Abstract:
The present invention provides an implant system of facilitated use and installation which comprise an implant and a prosthesis support and a method of installation thereof. The prosthesis support disclosed herein includes an abutment and a collar member. Prior art implant systems are mostly made of metallic parts which are assembled with a screw and are shaped to receive a tooth prosthesis. The design of the abutment allows it to be made from highly filled composite materials being of a better optical quality and being easily machinable and further allows its installation without the use of a screwing member. The design of the collar member allows minimization of bacteria growth and tartar formation. The optimization of the implant system proposed herein may reduce stress to the jaw bone and therefore minimize the risk of injury for the patient.

Description:
FIELD OF THE INVENTION  
       [0001]     The present invention relates to an implant system, a kit and a method of installation thereof. More particularly, the present invention relates to an implant system of facilitated use, assembly and installation.  
       BACKGROUND OF THE INVENTION  
       [0002]     It is of general knowledge that the loss of teeth may be compensated by artificial dental implants. A dental implant system typically includes an implant which is inserted firmly into the bone and an abutment which is usually directly or indirectly attached to the implant with a screwing member. The abutment supports the gum tissue and serves as a foundation for the dental prosthesis. The core of the implant is shaped to receive the abutment and an accurate mechanical interconnection is therefore provided between the two components. Such dental implant systems are described, for example, in U.S. Pat. No. 5,810,589, issued Sep, 22, 1998, and U.S. Pat. No. 5,759,036, issued Jun. 2, 1998. More particularly, U.S. Pat. No. 5,810,589 discloses an abutment which comprises a threaded post providing attachment of the abutment with the implant.  
         [0003]     In the prior art, the implant is first inserted into the bone and tissue ingrowth is allowed to take place. Once the implant is firmly anchored in the surrounding bone tissue and the bone has healed, the abutment is attached to the implant with an attaching means such as a screw. The abutment may be a metal structure which serves as a foundation to receive a prosthetic device such as a crown or a bridge. The prosthetic device is subsequently fabricated using traditional impression modeling techniques. Prosthetic devices usually possess a metal core to provide a metal to metal interconnection with the abutment.  
         [0004]     Prior art implant systems are submitted to a significant stress load, mainly supported by the implant and which is transferred to the bone. In fact, conventional dental implant systems generally do not adequately distribute the loads and stresses. Since dynamic forces are not always on a vertical plane the bone is loaded with forces pulling in different directions. These forces often lead to a tendency of the implant to rotate, therefore acting upon softer bone matrix.  
         [0005]     For example, U.S. Pat. No. 5,030,095, issued Jul. 9, 1991, discloses an abutment having two parts, the first being a platform joined to a post having screw threads and the second having a head joined to a shaft which is adapted for insertion into the first part and which needs to be screwed into an implant. This type of arrangement allows, for example, an angled head to be oriented in a more precise manner than with conventional system. However, the possibility of the components loosening and the stress imposed to the bone upon screwing the second part into the implant are two important factors unequivocally remaining with this type of system.  
         [0006]     Several problems have also been identified with conventional implant systems and with their use and installation: 
        the metal-implant to metal-abutment fixation requires a screw and a chimney for accessing it. The use of screws increases the overall cost of the installation. In addition, screws have a tendency to become loose over time     the metal-to-metal interconnection between the abutment and the implant is very rigid and therefore submits the bone to a significant stress load;     the installation and assembly of conventional implant system (with a screw) in the patient&#39;s mouth requires great accuracy;     metallic abutments cannot be shaped or carved and therefore, an associated impression coping and supplementary device (e.g., analogue system) is required for allowing a dental technician to generate the crown or bridge in a laboratory. The overall installation of conventional systems requires several visits to the dentist and a high cost for the patient;     metallic dental implant components are supplied in standard dimensions making it difficult to adjust to desired shape and size; and     the use of metallic abutments result in a prosthetic tooth with undesirable aesthetic properties.        
 
         [0013]     Recognizing the inconvenience of metal core abutments, other systems and methods have been developed. For example, U.S. Pat. No. 6,048,203, issued Apr. 11, 2000, uses fiber reinforced composite material coated with ceramic optimized polymer. U.S. Pat. No. 6,497,573, issued Dec. 24, 2002, discloses composite abutment having a metallic core, a shield surrounding the core and a polymeric cuff surrounding the core and shield.  
         [0014]     Further improvement in dental implant systems and their installation are needed.  
       SUMMARY OF THE INVENTION  
       [0015]     The implant system of the present invention may include an implant and a tooth prosthesis. More particularly, the implant system of the present invention may include a three-component system which may comprise, for example, an implant, a collar member and an abutment.  
         [0016]     As used herein, an “implant” is to be understood as a component of an implant system that is anchored into the bone. In parallel, an “abutment” is one of the components of the implant system that provides anchoring to the implant and allow fixation of the prosthesis.  
         [0017]     The present invention provides an implant system of a design allowing its assembly without the use of a separate attaching means, e.g., a coupling fastener.  
         [0018]     More particularly, the present invention provides, in one aspect thereof, an implant system which may comprise: 
        a) an implant which may have an elongated tubular body extending about a central longitudinal axis, the implant may also have a first opened end and a second closed end, an inner surface and an outer surface; and     b) a prosthesis support including a post, 
 
 the prosthesis support may be so configured and sized as to be inserted into the implant by substantially linear translation insertion of the post into the open end of the implant. The post may have, for example, a substantially smooth surface. 
       
