Abstract:
Methods for the restoration of a decayed portion of a tooth and dental matrices that may be used in the methods for the restoration of a decayed portion of a tooth are disclosed. Methods for direct elective composite additive crowning and veneering of teeth that may or may not have decay or previous restorations are also disclosed.

Description:
CROSS-REFERENCES TO RELATED APPLICATIONS 
       [0001]    This application claims priority from U.S. Patent Application No. 61/970,010 filed Mar. 25, 2014. 
     
    
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH 
       [0002]    Not Applicable. 
       BACKGROUND OF THE INVENTION 
       [0003]    1. Field of the Invention 
         [0004]    The present invention relates to methods for the restoration of a decayed portion of a tooth or re-restoration of a previously filled tooth, and to dental matrices that may be used in the methods for the restoration of a decayed portion of an anterior tooth. It also relates to the elective composite additive crowning and veneering of teeth that may or may not have decay or previous restorations. 
         [0005]    2. Description of the Related Art 
         [0006]    Dental cavities that have spread to the dentin or have undergone cavitation are typically treated by removing the decayed portion of the tooth and thereafter filling the missing tooth structure with a restorative material such as silver (amalgam), white (resin), porcelain, or gold. Cavities that are located adjacent to neighboring teeth are called interproximal cavities. 
         [0007]    When treating cavities, the dentist first removes the decayed portion of the tooth. In order to properly deposit the restorative material on the tooth without undesired leaking of the restorative material beyond the tooth, the dentist places a dental matrix around at least a portion of the tooth. The dental matrix may be a metallic or plastic strip, and when the matrix is placed around at least a portion of the tooth, the matrix acts as a form for the desired shape of the restored tooth. Various dental matrix bands are shown in U.S. Pat. Nos. 6,712,608, 6,619,956, 6,350,122, 6,142,778, 6,079,978, 5,975,906, 5,807,101, 5,730,592, 5,622,496, 5,501,595, 5,460,525, 5,425,635, 5,114,341, 4,997,367, 4,781,583, 4,718,849, 4,704,087, 4,601,662, 4,553,937, 4,536,155, 4,523,909, 4,024,643, 3,842,505, 3,108,377, 2,790,238 and 2,611,182, and U.S. Patent Application Publication Nos. 2006/0019217 and 2005/0089814. The disadvantages of these known matrix bands is that they are not truly anatomic and therefore, they must be conformed to the tooth by pressure or other means. As a result, these matrixes are inefficient in that more dentist time is needed to complete the restoration, and the final result may be a non-anatomic restoration. These matrices will also not allow the dentist to properly seat the matrix fully, resulting in gaps and voids and ledges in the subsequent near the gumline, which will result in recurrent decay and gingival irritation and periodontal disease and breakdown. The gingiva near these problems in the filling bleed easily and are unsightly with a reactive purplish color. Gingiva can be divided anatomically into marginal gingiva, attached gingiva, and interdental gingival papilla. The gingival zenith represents the most apical point at which each tooth emerges from the free gingival margin. 
         [0008]    Humanoid posterior teeth and anterior teeth have several significant differences that demand unique features in the matrices required to retain the filling material when restoring an anterior tooth.  FIGS. 1 and 2  show front and side views respectively of a human upper central incisor  11  having a root  12 , a crown  13 , and a root-crown junction  14 . In the view of mesial surface in  FIG. 2 , significant undulation is shown in the root-crown junction  14 . This roller coaster type rise and fall in the root-crown junction  14  can vary from 2 millimeters up to 5 millimeters. It is most pronounced at the midline and then flattens with each tooth as you move toward the posterior teeth. Although no two teeth are exactly the same, there are general trends and all anterior teeth exhibit this anatomic feature and all humanoids show a lessening of the rise and fall of the root-crown junction as you move posteriorly away from the midline toward the back of the back molar. Accommodating the slight rise and fall off the root-crown junction of the posterior tooth has not been necessary to achieve a good adaptation. This would explain why this feature is absent in commercially available matrices for posterior teeth. 
         [0009]    Looking at  FIG. 3 , there is shown the mesial surface  16  of a left upper central incisor  11 . In the past, a traditional flat clear matrix (e.g., Mylar™ plastic) strip  17  was placed after the cavity was prepared and often adapted with an interdental wedge or elastic spacer. As shown in  FIG. 3 , there have been problems with this previous technique. The problems with traditional clear Mylar™ plastic strips are that they are flat, and do not conform to the tooth. In this regard,  FIG. 3  shows how the gingival edge  18  of the matrix  17  meets resistance at the gingival margin  19  when seating the matrix  17  in the matrix seating direction shown in  FIG. 3 . This leaves a palatal gap G P  and a facial gap G F  between the matrix  17  and the gingival margin  19  shown in  FIG. 3 . This can lead to undesired pivotal movement of the matrix  17  about the point where the matrix  17  contacts the gingival margin  19 . 
         [0010]    An anterior tooth has a complex shape with multiple curvatures. It is asymmetrical from facial to lingual and from mesial to distal. Sectional clear flat matrix strips for anterior teeth, such as that shown in  FIG. 3 , have been available. Fillings today are performed nearly universally with tooth colored filling materials (composite resin) and require a medium to contain the filling material inside the cavity preparation. These matrix strips are translucent, and typically made from Mylar™ plastic material that is thin and pliable. 
         [0011]    Some problems with current flat plastic matrix strips for anterior teeth include: (1) the flat plastic matrix strips are flat (not anatomic), requiring crimping; (2) the flat plastic matrix strips require stabilizing with wedges or other devices; (3) the flat plastic matrix strips require further stabilizing with the operator&#39;s fingers or the dental assistant&#39;s fingers, and back to back fillings (two neighboring teeth with interproximal caries or failing fillings) present extreme challenges to manipulate four matrix ends simultaneously; (4) the flat plastic matrix strips require that the strip be “wrapped” to approximate the tooth after placement of filling material (such as a composite, glass ionomer, composite/glass ionomer mix) and prior to polymerization or light curing of the material; (5) time and energy is usually expended to remove excess and areas of bulky, non anatomic regions of the composite filling material because of the residual contour created by the flat, non anatomic clear strip; (6) the above mentioned finishing can lead to gum trauma and can lead to iatrogenic gouging of tooth surface and tooth surfaces of neighboring teeth; (7) the above mentioned finishing disturbs the smooth and highly cured surface left by the plastic strip and while this disturbed surface can be polished, it is virtually impossible to return to the original smoothness and these surfaces are manifested clinically as a matte finish, rough finish, or jagged finish and these three imperfect finish types collect bacteria more readily, are more prone to discoloration and predispose the tooth to decay and predispose the periodontal attachment (gum and bone) to deterioration from the destructive nature of periodontal diseases; (8) the flat matrix strip combined with a wedge often results in a flat contoured filling that has an unsightly gapping (dark triangle) between the teeth at the gum attachment area such that food and bacterial accumulation are also more common in these gaps; and (9) the pre curved sectional matrix bands for posterior teeth are too short to be used easily on anterior teeth as matrix bands for posterior teeth range from 4.5 millimeters to 6.5 millimeters in height, and the needs of anterior teeth range approximately from 8 millimeters to 13 millimeters in height. 
         [0012]    One of the challenges of doing an adequate filling is to have a matrix that is stiff and strong enough to withstand insertion and wedging pressure, and at the same time be thin enough so that upon removal of the matrix, the contact between the tooth being restored and the adjacent tooth is tight enough to avoid food impaction. “Open Contacts” are a significant problem with the advent of composite (tooth colored) fillings in comparison to silver amalgam fillings. This is mainly because the composite resins are not as packable as amalgam and therefore less expansion pressure is placed laterally on the matrix with the composite resin filling materials. Many solutions have been tried with limited success. Therefore an advance is needed. 
         [0013]    In addition, historically it has been a common practice in dentistry to prepare human teeth for coverage with partial or full crowns. In this process, typically the patient is anesthetized and the tooth is ground down to a peg shape for three main reasons. The first reason was to remove decay and old filling materials in the case where the tooth was too weak to support itself and retain the filling, or also to cosmetically cover a dark, worn or misshapen tooth. The second reason for the grinding down of the tooth was to give 1 to 2 millimeters of space for traditional crown materials such as a gold or porcelain that have certain thickness requirements for fabrication and strength. These crowns or caps are made from replicas of the tooth in the form of actual stone (plaster) models or more recently virtual models. This is referred to as an indirect restoration (cap or crown or veneer). Once the crown is returned to the dentist, it is cemented over the stump of the tooth. The third reason to grind the teeth to a tapered peg or “teepee” shape was for path of insertion of the crown on a tooth that is essentially the inverse of the necessary shape, i.e., the tooth is thickest at the incisal edge but this roundness and fullness must be eliminated to allow the margins (edges) of the crown access to the gum line. See  FIGS. 28 to 30  wherein T1 are anterior teeth before grinding down for an indirect restoration, T2 are anterior teeth after grinding down for an indirect restoration, and T3 are anterior teeth after the indirect restoration. The chewing edge of the tooth is “incisal” for anterior teeth or “occlusal” for posterior teeth. 
