Abstract:
The invention relates to a dental implant system comprising a dental implant ( 28 ), a dental restoration part ( 12 ), a connector ( 24 ) with a central through-hole ( 58 ) and a circumferential, radially outwardly projecting collar ( 30 ) and with a screw ( 52 ) passing through the through-hole ( 58 ) by means of which at least the connector ( 24 ) may be fixedly connected with the dental implant ( 28 ), wherein the collar ( 30 ) comprises a first stop surface ( 26 ) that interacts with the dental implant ( 28 ), and a second stop surface ( 32 ) that interacts with an abutment ( 16 ) or a dental restoration part ( 12 ). The color of the collar ( 30 ), in particular the color of the connector ( 24 ), at least corresponds to a tooth color or a gingival color. The connector ( 24 ) at least partially respectively extends into the dental implant ( 28 ) and/or into the abutment ( 16 ), and substantially consists of the same material as the abutment ( 16 ) or consists of zirconium oxide.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims the benefit of European Patent Application No. 10 182 811.9 filed Sep. 29, 2010, which is hereby incorporated by reference in its entirety. 
       TECHNICAL FIELD 
       [0002]    The invention relates to a dental implant system having a combination of elements more particularly, a combination of a dental implant, a connector and a restoration. 
       BACKGROUND OF THE INVENTION 
       [0003]    It has been known for a long time that with the aid of dental implant systems, dental restorations may be provided that do not affect or damage neighboring teeth. In this connection, the dental implant system typically comprises a dental implant as a basis therefor. The dental implant is screwed into the jawbone and incidentally offers safe anchorage for the dental implant system. 
         [0004]    The dental implant system in addition to the actual dental implant also comprises a dental restoration part for forming the dental restoration, said dental restoration part having a shape that typically corresponds to the one or more neighboring teeth of the patient. 
         [0005]    For the anchorage between the dental restoration part and the dental implant it is known to employ one or two molded or shaped parts that provide the connection. The molded or shaped part adjacent to the dental implant is referred to as a connector and for the most part it is connected to the dental implant in a positive or form-locking manner. Either the dental restoration part immediately follows the connector, or a so-called abutment extends between the connector and the dental restoration part. The abutment often comprises a truncated conical or conical structure in order to be able to extensively absorb and distribute the incurred masticatory forces without causing selective stress on the dental restoration part. 
         [0006]    For providing the connection between the connector and the dental implant, it has become known to provide a through-hole in the connector and to pass a screw there-through, said screw then being screwed in a corresponding threaded hole for providing a firm fit of the connector at this position. 
         [0007]    It has been proposed to also configure the portion of the connector extending into the dental implant with truncated conical shape in order to still further improve the fit of the connector within the dental implant. This solution, however, results in a bad or poor detachability of the connector if it has to be removed as it tends to particularly stick or adhere if the inclination of the cone or conical shape is small. 
         [0008]    Dental implant systems basically experience an extended use. The reason for this at least partially lies in the fact that, in particular, younger patients often dislike or reject to damage and remove the natural and healthy tooth structure of neighboring teeth for providing dental prostheses which is necessary for providing a bridge. Especially younger patients thus rather prefer the provision of a dental implant system. 
         [0009]    The implementation of dental implant systems of this kind already in middle-aged or even younger-aged persons, however, entails that the demands on durability and both functional and optical compatibility of dental implant systems have steadily increased. On the one hand, this means that in case of a possible color change there is a desire to exchange the dental restoration part if necessary without effecting a new bone injury. On the other hand, increased demands on the time in function of the dental restoration part imply that the load capacity or strength of the entire implant system, especially in the case of intensive alternating loads such as they arise when chewing, must be high. 
         [0010]    Dental implant systems, due to the increased spread, are also of more consequence in terms of costs so that there is the desire to enable a manufacture at the lowest possible cost on the one hand, and durability on the other hand, wherein aesthetic aspects may not be ignored nevertheless. US 2004/0076924 A1, which is hereby incorporated by reference, discloses a dental implant system comprising a two-part abutment, in which the lower part practically acts as a connector. This solution enables a torque-proof anchorage due to the form fit or positive locking between the connector and the dental implant. However, especially in the case of an alternating load, the connector is quite heavily loaded so that it may wear out or break. Moreover, the aesthetic appearance or impression in particular with gingival atrophy or periodontal disease is not particularly well. 
