WO2010026371A1

WO2010026371A1 - Dental implant

Info

Publication number: WO2010026371A1
Application number: PCT/GB2009/002108
Authority: WO
Inventors: Barry Noel Edwards
Original assignee: Barry Noel Edwards
Priority date: 2008-09-02
Filing date: 2009-09-02
Publication date: 2010-03-11
Also published as: GB0815895D0

Abstract

This invention relates to a dental implant. The dental implant comprises (a) a dental prosthesis mounting comprising a dental prosthesis base for supporting a dental prosthesis, (b) an implant root for securing the dental implant to a patient's jaw, and (c) a supporting post for securing the dental prosthesis mounting to the implant root. The implant root comprises a root recess shaped to hold the supporting post such that the supporting post and the dental prosthesis base can deflect relative to the implant root.

Description

DENTAL IMPLANT

[001] The present invention relates to a dental implant.

[002] When a patient has had a tooth removed or if the tooth is missing, either for medical or cosmetic reasons, it is well known to replace the removed or missing tooth with a dental implant. It is generally desirable that the function of a dental implant resembles that of the original healthy tooth as closely as possible.

[003] Dental decay and periodontal disease are the main causes of natural tooth loss. The tooth enamel and dentine are organic and are very susceptible to acid and bacterial attack causing decay. The periodontal ligament that connects the tooth root to the surrounding bone is very susceptible to infection that causes bone loss around the tooth, loosening the tooth and eventually leading to tooth loss.

[004] A dental implant has an advantage over a patient's natural tooth because it will normally be made from an inorganic biocompatible material that is not susceptible to decay. Also, the periodontal ligament for the tooth in question will not be present. A benefit of this is that the dental implant will not be prone to periodontal infection if the surface of the implant is in direct contact with the bone where it projects through the soft gum tissue into the mouth. A dental implant is therefore not prone to the two major causes of tooth loss, dental caries and periodontal disease.

[005] There is, however, a disadvantage in removing the periodontal ligament. One of the functions of the periodontal ligament is to allow the tooth to which it is attached to deflect slightly when the tooth experiences a compressive force, such as that which occurs during the chewing of food. This effectively provides a shock-absorbing capacity for the tooth and allows the chewing forces to be transmitted efficiently into the larger volume of the bone surrounding the tooth.

[006] Due to the lack of a periodontal ligament, dental implants have not had the shock-absorbing capacity of a patient's natural tooth. Prior dental implants have addressed the issue of distributing the forces experienced by the implant by increasing the surface area of the implant root where possible. Previous dental implants have also been designed with the root of the implant being rigidly connected to the dental prosthesis, for example by a rigid supporting post. A reason for this rigid connection is to prevent micro-leakage (ie ingress of fluid, eg saliva, into the interior of the implant) at the interface between the post and the root because this has been suggested as a reason for bone loss around the implant.

[007] A problem with such prior art dental implants is that patients can experience a condition known as peri-implant bone loss which can lead to eventual implant loss. When these prior dental implants experience compressive forces, such as those encountered during chewing or grinding, the resulting pressure on the implant is concentrated in a small area close to the surface of the surrounding supporting bone due to the lack of shock-absorbing capacity of the implant. This causes microfractures in the supporting bone and bone loss, as well as producing inflammation in the soft tissue that forms where the supporting bone is lost. This results in the patient's hard bone tissue being pushed away from the dental implant root, thereby expanding the hole into which the dental implant has been inserted during implantation. The enlarged hole in the bone surrounding the dental implant becomes filled with soft tissue which can easily be invaded by the same bacteria that can invade the periodontal ligament around a patient's natural tooth, causing peri- implantitis . Peri-implantitis is inflammation of the supporting soft tissue around the dental implant.

[008] A way of ameliorating this problem has been sought.

[009] According to the present invention there is provided a dental implant comprising:

(a) a dental prosthesis mounting comprising a dental prosthesis base for supporting a dental prosthesis, (b) an implant root for securing the dental implant to a patient's jaw, and

(c) a supporting post for securing the dental prosthesis mounting to the implant root, wherein the implant root comprises a root recess shaped to hold the supporting post such that the supporting post and the dental prosthesis base can deflect relative to the implant root.

[0010] An advantage of the dental implant of the present invention is that because the supporting post and the dental prosthesis base can deflect relative to the implant root, the implant can have a shock-absorbing capacity that mimics that of the periodontal ligament. This deflection, called micro movement, can absorb the stress from the implant despite only having a small amplitude.