         [0014]    The process of grinding the tooth down is damaging to the tooth however. A full crown preparation removes, on average, 75% of the actual volume of the tooth above the gum line; in other words, the area of the tooth to be covered with a crown must be reduced volumetrically by 75%. See  FIG. 31  which is from Edelhoff et al., “Tooth Structure Removal Associated with Various Preparation Designs for Posterior Teeth”  Int. J Periodontics Restorative Dent  2002: Vol 22: 3: 240-249. Truly, if patients were aware of this level of mutilation of the tooth, they would be less apt to accept treatment. The pulp (or nerve) inside of the tooth is connected to the outside of the tooth via dentin tubules, and this extent of tooth removal often creates sensitivity and pulpal death of the nerve which will require subsequent root canal therapy which demands making a hole in the crown that was recently placed. The morbidity rate for the pulp of the tooth has been shown in studies to be as high as 20%. See, Saunders et al., “Prevalence of Periradicular Periodontitis Associated with Crowned Teeth in a Scottish Population”,  Br Dent J  1998; 185: 137-140. 
         [0015]    Large fillings alone cannot be a substitute for when full coverage of a tooth is required. With advancements in adhesive materials and resin composite restorative filling materials, the composite can be bonded directly to the tooth directly without the use of cement or need for an indirect technique. The Bioclear® brand matrix (available at http://www.bioclearmatrix.com) has advanced this direct restoration with an injection molding process (see U.S. Patent Application Publication No. 2008/0064012) and tooth shaped (anatomic) matrices, and, for example, U.S. Pat. No. 8,393,897 for esthetic recontouring of the tooth to close diastemas (tooth gapping) or gum gapping (i.e., treatment of dental black triangles) using direct adhesion of the composite to the tooth. Even with these advancements, there is still a need for further advancements in the craft of coverage of the tooth with a veneer of restorative material. 
         [0016]    Thus, there is a need for improved dental matrices, particularly dental matrices intended for anterior teeth. 
       SUMMARY OF THE INVENTION 
       [0017]    The invention meets the foregoing needs by providing improved methods, dental matrices, and kits for the restoration of a decayed portion of a tooth, particularly an anterior tooth. 
         [0018]    In one aspect, the invention provides a dental matrix for use when placing a restorative material on a tooth. The matrix includes a non-flat sectional strip having a first end and an opposed second end, the strip being shaped to conform to at least a portion of a surface of the tooth. The strip includes a cut away inwardly directed toward a central portion of the strip, the cut away defining a first section of a gingival edge of the strip, the first section of the gingival edge corresponding in shape to a coronally directed projection of gingival papilla adjacent the tooth and underlying periodontal and bony attachments of the tooth. The strip is structured to be retained on the tooth without the use of any attachment elements extending from or contacting a facial, lingual, mesial, or distal surface of the strip when the matrix is placed on the tooth. 
         [0019]    A second section of the gingival edge may correspond in shape to a portion of gingival margin adjacent a facial surface of the tooth. A second section of the gingival edge may correspond in shape to a portion of gingival margin adjacent a facial surface of the tooth wherein the portion of gingival margin is on one side or both sides of the gingival zenith. The coronally directed projection of gingival papilla may be adjacent an incisor and/or a canine tooth. The coronally directed projection of gingival papilla may be in a mesial view of the tooth. The coronally directed projection of gingival papilla may be in a distal view of the tooth. 
         [0020]    The strip can have a length from the first end to the second end such that the strip can cover at least 90 degrees around side surfaces of the tooth covered by the strip. The matrix may be translucent. The strip may be pre-curved and universal for any interproximal surface of any anterior tooth. The matrix may be side specific for an anterior tooth. The matrix may be tooth specific for an anterior tooth. The matrix may be tooth and surface specific for an anterior tooth. The matrix may be fully anatomic for an anterior tooth. The matrix may be anatomically shaped such that the matrix is self stabilizing and hands free for the anterior tooth. The matrix may be fully anatomic for a posterior tooth. The matrix may be anatomically shaped such that the matrix is self stabilizing and hands free for the posterior tooth. 
         [0021]    In the dental matrix, at least a section of the gingival edge of the matrix may be curved inwardly and a spring-like nature of memory of shape of material comprising the strip provides tension to retain the matrix once it snaps onto the tooth. The section of the gingival edge of the matrix that is curved inwardly may be a facial section and/or a lingual section and/or a mesial section and/or a distal section. The gingival edge of the matrix may be curved inwardly a non-anatomic fashion. The gingival edge of the matrix may be curved inwardly an anatomic fashion. No wedging device or retainer or clamp device is needed to stabilize the matrix. The matrix may also include an additional feature for active hands-free wedge-free retention of the matrix, the feature being selected from (i) adhesive, (ii) static electricity charge, (iii) light cure adhesive, (iv) gingival harpoons, (v) mechanical prominences that lock under a contact or soft tissue, (vi) a first configuration wherein the matrix wraps past 180 degrees curving in an anatomic fashion, (vii) a second configuration wherein a radius of the entire matrix is smaller than an anatomic radius of the tooth creating tension to stabilize the matrix, and (viii) any combinations thereof. 
         [0022]    The dental matrix may be used in a method for the restoration of a tooth having an original shape including a surface. The method may include the steps of: removing a portion of the surface of the tooth to form a hollow cavity preparation; surrounding the removed portion of the surface of the tooth with the matrix; placing a restorative material into the hollow cavity preparation; and curing the restorative material contained in the cavity preparation. 
         [0023]    The dental matrix may be used in another method for the restoration of a tooth having an original shape including a surface. The method may include the steps of: (a) surrounding a portion of the surface of the tooth with the matrix; (b) placing a restorative material on the tooth; and (c) curing the restorative material. This version of the method does not remove any tooth structure before step (a), and the method adds fullness to beautify the tooth with a better shape or color by adding the restorative material to some or all of the tooth. 
         [0024]    In another aspect, the invention provides a dental matrix system for providing a form for direct complete veneering of a tooth. The veneering may be over 60% of the surface area of the tooth, or over 70% of the surface area of the tooth, or over 80% of the surface area of the tooth, or over 90% of the surface area of the tooth, or over 95% of the surface area of the tooth, or 100% of the surface area of the tooth. The dental matrix system includes a first matrix including a first strip of material having a length from a first end to a second end, the length of the first strip of material being sufficient to cover at least 120 degrees of the tooth, and the first end of the first strip of material defining a vertical edge of the first matrix. The dental matrix system includes a second matrix including a second strip of material having a length from a first end to a second end, the length of the second strip of material being sufficient to cover at least 120 degrees of the tooth, and the first end of the second strip of material defining a vertical edge of the second matrix. The first matrix and the second matrix are dimensioned to create a form for injecting with an adhesive dental restorative material for overmolding or crowning or veneering when the first matrix and the second matrix are placed on the tooth, and the first matrix and the second matrix are dimensioned such that a first portion of the first matrix and a second portion of the second matrix overlap when the first matrix and the second matrix are placed on the tooth. The dental matrix system allows for injection of adhesive veneering material to overmold the tooth. 
         [0025]    The length of the first strip of material may sufficient to cover at least 130 degrees of the tooth, or at least 140 degrees of the tooth, or at least 150 degrees of the tooth, or at least 160 degrees of the tooth, or at least 170 degrees of the tooth, or at least 180 degrees of the tooth. The length of the second strip of material may sufficient to cover at least 130 degrees of the tooth, or at least 140 degrees of the tooth, or at least 150 degrees of the tooth, or at least 160 degrees of the tooth, or at least 170 degrees of the tooth, or at least 180 degrees of the tooth. 
         [0026]    In the dental matrix system, the vertical edge of the first matrix and the vertical edge of the second matrix may be dimensioned to create an aperture that exposes the tooth when the first matrix and the second matrix are placed on the tooth. The aperture exposes the tooth from gingival margin to a point on a facial surface of the tooth when the first matrix and the second matrix are placed on the tooth. In the dental matrix system, the first matrix and the second matrix may be dimensioned to create a slit that exposes the tooth from gingival margin to an incisal or an occlusal surface of the tooth when the first matrix and the second matrix are placed on the tooth. The slit may be formed from the vertical edge of the first matrix and the vertical edge of the second matrix, and the vertical edge of the first matrix and the vertical edge of the second matrix are a uniform distance apart when the first matrix and the second matrix are placed on the tooth. 