 
         [0021]     The prosthesis support and the implant may be so configured as to be fixed to each other by an attaching means other than a screwing means.  
         [0022]     As used herein the expression “a prosthesis support” is to be understood as a combination between an abutment and a collar member of the present invention.  
         [0023]     In accordance with the present invention, the prosthesis support may comprise for example; 
        a) an abutment which may have an abutment head integral with the post, and;     b) a collar member (e.g., downwardly and inwardly curving) having a longitudinal passage therethrough.        
 
         [0026]     Furthermore, the abutment may be so configured and sized as to be assembled with the collar member by a substantially linear translation insertion of said post into said passage of the collar member. The abutment and the implant may be so configured as to be fixed to each other by an attaching means other than a screwing means.  
         [0027]     Also as used herein, the expression “a substantially linear translation insertion” is to be construed herein and in the appended claims as an insertion which does not require a screwing motion neither directly or indirectly, e.g., via a discrete fastener or screwing member. It is to be understood herein that the positioning of the abutment and the implant may require a slight rotational motion for aligning one component with the other(s). This type of motion is to be understood as distinct from a screwing motion.  
         [0028]     Similarly, the expression “non-screwable prosthesis support” or “non-screwable abutment” is to be construed herein and in the appended claims as a prosthesis support or an abutment which is not configured to be screwed into an implant, i.e., the post does not have a threaded section configured to interact directly with a threaded portion of the implant, nor configured to be attached by a separate coupling member via a screwing action.  
         [0029]     In a further aspect, the present invention provides an implant system which may comprise; 
        a) an implant which may have an elongated tubular body extending about a central longitudinal axis, the implant may also have a first end and a second end, an inner surface and an outer surface, the first end may be opened and may include a shouldered portion and the second end may be closed, and;     b) a cemented assembly or a non-screwable prosthesis support which may comprise 
            an abutment which may include an abutment head, a projection for engagement within said shouldered portion, and a post; and     a collar member (e.g., downwardly and inwardly curving) which may have a longitudinal passage therethrough; 
 
 the abutment and the implant may be so configured as to be fixed to each other by an attaching means other than a screwing means, also the projection and the shouldered portion may be so configured as to allow assembly of the abutment with the implant in a substantially linear translation insertion manner (motion). 
   
               
 
         [0034]     In accordance with the present invention, the abutment may be made, for example, from a highly filled composite material. The collar member may be made, for example, from a material that may be selected from the group consisting of a zirconium oxide and a zircon ceramic. The implant may be made, for example, from titanium.  
         [0035]     According to a third aspect of the present invention, there is provided a method for installing the system described hereinabove into a bone tissue of individual in need, said method may comprise: 
        a) installing the implant into a bone tissue;     b) shaping the abutment to a desired configuration, and;     c) assembling the prosthesis support (abutment and collar member) onto the implant as described herein.        
 
         [0039]     The method may also comprise fixing the abutment and the implant with composite cement.  
         [0040]     Therefore, it is to be understood herein that a direct and indirect restoration technique and their respective installation method are encompassed by the present invention.  
         [0041]     In a further aspect, the present invention provides a kit comprising; 
        a) an implant and;     b) a prosthesis support (i.e., an abutment and a collar-member).        
 
         [0044]     In accordance with the present invention, the kit may further comprise a cover screw. The kit may also further comprise a healing screw. The kit may also comprise an impression copying.  
         [0045]     It is to be understood herein, that if a “range” or the like is mentioned with respect to a particular characteristic (e.g. temperature, density, time and the like) of the present invention, it relates to and explicitly incorporates herein each and every specific member and combination of sub-ranges or sub-groups therein whatsoever. Thus, any specified range or group is to be understood as a shorthand way of referring to each and every member of a range or group individually as well as each and every possible sub-ranges or sub-groups encompassed therein; and similarly with respect to any sub-ranges or sub-groups therein, for example; 
        with respect to a flexural strength of between 200 and 1000 Pa, it is to be understood as specifically incorporating herein each and every individual range or values, as well as sub-range, such as for example 300±, 400±20, 700, 558.9, 994, 1000 etc.;     similarly with every other characteristics or range defined herein.        
 