       SUMMARY 
       [0011]    The invention is based on the object of providing a dental implant system that in view of the aesthetic appearance is also improved in the long term without causing particularly high production costs, wherein a secure and durable mounting of the dental restoration part is possible nevertheless. 
         [0012]    According to the invention it is particularly favorable that due to the at least partial extension of the connector into the dental implant, the connector itself is protected and thus is loaded to a lesser extent. Due to the screw that is known per se and that extends through the connector, the connector is pressure-loaded. This enables in a surprisingly easy manner to also produce the connector from an aesthetically appealing material from a metal material, a ceramic material, such as zirconium oxide, a composite material or plastic material at least at its outer periphery that is referred to as collar. This solution was banned in the prior art as the heavy load due to the alternating load would have resulted in a brittle fracture of the connector in the state of the art. 
         [0013]    The use of zirconium oxide or another ceramic material for abutments is indeed known for a long time. However, this has nothing to do with the material used for the connector since the connector typically is a mere mechanic force-receiving member that serves to support and bear the dental implant system in or at the dental implant, and the abutment when implanted typically already comes to rest above the gingival edge so that at this position aesthetic aspects always play a role, apart from the fact that a metal abutment would ruin the effect of translucency that is usually desired with dental restoration parts due to the transparent or translucent metal. 
         [0014]    According to the invention it is particularly favorable that also in case of periodontal disease for example with persons 30 years of age and older, aesthetic disadvantages through the connector are not to be feared. The dental implant is usually completely screwed into the jawbone and as a bone level implant does not extend beyond the jawbone. Following the jawbone, the collar of the connector is inventively provided that preferably has the color of the gingiva or tooth in order not to disturb visually. 
         [0015]    Nevertheless, a secure anchorage between the dental implant on the one hand, and the abutment and/or dental restoration part on the other hand, may be ensured in an inventively particularly favorable manner, the more so as the implementation of the connector made from ceramics or a composite is not opposed by the fact that positive locking elements may be provided at the outer circumference of the connector that interact with positive locking elements of the dental implant and ensure a rotationally fixed or torque-proof support. 
         [0016]    According to the invention it is particularly favorable if cylindrical sections extend on both sides of the collar of the connector instead of conical sections. Thereby it is excluded that the dental implant gets stuck, so that the releasability or detachability is readily ensured also after years. The conicity may be preferably simulated by forming the upper portion of the connector in a two-stage manner which portion is then formed by two successive cylindrical portions the diameter of which decreases to the top. 
         [0017]    It is particularly favorable if the second portion of the connector comprises an outer geometry that deviates from the round shape. Through this, a safe and form-stable mounting of the connector within the dental implant is possible. However, it is also possible to use a round outer geometry in order to thus easier enable minimum adjustments in the direction of rotation, wherein the angular position of the connector and thus the crown, is then determined by the position that is affixed by the screw passing through the connector. 
         [0018]    According to an advantageous embodiment it is provided that the connector consists of the same material as the dental restoration part, in particular consists of zirconium oxide, glass ceramics, titanium, a composite or plastic, and in that in particular the connector and the dental restoration part are free of metal and substantially have the same coefficient of thermal expansion. 
         [0019]    According to a further advantageous embodiment it is provided that the second portion of the connector comprises an outer symmetry that deviates from a round shape or at least comprises a protrusion or a profiling that prevents the dental restoration part from twisting relative to the connector. 
         [0020]    According to a further advantageous embodiment it is provided that the greatest height (H) of the collar that extends parallel to the longitudinal axis of the connector, amounts to 0.3 mm to 10 mm, in particular to 0.5 mm to 4 mm. 
         [0021]    According to a further advantageous embodiment it is provided that the outer diameter of the collar is conically shaped in a direction that runs in the same direction as the second portion of the connector. 
         [0022]    According to a further advantageous embodiment it is provided that the transition area between the collar and the second portion is square shaped, or at least is formed having a radius of 1 mm to 5 mm and/or at least comprising a conical, circumferential surface. 