         [0027]    At least one of the first strip and the second strip may include an inwardly directed cut away that corresponds in shape to a projection of gingival papilla adjacent the tooth and underlying periodontal and bony attachments of the tooth. At least one of the first strip and the second strip can have a variable thickness with a thinner contact area. The first matrix and the second matrix may be dimensioned such that 45% to 125% of surface area of the tooth is covered when the first matrix and the second matrix are placed on the tooth. The first matrix and the second matrix may be dimensioned such that 65% to 95% of surface area of the tooth is covered when the first matrix and the second matrix are placed on the tooth. The first matrix and the second matrix may be dimensioned such that at least 100% of surface area of the tooth is covered when the first matrix and the second matrix are placed on the tooth. The dental matrix system may include a third matrix dimensioned to engage the first matrix and the second matrix and close off an opening created by the first matrix and the second matrix opposite gingival margin when the first matrix and the second matrix are placed on the tooth. The first matrix and the second matrix may comprise a pair of matrices of the system, wherein one of the pair of matrices may be dimensioned to conform to a distal surface of the tooth, and the other of the pair of matrices being dimensioned may be conform to a mesial surface of the tooth. The invention is not limited to two or three matrix systems. For example, four or more matrices may be used in the system. 
         [0028]    The dental matrix system provides a form for veneering of a tooth wherein a first matrix and a second matrix create a form for direct complete veneering of a tooth. A two piece matrix of the invention is designed to allow a complete direct complete crowning (veneering) of the human tooth. A matrix or a pair of matrices overlap to allow insertion of dental restorative material around a bulbous tooth. A dental matrix or a pair of dental matrices that have a partition or vent hole allow escape of air bubbles and the lesser wetting composites as the heavier paste composite displaces them during an injection molding technique such as that described in U.S. Patent Application Publication No. 2008/0064012. In one version of the technique, the dental practitioner only injects dental restorative material from the incisal. In yet another technique, the dental practitioner injects dental restorative material from facial and/or incisal and/or lingual. 
         [0029]    In the dental matrix system, a pair of fully anatomic matrices can be used in making accurately sized and shaped veneered teeth directly on the tooth. The crowning/veneering dental matrices may be thin enough (less than 100 microns, preferably less than 70 microns, most preferably less than 60 microns) to allow overmolding of the tooth that upon their removal the contact with the neighboring tooth will be snug and snap the floss normally. The crowning/veneering dental matrices can slide 360 degrees between the tooth and gum, the depth of the sulcus around the tooth by virtue of fully anatomic shapes and a scallop roller coaster gingival shape. 
         [0030]    The dental matrix system may include variable thickness matrices, thicker and stiffer in some areas to retain their shape during injection molding, thinner at the contact areas to achieve a snug contact after matrix removal. 
         [0031]    In still another aspect, the invention provides a process for veneering of a tooth. The process may include the steps of: placing a first matrix and a second matrix on a tooth for providing a form for direct complete veneering of the tooth, wherein the first matrix and the second matrix are dimensioned such that a first portion of the first matrix and a second portion of the second matrix overlap when the first matrix and the second matrix are placed on the tooth; and direct overmolding of the tooth with an adhesive restorative material to perform a direct crown veneering of the tooth. The vertical edge of the first matrix and the vertical edge of the second matrix may be dimensioned to create an aperture that exposes the tooth when the first matrix and the second matrix are placed on the tooth. The first matrix and the second matrix may be dimensioned such that 45% to 125% of surface area of the tooth is covered when the first matrix and the second matrix are placed on the tooth. 
         [0032]    The process provides for direct overmolding of the tooth with adhesive material to perform a direct crown/360 degree veneering of the tooth. It is a process of additive dentistry where none of the tooth needs to be cut away for logistics, the tooth is just cleaned and conditioned for adhesion. The process provides for cosmetic or structural enhancement of a human tooth with direct overmolding of the tooth for cosmetic or structural enhancement. 
         [0033]    The process for veneering of a human tooth provide for direct overmolding of a tooth that has need of strengthening because of previous fillings and or new decay or fractures or wear or congenital defects or undersized teeth where a traditional filling does not provide a comprehensive structural remedy wherein the decay and old fillings are removed but no other tooth structure is removed before the crowning of the tooth. 
         [0034]    The dental matrix system is advantageous because the pair of matrices are designed to be used together. A two piece dental matrix system is a universal system because the crowning/veneering dental matrices expand apart or move together depending on the width of the teeth, instead of binding on a wide tooth or “accordioning” at the facial and/or lingual where the contact areas of the neighboring tooth would push the matrix in on itself. The dental matrix system may include a third matrix piece that closes off and forms the incisal portion of the dental matrix system. 
         [0035]    A veneer/crown kit may be provided as a pair (or sets of pairs for a full case of six or more teeth) of matrices, one for distal, one for mesial with between 45% to 125% of the tooth surfaces covered, wherein the less than 100% version would allow injection of restorative material without teasing the edges apart, the 100% and more version could have a hole-orifice for injection and a vent on the other side. 
         [0036]    In yet another aspect, the invention provides a dental matrix for use when placing a restorative material on a tooth. The dental matrix may include a sectional strip having a first end and an opposed second end. The strip may be shaped to conform to at least a portion of a surface of the tooth, and the strip may be pre-curved such that the strip can cover from 90 degrees up to 360 degrees around side surfaces of the tooth when the matrix is placed on the tooth. The strip has a variable thickness with a thinner contact area in a center region of the strip. The strip can have abrupt thinning in the thinner contact area. The thinner contact area may be offset toward occlusal in relation to peripheral areas of the matrix. The thinner contact area may extend from the first end to the second end of the strip. The strip may include a cut away inwardly directed toward a central portion of the strip, wherein the cut away defines a first section of a gingival edge of the strip, and the first section of the gingival edge corresponds in shape to a coronally directed projection of gingival papilla adjacent the tooth and underlying periodontal and bony attachments of the tooth. The thinner contact area may be defined by a first recessed area in a first side of the strip and a second recessed area in an opposite second side of the strip. The strip can comprise a metallic material. The contact area may be pre-burnished to create a thin, soft, flexible contact area. 
         [0037]    In another aspect, the invention provides a dental matrix for use when placing a restorative material on a tooth. The dental matrix includes a metallic sectional strip having a first end and an opposed second end, the strip being shaped to conform to at least a portion of a surface of the tooth, the strip being pre-curved such that the strip can cover from 90 degrees up to 360 degrees around side surfaces of the tooth when the matrix is placed on the tooth, wherein the strip has a variable thickness with a thinner contact area in a center region of the strip. In one version, the contact area has been pre-burnished. 
         [0038]    The dental matrix may be used in a method for the restoration of a tooth having an original shape including a surface. The method may include the steps of: removing a portion of the surface of the tooth to form a hollow cavity preparation; surrounding the removed portion of the surface of the tooth with the matrix of claim  25 ; placing a restorative material into the hollow cavity preparation; and curing the restorative material contained in the cavity preparation. 
         [0039]    The features, aspects, and advantages of the present invention will become better understood upon consideration of the following detailed description, drawings and appended claims. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0040]      FIG. 1  is a front view of a human left upper central incisor. 
           [0041]      FIG. 2  is a side view of the human left central incisor of  FIG. 1 . 
           [0042]      FIG. 3  is a side view similar to  FIG. 2  showing a traditional flat strip matrix being seated on the left central incisor. 
           [0043]      FIG. 4  is a front view of the top front teeth. 
           [0044]      FIG. 5  is a side view of the human left central incisor. 
           [0045]      FIG. 6  is a side view of the human left central incisor showing the palate P and the gingival margin. 
           [0046]      FIG. 7  is a side view of the human left central incisor showing the gingiva  20  and bone B. 
           [0047]      FIG. 8  shows a mesial view of a non-limiting example dental matrix according to the invention positioned on the human left central incisor. 
           [0048]      FIG. 9  shows a mesial view of another non-limiting example dental matrix according to the invention positioned on the human left central incisor. 
           [0049]      FIG. 10 a    is a side view of a prior sectional dental matrix. 
           [0050]      FIG. 10 b    is a top cross-sectional view of the prior sectional dental matrix of  FIG. 10 a    taken along line  10   b - 10   b  of  FIG. 10   a.    
           [0051]      FIG. 11 a    is a side view of an example embodiment of a sectional hands free and self stabilizing posterior dental matrix according to the invention. 