         [0048]     The content of each publication, patent and patent application mentioned in the present application is incorporated herein by reference.  
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0049]     In drawings which illustrate embodiments of the present invention:  
         [0050]      FIG. 1   a  is a cross-sectional view of an abutment which is part of an implant system according to a first embodiment of the invention;  
         [0051]      FIG. 1   b  is a side perspective view of the abutment of  FIG. 1   a;    
         [0052]      FIG. 2   a  is a cross-sectional view of a collar member which is part of the implant system according to a first embodiment of the present invention.  
         [0053]      FIG. 2   b  is a side perspective view of the collar member of  FIG. 2   a;    
         [0054]      FIG. 3   a  is a cross-sectional view of an implant which is part of an implant and abutment system according to a first embodiment of the invention;  
         [0055]      FIG. 3   b  is a side-perspective view of the implant of  FIG. 3   a;    
         [0056]      FIG. 4   a  is a cross-sectional view of the implant system upon assembly of the abutment of  FIG. 1   a,  the collar of  FIG. 2   a , and the implant of  FIG. 3   a  according to a first embodiment of the invention;  
         [0057]      FIG. 4   b  is a top view of the implant system of  FIG. 4   a;    
         [0058]      FIG. 5   a  is a side elevation view of a cover screw to be used with the implant of  FIG. 4   a;    
         [0059]      FIG. 5   b  is cross-sectional view of the cover screw of  FIG. 5   a  assembled with the implant of  FIG. 4   a;    
         [0060]      FIG. 6   a  is a side elevation view of a healing screw to be used with the implant of  FIG. 4   a;    
         [0061]      FIG. 6   b  is a cross-sectional view of the healing screw of  FIG. 6   a  assembled with the implant of  FIG. 4   a;    
         [0062]      FIG. 7   a  is a bottom view of an abutment having a projection according to an embodiment of the invention;  
         [0063]      FIG. 7   b  is a bottom view of an abutment having a projection according to another embodiment of the invention;  
         [0064]      FIG. 7   c  is a bottom view of an abutment having a projection according to a further embodiment of the invention;  
         [0065]      FIG. 7   d  is a bottom view of an abutment having a projection according to another embodiment of the invention;  
         [0066]      FIG. 8   a  is a cross-sectional front view of an implant system according to a second embodiment of the invention (V; vestibular side, D; distal side);  
         [0067]      FIG. 8   b  is a cross-sectional side view of the implant system of  FIG. 8   a  (M; mouth side, L; lingual side);  
         [0068]      FIG. 8   c  is a top view of the implant system of  FIG. 8   a;    
         [0069]      FIG. 9  is a cross-sectional view of an implant system according to a third embodiment of the present invention;  
         [0070]      FIG. 10   a  is a cross-sectional front view of an implant system according to a fourth embodiment of the invention (V; vestibular side, D; distal side);  
         [0071]      FIG. 10   b  is a cross-sectional side view of the implant system of  FIG. 10   a  (M; mouth side, L; lingual side);  
         [0072]      FIG. 10   c  is a top view of the implant system of  FIG. 10   a;    
         [0073]      FIG. 11   a  is a cross-sectional view of an implant system according to a fifth embodiment of the invention;  
         [0074]      FIG. 11   b  is a cross-sectional view of an implant system according to a sixth embodiment of the invention;  
         [0075]      FIG. 11   c  is a cross-sectional view of an implant system according to a seventh embodiment of the invention;  
         [0076]      FIG. 12   a  is a cross-sectional view of an impression copying used according to an embodiment of the invention; and  
         [0077]      FIG. 12   b  is an elevation view of a screw for the impression copying of  FIG. 12   a.   
     
