Abstract:
A dental implant ( 22 ) for surgical placement in a living jaw bone at least partially covered with gingival tissue and for mounting a cosmetic tooth prosthesis. The implant ( 22 ) includes an elongated body portion ( 24 ) to be received by the living jaw bone and an abutment portion ( 26 ) extending from the jaw bone and at least partially past the gingival tissue for receiving the cosmetic tooth prosthesis, wherein the body portion and the abutment portion form a single unit. The implant ( 22 ) further has a narrow profile.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]     None.  
       TECHNICAL FIELD  
       [0002]     This invention relates generally to a dental implant system and method of using same and more specifically to a one-piece dental implant.  
       BACKGROUND OF THE INVENTION  
       [0003]     Implant dentistry involves the restoration of one or more teeth in a patient&#39;s mouth using artificial components. Such artificial components typically include a dental implant, an abutment connected to the implant, and a prosthesis or artificial tooth secured to the abutment. The process for restoring a tooth is typically carried out in three stages.  
         [0004]     Stage I involves implanting the dental implant into the living bone of a patient&#39;s jaw. The oral surgeon first accesses the patient&#39;s jaw bone through the patient&#39;s gingival or gum tissue and removes any remains of the tooth to be replaced. Next, the specific site in the patient&#39;s jaw where the implant is to be anchored is made or widened by drilling and/or reaming to accommodate the width of the dental implant to be implanted. Then, the dental implant is inserted into the hole in the jaw bone.  
         [0005]     The implant itself is typically fabricated from pure titanium or a titanium alloy. Such materials are known to produce osseointegration of the implant fixture with the patient&#39;s jaw bone. Osseointegration is a process by which the living bone surrounding the implant will proliferate and grow into whatever spaces exist between the implant and the bone surfaces.  
         [0006]     In this way the newly generated bone tissue encases the implant to securely hold or anchor it in place. The dental implant fixture has also typically included a hollow threaded bore through at least a portion of its body and extending out through its proximal end which is exposed through the crestal jaw bone. The hollow threaded bore typically receives a dental abutment, either directly or by virtue of a separate securing device such as an abutment screw. The abutment ultimately supports the final tooth prosthesis. The prosthesis is typically secured to the abutment either by a cement or other adhesive or by use of a fastener such as a screw.  
         [0007]     After the implant is initially installed in the jaw bone, a healing screw (a cover) is secured over the exposed proximal end in order to seal the internal bore of the implant body. The patient&#39;s gums are then sutured over the screw covered implant to allow the implant site to heal and to allow desired osseointegration to occur. Complete osseointegration typically takes several months, ending this Stage  1  phase.  
         [0008]     During Stage II, the surgeon reaccesses the implant fixture by making an incision through the patient&#39;s gum tissues. The healing cover screw is then removed, exposing the proximal end of the implant. The hollow threaded bore of the implant is thoroughly cleaned and dried. The surgeon then attaches a temporary cap secured by a cover screw, which is screwed directly through the healing cap into the hollow threaded bore of the implant. The gingival tissues are again closed around the cap and sutured in place. To accurately record the position, the orientation and the shape of the final abutment, the surgeon can take a mold or impression of the patient&#39;s mouth. The impression, which includes the implant abutment sites, is then sent to the laboratory and is used to create a plaster or stone model which is a direct duplication of the patient&#39;s mouth. This provides the information needed to fabricate the prosthetic replacement tooth or any required intermediate prosthetic components. Stage II is now typically completed.  
         [0009]     Based on this Stage II model, the technician will construct the final restoration. The final five (5) steps required to complete the restorative procedures are as follows: 
        1) The sutures are removed;     2) The healing cap and the healing cap screw are removed;     3) The exposed hollow threaded bore of the implant body is thoroughly cleaned and dried;     4) The solid abutment is screwed into the implant body&#39;s hollow threaded bore; and,     5) The cosmetic final prosthesis is secured to the patient&#39;s mouth abutments with a dental adhesive cement.        
 
         [0015]     Dental implant systems of the prior art include multiple parts which are attached to each other in final usage, making the technique complex and dentist unfriendly as described above. Also, having multiple pieces increases overall size and decreases overall strength and integrity of the final assembled unit.  
         [0016]     The present invention provides an improved dental implant system and method. This system and method are simple, technique friendly with no component parts. In this invention there is no need for any component parts, such as a healing cap, a healing cap screw, a healing screw separant abutment component or a second surgical procedure involving the gingival tissue overgrowth to expose the top of the implant body to get access to the implant body threaded bore to place the solid abutment component.  