           [0052]      FIG. 11 b    is a top cross-sectional view of the sectional dental matrix of  FIG. 11 a    taken along line  11   b - 11   b  of  FIG. 11   a.    
           [0053]      FIG. 12 a    is a side view of an example embodiment of a sectional anterior hands free and self stabilizing dental matrix according to the invention. 
           [0054]      FIG. 12 b    is a top cross-sectional view of the sectional dental matrix of  FIG. 12 a    taken along line  12   b - 12   b  of  FIG. 12   a.    
           [0055]      FIG. 13  is a distal side view of another example embodiment of a sectional hands free and self stabilizing anterior dental matrix according to the invention. 
           [0056]      FIG. 14  is a front view of the anterior dental matrix of  FIG. 13 . 
           [0057]      FIG. 15  is another side view of the anterior dental matrix of  FIG. 13 . 
           [0058]      FIG. 16  is a rear view of the anterior dental matrix of  FIG. 13 . 
           [0059]      FIG. 17  is a perspective side view of the anterior dental matrix of  FIG. 13 . 
           [0060]      FIG. 18  is another perspective side view of the anterior dental matrix of  FIG. 13 . 
           [0061]      FIG. 19  is a side view of another example embodiment of a sectional hands free and self stabilizing anterior dental matrix according to the invention. 
           [0062]      FIG. 20  is a side view of another example embodiment of a sectional hands free and self stabilizing anterior dental matrix according to the invention. 
           [0063]      FIG. 21  is a side view of the sectional hands free and self stabilizing anterior dental matrix of  FIG. 19 . 
           [0064]      FIG. 22  is a cross-sectional view of the sectional dental matrix of  FIG. 21  taken along line  22 - 22  of  FIG. 21 . 
           [0065]      FIG. 23  is a cross-sectional view, similar to  FIG. 22 , of another sectional dental matrix according to the invention. 
           [0066]      FIG. 24  is a side view of the sectional hands free and self stabilizing anterior dental matrix of  FIG. 20 . 
           [0067]      FIG. 25  is a cross-sectional view of the sectional dental matrix of  FIG. 24  taken along line  25 - 25  of  FIG. 25 . 
           [0068]      FIG. 26  is a cross-sectional view, similar to  FIG. 25 , of another sectional dental matrix according to the invention. 
           [0069]      FIG. 27  is a cross-sectional view, similar to  FIG. 25 , of yet another sectional dental matrix according to the invention. 
           [0070]      FIG. 28  shows a front view of four anterior teeth before grinding down for an indirect restoration. 
           [0071]      FIG. 29  shows a front view of the anterior teeth of  FIG. 28  after grinding down for an indirect restoration. 
           [0072]      FIG. 30  shows a front view of the anterior teeth of  FIG. 29  after the indirect restoration. 
           [0073]      FIG. 31  shows the volumetric reduction of a tooth for various onlay or crown preparations. 
           [0074]      FIG. 32  shows a front view of a dental matrix system of the invention including a first sectional dental matrix and a second sectional dental matrix. 
           [0075]      FIG. 33  shows a front view of another dental matrix system of the invention including a first sectional dental matrix and a second sectional dental matrix. 
           [0076]      FIG. 34  shows another front view of the dental matrix system of  FIG. 33 . 
           [0077]      FIG. 35  shows a front view of an etching step in a method using the dental matrix system of  FIG. 33 . 
           [0078]      FIG. 36  shows a front view of the dental matrix system of  FIG. 33  with excess dental restorative material having flowed through an aperture in the dental matrix system. 
           [0079]      FIG. 37  shows a front view of an excess dental restorative material removal step in a method using the dental matrix system of  FIG. 33 . 
           [0080]      FIG. 38  shows a front view of yet another dental matrix system of the invention including a first sectional dental matrix and a second sectional dental matrix. 
           [0081]      FIG. 39  shows a front view of still another dental matrix system of the invention including a first sectional dental matrix and a second sectional dental matrix and a third sectional dental matrix. 
       
    
    
       [0082]    Like reference numerals will be used to refer to like parts from Figure to Figure in the following description of the drawings. 
       DETAILED DESCRIPTION OF THE INVENTION 
       [0083]    The invention provides improved methods, dental matrices, and kits for the restoration of a decayed portion of an anterior or posterior tooth. 
         [0084]    In an example method according to the invention for the restoration of a tooth, the dentist locates a tooth having a cavity. A hollow cavity preparation is prepared in a tooth. The tools and techniques for forming the hollow cavity preparation are well known in the art and therefore will not be explained further. 
         [0085]    In order to properly deposit the restorative material on the tooth without undesired leaking of the restorative material beyond the tooth, the dentist places a dental matrix around at least a portion of the tooth. In the invention, a sectional dental matrix is placed on the tooth. When the matrix is placed around at least a portion of the tooth, the matrix acts as a form for the desired shape of the restored tooth. 
         [0086]    A light curable composite resin is then placed in the cavity preparation. The filled cavity preparation is then cured using a curing light such as high intensity light emitting diode (LED) lights, plasma-arc curing lights, halogen lights, and laser lights. The matrix is then removed, and the restored tooth is polished with discs, strips, and rubber tipped and carbide burs. 
         [0087]    Various matrices are provided by the invention. Each matrix can be tooth specific, or the matrix can be tooth type specific, or the matrix can be tooth surface specific. By “tooth specific” it is meant that the matrix is configured to conform to the shape of the outer surface of the specific natural tooth being restored such as (without limitation) an upper left central incisor. By “tooth type specific” it is meant that the matrix is configured to conform to the shape of the outer surface of the specific type of natural tooth being restored such as (without limitation) an upper incisor. By “tooth surface specific” it is meant that the matrix is configured to conform to the shape of the outer surface of the specific natural tooth surface being restored such as (without limitation) an upper left incisor mesial surface. 
         [0088]    Turning to  FIG. 8 , a mesial view of a non-limiting example dental matrix  30  according to the invention is shown. In  FIG. 8 , an upper incisor  11  having a clear sectional dental matrix  30  placed on the incisor  11  is shown. The dental matrix  30  can be formed from a translucent or transparent material such as a polymeric film. One non-limiting example material is the polyester film commercially available as Mylar™. However, metallic (stiff) materials, such as stainless steel, can be used for the matrix  30 . Also, the matrix  30  may have variable thickness. Also, the matrix  30  may be opaque. The matrix  30  has a strip of material having a length from a first end to a second end sufficient to create a form for molding a restorative material to a surface of a tooth being restored. The length of the strip can surround 90 to 370 degrees of the tooth. The length of the pre-curved matrix  30  is approximately 13 millimeters and the height can range approximately from 10 millimeters to 13 millimeters. 
         [0089]    The matrix  30  has a root end section  32  that is anatomic in shape. The root end section  32  terminates at a gingival edge  38 . The actual anatomic shapes of the root end section  32  of the matrix  30  can be created from scans of natural teeth, molds of natural teeth, and/or molds of tooth models. Thus, by “anatomic”, it is meant that the root end section  32  of the matrix  30  has an inner surface that conforms to the shape of the outer surface of a particular region of the natural tooth that contacts the root end section  32  of the matrix  30 . In one non-limiting example form, the matrix  30  has an inner surface that conforms to the shape of the outer surface of a root end section of an incisor tooth. In another non-limiting example form, the matrix  30  has an inner surface that conforms to the shape of the outer surface of a root end section of a canine tooth. 
         [0090]    In  FIG. 8 , the mesial side of the root end section  32  of the matrix  30  has a downward cut away  36  creating a gingival edge  38  that corresponds in shape to a downward projection of gingival papilla at the gingival margin  19  adjacent the tooth  11  and underlying periodontal and bony attachments of the tooth  11 . The distal side of the root end section  32  of the matrix  30  can also have a downward cut away  36  creating a gingival edge  38  that corresponds in shape to a downward projection of gingival papilla at the gingival margin  19  adjacent the tooth  11  and underlying periodontal and bony attachments of the tooth  11 . The gingival papilla may have a generally pyramidal shape or a col shape (i.e., a saddle shape between two peaks). 
         [0091]    Alternatively, the matrix  30  can be used on lower teeth. In this case, the mesial side of the root end section  32  of the matrix  30  has an upward cut away creating a gingival edge  38  that corresponds in shape to an upward projection of gingival papilla at the gingival margin  19  adjacent the tooth  11  and underlying periodontal and bony attachments of the tooth  11 . The distal side of the root end section  32  of the matrix  30  can also have an upward cut away creating a gingival edge  38  that corresponds in shape to an upward projection of gingival papilla at the gingival margin  19  adjacent the tooth  11  and underlying periodontal and bony attachments of the tooth  11 . 