[0011] This can protect the patient's jaw where it contacts the implant root near the surface or crest of the alveolar ridge of supporting bone. This can reduce the occurrence or severity of peri-implantitis in a patient into whom the dental implant has been implanted. [0012] In some embodiments, the dental prosthesis mounting may define an aperture that is alignable with the root recess, the supporting post comprising a head. that is receivable by an end of the aperture that is proximal to the patient's jaw and a screw that screws into a recess in the head, and the aperture comprising a section that is shaped such that the head cannot pass through it so that the head is securable in the aperture using the screw. This provides means by which the dental prosthesis mounting may be secured to the implant root. In some embodiments, the head of the supporting post is tapered towards a distal end, the aperture having a complementarily shaped taper. This assists the dental surgeon in seating the dental prosthesis mounting on the head of the supporting post during implantation. In some embodiments, the head of the supporting post is not tapered, the aperture being shaped to receive the non-tapered head.

[0013] In some embodiments, the implant root of the dental implant may have a screw thread on its external surface for assisting in the integration of the dental implant into the patient's jaw.

[0014] In some embodiments, the dental prosthesis mounting of the dental implant may define an aperture that is alignable with the root recess such that the supporting post is receivable by the root recess through the aperture.

[0015] In some embodiments, the supporting post of the dental implant may comprise a body and a head, the head having a larger diameter than the body, and the aperture comprising a section that is shaped such that the head cannot pass through it and into the root recess. This can assist in securing the dental prosthesis mounting to the implant root. [0016] In some embodiments , the root recess of the dental implant may have an opening that is surrounded by a Hp having an arcuate cross- section that in use is contacted by a complementarily shaped curved face on the dental prosthesis mounting. This can assist the dental prosthesis mounting in maintaining contact with the implant root without exposing a root recess opening during deflection of the dental prosthesis base, thereby inhibiting the ingress of foreign matter into the root recess.

[0017] In some embodiments, the dental prosthesis mounting of the dental implant may comprise a connector on which the dental prosthesis base is mountable and that is shaped to abut the implant root.

[0018] In some embodiments, the dental prosthesis base of the dental implant is releasably couplable to the connector. This releasable coupling can allow the dental surgeon to attach a range of different dental prosthesis bases to the connector.

[0019] In some embodiments, the dental prosthesis base of the dental implant may comprise a screw-threaded prosthesis base projection that is shaped to be received by a screw-threaded connector recess in the connector. This screw-threaded coupling can permit easier replacement of the dental prosthesis base with an alternative.

[0020] In some embodiments, the connector of the dental implant may comprise a supporting pillar that is shaped to be received by the root recess. The supporting pillar can assist in maintaining the relative alignment of the implant root and the dental prosthesis mounting during use, and/or in limiting the movement of the dental prosthesis base relative to the implant root. [0021] In some embodiments, a gap is provided between the root recess and the supporting pillar. This gap can assist in allowing the supporting pillar, and therefore the dental prosthesis base, to deflect relative to the implant root.

[0022] In some embodiments, the supporting pillar of the dental implant may have a non-circular cross-section that is shaped to be received by a part of the root recess having a corresponding non-circular cross-section. This can assist in inhibiting the rotation of the dental prosthesis mounting relative to the implant root. In some embodiments, the supporting pillar of the dental implant may have a hexagonal cross-section that is shaped to be received by a part of the root recess having a corresponding hexagonal cross-section. In some embodiments, the part of the root recess having a hexagonal cross-section may comprise a screw thread having crests with a hexagonal cross-section and roots with a circular cross-section.

[0023] In some embodiments, the root recess of the dental implant may comprise a screw thread that is shaped to receive a screw thread on the supporting post. This can help to secure the supporting post in the root recess.

[0024] In some embodiments, the head of the supporting post of the dental implant may be shaped to receive a tool for screwing the screw thread of the supporting post into the screw thread of the root recess. This can assist the dental surgeon when screwing the screw thread on the supporting post into the screw thread on the root recess . In some embodiments the head of the supporting post is shaped to receive an Allen key.

[0025] In some embodiments, the dental implant may comprise a resiliently deformable member shaped to be received by the root recess and to contact the supporting post. The resiliently deformable member can assist in absorbing deflective forces experienced by the dental prosthesis base, which can reduce the occurrence or severity of peri- implantitis in a patient. In some embodiments the resiliently- deformable member is a spring. The tension of the spring may be selected depending upon the patient's requirements.

[0026] In some embodiments, the dental prosthesis mounting of the dental implant may comprise a supporting pillar that is shaped to be received by the root recess, the supporting pillar having a screw thread on its external surface that is shaped to be received by a screw thread in the root recess. This provides a means by which the dental prosthesis mounting can be secured to the implant root.

[0027] In some embodiments, the dental prosthesis mounting of the dental implant may define an aperture that is alignable with the root recess such that the supporting post is receivable by the root recess through the aperture.

[0028] In some embodiments, a gap is provided between the aperture defined by the dental prosthesis mounting and the supporting post. This gap can assist in allowing the supporting post, and therefore the dental prosthesis base, to deflect relative to the implant root.

