Patent Publication Number: US-2007111163-A1

Title: Dental implant system

Description:
RELATED APPLICATIONS  
      This application claims the benefit of U.S. Provisional Patent Application No. 60/732,471 filed on Nov. 2, 2005 and entitled “Dental Implant System” and this provisional application is hereby incorporated by reference in its entirety. 
    
    
     FIELD OF THE INVENTION  
      This invention relates generally to dental implants and, in particular, to a dental implant that extends through the gingiva and to associated tools and restorative and prosthetic components.  
     BACKGROUND OF THE INVENTION  
      It is becoming more common to replace a missing tooth with a prosthetic tooth that is placed upon and attached to a dental implant. The dental implant serves as the artificial root that integrates with the bone tissue of the mouth. The prosthetic tooth preferably has a size and color that mimics the missing natural tooth. Consequently, the patient has an aesthetically pleasing and structurally sound artificial tooth.  
      One current surgical protocol by which implants are integrated into the patient involves two stages. In the first stage, the implant is inserted into the jawbone, covered by suturing the overlying gingival tissue, and allowed to osseointegrate for a period of two to four months. Covering the implant with the overlying gingiva minimizes the likelihood of infection around the implant and is believed to guard against disturbances that may slow its rate of osseointegration. The implants used in the two stage protocol are sometimes referred to as “subgingival implants.” 
      After osseointegration is complete, the second stage is encountered in which the gingiva is again cut open and a gingival healing abutment is placed onto the implant. The overlying gingiva is sutured to allow it to properly heal around the healing abutment. When the healing abutment is removed and the prosthetic tooth is placed on the implant, the gingiva nicely conforms around the prosthetic tooth. It typically takes four to eight weeks, however, before the gingiva is healed. Thus, the overall procedure may take three to six months.  
      Another implant surgical protocol requires one stage and uses an implant called a “transgingival implant” or “single-stage implant” that simultaneously promotes osseointegration and healing of the gingiva. This is accomplished by providing an implant that has a portion that integrates with the jawbone and a portion that extends through the overlying gingiva so that the gingiva properly heals therearound. Thus, the four to eight week gingival healing process in the two stage process occurs during the two to four month period of osseointegration. Consequently, the patient is fitted with a prosthesis in a shorter period of time. And, the gingiva is lacerated and sutured one less time compared with two stage systems which reduces the trauma to that region, the discomfort experienced by the patient, and minimizes the overall cost.  
      Additionally, some clinical studies suggest that the interface between the subgingival implant and the mating abutment in a two-stage process creates bone resorption in the region adjacent to the interface. As such, transgingival implants, which lack such an interface in the bone region, should not produce the same amount of bone resorption. Additionally, because the gingival height often follows the underlying bone, a transgingival implant may minimize the reduction in the gingival height associated with bone resorption, thereby maintaining proper aesthetics.  
      The present invention is directed to an improved transgingival implant system including an implant, a installation system for driving the implant into the bone, and components that mate with the implant. Such a system should help the clinician maintain proper gingival height and shape.  
     SUMMARY OF THE INVENTION  
      The present invention relates to a new dental implant system, comprising a dental implant and a mating component. The implant has a lower section for engaging bone, a middle section for passing through the gingiva, and a top section with a first non-rotational feature. The mating component has a second non-rotational feature for mating with the first non-rotational feature of the dental implant. The mating component has a larger width dimension than the dental implant such that a lower portion of the mating component surrounds the middle section of the dental implant and the top section of the dental implant is located within the component. The lowermost surface of the mating component is preferably scalloped.  
      In another aspect, the dental implant system comprises a dental implant, a first component, and a second component. The dental implant has a lower section for engaging bone, a middle section for passing through the gingiva, and a top section with a first non-rotational feature. The first component has a larger width dimension than the dental implant such that a first lower portion of the first component surrounds the middle section of the dental implant. The first lower portion has a first scalloped lowermost end surface assisting to form the gingiva around the middle section of the dental implant. A second component attaches to the dental implant after the first component. The second component has a second lowermost portion with a second scalloped lowermost end surface that is substantially similar to the first scalloped lowermost end surface of the first component.  