         [0092]    The root end section  32  of the matrix  30  can be fully or partially anatomic. As a result, the matrix  30  can be used without interdental wedges or elastic separators or spacers. The anatomic shape allows hands-free and wedge-free use as the matrix  30  hugs the tooth  11 . The root end section  32  can have a vertical dimension in the range of 0.5 to 2 millimeters. The sectional matrix  30  has a second section  34  that is integral with the root end section  32 . In the non-limiting embodiment of  FIG. 8 , the second section  34  of the matrix  30  is not anatomically shaped to conform to the shape of the outer surface of the tooth  11 . 
         [0093]    Turning to  FIG. 9 , a mesial view of another non-limiting example dental matrix  130  according to the invention is shown. In  FIG. 8 , an upper incisor  11  having a clear sectional dental matrix  130  placed on the incisor  11  is shown. The dental matrix  130  can be formed from a translucent or transparent material such as a polymeric film. One non-limiting example material is the polyester film commercially available as Mylar™. However, metallic (stiff) materials, such as stainless steel, can be used for the matrix  130 . Also, the matrix  130  may have variable thickness. Also, the matrix  130  may be opaque. The matrix  130  has a strip of material having a length from a first end to a second end sufficient to create a form for molding a restorative material to a surface of a tooth being restored. The length of the pre-curved matrix  130  is approximately 13 millimeters and the height can range approximately from 10 millimeters to 13 millimeters. 
         [0094]    The matrix  130  has a root end section  132  that is anatomic in shape. The root end section  132  terminates at a gingival edge  138 . The actual anatomic shapes of the root end section  132  of the matrix  130  can be created from scans of natural teeth, molds of natural teeth, and/or molds of tooth models. Thus, by “anatomic”, it is meant that the root end section  132  of the matrix  130  has an inner surface that conforms to the shape of the outer surface of a particular region of the natural tooth that contacts the root end section  132  of the matrix  30 . 
         [0095]    In  FIG. 9 , the mesial side of the root end section  132  of the matrix  130  has an upward cut away  136  creating a gingival edge  138  that corresponds in shape to an upward projection of gingival papilla at the gingival margin  19  adjacent the tooth  11  and underlying periodontal and bony attachments of the tooth  11 . The distal side of the root end section  132  of the matrix  130  can also have an upward cut away  136  creating a gingival edge  138  that corresponds in shape to an upward projection of gingival papilla at the gingival margin  19  adjacent the tooth  11  and underlying periodontal and bony attachments of the tooth  11 . 
         [0096]    Alternatively, the matrix  130  can be used on lower teeth. In this case, the mesial side of the root end section  132  of the matrix  130  has an upward cut away creating a gingival edge  138  that corresponds in shape to an upward projection of gingival papilla at the gingival margin  19  adjacent the tooth  11  and underlying periodontal and bony attachments of the tooth  11 . The distal side of the root end section  132  of the matrix  130  can also have an upward cut away creating a gingival edge  138  that corresponds in shape to an upward projection of gingival papilla at the gingival margin  19  adjacent the tooth  11  and underlying periodontal and bony attachments of the tooth  11 . 
         [0097]    The root end section  132  of the matrix  130  can be fully or partially anatomic. As a result, the matrix  130  can be used without interdental wedges or elastic separators or spacers. The anatomic shape allows hands-free and wedge-free use as the matrix  130  hugs the tooth  11 . The root end section  132  can have a vertical dimension in the range of 0.5 to 2 millimeters. The sectional matrix  130  has a second section  134  that is integral with the root end section  132 . In the non-limiting embodiment of  FIG. 9 , the second section  134  of the matrix  130  is anatomically shaped to conform to the shape of the outer surface of the tooth  11 . Thus, a fully anatomic matrix is also in accordance with the invention. By “anatomic”, it is meant that the matrix has an inner surface that conforms to the shape of the outer surface of the region of the natural tooth being restored. In one non-limiting example form, the matrix  130  has an inner surface that conforms to the shape of the outer surface of a root end section of an incisor tooth. In another non-limiting example form, the matrix  130  has an inner surface that conforms to the shape of the outer surface of a root end section of a canine tooth. 
         [0098]    The root end section  132  and the second section  134  of the matrix  130  can be tooth specific. By “tooth specific” it is meant that the root end section  132  and the second section  134  of the matrix  130  are configured to conform to the shape of the outer surface of the specific natural tooth being restored, such as (without limitation) a maxillary lateral incisor. The root end section  132  and the second section  134  of the matrix  130  can also be tooth type specific. By “tooth type specific”, it is meant that the root end section  132  and the second section  134  of the matrix  30  are configured to conform to the shape of the outer surface of the specific type of natural tooth such as (without limitation) an incisor. The root end section  132  and the second section  134  of the matrix  130  can be tooth surface specific. By “tooth surface specific” it is meant that the root end section  132  and the second section  134  of the matrix  130  are configured to conform to the shape of the outer surface of the specific natural tooth surface such (without limitation) a lingual or buccal incisor surface. 
         [0099]    A sectional matrix according to the invention can be anatomically shaped such that the matrix is hands free and self stabilizing (i.e., there is no requirement for a matrix stabilizer that conforms the matrix to the tooth). Ends of the matrix can be curved inwardly in a non-anatomic fashion or an anatomic fashion, and the spring-like nature of the memory of the shape can provide tension to retain the matrix once it snaps onto the tooth. No wedging device or retainer or clamp device is needed to stabilize the matrix. The matrix may include a feature for active hands-free wedge free retention of the matrix. The feature may selected from (a) adhesive, (b) static electricity charge, (c) light cure adhesive, (d) gingival harpoons, (e) mechanical prominences that lock under a contact or soft tissue, (f) a first configuration wherein the matrix wraps past 180 degrees curving in an anatomic fashion, (g) a second configuration wherein a radius of the entire matrix is smaller than an anatomic radius of the tooth creating tension to stabilize the matrix, and (h) any combinations thereof. 
         [0100]      FIGS. 11 a  and 11 b    show an example embodiment of a sectional hands free and self stabilizing posterior dental matrix according to the invention. The dental matrix  230  can be formed from a translucent or transparent material such as a polymeric film. One non-limiting example material is the polyester film commercially available as Mylar™. However, other flexible materials, such as stainless steel, can be used for the matrix  230 . Also, the matrix  230  may have variable thickness. Also, the matrix  230  may be opaque. The matrix  230  has a strip of material having a length from a first end to a second end sufficient to create a form for molding a restorative material to a surface of a tooth being restored. 
         [0101]    In  FIG. 11 a   , the root end section  232  of the matrix  230  has an inwardly curved shape creating an inwardly directed gingival edge  238  which is purposely curled in at the edge to create a mechanical snap fit on the tooth, and the shape memory of the Mylar™ polyester film will stabilize the matrix  230  during bonding and filling or injecting activities on the tooth. The inwardly curved shape of the root end section  232  may be non-anatomic or anatomic. The matrix  230  wraps past 180 degrees curving in an anatomic fashion. Before placing the matrix  230  on a tooth, a radius R (see  FIG. 11 b   ) of the entire matrix  230  is preferably smaller than an anatomic radius of the tooth creating tension to stabilize the matrix  230  on the tooth. In one non-limiting example form, the matrix  230  has an inner surface that conforms to the shape of the outer surface of a root end section of an incisor tooth. In another non-limiting example form, the matrix  230  has an inner surface that conforms to the shape of the outer surface of a root end section of a canine tooth. 
         [0102]      FIGS. 12 a  and 12 b    show an example embodiment of a sectional anterior hands free and self stabilizing dental matrix according to the invention. The dental matrix  330  can be formed from a translucent or transparent material such as a polymeric film. One non-limiting example material is the polyester film commercially available as Mylar™. However, other flexible materials, such as stainless steel, can be used for the matrix  330 . Also, the matrix  330  may have variable thickness. Also, the matrix  330  may be opaque. The matrix  330  has a strip of material having a length from a first end to a second end sufficient to create a form for molding a restorative material to a surface of a tooth being restored. 
         [0103]    In  FIG. 12 a   , the root end section  332  of the matrix  330  has an inwardly curved shape creating an inwardly directed gingival edge  338  which is purposely curled in at the edge to create a mechanical snap fit on the tooth, and the shape memory of the Mylar™ polyester film will stabilize the matrix  330  during bonding and filling or injecting activities on the tooth, especially helpful on front teeth where there is no wedge or Tofflemire type device to winch it tight or wedge it to keep it from flopping around. The inwardly curved shape of the root end section  332  may be non-anatomic or anatomic. The matrix  330  wraps past 180 degrees curving in an anatomic fashion. Before placing the matrix  330  on a tooth, a radius (similar to R in  FIG. 11 b   ) of the entire matrix  330  is preferably smaller than an anatomic radius of the tooth creating tension to stabilize the matrix  330  on the tooth. In one non-limiting example form, the matrix  330  has an inner surface that conforms to the shape of the outer surface of a root end section of an incisor tooth. In another non-limiting example form, the matrix  330  has an inner surface that conforms to the shape of the outer surface of a root end section of a canine tooth. 