    
     DETAILED DESCRIPTION  
       [0078]     Referring now to  FIGS. 1   a  to  4   b , an implant system according to a first embodiment of the present invention will be described. The implant system includes a prosthesis support in the form of the combination of an abutment  10  illustrated in  FIGS. 1   a  and  1   b  and a collar member  30  illustrated in  FIGS. 2   a  and  2   b ; and an implant  46  illustrated in  FIGS. 3   a  and  3   b .  FIGS. 4   a  and  4   b  illustrate the assembly of the prosthesis support and the implant  46 .  
         [0079]     Turning now more specifically to  FIGS. 1   a  and  1   b,  the abutment  10  includes an external member defined by an abutment head  12  of a frusto-conical shape, adjacent to a junction segment  14  which is connected to a projection  16  of a substantially polygonal shape. The projection  16  of the abutment  10  is adjacent to an elongated post  18 . The abutment head  12 , the segment  14 , the projection  16  and the post  18  may be integrally made of a single piece of material.  
         [0080]     The abutment  10  includes a central throughbore  19  which spans the entire length of the abutment  10  starting from a surface  20  of the abutment head  12  and ending at a surface  22  of the post  18 .  
         [0081]     The abutment head  12  starts from surface  20  and downwardly and outwardly extends until the junction segment  14  is reached. The junction segment  14  is illustrated as having a substantially cylindrical shape ending with a flat surface connected to the projection  16 . The projection  16  is also connected to the post  18 . The abutment head  12 , junction segment  14 , projection  16  and post  18  are coaxial and parallel to the abutment central axis  26 .  
         [0082]      FIG. 1   b,  better illustrates projection  16  which is shown as being generally pentagonal.  
         [0083]      FIGS. 2   a  and  2   b  illustrate the collar member  30  which has a generally toroidal shape when seen from a top view. The collar member  30  starts with a substantially planar top surface  32  having a downwardly and outwardly extending flange  34  and continues with a downwardly and inwardly curved section  36 . The curved section  36  ends with a shoulder  38  which is connected to a cylindrical section  40 . The collar member  30  is illustrated has having a passage  42  therethrough. As will be clear from the following description, the collar member may take other shapes such that one side may be higher than the opposite side (a contoured collar member).  
         [0084]      FIGS. 3   a  and  3   b  illustrate the implant  46  which is configured and sized to be used with the abutment  10  of  FIGS. 1   a  and  1   b  and the collar member  30  of  FIGS. 2   a  and  2   b  as will be further described.  
         [0085]     The implant  46  has a generally elongated tubular body extending about a central longitudinal axis  48  and is defined by a head section  50 , a root section  52  and a generally tapered section  56 . The sections  50 ,  52  and  56  are being integrally made of a single piece of material.  
         [0086]     The head section  50  becomes the elongated root section  52  which is generally tubular as will be described hereinbelow. The elongated root section  52  is shown has having threads  54  on its outer surface (shown in  FIG. 3   b ). The purpose of the threads  54  will be described hereinbelow.  
         [0087]     The elongated root section  52  ends with an inwardly and downwardly tapered section  56  having a rounded tip  62  defining a closed end of the implant  46 .  
         [0088]     The open end  64  of implant  46  has two shoulder portions  66  and  67 , having a substantially cylindrical shape and a substantially pentagonal shape, respectively, as can be better seen in  FIG. 3   b . These shoulder portions further extend into a central bore  68 . The central bore  68  downwardly extends and ends with a tapered section  70 . The inner surface of the implant  70  includes a threaded portion  72 , the purpose of which will be described hereinbelow.  
         [0089]     As can be better seen from  FIG. 3   b , the shoulder portion  66  is so configured and sized as to receive the cylindrical section  40  of the collar member  30 . Similarly the shoulder portion  67  is so configured and sized as to receive the projection  16  of the abutment.  
         [0090]      FIGS. 4   a  and  4   b , illustrate the assembled implant system according to a first embodiment of the present invention. The abutment  10  is shown sitting onto the collar member  30  and inserted into the implant  46 .  FIG. 4   b  is a top view of the implant system of  FIG. 4   a , showing the substantially circular shape of each of the component of the implant system, when seen from a top view.  
         [0091]     As may be glanced from  FIG. 4   a , the junction segment  14  of the abutment is so configured and shaped to fit the passage  42  of the collar member  30 . In addition, the projection  16  and post  18  of the abutment  10  are configured and sized to fit the shoulder portion  67  and the central bore  68  of the implant  46 , respectively. Furthermore, the cylindrical portion  40  of the collar member is also configured and sized to fit with the shoulder portion  66  of the implant. This type of configuration of each of the component insures stability and easy installation of the implant system of the invention. Furthermore, as may be seen from  FIG. 4   a , flange  34  of the collar member  30  extends beyond the base of the abutment head  12 . Flange  34  thus serves as a base for supporting a dental prosthesis.  
         [0092]      FIG. 5   a  illustrates a cover screw  80  used during one of the installation step of the implant system. The cover screw  80  is shown has having a substantially flat head  82  which is connected to a threaded post  83 .  FIG. 5   b  illustrates the cover screw secured to the implant  46  of  FIGS. 3   a  and  3   b . As may be seen from  FIG. 5   b  the head  82  of the cover screw  80  sits on top of the open end  64  of the implant and therefore provides a seal of the central bore  68 .  
         [0093]      FIG. 6   a  illustrates a healing screw  84  which is also used during one of the installation step of the implant system of the invention. The head  86  of the healing screw  84  has a cylindrical section  88  and a curved section  90  and is connected to a threaded post  92 . The curved section  90  of the healing screw mimics the curved section  36  of the collar member  30  of  FIGS. 2   a  and  2   b .  FIG. 6   b  illustrates the healing screw secured over the implant  46 . The healing screw  84  also provides a seal of the central bore  68 .  
         [0094]      FIGS. 7   a  to  7   d , illustrate bottom views of abutments  10  having a projection  16  of varying shape according to other embodiments of the present invention.  FIG. 7   a  is a bottom view of the abutment of  FIG. 1   a.    FIG. 7   a  better illustrates the pentagonal shape of projection  16 . For purpose of concision,  FIG. 7   b  to  7   d  will be described only with respect to their differences relative to  FIG. 7   a . As may be seen,  FIG. 7   b  illustrates an abutment  10  having a projection  16  of a hexagonal shape.  FIG. 7   c  illustrates an abutment  10  having a projection  16  of a substantially cylindrical shape and further having an aligning means  92  in the form of a ridge.  FIG. 7   d  illustrates an abutment  10  having a projection of an irregular shape.  