[0029] In some embodiments, the supporting post of the dental implant may comprise two heads separated by a body, the heads having a larger diameter than the body and at least one head being releasably couplable to the body, and the aperture comprising a section that is shaped such that the heads c annot pass through it. The heads may therefore assist in securing the supporting post at either end of this section of the aperture. In some embodiments, one head, both heads and/or the body may have a non-circular cross-section . that is shaped to be received by a part of the root recess and/or a part of the aperture defined by the dental prosthesis mounting and the supporting post having a corresponding non-circular cross-section. This can assist in inhibiting the rotation of the dental prosthesis mounting relative to the implant root. In some embodiments, one head, both heads and/or the body may have a hexagonal cross-section that is shaped to be received by a part of the root recess and/or a part of the aperture defined by the dental prosthesis mounting and the supporting post having a corresponding hexagonal cross-section.

[0030] In some embodiments, the at least one releasably coupled head of the supporting post may comprise a screw-threaded head protrusion that is shaped to be received by a screw-threaded head protrusion recess in the body. This can make it easier for the dental surgeon to couple and uncouple the head during use. In some embodiments, at least one releasably coupled head may be shaped to receive a tool (eg an Allen key) for screwing it into the body.

[0031] In some embodiments, the dental prosthesis mounting of the dental implant may comprise a connector on which the dental prosthesis base is slidably mountable and that is shaped to abut the implant root, wherein the connector comprises a curved face having an arcuate cross- section that in use is contacted by a complementarily shaped curved face on the dental prosthesis base. This assists the dental prosthesis base in maintaining contact with the connector during deflection of the dental prosthesis base without exposing a root recess opening, thereby inhibiting the ingress of foreign matter into the root recess.

[0032] In some embodiments, the dental prosthesis base may be substantially parallel to the implant root. In some embodiments, the dental prosthesis base may be offset relative to the implant root. Suitable offsets are in the range 0 degrees to 40 degrees, preferably in 5 degree increments. For example, a kit may be provided comprising an implant root, a supporting post and dental prosthesis bases having various offsets relative to the implant root.

[0033] According to the present invention there is also provided a method of cosmetic dental treatment comprising the steps of:

(a) providing a dental implant according to the invention,

(b) securing the implant root to the patient's jaw, (c) securing the dental prosthesis mounting to the implant root using the supporting post, and

(d) mounting a dental prosthesis on the dental prosthesis mounting.

[0034] The present invention will be further described in greater detail by reference to the following Figures of the accompanying drawings which are not intended to limit the scope of the invention claimed, in which:

Figure 1 shows a cross-sectional view of an assembled dental implant according to a first embodiment of the present invention.

Figure 2 shows a cross-sectional view of the supporting post and dental prosthesis mounting of the dental implant of Figure 1.

Figure 3 shows a cross-sectional view of the dental implant of

Figure 1 in which the supporting post is not inserted into the root recess.

Figure 4 shows a cross-sectional view of an assembled dental implant according to a second embodiment of the present invention. Figure 5 shows a cross-sectional view of the dental implant of Figure 4 in which the supporting post and the dental prosthesis mounting have been removed from the root recess.

Figure 6 shows a cross-sectional view of an assembled dental according to a third embodiment of the present invention.

Figure 7 shows a cross-sectional view of the dental implant of Figure 6 in which the supporting post and dental prosthesis mounting have been removed from the root recess.

Figure 8 shows a cross-sectional view of the implant of Figure 6 in which an alternative connector has been used and the support post and the dental prosthesis mounting have been removed from the root recess.

Figure 9 shows a cross-sectional view of an assembled dental implant according to a fourth embodiment of the present invention.

Figure 10 shows a cross-sectional view of the dental implant of

Figure 9 in which the supporting post and the dental prosthesis mounting have been removed from the root recess.

Figure 11 shows a cross-sectional view of the supporting post and dental prosthesis mounting of the dental implant of Figure 9 in which an alternative prosthesis base has been used.

Figure 12 shows a cross-sectional view of the implant root of the dental implant of Figure 3 along line R-R. Figure 13 shows a cross-sectional view of the supporting post of the dental implant of Figure 2 along line S-S.

Figure 14 shows a cross-sectional view of the supporting post of the dental implant of Figure 11 along line U-U.

Figure 15 shows a cross-sectional view of the supporting post of the dental implant of Figure 11 along line V-V.

Figure 16 shows a cross-sectional view of the supporting post of the dental implant of Figure 11 along line W-W.

Figure 17 shows a cross-sectional view of the dental prosthesis mounting of the dental implant of Figure 11 along line X-X.

[0035] Figures 1, 2 and 3 depict a dental implant 1 according to the first embodiment of the present invention for insertion into a patient's jaw. The dental implant 1 comprises an implant root indicated generally at 5 (not shown in Figure 2) , a supporting post indicated generally at 10 and a dental prosthesis mounting indicated generally at 15 comprising prosthesis base 95 and supporting pillar 90.