         [0104]      FIGS. 13-18  show another example embodiment of a sectional hands-free and self stabilizing anterior dental matrix according to the invention. The dental matrix  430  can be formed from a translucent or transparent material such as a polymeric film. One non-limiting example material is the polyester film commercially available as Mylar™. However, other flexible materials, such as stainless steel, can be used for the matrix  430 . Also, the matrix  430  may have variable thickness. Also, the matrix  430  may be opaque. The matrix  430  has a strip of material having a length from a first end  434  to a second end  435  sufficient to create a form for molding a restorative material to a surface of a tooth being restored. 
         [0105]    The root end section  432  of the matrix  430  has an inwardly curved shape creating an inwardly directed gingival edge  438  which is purposely curled in at the edge to create a mechanical snap fit on the tooth, and the shape memory of the Mylar™ polyester film will stabilize the matrix  430  during bonding and filling or injecting activities on the tooth, especially helpful on front teeth where there is no wedge or Tofflemire type device to winch it tight or wedge it to keep it from flopping around. The inwardly curved shape of the root end section  432  may be non-anatomic or anatomic. The matrix  430  wraps past 180 degrees curving in an anatomic fashion. Before placing the matrix  430  on a tooth, a radius R1 (see  FIG. 13 ) of the entire matrix  430  is preferably smaller than an anatomic radius of the tooth creating tension to stabilize the matrix  430  on the tooth. The gingival edge  438  is inwardly directed toward a centerpoint of radius R1. In one non-limiting example form, the matrix  430  has an inner surface that conforms to the shape of the outer surface of a root end section of an incisor tooth. In another non-limiting example form, the matrix  430  has an inner surface that conforms to the shape of the outer surface of a root end section of a canine tooth. 
         [0106]    As can be seen in  FIG. 15 , at the facial side  477  of the root end section  432  of the matrix  430 , the gingival edge  438  is concave to correspond in shape to the gingival margin adjacent the tooth and underlying periodontal and bony attachments of the tooth. Also, at the lingual side  478  of the root end section  432  of the matrix  430 , the gingival edge  438  is concave to correspond in shape to gingival margin adjacent the tooth and underlying periodontal and bony attachments of the tooth. The facial side  477  of the root end section  432  of the matrix  430  is free of any facially projecting element that may hinder the process of placing the restorative material on the tooth. Likewise, the lingual side  478  of the root end section  432  of the matrix  430  is free of any lingually projecting element that may hinder the process of placing the restorative material on the tooth. Likewise, the mesial (or distal) side  479  of the root end section  432  of the matrix  430  is free of any mesially (or distally) projecting element that may hinder the process of placing the restorative material on the tooth. A grasping tab  489  extends longitudinally from the mesial (or distal) side of the matrix  430 . 
         [0107]    Variable thickness matrices are also provided by the invention. One version of a variable thickness matrix is indicated at  530  in  FIGS. 19 and 21 . This matrix  530  has a gingival edge  534  and an occlusal edge  536  and a root-crown junction region  538 . This matrix  530  has an ovoid area  532  that can be between 1 millimeter by 2 millimeters and up to 4 millimeters by 6 millimeters in size. The average thickness of the matrix  530  is between 10 microns and 75 microns. The thinner ovoid area  532  of the matrix  530  is between 1% thinner up to 99% thinner than the above mentioned thicknesses of the matrix  530 . The thinning can be abrupt (e.g., a stepped transition in thickness) as in the cross section of  FIG. 22 . In an alternative matrix  530   a  of  FIG. 23 , the matrix  530   a  can be thinned from both sides. Preferably, the area of thinned material is only at the contact area between teeth. In one non-limiting example form, the matrix  530  has an inner surface that conforms to the shape of the outer surface of a root end section of an incisor tooth. In another non-limiting example form, the matrix  530  has an inner surface that conforms to the shape of the outer surface of a root end section of a canine tooth. 
         [0108]    Another version of a variable thickness matrix is indicated at  630  in  FIGS. 20 and 24 and 25 . Matrix  630  has a 1-4 millimeter band  632  of thinned material from left to right across the entire width of the matrix  630  in the occlusal third of the matrix. This matrix  630  has a gingival edge  634  and an occlusal edge  636  and a root-crown junction region  638 . The average thicknesses of the matrix  630  can vary between 10 microns and 75 microns. The thin band  632  of the matrix  630  would be between 1% thinner up to 99% thinner than the above mentioned thicknesses of the matrix  630 . The thinning can be abrupt as in the cross section of  FIG. 25 . The matrix  630  can be thinned from one side as in the cross section of  FIG. 25 . Another matrix  630   a  is thinned from both sides as in the cross section of  FIG. 26 . In another matrix  630   b , the change in thickness of the matrix  630   b  would transition over the entire area of the matrix  630   b  in both occlusal-gingival directions and buccal-lingual directions as in the cross section of  FIG. 27 , or any combination thereof. In one non-limiting example form, the matrix  630  has an inner surface that conforms to the shape of the outer surface of a root end section of an incisor tooth. In another non-limiting example form, the matrix  630  has an inner surface that conforms to the shape of the outer surface of a root end section of a canine tooth. 
         [0109]    The thinned areas of the dental matrices  530 ,  530   a ,  630 ,  630   a , and  630   b  can be achieved using different manufacturing methods. For example, a stainless steel strip can be thinned from inside and out using indenting (such as by hammering) from both sides. First one makes a strip, and then indents the strip as a secondary operation. The stainless steel strip can be thinned from inside and out using burnishing. Hammered steel may be more malleable such that a pre-burnished/hammered contact area that is more flexible than normal steel or heat-treated for stiffness steel. 
         [0110]    The dental matrices  530 ,  530   a ,  630 ,  630   a , and  630   b  can be for anterior and/or posterior teeth. The matrices  530 ,  530   a ,  630 ,  630   a , and  630   b  can be sectional, or 360 degree (Tofflemire type) matrices. The dental matrices  530 ,  530   a ,  630 ,  630   a , and  630   b  can be formed from a translucent or transparent material such as a polymeric film. One non-limiting example material is the polyester film commercially available as Mylar™. However, metallic (stiff) materials, such as stainless steel, can be used for the dental matrices  530 ,  530   a ,  630 ,  630   a , and  630   b . Also, the dental matrices  530 ,  530   a ,  630 ,  630   a , and  630   b  may be opaque. 
         [0111]    In a two step process, a dentist can forgo the use of a matrix stabilizer for the first step when the cavity is deep and/or on the root surface and first apply composite to create an undercut that will allow the subsequent use of a matrix stabilizer with more ease in a single step injection molding technique to finish the filling. 
         [0112]    While certain methods and matrices of the present disclosure have been described as providing methods and matrices for the restoration of a decayed portion of an anterior tooth or re-restoration of a previously filled anterior tooth, the invention is not limited to this use. The scalloped matrix described herein is useful for other applications. For example, the matrix can used for: (1) diastema closure (i.e., the tooth may not be decayed, the use of the matrix is strictly for esthetic veneering of the tooth to close a space); and (2) a veneering of the tooth when there is no need to close a space in the case of worn, dark, misaligned or other aesthetic problems that the patient desires to be covered over. Also, different sized matrices can be provided in a kit. 
         [0113]    Turning to  FIG. 32 , a front view of a non-limiting example dental matrix system  720  according to the invention is shown. In  FIG. 32 , an upper incisor  711  having dental matrix system  720  including a first clear sectional dental matrix  725  and a second separate clear sectional dental matrix  730  placed on the incisor  711  is shown. The dental matrices  725  and  730  can be formed from a translucent or transparent material such as a polymeric film. One non-limiting example material is the polyester film commercially available as Mylar™. The dental matrices  725  and  730  may have variable thickness such as in any of dental matrices  530 ,  530   a ,  630 ,  630   a , and  630   b . Each of the dental matrices  725  and  730  has a strip of material having a length from a first end to a second end sufficient to create a form for molding a restorative material to a surface of a tooth being restored. The length of the strip of each of the dental matrices  725  and  730  can surround 180 to 250 degrees of the tooth. In one non-limiting version, the length of the pre-curved dental matrices  725  and  730  is approximately 13 millimeters and the height can range approximately from 10 millimeters to 13 millimeters. 
