the respective mold body to the at least one tooth, or applying the restorative material to the tooth before attaching the respective mold body to the at least one tooth. 
     These and other examples are within the scope of the following claims.