         [0095]     The installation of the implant system of  FIGS. 4   a  and  4   b  may proceed as follows. First, the oral surgeon access the patient&#39;s jawbone through the patient&#39;s gum tissue and remove any remains of the tooth to be replaced. Next, the anchoring site where the implant  46  is to be installed may be widened to accommodate the implant  46 . The implant  46  is inserted into the jawbone, typically by screwing it with the help of the its external threads  54 , although other methods may be used.  
         [0096]     It is to be noted that it may be useful to install the implant so that one side of the projection  16  (e.g., when polygonal) is parallel with either face (external or internal) of the gum. This may facilitate the surgeon&#39;s work as it may provide a point of reference for subsequent alignment of the abutment  10 .  
         [0097]     The cover screw  80  is secured on top of the implant  46  by screwing the threaded post  83  into the implant  46  using the internally threaded portion  72  of the central bore  68 . The patient&#39;s gum is then sutured over the sealed implant  46 . Tissue ingrowth (i.e., ossointegration) is allowed to take place for about  3  to  8  months. The external threads  54  help in stabilizing and anchoring the implant  46  into the bone and/or minimize rotation of the implant  46  with respect to the bone once tissue ingrowth is achieved.  
         [0098]     Once the implant  46  is firmly anchored in the surrounding bone tissue and the bone has healed, the surgeon re-accesses the implant  46  by making an incision through the patient&#39;s gum tissue. The cover screw  80  is removed and a healing screw  84  is installed by screwing its threaded post  92  in to the implant  46 . Within the next few days or weeks the gum tissue will heal and will surround the healing screw  84  mainly at the level of its curved section  90 . The cylindrical section  88  of the healing screw  84  extends further from the gum line.  
         [0099]     The configuration of the healing screw  84  allows the gum to take an appropriate shape for later installation of the collar member  30  and abutment  10 . More particularly, since both the curved section  90  of the healing screw  84  and the curved section  36  of the collar member  30  have a similar configuration the gum will heal leaving an area which will adequately receive the collar member  30 .  
         [0100]     Once the gum has healed, the healing screw  84  is removed and the collar member  30  is installed onto the implant  46  or alternatively assembled with the abutment  10 . The abutment  10  is then aligned with the implant  46  and inserted in a substantially linear translation movement.  
         [0101]     As will be clear from the description and drawings, the assembly of the implant system may be carried in more than one way. For example, the abutment may first be inserted into the collar member&#39;s passage and second being joined, by a substantially linear translation insertion, with the implant. Alternatively, the collar member may be positioned onto the implant and the abutment may then be inserted through the collar member&#39;s passage and into the implant central bore by a substantially linear translation insertion. The assembly of the abutment  10  and collar member  30  is of the tight fit type.  
         [0102]     Once the abutment  10  is shaped to the required configuration, using the direct or indirect technique which will be described hereinbelow, it may be permanently fixed to the implant  46  by the mordancy technique. For example, the post  18  of the abutment  10  may be acid etched. A composite cement may be inserted into the implant&#39;s central bore  68  (e.g., before assembling the prosthesis support with the implant) and both pieces are subsequently joined. The composite cement may thereafter be cured to insure a permanent fixation. As discussed herein, the threaded surface  72  serves to attach the cover screw, the healing screw (healing cup) and the impression copying. However, the threaded surface  72  also permits here a mechanical retention of the abutment  10  with the implant  46  during cementation. The central throughbore  19  of the abutment  10  allows the air under pressure and surplus sealing mordancy to escape the bore  68  upon assembly. The collar member  30  may be held between the abutment  10  and implant  46  without additional attachment. Therefore, the assembly and fixation mechanism of the implant system does not require the use of a screwing member, e.g., a separate screw or integral threaded post. A permanent fixation between the two components is thus provided and the use of a discrete fastener, such as a screw is avoided.  
         [0103]     The dimensions of the junction segment  14 , projection  16  and post  18  may be slightly smaller than the dimensions of the shoulder portions  66 ,  67  and central bore  68 . Assembly of post  18  and central bore  68  is of the clearance fit type. Assembly of the projection  16  and shoulder portion  67  is of the slide fit type. A shock absorbing gap may thus be provided by the empty spaces between the abutment  10 , collar member  30  and implant  46  surfaces. This arrangement may allow the abutment  10  to flex slightly relative to the implant  46  as it is submitted to chewing forces.  
         [0104]     The materials which are suitable for the implant system of the present invention, include those described hereinbelow.  
         [0105]     The abutment may be made from a material compatible with the CAD/CAM milling procedures and system and also compatible with hand operated dentistry tools such as chisels, milling machines, trimmers, etc. CAD/CAM systems are composed of a data acquisition and analysis unit as well as a machine that is able to shape machinable pieces based on a 3D model. Dental material that may be used with the CAD/CAM system are known in the art. These include for example, ceramics and highly filled composite material such as the following: 
        3M* Paradigm* MZ100 block for CEREC*; 85 Wt % ultrafine zirconia-silica ceramic particles that reinforce a highly crosslinked polymeric matrix. The polymer matrix consists of Bisphenol A diglycidyl ether dimethacrylate and triethylene glycol dimethacrylate.     Vita Mark II Vitabloc for CEREC*; This product is manufactured from fine particles of dental ceramics with wear characteristics similar to natural tooth enamel. This product has a homogenous microstructure and a flexural strenght of about 160 Mpa.     Lithium Disilicate for CAD/CAM (Jeneric Pentron, USA); This material is similar to OPC 3G (Jeneric Pentron, USA) and comprises about 60% of interlocked needle-shaped lithium disilicate crystals embedded into alumino-borosilicate glass matrix and possesses a resistance to cleavage of about 300 Mpa.     IPS Empress* 2; leucite-reinforced ceramic pressable containing latent nucleating agents. The leucite-reinforced ceramic powder is pressed into ingots and sintered.  *Trademark          
 