       SUMMARY OF THE INVENTION  
       [0017]     The present invention is directed to a one-piece unit which includes both the abutment section and the implant body, and no component parts. The dental implant when surgically placed in a living jaw bone is not covered with any gingival tissue. Subsequently, mounting a cosmetic tooth prosthesis to the exposed abutment is a simple procedure, exactly the same procedure as in the cementation of routine crowns. This is possible wherein the body portion and the abutment portion form a single unit. As a result of the present invention, the steps outlined above in Prior Type Stage II are unnecessary. Most significantly, the present invention allows implanting in narrow areas, such as those associated with lower front teeth and congenitally missing maxillary lateral incisors. Subsequently, the final placement of the cosmetic tooth prosthesis to the abutment portion is a familiar procedure. One merely cements the prosthesis to the exposed abutment section with an adhesive dental cement as one would do when cementing the routine crown to a tooth. There is thus no necessity to surgically remove any gingival tissue because initially, in the placement of the present new invention implant into the bone site, it does not require any surgical gingival flap procedures, as it does with the prior art implant placement procedures, during which time the gingival tissues must be sutured over the embedded implant body. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0018]     The dental implant system, and method of using same, of the invention will now be described with reference to the accompanying drawings in which:  
         [0019]      FIG. 1  is an exploded view of a typical prior art dental implant assembly;  
         [0020]      FIG. 2  is a perspective view of a dental implant according to the teachings of the present invention;  
         [0021]      FIG. 3  is a side view of the dental implant of the present invention shown in  FIG. 2 ;  
         [0022]      FIG. 3   a  is a partial side view showing details of a threaded portion of the dental implant shown in  FIG. 2 ;  
         [0023]      FIG. 4  is a top view of the implant of  FIG. 2 ;  
         [0024]      FIG. 5  is a side view of an impression transfer thimble;  
         [0025]      FIG. 5   a  is a top view of the thimble of  FIG. 5 ;  
         [0026]      FIG. 6  is a side sectional view of the thimble of  FIG. 5 ;  
         [0027]      FIG. 7  is a lower perspective view of the thimble of  FIG. 5 ;  
         [0028]      FIGS. 8   a - 8   g  schematically depict the process of creating a mold of a patient&#39;s mouth incorporating the implant of  FIG. 2  and the thimble of  FIG. 5 ;  
         [0029]      FIG. 9  is a side sectional view of a pattern thimble;  
         [0030]      FIG. 9A  is a side sectional view of an alternative pattern thimble; and,  FIG. 10  is a lower perspective view of the thimble of  FIG. 9 . 
     
    
     DETAILED DESCRIPTION  
       [0031]     While this invention is susceptible of embodiment in many different forms, there is shown in the drawings and will herein be described in detail preferred embodiment(s) of the invention with the understanding that the present disclosure is to be considered as an exemplification of the principles of the invention and is not intended to limit the broad aspect of the invention to the embodiments illustrated.  
         [0032]      FIG. 1  depicts a dental implant assembly  10  of the prior art. The assembly  10  includes an implant  12 , an abutment  14 , and an abutment screw  16  for securing the abutment  14  to the implant  12 . A healing cap  18 , and a cap screw  20  for securing the cap  18  to the implant  12  and/or the abutment  14  may also be employed. Other dental implant assemblies are known in the prior art, all incorporating multiple components.  
         [0033]     In use, the prior art implant  12  is inserted into a living jaw bone of a patient, after the insertion site is properly prepared by the oral surgeon in a manner similar to the above Stage I description. Then the abutment  14  is attached to the implant  12  by virtue of the abutment screw  16 . An impression of the site and surrounding portions of the mouth may be taken at this point for use in creating a cast of the patient&#39;s mouth, either by a dentist or by a lab technician. The component parts  14  and  16  are removed and the healing cap  18  is then secured to the abutment  12  by use of the healing cap screw  20 . The healing cap  18  is typically left in place while the gums heal and while the jaw bone further osseointegrates with the implant. At a later point, the healing cap  18  is removed and replaced by a final restorative tooth prosthesis secured to the abutment  14 , by virtue of the abutment screw  16 .  
         [0034]      FIGS. 2-4  depict a dental implant  22  according to the present invention. The dental implant  22  is a single piece comprising an elongated body portion  24 , an abutment portion  26  and a transition portion  28  between the body portion  24  and the abutment portion  26 .  
         [0035]     The body portion  24  has a generally circular cross section and includes a helical thread  27  extending substantially the length of the body portion  24 . While the body portion  24  may be tapered, it has been found that a cylindrical, non-tapered construction is best. As such, the body  24  has equal contact with surrounding material at both a point (x) adjacent the distal end  30  and a point (y) adjacent the transition portion  28 . As shown in the Figures, the thread  27  includes a thread angle α of approximately 22 degrees to a perpendicular of a longitudinal axis  29  of the body portion  24 .  FIG. 4  shows further details of the thread  27 . An upper thread surface  32  extends away from the body portion  24  generally perpendicular to the longitudinal axis  29  while a lower thread surface  34  slopes at an angle from an outer thread edge  36  to the body portion. It should be noted that this design presents a reverse-angle of thread. A distal end  30  of the body portion  24  is rounded and includes no sharp corners or other sharp edges. In this manner, it is unlike a typical screw. The pitch angle of 22 degrees is substantially greater than found in any currently available dental implants known to the inventors and has been found to be generally preferred.  