      The invention is a method for installing a dental implant. The method includes engaging the dental implant to a driver mechanism. The engaging includes mating corresponding non-rotational features of the driver mechanism and the dental implant. The driver mechanism telescopes over the dental implant such than an upper segment of the implant is located within the driver mechanism and a lowermost end surface of the driver mechanism is located along an exterior side surface of the dental implant. The method further includes placing the dental implant into a hole in the bone by applying force to the driver mechanism. The method may further include attaching related components to the implant after the driver mechanism is removed. The related components and the driver mechanism may have substantially matching scalloped lowermost surfaces. The driver mechanism can be a driver mount that is pre-packaged with the dental implant or a driver tip, which directly engages the implant and which is coupled to a mechanical or manual drive mechanism.  
      The above summary of the present invention is not intended to represent each embodiment, or every aspect, of the present invention. This is the purpose of the Figures and the detailed description which follow. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
      The foregoing and other advantages of the invention will become apparent upon reading the following detailed description and upon reference to the drawings.  
       FIGS. 1A, 1B , and  1 C are a side view, an end view, and a cross-sectional view respectively, of an implant according to the present invention;  
       FIGS. 2A, 2B , and  2 C are a side view, an end view, and a cross-sectional view, respectively, of an implant mount used with the implant of  FIG. 1  for installing the implant in bone;  
       FIGS. 3A, 3B ,  3 C and  3 D are a side view, an end view, a cross-sectional view, and an isometric view, respectively, of a gingival healing cap used with the implant of  FIG. 1 ;  
       FIGS. 4A, 4B ,  4 C and  4 D are a side view, an end view, a cross-sectional view, and an isometric view, respectively, of an impression coping used with the implant of  FIG. 1 ;  
       FIGS. 5A, 5B ,  5 C are a side view, an end view, and a cross-sectional view, respectively, of a temporary cylinder for use with the implant of  FIG. 1 ;  
       FIGS. 6A, 6B ,  6 C and  6 D are a side view, an end view, a cross-sectional view, and an isometric view, respectively, of a permanent cylinder for use with the implant of  FIG. 1 ;  
       FIG. 7  is a side view of an alternative implant having a ceramic central portion;  
       FIG. 8  is a side view of an alternative implant that is of a two-piece construction; and  
       FIG. 9  is a side view of a driver tip that is used for directly engaging the implant to drive it into the bone. 
    
    
      While the invention is susceptible to various modifications and alternative forms, specific embodiments have been shown by way of example in the drawings and will be described in detail herein. It should be understood, however, that the invention is not intended to be limited to the particular forms disclosed. Rather, the invention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention as defined by the appended claims.  
     DETAILED DESCRIPTION OF THE DRAWINGS  
       FIGS. 1A-1C  illustrate an implant  10  that includes an upper section  12 , a middle section  14 , and a threaded lower section  16 . The implant  10  is preferably made of titanium or a titanium alloy, although other materials such as ceramics or ceramic-titanium combinations are possible.  FIGS. 7-8 , which are discussed below, describes an alternative implant designs that have a similar shape to the implant  10  of  FIG. 1 .  
      In the implant  10  of  FIG. 1 , the exterior of the threaded lower section  16  includes a thread  20  that makes a plurality of turns around the implant.  10 . The threaded portion preferably includes a self-tapping region that allows the implant  10  to be installed without the need for a bone tap.  
      The upper section  12  includes a polygonal boss  22  (as shown, a hexagonal boss) that is useful for engaging the tool (e.g., the implant mount in  FIG. 2 ) that applies torque to the implant  10  when the implant  10  is being installed. The polygonal boss  22  is also used for non-rotationally engaging a correspondingly shaped socket on a restorative or prosthetic component (see  FIGS. 3-6 ) that is attached to the implant  10 . The upper section  12  also includes the opening to a threaded bore  24  for receiving a screw that retains the restorative or prosthetic component on the implant  10 .  
      At the base of the polygonal boss  22 , the upper section  12  includes a table  26 , which can be used to support a component mounted thereon. The polygonal boss  22 , as shown best in  FIG. 1B , has tapered side surfaces extending at least along a portion from the end surface of the polygonal boss  22  toward the table  26 .  
      The middle section  14  is designed to extend through the gingiva. Preferably, it is a smooth surface that includes a titanium nitride coating so the underlying titanium or titanium alloy is not readily seen through the gingiva. The lower threaded section  16  can include various thread structures and is preferably roughened to increase the osseointegration process. Several preferred roughening processes are disclosed in U.S. Pat. Nos. 5,603,338, 6,491,723, and 6,652,765, which are herein incorporated by reference in their entireties.  