         [0023]    According to a further advantageous embodiment it is provided that the outer surface of the second portion and/or at least one inner surface of the dental restoration part is provided with a surface profiling or pattern that in particular comprises undercuts. 
         [0024]    According to a further advantageous embodiment it is provided that the dental restoration part includes an abutment and/or a crown. 
         [0025]    According to a further advantageous embodiment it is provided that the mounting of the connector, or of the connector and the abutment, or of the connector, the abutment and the crown on the dental implant is effected by means of a screw, wherein the head of the screw is supported on the connector or the abutment or the crown. 
         [0026]    According to a further advantageous embodiment it is provided that the connector and the abutment and/or the abutment and the crown are connected with one another in a manner known per se by gluing or soldering. 
         [0027]    According to a further advantageous embodiment it is provided that the abutment or the crown, or the abutment and the crown comprise a central pass-through recess or through-hole through which a tool for the screw may at least partially pass through. 
         [0028]    According to a further advantageous embodiment it is provided that the abutment consists of zirconium oxide, glass ceramics, titanium, a composite or plastic, and in that the second portion of the connector and the crown consist of glass ceramics, zirconium oxide, a composite or plastic. 
         [0029]    According to a further advantageous embodiment it is provided that at least the collar of the connector has a thin coating of color or at least partially is dyed through. 
         [0030]    According to a further advantageous embodiment it is provided that the outer surface of the collar smoothly merges with the outer contour of the abutment or the crown. 
         [0031]    According to a further advantageous embodiment it is provided that the zirconium oxide from which the connector is made, comprises a solubility of about &lt;100 μg/cm 2  and/or a biaxial bending strength of greater than about 800 MPa and/or a fracture toughness of greater than or equal to about 5 MPa m 1/2 . 
         [0032]    According to a further advantageous embodiment it is provided that the dental implant system comprises a dental implant, a dental restoration part and a connector as well as a circumferential, radially outwardly projecting collar, wherein the color of the collar, in particular the color of the connector, at least corresponds to a tooth color or a gingival color, and wherein at least one portion of the connector following the collar extends into the dental restoration part, and wherein the portion upon manufacture thereof comprises a length that is larger than the smallest height of the dental restoration parts as it occurs in practice, wherein the portion extends into the dental restoration part and wherein the portion may be shortened to the required length if applicable and necessary. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0033]    Embodiments of the present invention will be more fully understood and appreciated by the following Detailed Description in conjunction with the accompanying drawings, in which: 
           [0034]      FIG. 1  is a schematic view of an embodiment of the dental implant system according to the invention prior to its assembly; 
           [0035]      FIG. 2  is a further embodiment of an inventive dental implant system; 
           [0036]      FIG. 3  is a further embodiment of an inventive dental implant system; 
           [0037]      FIG. 4  is a further embodiment of an inventive dental implant system; 
           [0038]      FIG. 5  is a further embodiment of an inventive dental implant system; 
           [0039]      FIG. 6  is a further embodiment of an inventive dental implant system; 
           [0040]      FIG. 7  is a schematic view of a detail of an inventive dental implant system in one embodiment showing the collar of the connector; 
           [0041]      FIG. 8  is a modified embodiment of the view according to  FIG. 7 ; 
           [0042]      FIG. 9  is a further modified embodiment of the view according to  FIG. 7 ; and 
           [0043]      FIG. 10  is a further modified embodiment of the view according to  FIG. 7 . 
       
    
    
     DETAILED DESCRIPTION 
       [0044]    The dental implant system  10  represented in  FIG. 1  comprises a dental restoration part  12 , as can be seen from the schematic representation. The dental restoration part  12  may for example have the shape of an artificial incisor at its exposed region, as it becomes apparent from  FIG. 1 . The dental restoration part comprises a recess  14  in a manner known per se. 
         [0045]    According to the invention, a connector  24  is provided that comprises a specific shape and a specific structure. The connector  24  is basically divided into three parts. It comprises a first portion  26  that is suitably formed to project into a dental implant  28 , a collar  30  and a second section  32 . All of the three parts are each cylindrical and according to the invention are accordingly preferably not conical, however, have special features. The connector may consist of zirconium oxide, titanium, glass ceramics, a composite or plastic. 