[0036] As shown in Figures 1 and 3, implant root 5 for securing the dental implant to a patient's jaw has screw thread 20 formed on its curved outer surface and is cylindrical (not shown) . Root recess indicated generally at 25 is partly cylindrical (or circular) and partly hexagonal in cross-section (not shown) , is formed in implant root 5 and extends from root recess opening 30 at a distal end 31 of implant root 5. In other embodiments, root recess 25 may have an entirely circular or entirely hexagonal cross-section. [0037] Root recess 25 extends approximately 3/4 of the length of implant root 5 to root recess base 32 near domed proximal end 33 of implant root 5. This is so that root recess 25 can hold supporting post 10 whilst also providing space for the deflection of supporting post 10 relative to implant root 5.

[0038] Root recess 25 comprises three sections, a proximal section 35 that is closest to proximal end 33 of implant root 5, a distal section 40 that is adjacent to root recess opening 30, and an intermediate section 45 that is between proximal section 35 and distal section 40.

[0039] Proximal section 35 of root recess 25 is cylindrical and has cylindrical screw thread 50 formed on its curved inner surface. Proximal section 35 has a smaller diameter than either intermediate section 45 or distal section 40.

[0040] Intermediate section 45 of root recess 25 is cylindrical and has a diameter that is larger than that of proximal section 35, but smaller than that of distal section 40.

[0041] Distal section 40 of root recess 25 has a diameter that is larger than that of either intermediate section 45 or proximal section 35. As shown in Figure 12, distal section of 40 of root recess 25 has a hexagonal cross-section. This hexagonal cross-section is provided by a screw thread 41 formed on the internal surface of distal section 40. Screw thread 41 has crests which are hexagonal in cross-section as shown in Figure 12. However, the roots of screw thread 41 are circular in cross-section. This means that distal section 40 can engage a supporting pillar 90 with a hexagonal cross-section in a way that limits relative rotation of the implant root 5 and the dental prosthesis mounting 15. In addition, distal section 40 can engage a supporting pillar 90 provided with a screw thread of circular cross-section.

[0042] Thus, the root recess 25 has a progressively decreasing diameter from root recess opening 30 to root recess base 32. This is so that the supporting post 10 can be held in the narrowest, proximal section 35 of the root recess 25 whilst the wider intermediate 45 and distal sections 40 have a sufficient diameter to allow the supporting post 10 to deflect relative to the implant root 5.

[0043] Root recess opening 30 is surrounded by arcuate lip 51. Lip 51 comprises inner edge 55 that defines root recess opening 30 and outer edge 60 that is adjacent to screw thread 20 formed on the curved outer surface of implant root 5. Lip 51 curves downwards from inner edge 55 to outer edge 60 such that the cross-section of lip 51 is arcuate. This is so that lip 51 can slidably contact a corresponding surface on the dental prosthesis mounting 15.

[0044] As depicted in Figures 1, 2 and 3, supporting post 10 is in the form of a metal screw and comprises screw thread 70 extending from a proximal end 65 of supporting post 10, head 80 formed at a distal end 75 of supporting post 10 and body 81 intermediate screw thread 70 and head

80. Supporting post 10 is for securing the dental prosthesis mounting 15 to the implant root 5 and for allowing prosthesis base 95 to deflect relative to implant root 5.

[0045] Screw thread 70 of supporting post 10 extends approximately 1/4 of the length of supporting post 10 from proximal end 65. The length and shape of screw thread 70 is such that it will mate with screw thread 50 of proximal section 35 of root recess 25. Screw thread 70 of supporting post 10 engages screw thread 50 of proximal section 35 of root recess 25 at a calculated distance from lip 51 so as to allow adequate deformation and stress absorption along the length of supporting post 10.

[0046] Head 80 of supporting post 10 is cylindrical in shape (not shown) and is of a larger diameter than body 81. Head 80 extends approximately 1/6 of the length of supporting post 10 from the distal end 75. This is so that it can be used to secure the dental prosthesis mounting 15 to the implant root 5 when the screw thread 70 of supporting post 10 is screwed into screw thread 50 of proximal section 35 of root recess 25. Head recess 85 is formed in head 80 and extends approximately 4/5 of the way into head 80 from distal end 75. Head recess 85 has a hexagonal cross- section, for example so that it can receive an Allen key.

[0047] As shown in Figures 1, 2 and 3, dental prosthesis mounting 15 for supporting a dental prosthesis (not shown) comprises prosthesis base 95 mounted on connector 100, connector 100 being mounted on supporting pillar 90. Aperture indicated generally at 115 for accepting supporting post 10 is formed through dental prosthesis mounting 15 along axis A shown in Figures 1 and 2.