         [0036]     An outer surface area  38  of the transition portion  28  and the body portion  24 , including the thread  27  is bead blasted, similar to sand blasting, during its manufacturing process to result in a textured outer surface area  38 . The bead blasting process results in a rough surface area  38  that includes a plurality of very small protrusions and/or depressions about the outer surface area  38 . Other types of mechanical or physical texturing of the outer surface area  38  may be utilized while remaining within the scope of the invention. Typical prior art implant surface areas are sprayed with a titanium plasma spray to achieve a textured surface. The texturing achieved through the bead blasting of the present invention increases the speed with which the living jaw bone osseointegrates with the implant  22  after surgical placement. Also, the bead blasting technique decreases the cost and complexity of the manufacturing process.  
         [0037]     The implant  22  is specifically designed to present a narrow profile. That is, due in part to its one piece construction, the implant  22  depicted in  FIGS. 2-4  includes a body portion  24  having a diameter ‘d’ including the thread  27  of approximately 2.4 mm. Conventional dental implants range in diameter from approximately 4.0 mm (including any threading) and greater. It is noted that in accord with the present invention, diameters smaller than the 2.4 mm diameter ‘d’ of the embodiment of the invention depicted in the Figures can be obtained in practicing the invention. One advantage of a narrow profile for the implant  22  is that the narrow profile can be utilized for implant placement especially in the mandibular jaw. Typically, in anterior incisal areas where the edentuous boney areas are narrow, limited mass of bone exists. This implant&#39;s narrow profile makes it feasible and possible for implant anchoring in these areas. Being one piece, this invention makes it stronger than a two-piece implant system with the same diameter.  
         [0038]     The abutment portion  26  is generally conical having a generally circular cross section. An abutment base  39  is adjacent the transition portion  28 . A proximal end  40  of the abutment portion  26  has a cross section with a smaller diameter than a cross section of the abutment base  39 . The abutment portion  26  includes a longitudinal groove  42  for mating with any of a number of known tools for assisting surgeons in inserting, screwing, holding or otherwise manipulating dental implants. The abutment portion  26  includes a polished surface area  26   a.    
         [0039]     The implant  22  is made from medical grade titanium or titanium alloy. The implant  22  may be made from any suitable medical grade material of sufficient strength characteristics and properties.  
         [0040]     As noted, the implant  22  shown in the Figures is constructed from a single piece of material, in this case a titanium alloy. While the body portion  24 , abutment portion  26  and transition portion  28  can be a single piece, they can be separately constructed and then fused together or otherwise jointed to form a single, unitary, integrated piece prior to implantation.  
         [0041]     The bead blasted surface of the implant  22  of the present invention increases the speed and effectiveness of the osseointegration process as compared to prior art implant systems. The applicants have observed that the textured outer surface area  38 , the pitch angle of 22 degrees and the cross-section shape of the thread  27  each, and in combination, increase the anchoring effects of the osseointegration process.  
         [0042]      FIGS. 5-7  depict an impression transfer thimble  44 , for use in the present invention. The thimble  44  is shaped generally to closely correspond and fit over the shape of the abutment portion  26  of the implant  22 . The thimble  44  includes a base wall  46  and an annular side wall  48  depending therefrom as seen in  FIGS. 5-7 . The base wall  46  and side wall  48  are relatively thin. In the embodiment depicted in  FIGS. 5-7 , the base wall  46  and side wall  48  have a thickness ‘t’ of approximately 0.5 mm. An interior surface  41  of the side wall  48  includes a longitudinal protrusion  50  shaped to align with and correspond to the longitudinal groove  42  of the abutment portion  26 . The impression transfer thimble  44  is typically constructed from an acrylic type polystyrene or other acrylic compatible with the adhesives typically used with the transfer thimble  44 .  
         [0043]      FIGS. 9 and 10  show a pattern burn out thimble.  
         [0044]     A pattern thimble  52  would also include a base wall  54  (with extending prongs  57 ) and an annular side wall  56  and is over-all shaped to closely correspond to and fit over the shape of the abutment portion  26  of the implant  22 . However, an interior surface  58  of the side wall  56  is smooth and includes no protrusions or grooves. In the Figures, the base wall  54  is shown to have the extending prongs  57  catch the thimble when it is pulled with impression material. However, it should be understood that the base wall  54  can be constructed without prongs as in  FIG. 9A . The thimble  52  is made of a lab burn-out resin. The pattern thimble  52  is used in the conventional manner.  