         [0114]    Each of the dental matrices  725  and  730  has a root end section (similar to root end section  32  in  FIG. 8 ) that is anatomic in shape. The root end section of each of the dental matrices  725  and  730  terminates at a gingival edge. The actual anatomic shapes of the root end sections of each of the dental matrices  725  and  730  can be created from scans of natural teeth, molds of natural teeth, and/or molds of tooth models. Thus, by “anatomic”, it is meant that the root end section of each of the dental matrices  725  and  730  has an inner surface that conforms to the shape of the outer surface of a particular region of the natural tooth that contacts the root end section of each of the dental matrices  725  and  730 . 
         [0115]    The side of the root end section of the dental matrix  725  has a downward cut away (similar to the downward cut away  36  in  FIG. 8 ) creating a gingival edge that corresponds in shape to a downward projection of gingival papilla at the gingival margin adjacent the tooth and underlying periodontal and bony attachments of the tooth. The side of the root end section of the dental matrix  730  can also have a downward cut away creating a gingival edge (similar to gingival edge  38  in  FIG. 8 ) that corresponds in shape to a downward projection of gingival papilla at the gingival margin adjacent the tooth and underlying periodontal and bony attachments of the tooth. 
         [0116]    Alternatively, each of the dental matrices  725  and  730  can be used on lower teeth. In this case, the sides of the root end section of each of the dental matrices  725  and  730  has an upward cut away creating a gingival edge that corresponds in shape to an upward projection of gingival papilla at the gingival margin adjacent the tooth and underlying periodontal and bony attachments of the tooth. 
         [0117]    The root end section of each of the dental matrices  725  and  730  can be fully or partially anatomic. As a result, each of the dental matrices  725  and  730  can be placed on the tooth without interdental wedges or elastic separators or spacers. The anatomic shape allows hands-free and wedge-free use as each of the dental matrices  725  and  730  hugs the tooth. 
         [0118]    The dental matrix  725  has a vertical edge  727 , and the dental matrix  730  has a vertical edge  732 . The section of the dental matrix  725  adjacent the vertical edge  727  overlaps a portion of the section of the dental matrix  730  adjacent the vertical edge  732 . A hole  740  is created that allows excess dental restorative material to flow away from the tooth when dental restorative material is injected between the dental matrices  725  and  730  and the tooth  711 . 
         [0119]    The two sectional matrices  725  and  730  that each cover 180 to 250 degrees of the tooth  711  are placed on both sides of the tooth (mesial and distal or buccal and lingual) using a pliers as shown in  FIG. 32  and together allow a full crown to be made directly with injection of composite. A one piece matrix ring cannot physically be used to form the crown unless the tooth is first ground down to a peg. The contact point of the neighboring teeth can be bypassed by lightly sanding the touch points, open to say 20 or 30 microns gap. Once inserted, a matrix at 50 microns will slide easily and push the teeth apart slightly. A second alternative is to temporarily tease the teeth apart with a dental instrument to allow passage of the matrix through the contact points. 
         [0120]    Turning to  FIGS. 33-37 , a front view of a non-limiting example dental matrix system  820  according to the invention is shown. In  FIGS. 33-37 , an upper incisor  811  having dental matrix system  820  including a first clear sectional dental matrix  825  and a second clear sectional dental matrix  830  placed on the incisor  811  is shown. The dental matrices  825  and  830  can be formed from a translucent or transparent material such as a polymeric film. One non-limiting example material is the polyester film commercially available as Mylar™. The dental matrices  825  and  830  may have variable thickness such as in any of dental matrices  530 ,  530   a ,  630 ,  630   a , and  630   b . Each of the dental matrices  825  and  830  has a strip of material having a length from a first end to a second end sufficient to create a form for molding a restorative material to a surface of a tooth being restored. The length of the strip can surround 180 to 250 degrees of the tooth. In one non-limiting version, the length of the pre-curved dental matrices  825  and  830  is approximately 13 millimeters and the height can range approximately from 10 millimeters to 13 millimeters. 
         [0121]    Each of the dental matrices  825  and  830  has a root end section (similar to root end section  32  in  FIG. 8 ) that is anatomic in shape. The root end section of each of the dental matrices  825  and  830  terminates at a gingival edge. The actual anatomic shapes of the root end sections of each of the dental matrices  825  and  830  can be created from scans of natural teeth, molds of natural teeth, and/or molds of tooth models. Thus, by “anatomic”, it is meant that the root end section of each of the dental matrices  825  and  830  has an inner surface that conforms to the shape of the outer surface of a particular region of the natural tooth that contacts the root end section of each of the dental matrices  825  and  830 . 
         [0122]    The side of the root end section of each of the dental matrix  825  has a downward cut away (similar to the downward cut away  36  in  FIG. 8 ) creating a gingival edge that corresponds in shape to a downward projection of gingival papilla at the gingival margin adjacent the tooth and underlying periodontal and bony attachments of the tooth. The side of the root end section of the dental matrix  830  can also have a downward cut away creating a gingival edge (similar to gingival edge  38  in  FIG. 8 ) that corresponds in shape to a downward projection of gingival papilla at the gingival margin adjacent the tooth and underlying periodontal and bony attachments of the tooth. 
         [0123]    Alternatively, each of the dental matrices  825  and  830  can be used on lower teeth. In this case, the sides of the root end section of each of the dental matrices  825  and  830  has an upward cut away creating a gingival edge that corresponds in shape to an upward projection of gingival papilla at the gingival margin adjacent the tooth and underlying periodontal and bony attachments of the tooth. 
         [0124]    The root end section of each of the dental matrices  825  and  830  can be fully or partially anatomic. As a result, each of the dental matrices  825  and  830  can be used without interdental wedges or elastic separators or spacers. The anatomic shape allows hands-free and wedge-free use as each of the dental matrices  825  and  830  hugs the tooth. 
         [0125]    The dental matrix  825  has a vertical edge  827 , and the dental matrix  830  has a vertical edge  832 . The section of the dental matrix  825  adjacent the vertical edge  827  overlaps a portion  837  (see  FIG. 34 ) of the section of the dental matrix  830  adjacent the vertical edge  832 . An aperture  840  is created below the incisal edge  844  of the tooth  811  that allows dental restorative material  860  (see  FIG. 37 ) to flow away from the tooth  811  when dental restorative material is injected between the dental matrices  825  and  830  and the tooth  811  at the incisal edge of the tooth  811 . The aperture  840  exposes the tooth from gingival margin to a point P (see  FIG. 34 ) on a facial surface of the tooth when the matrix  825  and the matrix  830  are placed on the tooth  811 . 
         [0126]    The two sectional matrices  825  and  830  that each cover 180 to 250 degrees of the tooth  811  are placed on both sides of the tooth (mesial and distal or buccal and lingual) using a pliers (as shown in  FIG. 32 ) and together allow a full crown to be made directly with injection of composite. A one piece matrix ring cannot physically be used to form the crown unless the tooth is first ground down to a peg. The contact point of the neighboring teeth can be bypassed by lightly sanding the touch points, open to say 20 or 30 microns gap. Once inserted, a matrix at 50 microns will slide easily and push the teeth apart slightly. A second alternative is to temporarily tease the teeth apart with a dental instrument to allow passage of the matrix through the contact points. 
         [0127]    It is customary in the art of reconstructing the aging, worn or heavily filled tooth to leave the tooth thicker than before beginning the procedure. In  FIGS. 33-37 , paired matrices  825 ,  830  are used to lengthen and thicken severely worn teeth without grinding the teeth at all. In the procedure, a dental practitioner prepares the tooth surfaces by first removing the biofilm and contamination off of the teeth with a mild abrasive water/abrasive spray. Then, the teeth are ready for modern adhesion and overmolding of the teeth. The teeth are etched (see  FIG. 35  showing etchant being expressed from a syringe  850 ), then rinsed, then dried, and then adhesive is placed (all of these can be done with the dual matrices  825 ,  830  in position). Then, flowable composite is placed, and then heavier paste composite is placed driving out some or most of the excess flowable composite through the aperture  840 . The excess dental restorative material  862  is removed using a tool  870  (see  FIG. 37 ) and the restoration is cured (photo polymerized). 
         [0128]    Looking at  FIG. 33 , a section of the gingival edge  893  of the dental matrix  825  corresponds in shape to a portion of the gingival margin M adjacent the facial surface of the tooth. In this regard, the section of the gingival edge  893  corresponds in shape to portions of the gingival margin Mon both sides of the gingival zenith Z. Alternatively, the section of the gingival edge  893  may correspond in shape to a portion of the gingival margin Mon one side of the gingival zenith Z. 