[0048] Supporting pillar 90 of dental prosthesis mounting 15 has a proximal end 91 comprising pillar opening 130. The diameter of supporting pillar 90 is slightly smaller than that of distal section 40 of the root recess 25. This is so that supporting pillar 90 can deflect relative to implant root 5. As shown in Figure 13, the external cross-section of supporting pillar 90 is hexagonal so that it can engage the hexagonal distal section 40 of root recess 25 in a way that limits relative rotation of the root 5 and dental prosthesis mounting 15. The cross-section of pillar opening 130 is circular. [0049] Connector 100 of dental prosthesis mounting 15 has a curved face 105 that is adjacent to supporting pillar 90, curved face 105 having an arcuate cross-section that corresponds to Hp 51 on implant root 5. Connector 100 has a curved face 105 so that it can slidably contact arcuate lip 51 on the implant root 5.

[0050] Connector 100 of dental prosthesis mounting 15 also has a flat face 110 that is on the opposite side of the connector 100 to the curved face 105. Flat face 110 comprises a flat surface onto which is mounted prosthesis base 95. In this version of the first embodiment flat face 110 is angled such that prosthesis base 95 is provided at an angle of approximately 40 degrees to vertical line A. However, in alternative versions of the implant 1 this angle may be different, for example between 0 degrees and 40 degrees with respect to vertical line A, depending upon the requirements of the patient.

[0051] Prosthesis base 95 of dental prosthesis mounting 15 is mounted on flat face 110 of connector 100. Prosthesis base 95 comprises side face 97 in which is formed dental prosthesis opening 96. Prosthesis base 95 is shown as being roughly cuboid in shape such that it will mate with a corresponding recess on a dental prosthesis (not shown) . However, alternative shapes of prosthesis base can be provided depending upon the nature of the dental prosthesis used. In the version of the first embodiment shown in the Figures, the prosthesis base 95 has a major axis P (see Figure 2) at an angle of approximately 40 degrees to vertical line A due to its mounting on flat end 110 of connector 100.

[0052] Aperture 115 is formed in dental prosthesis mounting 15 along axis A in Figures 1 and 2. Aperture 115 is cylindrical in shape (not shown) and extends from pillar opening 130 at the proximal end 91 of supporting pillar 90 to dental prosthesis opening 96 in side face 97 of prosthesis base 95.

[0053] Aperture 115 of dental prosthesis mounting 15 comprises proximal section 120 that extends from pillar opening 130 and distal section 125 that extends from dental prosthesis opening 96. Proximal section 120 is substantially within connector 100 and supporting pillar 90, and distal section 125 is substantially within prosthesis base 95.

[0054] The diameter of proximal section 120 of aperture 115 is such that it will allow body 81 of supporting post 10 to be inserted into it, but is too narrow to accept head 80 of supporting post 10. The diameter of distal section 125 of aperture 115 is larger than that of the proximal section 120 such that it will allow head 80 of supporting post 10 to be inserted into it. The differing diameters of the proximal 120 and distal 125 sections mean that the head 80 of supporting post 10 can be used to secure dental prosthesis mounting 15 to implant root 5.

[0055] During implantation, implant root 5 is secured into the patient's jaw. Supporting pillar 90 of dental prosthesis mounting 15 is then inserted into distal section 40 of root recess 25. This brings curved face 105 of connector 100 into contact with lip 51 of implant root 5.

[0056] Proximal end 65 of supporting post 10 is then inserted through aperture 115 and into root recess 25 such that screw thread 70 of supporting post 10 contacts screw thread 50 of proximal section 35 of root recess 25.

[0057] An Allen key (not shown) is then inserted into head recess 85 of supporting post 10 and the Allen key is used to screw supporting post 10 into root recess 25. Because head 80 of supporting post 10 is too large to pass through proximal section 120 of aperture 115 , this secures dental prosthesis mounting 15 to implant root 5.

[0058] The diameter of supporting pillar 90 of dental prosthesis mounting 15 is smaller than that of distal section 40 of root recess 25 such that in use there is a gap between supporting pillar 90 and distal section 40 of root recess 25. This is so that supporting pillar 90 can deflect relative to implant root 5.

[0059] In addition, the diameter of the supporting post 10 is smaller than that of the distal 40 and intermediate 45 sections of root recess 25. This is so that the supporting post 10 can deflect within the root recess 25 relative to the implant root 5. This means that the head 80 of supporting post 10, and therefore prosthesis base 95 of dental prosthesis mounting 15, can deflect relative to implant root 5. Proximal end 65 of supporting post 10 is held in proximal section 35 of root recess 25. The extent of the deflection is determined by how much the diameters of supporting pillar 90 and supporting post 10 are smaller than the proximal 40 and intermediate 45 sections respectively of root recess 25.

[0060] During the deflection of prosthesis base 95 relative to implant root 5, curved face 105 of connector 100 of dental prosthesis mounting 15 slides over lip 51 of implant root 5. The curved face 105 maintains contact with lip 51 such that root recess opening 30 is not exposed, thereby inhibiting the ingress of foreign matter into root recess 25. 3 dimensional computer analysis may be used to design a lip 51 and curved face 105 having dimensions so as to achieve this.