         [0110]     Other material which may be used to make the abutment of the implant system include: Vita Zeta HC Composite or Vita Zeta Heat Cure Composite, VitaPress, Ivoclar ProCAD blocks (this material is also reinforced with leucite particles).  
         [0111]     A variety of highly filled composite material may be suitable for the abutment of the present invention. Such highly filled composite materials may have, for example, the following characteristics: 
        a composition comprising between 50 and 98% (w/w) of solid substrate, e.g., between 50 and 95% of solid substrate or for example, between 50 and 90% of solid substrate;     a density of between 2.0 and 3.8 g/cm 3 ;     a flexural strength of between 100 and 600 MPa, for example between 100 and 450 MPa. Generally, the material used for the abutment  10  may be chosen based with a flexural strength which is similar to or slightly lower than the flexural strength of the implant  46 ;     a Young&#39;s modulus of between 4 and 200 GPa;     a flexural modulus of between 4 and 40 GPa;     a fracture toughness of between 0.6 and 1.5 GPa; and/or     a compressive strength of between 300 and 900 MPa.        
 
         [0119]     When a highly filled composite material is used for the abutment  10 , the aesthetic appearance (desired color, translucence) of the tooth prosthesis is improved. For example, the shade or color may be selected according to the color of the surrounding tooth or teeth which is not possible for metallic abutments. In addition, an abutment made from a highly filled composite material may be fixed to the implant by the mordancy technique which may prove difficult when using metallic components. Furthermore, fixation of the tooth prosthesis (e.g. porcelain) is more easily achieved.  
         [0120]     According to embodiments of the present invention, the implant  46  may be made from a material allowing ossointegration, more particularly, a material such as titanium, titanium alloy, gold, zirconium oxide, aluminum oxide, ceramics, i.e., bio-ceramics (e.g., zircon ceramics), or other biocompatible material  
         [0121]     Also according to embodiments of the present invention the collar member  30  may be made, for example, from a material such as titanium, titanium alloy, gold, zirconiumi oxide, or ceramics (e.g., zircon ceramics). Since the collar member is in close contact with the gum tissue, the use of zirconium oxide or zircon ceramics has been found to minimize the risk of bacteria growth, decrease tartar formation and increase the esthetic and optical quality of the dental fixture (shade, translucency). Ceramics used to make the collar member may include, for example, a ceramic made from aluminum oxide, zirconium oxide and the like as well as combination thereof. Such ceramics may have, for example, the following characteristics; 
        a density of between 2.4 and 6.2 g/cm 3  (e.g., 2.4, 3.8, 3.9, 4, 5.8, 6.1, etc.);     an elastic modulus of between 100 and 380 GPa (e.g., 104±4, 350±20, 370±20, 360±20, 200±20, etc.);     a Poisson&#39;s ratio of between 0.22 and 0.34 (e.g., 0.22, 0.23, 0.30, 0.34, etc.);     a flexural strength of between 200 and 1600 MPa (e.g., 300±30, 400±20, 700±20, 900±30 1200±20, etc.);     a fracture toughness of between 2 and 15 MPa×m ½ (e.g., 2, 3, 4, 5, 6, 9, 13, 15, etc.)     a hardness of between 6 and 15 GPa (e.g., 6, 7, 12.8, 13.2, 13.6, 14.2, 14.6, 15, etc.) and/or     CTE (coefficient of thermal expansion) of between 9 and 11 10 −6 ×° C. −1  (e.g., 10.3 (from 25° C. to 1000° C.), 8 (from 25° C. to 1000° C.), etc.).        
 