         [0045]     In use ( FIGS. 8   a - 8   g ) an oral surgeon will prepare the surgical site where the implant  22  is to be placed in a patient&#39;s jaw. This includes accessing the jaw bone  70  which may include incising the surrounding gingival tissue  72 . Any remaining portion of a prior existing natural tooth structure is removed. The specific site of implantation is then drilled or reamed by the surgeon so as to accommodate the implant. A cylindrical recess  60  ( FIGS. 8   a - 8   g ) of a diameter slightly smaller than the diameter ‘d’ of the body portion  24  of the implant  22  is created. In this case, the diameter of the recess  60  should be slightly less then 2.4 mm. The surgeon then cleans the recess  60 .  
         [0046]     The body portion  24  of the implant  22  is then screwed into the recess  60  using any known implant driver or other tool adapted to fit the implant  22 . The outer thread edge  36  then engages the jaw bone within the recess  60 , cutting a corresponding groove (not specifically shown) in the jaw bone. In this way, the implant becomes securely held or anchored by the jaw bone. The surgeon or dentist may then fit a temporary cap or crown to the abutment portion  26  (without any degradation) immediately after surgery using a cement or other adhesive during this healing period. The healing and osseointegration time allows the gingival tissue time to heal and any swelling to subside.  
         [0047]     It is noted that at this point ( FIG. 8   a ), substantially all of the body portion  24  is located within the recess  60 , and substantially all of the abutment portion  26  is located above the gingival tissue level.  
         [0048]     The impression thimble  44  is placed upon the abutment portion  26  to cover same ( FIG. 8c ). Impression material is formed over the thimble  44  and the surrounding area of the jaw, including the surrounding teeth and gum or gingival lines ( FIG. 8   d ). When the impression  74  material hardens, it is removed from the jaw with the thimble  44  embedded therein. The impression  74  is then typically sent to a laboratory to be used in creating the final prosthesis.  
         [0049]     A lab technician will then insert an analogue  62  into the thimble embedded in the impression ( FIG. 8   e ). The analogue  62  simulates the actual implant and its position in the patient&#39;s mouth, to be seen. The analogue  62  includes an abutment portion  64  that exactly duplicates the abutment portion  26  of the implant  22  in the patient&#39;s jaw bone, including a longitudinal groove  65 . The analogue  62  also includes a body portion  66  very generally corresponding to the previously described body portion  24  of the implant  22 . However, the body portion  66  does not include any threads. Rather, it includes a flattened surface  68 .  
         [0050]     The technician will then pour up the impression in artificial stone  76  having the embedded thimble  44  and analogue  62  in place ( FIG. 8   f ). Once the poured material hardens, it forms a plaster or stone cast  78  and is removed from the impression ( FIG. 8   g ). The analogue  62  is now embedded within the stone cast which now forms a precise positive model of the patient&#39;s jaw duplicating the location and orientation of the abutment portion  24  in relation to the surrounding teeth and gum lines.  
         [0051]     The technician uses this model to form and create the final tooth prosthesis using a well known wax bum out technique not described in detail here. In short, the technician will then place the pattern thimble  52  over the abutment analog portion  64  protruding from the stone cast. The technician then uses a wax material to form a wax model of a final prosthesis over the pattern thimble  52 . The absence of any longitudinal protrusion in the pattern thimble makes it easier for the technician to form the wax model. This is because the pattern thimble  52  can rotate about the abutment portion  64  making minor modification to the wax model easier to make by the technician. Because there is no timing device procedure, the restorative crown can spin or rotate 360° freely on the abutment form.  
         [0052]     The lab bum-out thimble  52  with round wax (vent) sprue attached is connected to a sprue former and casting ring. This casting ring assembly is filled with a christolbolite investment plaster. The ring is heated and the wax is “burnt out.” That is, the wax melts and flows leaving a void in the heating casting ring. Gold or some type of metal is melted and forced in the “void” duplicating the bum out pattern thimble. The casting is removed from the casting ring assembly dressed to receive the porcelain veneers covering the metal to produce a cosmetic implant crown prosthesis. This prosthesis is then returned to the dentist. (Of course, in many instances, a dentist may handle his or her own prosthesis casting.)  
         [0053]     The dentist will then remove the temporary cap or crown and replace it with the final prosthesis. The final prosthesis will typically be secured to the abutment portion  26  using a cement or other relatively permanent adhesive.  
         [0054]     While the specific embodiments and various details thereof have been illustrated and described, numerous modification come to mind without significantly departing from the spirit of the invention and the scope of protection is only limited by the following claims.