[0061] Figures 4 and 5 depict a dental implant indicated generally at 200^' according to a second embodiment of the present invention for insertion into a patient's jaw. Like features to the first embodiment are indicated with like reference numerals.

[0062] The dental implant 200 of the second embodiment of the present invention comprises an implant root generally indicated at 5, a supporting post generally indicated at 10 and a dental prosthesis mounting generally indicated at 215. The implant root 5 and supporting post 10 of the second embodiment are the same as those of the first embodiment.

[0063] Dental prosthesis mounting 215 comprises prosthesis base 195 mounted on connector 196, connector 196 being mounted on supporting pillar 90. The second embodiment of the invention differs from the first embodiment in that in the second embodiment the prosthesis base 195 and the connector 196 of the dental prosthesis mounting 215 are formed as separate components. The cross-section of supporting pillar 90 is the same as that of the first embodiment.

[0064] Figures 4 and 5 show a version of the second embodiment of the invention in which the prosthesis base 95 is substantially parallel to vertical line A shown in Figure 4.

[0065] Supporting pillar 90 of dental prosthesis mounting 215 has a proximal end 91 comprising pillar opening 130. The diameter of supporting pillar 90 is slightly smaller than that of distal section 40 of the root recess 25. This is so that supporting pillar 90 can deflect relative to implant root 5.

[0066] Connector 196 of dental prosthesis mounting 215 has a curved face 105 that is adjacent to supporting pillar 90, curved face 105 having an arcuate cross-section that corresponds to lip 51 on implant root 5. Connector 196 has a curved face 105 so that it can slidably contact arcuate lip 51 on the implant root 5.

[0067] Connector 196 of dental prosthesis mounting 215 also has a flat face 110 that is on the opposite side of the connector 100 to the curved face 105. Flat face 110 comprises a flat surface onto which is mounted prosthesis base 195. In the version of the second embodiment shown in the Figures, flat face 110 is angled such that prosthesis base 195 is parallel to axis A (shown in Figure 4) .

[0068] As for the first embodiment, aperture 115 is formed in dental prosthesis mounting 215 along axis A shown in Figure 4.

[0069] Prosthesis base recess 155 is formed in connector 196 and extends from flat face 110 of connector 196. In the version of the second embodiment of the invention shown in Figures 4 and 5, prosthesis base recess 155 is coincident with aperture 115 such that prosthesis base 195 is substantially parallel to axis A shown in Figure 4.

[0070] Prosthesis base recess 155 has screw thread 135 formed on its curved inner surface. Screw thread 140 is formed on protrusion 145 that extends from proximal end 150 of prosthesis base 195. The shape of screw thread 140 is such that it will mate with screw thread 135 of prosthesis base recess 155.

[0071] During implantation, implant root 5 is secured in the patient's jaw. Supporting pillar 90 of connector 196 of dental prosthesis mounting 215 is then inserted into distal section 40 of root recess 25. This brings curved face 105 of connector 196 into contact with lip 51 of implant root 5. [0072] Proximal end 65 of supporting post 10 is then inserted through aperture 115 such that screw thread 70 of supporting post 10 contacts screw thread 50 of proximal section 35 of implant root 5.

[0073] An Allen key (not shown) is then inserted into head recess 85 of supporting post 10 and the Allen key is used to screw supporting post 10 into implant root 5. Because head 80 of supporting post 10 is too large to pass through proximal section 120 of aperture 115, this secures supporting pillar 90 and connector 196 to implant root 5.

[0074] Protrusion 145 of prosthesis base 195 is then inserted into prosthesis base recess 155 such that screw thread 140 of protrusion 145 contacts screw thread 135 of prosthesis base recess 155. Prosthesis base 195 is then rotated about axis A in order to screw it into connector 196.

[0075] Figures 6, 7 and 8 depict a dental implant indicated generally at 250 according to a third embodiment of the present invention for insertion into a patient's jaw. Like features to the first embodiment are indicated with like reference numerals.

[0076] Dental implant 250 of the third embodiment comprises an implant root generally indicated at 5, a supporting post generally indicated at 210 and a dental prosthesis mounting generally indicated at 240 comprising prosthesis base 195. The implant root of the third embodiment is the same as that of the first embodiment.

[0077] As depicted in Figures 6, 7 and 8, supporting post 210 is in the form of a metal screw and comprises screw thread 70 extending from a proximal end 65 of supporting post 210. At a distal end 75 of supporting post 210 is head generally indicated at 220 in which is formed slot 211. Slot 211 mates with screw indicated generally at 212. Between screw thread 70 and head 220 is body 81 of supporting post 210. Supporting post 210 is for securing dental prosthesis mounting 240 to implant root 5 and for allowing prosthesis base 195 to deflect relative to implant root 5.