         [0129]    Referring now to  FIG. 38 , a front view of a non-limiting example dental matrix system  920  according to the invention is shown. An upper incisor with incisal edge  944  has a first clear sectional dental matrix  925  and a second clear sectional dental matrix  930  placed on the incisor. The dental matrices  925  and  930  can be formed from a translucent or transparent material such as a polymeric film. One non-limiting example material is the polyester film commercially available as Mylar™. The dental matrices  925  and  930  may have variable thickness such as in any of dental matrices  530 ,  530   a ,  630 ,  630   a , and  630   b . The area of thinned material may only be at the contact area between teeth. Each of the dental matrices  925  and  930  has a strip of material having a length from a first end to a second end sufficient to create a form for molding a restorative material to a surface of a tooth being restored. The length of each strip may independently surround 120 to 250 degrees of the tooth. 
         [0130]    Each of the dental matrices  925  and  930  has a root end section  924 ,  934  respectively, that is anatomic in shape. The root end section  924 , 934  of each of the dental matrices  925  and  930  terminates at a gingival edge  950 ,  960  respectively. The actual anatomic shapes of the root end sections of each of the dental matrices  925  and  930  can be created from scans of natural teeth, molds of natural teeth, and/or molds of tooth models. Thus, by “anatomic”, it is meant that the root end section of each of the dental matrices  925  and  930  has an inner surface that conforms to the shape of the outer surface of a particular region of the natural tooth that contacts the root end section of each of the dental matrices  925  and  930 . 
         [0131]    The side of the root end section  924  of each of the dental matrix  925  has a downward cut away (similar to the downward cut away  36  in  FIG. 8 ) creating a gingival edge  950  that corresponds in shape to a downward projection of gingival papilla at the gingival margin adjacent the tooth and underlying periodontal and bony attachments of the tooth. The side of the root end section  934  of the dental matrix  930  can also have a downward cut away creating a gingival edge  960  (similar to gingival edge  38  in  FIG. 8 ) that corresponds in shape to a downward projection of gingival papilla at the gingival margin adjacent the tooth and underlying periodontal and bony attachments of the tooth. 
         [0132]    Alternatively, each of the dental matrices  925  and  930  can be used on lower teeth. In this case, the sides of the root end section of each of the dental matrices  925  and  930  has an upward cut away creating a gingival edge that corresponds in shape to an upward projection of gingival papilla at the gingival margin adjacent the tooth and underlying periodontal and bony attachments of the tooth. 
         [0133]    The root end section of  924 ,  934  each of the dental matrices  925  and  930  can be fully or partially anatomic. As a result, each of the dental matrices  925  and  930  can be used without interdental wedges or elastic separators or spacers. The anatomic shape allows hands-free and wedge-free use as each of the dental matrices  925  and  930  hugs the tooth. 
         [0134]    The dental matrix  925  has a vertical edge  927 , and the dental matrix  930  has a vertical edge  932 . A slot  940  is created between the vertical edge  927  and the vertical edge  932  that allows dental restorative material to flow away from the tooth when dental restorative material is injected between the dental matrices  925  and  930  and the tooth. The vertical edge  927  and the vertical edge  932  may be dimensioned to be parallel when the dental matrices  1025  and  1030  are placed on the tooth. 
         [0135]    The two sectional matrices  925  and  930  that each cover a portion of the tooth are placed on both sides of the tooth (mesial and distal or buccal and lingual) using a pliers (as shown in  FIG. 32 ) and together allow a full crown to be made directly with injection of composite. A one piece matrix ring cannot physically be used to form the crown unless the tooth is first ground down to a peg. The contact point of the neighboring teeth can be bypassed by lightly sanding the touch points, open to say 20 or 30 microns gap. Once inserted, a matrix at 50 microns will slide easily and push the teeth apart slightly. A second alternative is to temporarily tease the teeth apart with a dental instrument to allow passage of the matrix through the contact points. 
         [0136]    Turning now to  FIG. 39 , a front view of a non-limiting example dental matrix system  1020  according to the invention is shown. An upper incisor has a first clear sectional dental matrix  1025  and a second clear sectional dental matrix  1030  and a third clear sectional dental matrix  1030  placed on the incisor. The dental matrices  1025  and  1030  and  1050  can be formed from a translucent or transparent material such as a polymeric film. One non-limiting example material is the polyester film commercially available as Mylar™. The dental matrices  1025  and  1030  and  1050  may have variable thickness such as in any of dental matrices  530 ,  530   a ,  630 ,  630   a , and  630   b . Each of the dental matrices  1025  and  1030  has a strip of material having a length from a first end to a second end sufficient to create a form for molding a restorative material to a surface of a tooth being restored. The length of each strip can independently surround 120 to 250 degrees of the tooth. 
         [0137]    Each of the dental matrices  1025  and  1030  has a root end section  1024 ,  1034  respectively, that is anatomic in shape. The root end section  1024 ,  1034  of each of the dental matrices  1025  and  1030  terminates at a gingival edge  1050 ,  1060  respectively. The actual anatomic shapes of the root end sections of each of the dental matrices  1025  and  1030  can be created from scans of natural teeth, molds of natural teeth, and/or molds of tooth models. Thus, by “anatomic”, it is meant that the root end section of each of the dental matrices  1025  and  1030  has an inner surface that conforms to the shape of the outer surface of a particular region of the natural tooth that contacts the root end section of each of the dental matrices  1025  and  1030 . 
         [0138]    The side of the root end section  1024  of the dental matrix  1025 ,  1030  has a downward cut away (similar to the downward cut away  36  in  FIG. 8 ) creating a gingival edge that corresponds in shape to a downward projection of gingival papilla at the gingival margin adjacent the tooth and underlying periodontal and bony attachments of the tooth. The side of the root end section  1034  of the dental matrix  1030  can also have a downward cut away creating a gingival edge (similar to gingival edge  38  in  FIG. 8 ) that corresponds in shape to a downward projection of gingival papilla at the gingival margin adjacent the tooth and underlying periodontal and bony attachments of the tooth. 
         [0139]    Alternatively, each of the dental matrices  1025  and  1030  can be used on lower teeth. In this case, the sides of the root end section  1024 ,  1034  respectively of each of the dental matrices  1025  and  1030  has an upward cut away creating a gingival edge that corresponds in shape to an upward projection of gingival papilla at the gingival margin adjacent the tooth and underlying periodontal and bony attachments of the tooth. 
         [0140]    The root end section  1024 ,  1034  of each of the dental matrices  1025  and  1030  can be fully or partially anatomic. As a result, each of the dental matrices  1025  and  1030  can be used without interdental wedges or elastic separators or spacers. The anatomic shape allows hands-free and wedge-free use as each of the dental matrices  1025  and  1030  hugs the tooth. 
         [0141]    The dental matrix  1025  has a vertical edge  1027 , and the dental matrix  1030  has a vertical edge  1032 . A slot  1040  may be created between the vertical edge  1027  and the vertical edge  1032  that allows dental restorative material to flow away from the tooth when dental restorative material is injected between the dental matrices  1025  and  1030  and the tooth. The vertical edge  1027  and the vertical edge  1032  may be dimensioned to be parallel (thereby creating a uniform distance between the vertical edge  1027  and the vertical edge  1032 ) when the dental matrices  1025  and  1030  are placed on the tooth. Alternatively, the vertical edge  1027  and the vertical edge  1032  may contact each other in abutting fashion such that no slot is formed when the dental matrices  1025  and  1030  are placed on the tooth. 
         [0142]    The two sectional matrices  1025  and  1030  that each cover a portion of the tooth are placed on both sides of the tooth (mesial and distal or buccal and lingual) using a pliers (as shown in  FIG. 32 ). Then, the third sectional dental matrix  1050  can be used to cover the incisal end of the dental matrices  1025  and  1030 . The dental matrices  1025  and  1030  and  1050  together allow a full crown to be made by directly injecting composite through an access hole  1060  in matrix  1025  and then curing the composite. In another embodiment, the dental matrices  1025  and  1030  and  1050  are integral and the integral dental matrices  1025  and  1030  and  1050  (360 degrees) are preloaded with the composite filling/veneering material and then placed over the tooth. In yet another embodiment, a scan or impression is done preoperatively and then a matrix and/or matrices are 3-D printed or CAD ground down to make an immediate pair of matrices on site and chair side. 
         [0143]    Although the invention has been described in considerable detail with reference to certain embodiments, one skilled in the art will appreciate that the present invention can be practiced by other than the described embodiments, which have been presented for purposes of illustration and not of limitation. Therefore, the scope of the appended claims should not be limited to the description of the embodiments contained herein.