         [0129]     Two restorative options are possible using the implant system of the present invention, especially when a highly filled composite material is used to make the abutment (i.e., a material having the machinability advantages (properties) of a direct restorative material and those of an indirect restorative material):  
         [0130]     A direct restorative technique : a dentist may shape the abutment to fit the required configuration directly in the patient&#39;s mouth for subsequent installation of the prosthetic tooth. It is possible to add or remove material from the abutment. This technique does not require impression coping or an impression copying. For example, material may be added or removed from the abutment head  12  depending on the shape, dimension and angularity (with respect to the implant or post) needed by the patient and determined by the dentist. The dentist therefore machines the abutment head  12  (e.g., using traditional dentistry tools) of the abutment  10  to fit with the prosthesis. The prosthesis is subsequently installed.  
         [0131]     An indirect restorative technique: a dentist may take an impression of the patient&#39;s mouth using the impression copying (analogue system) described herein and the abutment may be sent to an outside laboratory which will shape the abutment to the required configuration (e.g., using a CAD/CAM system) based on the impression. The installation of the shaped abutment is thus performed as a separate step. The prosthesis is subsequently installed. The indirect approach requires more chair time.  
         [0132]     Abutments  10 , according to embodiments of the present invention may be provided with different shapes and dimensions such as, for example oval (e.g., when seen from a top view), circular, rectangular, frusto-conical, square or even irregular shapes may be used. The same applies for collar members  30  and implants  46 . For example, the abutment  10 , the collar member  30  and the implant  46  may be provided in a variety of sizes suitable for either lateral, central, cuspid and bicuspid teeth and for molars or suitable for the specific needs of an individual. The dimensions of the curved section  36  of the collar member  30  may vary to accommodate various tissue heights. Also, the junction segment  14  of the abutment may be tapering inwardly and downwardly toward the post. Therefore, any variation in shape, length, diameter, width, angularity etc. of any component or any individual part of a component of the implant system, impression copying, screws (cover, screw, healing screw, screw of the impression copying) of the present invention are encompassed herein.  
         [0133]     As another example, the projection  16  may take any other shapes than the pentagonal shape illustrated in  FIG. 1   b.  The projection may have any other suitable polygonal shape (e.g., hexagonal, etc.), oval shape or even an irregular shape. Implant system having projection  16  which tapers inwardly and downwardly are also encompassed by the present invention. Whatever the shape and size of the projection  16  it would be preferable to provide an implant  46  with a matching shoulder  67 . It may be preferable to have a projection  16  with a low number of sides (e.g., a three-sided polygon, a five-sided polygon, a seven-sided polygon) for allowing alignment of the abutment  10  with the implant  46  in a limited number of positions. It may also be useful to have a projection  16  with an uneven number of sides.  
         [0134]     As will easily be understood by one skilled in the art, the projection  16  only allows alignment of the abutment  10  with the implant  46  in a limited number of positions, five in the case of  FIG. 1   a  and  FIG. 1   b.  Alignment is performed by positioning the abutment  10  onto the implant  46  in such a way that the shape of the projection  16  of the abutment  10  is matched and fitted into the shouldered portion  67  of the implant  46 . The projection  16  also prevents rotation of the abutment  10  with respect to the implant  46 .  
         [0135]     The expression “limited number of positions” is to be understood herein as the number of possible positions for inserting the abutment into the implant, this number being, for example preferably below 20 possible positions, more preferably below 10 possible positions.  
         [0136]     It is also understood herein, that an abutment having a substantially circular shaped projection  16 , may also serve for aligning the abutment with the implant, provided that the projection  16  would have one or more additional aligning means as illustrated by ridge  92  in  FIG. 7   c . Such additional aligning means may be, for example, selected from the group consisting of a protrusion, a notch, a ridge, a concave structure, a convex structure, a tapered structure, a pin, and combinations thereof. Therefore, the aligning means would also partially block or minimize rotation. Of course, in the event a projection  16  would have aligning means  92  (as illustrated in  FIG. 7   c ), the shoulder portion  67  would also be configured to match it, e.g., in a male-female type of structure (not illustrated).  
         [0137]     Turning now to  FIGS. 8   a ,  8   b  and  8   c , an implant system  100  according to another embodiment of the present invention will be described. It is to be noted that the implant system  100  of these figures is very similar to the implant system illustrated in  FIGS. 1   a  to  6   b . Therefore, for concision purposes, only the differences between these implant systems will be described hereinbelow.  
         [0138]     The main difference between the implant system  100  and the implant system described hereinabove is that the abutment head  112  of the abutment  110  is substantially oval (when seen from a top view). In addition, the collar member  130  is also illustrated as having an oval shape. Those dimensions may be useful, for example, for an implant installed in place of a cuspid or bicuspid tooth. A position that the implant system may held once installed in the mouth of an individual is suggested in  FIG. 8   a  and  FIG. 8   b  where V is the vestibular side, D is the distal side, M is the mouth side and L is the lingual side. Other positions may be assumed depending on the need of the patient.  
         [0139]      FIG. 9  of the appended drawings illustrates an implant system  200 , according to a third embodiment of the present invention. Again, only the differences between the implant system  200  and the implant system described hereinabove with reference to  FIGS. 1   a  to  6   b  will be described.  
         [0140]     In  FIG. 9 , the collar member  230  is illustrated has having one of its side higher than the opposite side. This type of implant system or collar member  230  is referred as being contoured. Accordingly the abutment  210 , more particularly the abutment head  212  and the junction segment  214 , is adapted to fit with the contoured collar member. This type of system may be particularly useful for substantially circular or substantially square teeth, such as a molar, especially when one side of the gum tissue is higher than the opposite side (e.g., lingual v mouth).  