[0078] Screw thread 70 of supporting post 210 extends approximately 1/4 of the length of supporting post 210 from proximal end 65 and is shaped to mate with screw thread 50 of proximal section 35 of root recess 25.

[0079] In the version shown in Figures 6, 7 and 8, head 220 of supporting post 210 comprises proximal section 221 which has a larger diameter than body 81 of supporting post 210. Head 220 of supporting post 210 also comprises distal section 222 which has a diameter substantially the same as that of body 81 of supporting post 210. Thus, head 220 tapers from proximal section 221 to distal section 222. Alternatively, the proximal 221 and distal 222 sections of head 220 of supporting post 210 may have the same diameter such that head 220 is not tapered.

[0080] Slot 211 of head 220 extends approximately 1/4 of the length of supporting post 210 from distal end 75 of supporting post 215. Slot 211 is not tapered.

[0081] Slot 211 of head 220 comprises walls 213 and proximal end 214. Walls 213 have screw thread 216 formed on them. Walls 213 are curved (not shown) such that screw thread 216 of slot 211 will mate with screw thread 223 on screw 212.

[0082] As mentioned above, screw 212 of supporting post 215 has screw thread 223 formed on the curved (not shown) outer surface of its body 228. Screw 212 also has head 224 formed at a distal end 225. Head recess 226 is formed in head 224 and extends approximately 1/2 of the way into head 224 from distal end 225. Head recess 226 has a hexagonal cross-section, for example so that it can receive an Allen key.

[0083] In the version of the third embodiment shown in Figures 6 and 7, dental prosthesis mounting 240 for supporting a dental prosthesis (not shown) comprises prosthesis base 195 mounted on connector 296, connector 296 being mounted on supporting pillar 290. The cross-section of supporting pillar 290 through line R-R is the same as that of supporting pillar 90 of the first embodiment shown in Figure 13.

[0084] In the version of the third embodiment shown in Figures 6 and 7, connector 296 of dental prosthesis mounting 240 has a curved face 105 that is adjacent to supporting pillar 290, curved face 105 having an arcuate cross-section that corresponds to lip 51 on implant root 5.

[0085] In the version of the third embodiment shown in Figures 6 and 7, connector 296 of dental prosthesis mounting 240 also has flat face 110 that is on the opposite side of the connector 196 to the curved face 105. In the version of the third embodiment shown in Figures 6 and 7, flat face 110 comprises a flat surface that is perpendicular to axis A shown in Figure 6. This means that in the version shown in Figures 6 and 7, prosthesis base 195 is substantially parallel to axis A in Figure 6.

[0086] An alternative version of the third embodiment is shown in Figure 8. In this version an alternative connector 197 is provided in which flat face 110 is angled such that prosthesis base 195 is provided at an angle of approximately 40 degrees to vertical line A.

[0087] The dental prosthesis mounting 240 of the third embodiment differs from that of the first embodiment in that in the third embodiment the prosthesis base 195 and the connector 197,296 of the dental prosthesis mounting 240 are formed as separate components and in that the aperture 235 through dental prosthesis mounting is shaped to receive tapered head 220 of supporting post 210. Alternatively, if head 220 is not tapered, aperture 235 may be shaped to receive non-tapered head 220.

[0088] Supporting pillar 290 of dental prosthesis mounting 240 has a proximal end 291 comprising pillar opening 230. The diameter of supporting pillar 290 is slightly smaller than that of distal section 40 of root recess 25 so that supporting pillar 290 can deflect relative to implant root 5.

[0089] Aperture indicated generally at 235 is formed in dental prosthesis mounting 240. Aperture 235 comprises proximal section 237 for accepting supporting post 210 and distal section 255 for accepting prosthesis base 195. Proximal section 237 of aperture 235 is formed entirely along axis A shown in Figure 6. Aperture 235 is cylindrical in shape (not shown) and extends from pillar opening 230 at proximal end 291 of supporting pillar 290 to opening 114 in flat face 110.

[0090] Proximal section 237 of aperture 235 tapers from proximal end 291 of supporting pillar 290 to distal end 292 of supporting pillar 290. The shape of the taper is such that proximal section 237 of aperture 235 will accept tapered head 220 of supporting post 210.

[0091] At distal end 292 of supporting pillar 290 proximal section 237 of aperture 235 connects to distal section 255. Distal section 255 of aperture 235 is formed in connectors 197,296 of dental prosthesis mounting 240 and extends from opening 114 in flat face 110 of connectors 196 and 197 to distal end 292 of supporting pillar 290. [0092] Distal section 255 of aperture 235 is formed such that ft is perpendicular to flat face 110 of connector 197,296. Thus, in the version of the third embodiment shown in Figures 6 and 7, distal section 255 is substantially parallel to axis A shown in Figure 6. In the version of the third embodiment shown in Figure 8, distal section 255 has a major axis E at an angle of approximately 40 degrees to axis A.