         [0046]    The first section  26  comprises positive locking elements  34  that impart an unround outer shape to the cylinder arranged there. The positive locking elements  34  exactly fit into respective recesses in the dental implant  28 . During the insertion of the connector  24  into the dental implant  28 , the collar  30  with its lower first connection surface ends up on the top side of the dental implant  28 . The outer diameter of the collar  30  corresponds to the outer diameter of the dental implant at its connection  40 . Thus a flush transition between the collar  30  and the connection  40  is possible. 
         [0047]    The connector  24  at least in the region of the collar  30  or the outer side thereof consists of a material that either has the color of the tooth or the gingiva. It is preferred that the connector  24  in total consists of a ceramic material such as zirconium oxide, however, it is also possible to make it from a composite, plastic or metal, such as titanium, wherein right in the latter case the outer region of the collar  30  is then provided with the tooth color or color of the gingiva. 
         [0048]    The second portion  32  of the connector  24  itself is divided into two parts. It comprises a first cylindrical section  42  and a second cylindrical section  44 . The first cylindrical section  42  comprises a larger diameter than the second cylindrical section  44 . Considering the sequence of diameters of the collar  30 , the first cylindrical section  42  and the second cylindrical section  44 , a simulated cone arises despite the use of individual cylinders. 
         [0049]    In this way, the connector  24  with its first section  26  readily fits into a respective recess  24  in the dental restoration part  12  and lies flush there. 
         [0050]    For the fixation of the angular position, two opposing positive locking elements  36  and  37  are provided in the recess  14  and at the second section  32 . 
         [0051]    The flush arrangement, on the other hand, implies that the diameter of the collar  30  corresponds to the diameter of the lower end  22  of the dental restoration part  12 . The diameter of the collar  30  which in the illustrated embodiment of  FIG. 1  is designed cylindrically, at the same time corresponds to the upper diameter of the dental implant  28  at the connection  40  thereof. 
         [0052]    In a manner known per se, the dental implant  28  comprises a thread  50  at its outer circumference that serves for the anchorage in the jawbone. 
         [0053]    For providing the inventive dental implant system  10 , first the dental implant  28  with the thread  50  is introduced into the jawbone in a manner known per se, too. This, for example, is effected with the aid of a screw wrench that ends with positive locking elements at the end thereof corresponding to the positive locking elements  34  of the connector  24 . 
         [0054]    The dental implant  28  comprises an internal thread below these positive locking recesses. The internal thread matches the external thread of a screw  52 . The screw  52  is designed so that it passes through a through hole  58  in the connector  24 . After the dental implant  28  has been attached, the screw  52  is now inserted through the connector  24 . In the exemplary embodiment according to  FIG. 1  the screw  52  is screwed into the internal thread of the dental implant  28  so that the screw head  54  of the screw rests on the second portion  32  of the connector  24 , if necessary in a recess known per se, and safely holds the connector  24  in the dental implant  28  and in particular in a rotatably fixed manner. 
         [0055]    Following to this, the dental restoration part  12 , that is to say the corresponding crown in the illustrated exemplary embodiment, with the recess  14  thereof is put on the formed unit consisting of the screw  52  and the connector  24 , and is affixed there in a suitable manner, for example by soldering or gluing. 
         [0056]    The embodiment according to  FIG. 1  provides that the dental implant system or the dental restoration system is implemented without an abutment and that the connector  24  with its second portion  32  immediately enters the recess  14  of the dental restoration part, wherein it is to be understood that the recess  14  must then be formed correspondingly. 
         [0057]    According to the invention it is favorable if the connector  24  consists of a translucent material such as zirconium oxide. Surprisingly it is not necessary to use a material such as titanium for the connector, that is probably attributed to the fact that the connector  24  with its first portion  26  is safely accommodated in the dental restoration part  12  that for example may also consist of titanium. 
         [0058]    According to  FIG. 2  it is provided to implement a dental implant system that also does not comprise an abutment  16 . This embodiment differs from the embodiment according to  FIG. 1  in the crown  12  having a through-hole  56  that extends between the upper side thereof and the recess  14 . The through-hole  56  comprises a diameter that is suitable for accommodating a tool for screwing in or releasing the screw  52 , wherein the diameter, however, is not selected to be substantially larger than the respective shank of the tool. After the screw  52  has been tightened, the through-hole  56  is closed in a manner known per se with a suitable filler or sealing compound, wherein it is preferred that the through-hole  56  does not end at a labial, but a lingual side of a front tooth. 