         [0141]     An implant system  300 , according to a fourth embodiment of the present invention will now be described with reference to  FIGS. 10   a,    10   b  and  10   c.    
         [0142]     As shown in  FIG. 10   b,  the collar member  330  is contoured as the collar member  230  of  FIG. 9 . In addition, the collar member  330  and the abutment  310  illustrated in  FIGS. 10   a,    10   b  and  10   c  have a substantially oval shape. Again, the abutment  310 , more particularly the abutment head  312  and the junction segment  314 , is configured to match the collar member  330 . This type of system may be particularly useful for oval teeth, such as a cuspid or bicuspid tooth, especially when one side of the gum tissue is higher than the opposite side (e.g., lingual v mouth). A position that the implant system may held once installed in the mouth of an individual is suggested in  FIG. 10   a  and  FIG. 10   b  where V is the vestibular side, D is the distal side, M is the mouth side and L is the lingual side. Other positions may be assumed depending on the need of the patient.  
         [0143]      FIGS. 11   a,    11   b  and  11   c  illustrate implant systems  400 ,  500 , and  600  respectively according to additional embodiments of the present invention. In  FIGS. 11   a,    11   b  and  11   c,  the collar members  430 ,  530  and  630  are of the contoured type. However, the top surface of each abutment is at an angle with respect to the implant central longitudinal axis. The abutment  410  and more particularly the abutment head  412  of  FIG. 11   a  is shown with an angle of approximately 18° with respect to the central longitudinal axis  448  (as well as with respect to the post  418 ). The abutment  510  and more particularly the abutment head  512  of  FIG. 11   b  is shown with an angle of approximately 23° with respect to the central longitudinal axis  548  (as well as with respect to the post  518 ). The abutment  610  and more particularly the abutment head  612  of  FIG. 11   c  is shown with an angle of approximately 30° with respect to the central longitudinal axis  648  (as well as with respect to the post  618 ). More particularly angles of between 15° and 35° (or −15° to −35°) are encompassed by the present invention. These types of implant system may be required depending on the specific needs of an individual which is easily determined by the dentist. Of course, the length, shape (oval v circular) size may vary as described herein.  
         [0144]     Turning now to  FIGS. 12   a  and  12   b  of the appended drawings, an impression copying  700 , compatible with the implant  46  will be described.  
         [0145]     The impression copying  700  comprises an elongated section  702 , a curved section  704  and a cylindrical section  706 . The impression copying  700  has a channel  708  passing therethrough. The impression copying  700  possesses, on its external face  710 , substantially horizontal grooves  712  and substantially vertical grooves  713  which are found on the elongated section  708 . The curved section  704  of the impression copying mimics the curved section  36  of the collar member  30  illustrated in  FIGS. 2   a  and  2   b . The cylindrical section  706  of the impression copying  700  mimics the cylindrical section  40  of the collar member  30  as also illustrated in  FIGS. 2   a  and  2   b . The impression copying  700  may therefore be installed onto the implant  46  and may be temporarily held in place with the help of an attaching means such as a screw  714  as the one illustrated in  FIG. 12   b . The screw  714  of  FIG. 12   b  has a substantially elongated cylindrical head  716 , a junction segment  718  and a threaded post  720 . Each part of the screw  714  matches the corresponding internal dimensions of the impression copying  700 .  
         [0146]     In use, the impression copying  700  is installed onto the implant  46  and secured with the help of a screw  714 . An impression is then taken around the impression copying  700 , using for example, a silicone material, such as an addition-curing silicone impression material, a condensation curing silicone impression material, etc. The impression copying  700  may afterward be removed. The laboratory uses the resulting impression to form a prosthetic tooth. The silicone impression will carry impressed threads matching grooves  712  and  713  which will therefore reflect the initial position of the impression copying  700  in the patient&#39;s mouth.  
         [0147]     It is to be understood herein that an implant system having one or more of the individual characteristics described herein is encompassed by the present invention. For example, an implant system having an oval shaped implant, a contoured and oval shaped collar member and an oval shaped angled abutment is also encompassed by the present invention. Similarly, any of the individual characteristics in any implant system&#39;s components or any component&#39;s part may be mixed to provide a desired implant system in accordance with the present invention.  
         [0148]     It may be advantageous in some instance to manufacture a collar member and abutment in a single piece. However, one main advantage of providing two distinct pieces is that both pieces may be made from distinct material as described herein.  
         [0149]     The different components of the implant system (abutment, collar member, implant, which may include a cover screw and a healing screw) and impression copying (when required) may be provided in separate pieces to the dentist or as a standard set of defined dimensions. It may also be useful to have an abutment with the characteristics described herein specifically designed to be used with prior art implant. In addition, a separate implant having the characteristics described herein is also encompassed by the present invention.  
         [0150]     Other variations of the invention encompassed by the present invention include the following. For example, the elongated post  18  of the abutment may be provided with a tapered section at its tip. A tapered section may generally increase the flow of mordancy upon fixation of the abutment  10  to the implant  46 . Also, the tip  62  of the implant  46 , illustrated in the appended figures as being rounded may be more pointed as illustrated in  FIGS. 8   a  and  8   b  or may have other configuration.  
         [0151]     In addition, it may be useful to provide a collar member having a threaded passage. This may facilitate assembly of the abutment and collar member when, for example, their assembly is required or preferable prior to their installation onto the implant. A prior assembly of an abutment and a collar member may be useful, for example, to prevent lost of one of the component or may facilitate their distribution to the customer.  
         [0152]     Although the present invention has been described in details herein and illustrated in the accompanying drawings, it is to be understood that the invention is not limited to the embodiments described herein and that various changes and modifications may be effected without departing from the scope or spirit of the present invention.