       FIGS. 2A-2C  illustrate an implant mount  30  that is used for installing the implant  10  of  FIG. 1  in bone. The implant mount  30  includes an non-rotational portion  32  that engages a drive mechanism, which can be either manually driven or power driven. As shown, the non-rotational portion  32  is a hexagonal boss at the uppermost end of the implant mount  30 . Other shapes and locations for the non-rotational portion  32  are also possible. A stop surface  34  is located below the non-rotational portion  32  to limit the axial movement of the drive mechanism with respect to the implant mount  30 .  
      The implant mount  30  includes a lower portion  36  that is used for engaging a dental implant  10  of  FIG. 1 . The lower portion  36  includes a lowermost end surface  38  that has a scalloped shape. Furthermore, the lower portion  36  includes an axial socket  40  into which the upper section  12  and a portion of the middle section  14  of the implant  10  ( FIG. 1 ) is inserted. The axial socket  40  includes a correspondingly shaped non-rotational region  42  for mating with the polygonal boss  22  of the implant  10 . The implant mount  30  is axially held on to the implant  10  by the use of a screw (not shown) that extends through a top opening  44  of the implant mount  30 .  
      In a typical arrangement, the implant mount  30  is prepackaged in a sterile environment with the implant  10  attached thereto. The implantation site is prepared with an opening in the gingiva (typically, “flapless surgery”) and an osteotome to the correct depth within the bone. The clinician opens the sterile package, attaches the drive mechanism to the non-rotational portion  32  of the drive mount  30 , and installs the implant  10  to the appropriate depth in the osteotomy. Grooves  46  may be provided at known distances (e.g., 1 mm spacing) from the lowermost end surface  38  of the implant mount  30  to inform the clinician of the depth of insertion below the gingiva&#39;s exterior surface. After installation is complete, the screw is removed from the top opening  44  and the implant mount  30  is detached from the implant  10 . Alternatively, the clinician can attach the implant mount  30  to the implant  10  prior to installation if the implant  10  is not provided to the clinician with a pre-attached implant mount.  
      As will be discussed below, the scalloped-shaped end surface  38  has the same profile as other restorative and prosthetic components that are attached to the implant  10 . Consequently, when the clinician installs the implant  10  with the drive mechanism, the clinician can visually verify the position of the scalloped-shaped end surface  38  to ensure that it is properly aligned to the desired gingival contour at the implantation site. Because the scalloped-shaped end surface  38  is “timed” with the non-rotational region  42  that mates with the polygonal boss  22 , when other mating restorative and prosthetic components are attached to the implant  10  via the polygonal boss  22 , their lowermost surfaces will fit around the middle section  14  of the implant  10  in the same manner as the lowermost end surface  38  of the implant mount  30 .  
      After the implant  10  has been installed, it is often necessary to shape the gingiva around the implant  10  as the gingiva heals. This function can be accomplished by a healing cap  50 , which is shown in  FIGS. 3A-3D . The healing cap  50  is preferably made of a polymeric material, such as PEEK, although other materials will work as well. The healing cap  50  includes a main body  52  having an opening  54  had its upper end. The main body  52  includes a lowermost end surface  56  that is scalloped in the same shape as the lowermost end surface  38  of the implant mount  30 . A lower socket  58  receives the top section  12  and a portion of the middle section  14  of the implant  10  of  FIG. 1 . The lower socket  58  includes a non-rotational portion  60  for engaging the polygonal boss  22  of the implant  10 .  
      Once the implant  10  is installed and the healing cap  50  is placed over the implant  10 , the gingiva can be sutured (if needed) around the combination of the implant  10  and healing cap  50 . Over the next several weeks, the gingiva will heal to shape that corresponds to the scalloped shape of the lowermost end surface  56  of the healing cap  50 . The lowermost end surface  56  acts to limit the height of the gingival growth. Hence, the desired shape of the gingiva around the implantation site can be substantially controlled by the shape and size of the healing cap  50  that is used.  
      Furthermore, the healing cap  50  preferably has a wider lowermost surface  56  (in the radial direction with respect to the central axis of the implant  10 ) than the lowermost surfaces of the other mating components (discussed below) that are later mated with the implant  10 . When the healing cap  50  is removed, the gingiva may collapse towards the middle section  14  of the implant  10 . If the other components have thinner lowermost surfaces, then they will fit easier into the gingival opening produced by the healing cap  50 . The shape of the healing cap  50  may taper outwardly to develop more of an aesthetic emergence profile through the gingiva.  