         [0059]    The embodiment according to  FIG. 3  differs from the embodiment according to  FIG. 1  and  FIG. 2  in having an abutment  16 . The recess  14  is accordingly configured in a different manner. 
         [0060]    The abutment  16  that is configured according to the shape of the recess  14  and which for example runs slightly conically, fits into the recess  14 . 
         [0061]    In the later finished state, the abutment  16  and the dental restoration part  12  are connected with one another by means of a suitable medium such as dental cement. The abutment  16  as well as the dental restoration part consists of ceramics, however, preferably of a quite solid ceramic material such as zirconium oxide, whereas a lithium disilicate ceramic material may be used for the dental restoration part  12 , or for example a plastic material or a composite. 
         [0062]    In a manner known per se, the abutment  16  comprises a connection cone  18  at the lower portion thereof. The connection cone  18  has a diameter at the upper end  20  thereof that corresponds to the diameter of the lower end  22  of the dental restoration part  12  so that a flush transition is given at this position. 
         [0063]    Even if the remaining wall thickness of the abutment  16  surrounding the recess  46  is represented to be quite small, it is to be understood that in practice said wall thickness may be adapted to the requirements in broad areas in order to ensure the desired strength and safety. 
         [0064]    A through hole or recess  58  is provided in the abutment  16  for accommodating the screw  52 . In the embodiment according to  FIG. 3 , the through-hole  58  is designed somewhat larger than the screw head  54  so that the screw  52  may be freely passed through the abutment  16 . For assembly, the connector  24  is inserted into the recess  46  of the abutment  16  and the unit consisting of the screw  52  and the connector  24  is attached to the dental implant  28  with the aid of the screw  52 . According to the invention it is favorable that said connection may be undone by unscrewing the screw  52  if desired. Following to this, the dental restoration part  12  is attached to the abutment  16  in a manner known per se. It is preferred that the abutment  16  has been previously glued to the projecting unit. 
         [0065]    In the embodiment according to  FIG. 4  it is provided that the abutment  16  comprises a through hole  58 , the diameter of which is somewhat larger than the shank of the screw  52 , however, smaller than the diameter of the screw head  54 . In this embodiment, the screw  52  thus also holds the abutment  16  so that a pre-assembled solid unit consisting of the dental implant  28 , the connector  24 , the abutment  16  and the screw  52  is the result, on which the crown may then be affixed. 
         [0066]    For accommodating the screw head  54 , following to the through hole  58  a somewhat enlarged recess  60  is provided in the top end of the abutment  16  so that the screw head  54  may be accommodated in the abutment  16  in a recessed manner. 
         [0067]    The embodiment according to  FIG. 5  basically represents a combination of the embodiments according to  FIG. 2  and  FIG. 4 . In contrast to the embodiment according to  FIG. 4  a through-hole  56  is provided here that passes through the crown  12  and enables the insertion of a tool for the screw head  54 . 
         [0068]      FIG. 6  shows a further modified embodiment. In this embodiment no abutment  16  is provided, in fact the connector  24  is immediately accommodated within the recess  14  of the crown  12 . The crown  12  comprises a through-hole  56  that accommodates the screw head  54  in its upper part. Distinctly above the recess  14 , however, the through-hole  56  has a reduced diameter so that the diameter is smaller there than the diameter of the screw head  54 , however, is larger than the diameter of the shank of the screw  52 . Because of this, the screw head  54  rests on an abutment or stop surface  62  within the crown  12  so that the unit consisting of the crown or dental restoration part  12 , the screw  52 , the connector  24  and the dental implant  28  is screwed together by tightening the screw  52 . It is to be understood that the abutment or stop surface  62  may also be selected to be notedly larger as shown in  FIG. 6  and that also notedly more material for the support of the screw head  54  may be provided in the crown  12 . 
         [0069]    In the embodiments according to  FIGS. 1 to 6 , the collar  30  of the connector  24  is formed in flat-cylindrical manner according to the invention, that is to say it has an outer surface that extends parallel to an axis  66  of the dental implant system  10 . It is to be understood that according to the invention a flush transition of the collar  30 , in particular with respect to the abutment  16  or to the crown  12  is desired, and in particular with respect to the dental implant  28 . In the  FIGS. 7 to 10  suitable configurations of the outer circumference of the collar  30  are represented. In the embodiment according to  FIG. 7  the collar  30  is designed in a conical manner with respect to its outer surface. The connector  24  has a larger outer diameter at its first portion  26  compared to its second portion  32 ; compared to both portions, however, the collar  30  projects significantly. The projection extents or degrees  74  and  75  in this embodiment, however, are approximately equal as the cone angle of the outer surface  70  is selected to be quite large and amounts to approximately 45 degrees, and as the height H of the collar  30  approximately corresponds to the projection degree or extent. Preferably, it corresponds to a tenth up to a third of the diameter of the collar  30 . 
         [0070]      FIG. 7  represents the accommodation of the first part  26  in a crown  12 . It is to be understood that in a similar manner also the accommodation in an abutment  16  having a connection cone  18  may be provided, as it is represented in  FIG. 3 ,  FIG. 4  and  FIG. 5 . 
         [0071]    According to the invention it is particularly favorable if the transition between the first portion  26  and the collar  30  is curved or smoothed out. According to  FIG. 7 , a curve or fillet  72  with a radius is provided at this position, said radius approximately corresponding to the projection degree or extent  74 . 
         [0072]    According to  FIG. 8  a further embodiment of the connector  24  is represented. In this embodiment, the collar  30  comprises a notedly smaller height H compared to the embodiment according to  FIG. 7 . The height amounts to approximately one third of that of  FIG. 7  and thus also one third of the size of the projection extent  74 . 
         [0073]    A further embodiment of a connector  24  is represented in  FIG. 9 . In this embodiment, the collar  30  at its outer surface  70  is designed to be spherical or convex, basically in an extension of the convexity  80  of the crown  12  at its outer side. The collar  30  also here merges with the first portion  26  by means of a fillet  72 . Due to the convexity, the collar at the lower end thereof practically merges with the second portion  32  without transition. The outer surface  70  of the collar  30  in this embodiment is even more strongly inclined than in the embodiments according to  FIG. 7  and  FIG. 8 ; the average angle of inclination with respect to the axis  66  (please compare  FIG. 6 ) amounts to approximately 60 degrees. 
         [0074]    A still larger inclination of the outer surface  70  of the collar  30  of the connector  24  becomes apparent from  FIG. 10 . In this embodiment also the height H of the collar  30  is smaller, approximately half the size of height H of the collar in the embodiments according to  FIG. 7  and  FIG. 9 . This causes a still steeper angle of inclination of the outer surface  70  with respect to the axis  66  according to  FIG. 6 , which in the illustrated embodiment amounts to approximately 70 degrees. 
         [0075]    In a modified embodiment of the invention it is provided to optimize the structure of the second portion  32 . In a primary embodiment, the second part  32  of the connector  24  thus at least partially extends in a conically tapering manner. Alternatively, it is tapered in a stepped manner. In a further particularly preferred embodiment the second portion  32  is clearly extended compared to the representation in the figures. It extends with a height that at least corresponds to 0.4 times the dental restoration part  12 , or with an even larger height than the dental restoration part  12 . With this solution, the portion  32  may then be shortened as required before the dental restoration part  12  is attached. This embodiment also offers the advantage of considerably reducing the costs of storage. The connector  24  merely needs to be held available in one single height, even if tooth heights of completely different provenance are to be covered. 
         [0076]    In order to impart a particularly good support to the entire dental restoration it is also conceivable that the second portion passes through the dental restoration part in the area of the chewing or occlusal surface. After the dental restoration part  12  has been attached, as the case may be with the abutment  16 , the second portion is then shortened to the required length and closed and forms part of the chewing or occlusal surface. 
         [0077]    Although preferred embodiments have been depicted and described in detail herein, it will be apparent to those skilled in the relevant art that various modifications, additions, substitutions, and the like can be made without departing from the spirit of the invention and these are therefore considered to be within the scope of the invention as defined in the claims which follow.