      To make an impression of the implantation site, an impression coping  70 , which is shown in  FIGS. 4A-4D , is attached to the implant  10  of  FIG. 1 . The impression coping  70  is preferably made of a polymeric material, such as PEEK, or it may be CP titanium, titanium alloy, or other materials. The impression coping  70  includes a top portion  72  and a main body  74  that become encased in impression material. An axial hole  76  receives a screw (not shown) to hold the impression coping  70  on the implant  10 .  
      The main body  74  includes a lowermost surface  78 , which is scalloped in the same manner as provided with the previous components. The main body  74  also includes a lower socket  80  that includes a non-rotational region  82  for engaging the polygonal boss  22  of the implant  10 . The impression coping  70  may include a plurality of axial grooves  84  along the main body  74  as well as a plurality of grooves  86  adjacent the lowermost surface  78 . The purpose of these grooves  84  and  86  is to help retain the impression material on the impression coping  70 . The plurality of grooves  86  also helps the clinician to identify the depth below the gum tissue that the impression coping  70  is inserted.  
      In one method, after the healing cap  50  of  FIG. 3  is used to develop the shape of the gingiva, the healing cap  50  is removed. Then, the impression coping  70  is placed over the implant  10  and is affixed to the implant  10  by a screw (not shown), which has a long head portion that extends well above the impression coping  70 . The clinician can then place impression material around the impression coping  70  and the adjacent teeth. After the impression material hardens, the screw can be released and the entire impression, including the impression coping  70 , is removed from the patient&#39;s mouth. A corresponding implant analog is attached to the impression coping  70 . A stone model is then poured within the impression, providing a model of the implantation site that includes the implant analog at the location and orientation corresponding to the implant  10  within the bone. Because the scallop of the impression coping  70  is substantially the same as the healing cap  50 , the scallop of the impression coping  70  should substantially correspond to the gingival shape after the gingiva has healed around the healing cap  50 . Alternatively, the scallop of the impression coping  70  may be slightly shorter than the scallop of the healing cap  50  (e.g., 1 mm shorter) so that the impression material can engage the gingival tissue below the scallop of the impression coping  70  to capture its exact shape.  
       FIG. 5  illustrates a temporary cylinder  90  that can be used to receive tooth-like material (e.g., acrylic) to develop a temporary tooth for the patient while a final prosthesis is being developed by a laboratory. The temporary cylinder  90  includes a main body  92  having a plurality of axial and circumferential grooves  93  for receiving and holding the tooth-like material. The main body  92  includes an axial hole  94  for receiving a screw to hold the temporary cylinder  90  on the implant  10 . Like the previously discussed components, the lowermost end  96  of the main body  92  has a scalloped shaped. Additionally, a lower socket  98  for receiving the implant  10  includes a non-rotational region  100  for engaging the polygonal boss  22  of the implant  10 . It should be noted that it is possible to avoid the use of the healing cap  50  of  FIG. 3  and simply use the temporary cylinder  90  to restrict and control the gingival shape while also providing for the temporary prosthetic tooth.  
       FIG. 6  illustrates a permanent cylinder  110  that can be made from a variety materials, such as titanium or, preferably, a ceramic material such as zirconium oxide. The permanent cylinder  110  includes a lower portion  112  and an upper portion  114 , which is shaped generally like the shape of the tooth being replaced. As such, various shapes may be available for the permanent cylinder  110 . The upper portion  114  includes an axial hole  116  for receiving a screw to hold the permanent cylinder  110  on the implant  10 . The lower portion  112  includes an axial socket  118  for receiving the implant  10  and a scalloped lowermost end surface  120 , which corresponds to the scallop provided on the previous components. The axial socket  118  includes a non-rotational region  122  for mating with the polygonal boss  22  of the implant  10 .  
      In operation, the permanent cylinder  110  receives permanent tooth-like material (e.g., porcelain) in a laboratory that is used to develop the final prosthesis from the impression of the patient&#39;s mouth. As such, the tooth-like material adheres to the outer surface of the upper portion  114  and possibly segments of the lower portion  112 . When the final prosthesis is sent to the clinician from the laboratory, the clinician can remove the previous components that were used (e.g., the healing cap  50  if it is still in place, or the temporary cylinder  90  with its temporary tooth) and install the final prosthesis via a screw through the axial hole  116 . The screw hole  116  can be filled with other tooth-like material by the clinician.  
       FIG. 7  illustrates an alternative implant  130  that has the same general shape as the implant  10  of  FIG. 1 . Specifically, the implant  130  includes a top section  132 , a middle section  134 , and a lower section  136 . The middle section  134  includes an internal metallic core  138  and a ceramic outer portion  140 . The ceramic outer portion  140  can be one of many types of ceramics, such as zirconium oxide. The ceramic outer portion  140  can be sprayed on to the metallic core  138 , or a sheath (or sheath sections) can be placed around the metallic core  138  and held there via a glue or epoxy. The implant  130  can be used with the various components described with respect to  FIGS. 2-6  and provides additional aesthetic benefits when compared to an entirely metallic implant.  
       FIG. 8  illustrates yet another alternative implant  150  that has the same general shape as the implant  10  of  FIG. 1 . The implant  150 , however, is constructed of two primary pieces—a lower implant portion  152  and an upper implant portion  154 . The lower implant portion  152  and the upper implant portion  154  are held together through a non-rotational connection  156  (e.g., a hexagonal boss and a corresponding hexagonal socket) and an axial screw  158 . The axial screw  158  is inserted into a through bore  160  in the upper implant portion  154  and mates with a threaded bore  162  within the lower implant portion  152 . The only external difference between the implant  10  of  FIG. 1  and the implant  150  of  FIG. 8  is the interface line between the upper implant portion  154  and the lower implant portion  152 . While the interface between the lower implant portion  152  and the upper implant portion  154  is shown near the thread on the implant  150 , it can be located substantially closer to the uppermost non-rotational boss  164 , such that the upper implant portion  154  is much shorter. In any event, the implant  150  can be used with the various components prescribed with respect to  FIGS. 2-6 .  
       FIG. 9  illustrates an alternative drive mechanism that is useful for installing the implant via a direct-drive technique. A driver tip  170  includes a lower end  172  that is shaped and configured in a similar manner as the lower end of the driver mount  30  of  FIG. 2 . The lower end  172  fits around the implant  10  and non-rotationally engages the implant. When torque is applied to an upper end  174  of the driver tip  170 , which includes a latch mechanism (e.g., an ISO-latch), the implant  10  can be installed into the bone. As such, the dental implant  10  does not need to be pre-packaged with the driver mount  30  ( FIG. 2 ) and the driver tip  170  may be reusable by the clinician.  
      The overall widths of the implant  10 , the implant  130 , and the implant  150  are in the range from about 2.75 mm to about 6.0 mm. The present invention contemplates that the components described in  FIGS. 2-6  will be provided in kits (preferably, color coded) for mating with the various sizes of the dental implants.  
      The present invention also contemplates a series of restorative and prosthetic components as shown in  FIGS. 2-6  having different dimensions and shapes for the scalloped lowermost surfaces. In other words, a first patient may require a deeper scallop, resulting in a longer circumferential path along the lowermost end surfaces of these components. Yet, a second patient may require or a shallower scallop, resulting in a shorter circumferential path along the lowermost end surfaces of these components. In these situations, the driver mount  30  ( FIG. 2 ) may still have the same scallop for each patient since the scalloped lowermost end surface on the driver mount  30  is for helping the clinician to identify the relative positions of scalloped lowermost end surfaces of the restorative and prosthetic components when they are attached to the implant after the driver mount  30  has been removed.  
      It should also be noted that the middle section  14  of the implant  10  may include a microstructure, a treatment, or an additive that encourages the growth and attachment of the gingival tissue. As such, when the healing cap  50  ( FIG. 3 ) or the temporary cylinder  90  ( FIG. 5 ) is telescoped over the middle section  14  of the implant, the healing cap  50  or the temporary cylinder  90  acts as a mask such that only the exposed portion of the middle section  14  having such a microstructure, a treatment, or additive will encourage growth of the gingival tissue. Some exemplary methods for encouraging the growth and attachment of the gingival tissue include nano-particle deposition, collagen treatment or embedment, or an antimicrobial surface.  
      While the present invention has been described with reference to one or more particular embodiments, those skilled in the art will recognize that many changes may be made thereto without departing from the spirit and scope of the present invention. Each of these embodiments and obvious variations thereof is contemplated as falling within the spirit and scope of the claimed invention, which is set forth in the following claims.