[0093] Distal section 255 of aperture 235 has screw thread 135 formed on its curved inner surface. In addition, at the end of distal section 255 of aperture 235 that connects to proximal section 237 there is formed narrowed section 236. Narrowed section 236 is shaped such that it will accept only distal end 75 of head 220 of supporting post 210 and will not allow the rest of head 220 to pass through it. In addition, the diameter of body 228 of screw 212 is such that it can pass through narrowed section 236 of aperture 235, but the diameter of head 224 of screw 212 is too large to pass through narrowed section 236. Thus, when head 220 of supporting post 210 is inserted into proximal section 237 of aperture 235, body 228 of screw 212 can be inserted through narrowed section 236 from the distal section 255 side so that screw thread 216 of supporting post 210 mates with screw thread 223 on screw 212. In this way supporting post 210 can be secured to dental prosthesis mounting 240.

[0094] Prosthesis base 195 has protrusion 145 extending from its proximal end 150. Screw thread 140 is formed on protrusion 145, screw thread 140 being shaped such that it will mate with screw thread 135 of distal section 255 of aperture 235.

[0095] During implantation, implant root 5 is secured in the patient's jaw. Proximal end 65 of supporting post 210 is then inserted into root recess 25 such that screw thread 70 contacts screw thread 50 of proximal section 35 of implant root 5. A specially adapted screwdriver (not shown) is then used to screw supporting post 210 into implant root 5.

[0096] Supporting pillar 290 of connector 197,296 of dental prosthesis mounting 240 is then inserted into distal section 40 of implant root 5 such that head 220 of supporting post 210 is received by proximal section 237 of aperture 235.

[0097] Screw 212 is then inserted through distal section 255 of aperture 235 into slot 211 of supporting post 210 such that screw thread 223 of screw 212 contacts screw thread 216 of slot 211. An Allen key (not shown) is then inserted into head recess 226 of screw 212 and the Allen key is used to drive screw 212 into slot 211.

[0098] Protrusion 145 of prosthesis base 195 is then inserted into distal section 255 of aperture 235 such that screw thread 140 of protrusion 145 contacts screw thread 135 of distal section 255. Prosthesis base 195 is then rotated about axis B in order to screw it into connector 196.

[0099] Figures 9, 10 and 11 depict a dental implant indicated generally at 300 according to a fourth embodiment of the present invention for insertion into a patient's jaw. Like features to the first embodiment are indicated with like reference numerals.

[00100] The dental implant 300 of the fourth embodiment of the invention comprises an implant root generally indicated at 305, a supporting post generally indicated at 310 and a dental prosthesis mounting generally indicated at 315.

[0010I] As shown in Figures 9 and 10, implant root 305 for securing the dental implant 300 to a patient's jaw has screw thread 20 formed on its curved outer surface and is cylindrical (not shown) . Root recess indicated generally at 25 is partly cylindrical (or circular) and partly hexagonal in cross-section (not shown) , is formed in implant root 305 and extends from root recess opening 30 at distal end 31 of implant root 305. In other embodiments, root recess 25 may have an entirely circular or entirely hexagonal cross-section.

[00102] Root recess 25 comprises three sections, a proximal section 35 that is furthest from root recess opening 30, a distal section 40 that is adjacent to root recess opening 30, and an intermediate section 45 between proximal section 35 and distal section 40. Distal section 40 has a larger diameter than intermediate section 45, and intermediate section 45 has a larger diameter than proximal section 35.

[00103] Distal section 40 of recess 25 of implant root 305 has screw thread 41 formed on its curved inner surface. As discussed in relation to the embodiment of the invention shown in Figures 1-3, screw thread 41 has crests which provide a hexagonal cross-section and roots which are circular in cross-section. Thus, screw thread 41 is shaped such that it will mate with a screw thread on the dental prosthesis mounting 315. Proximal section 35 may (ie as it has in the first embodiment of the invention) or may not have a screw thread 50 formed on its curved inner surface .

[00104] The fourth embodiment of the invention differs from the first embodiment in that supporting post 310 comprises body 81 with head 66 at a proximal end 65 and head 80 at a distal end 75. Supporting post 310 is for securing dental prosthesis mounting 315 to implant root 305. [00105] Head 80 of supporting post 310 is separable from body 81. Head 80 has head protrusion 160 extending from its proximal end 170. Head protrusion 160 has a screw thread 165 formed on its curved outer surface.

[00106] Head protrusion recess 175 is formed at distal end 185 of body 81 of supporting post 310. Head protrusion recess 175 has screw thread 180 formed on its curved inner surface. The shape of screw thread 180 is such that it will mate with screw thread 165 of head protrusion 160 of head 80. As shown in Figure 16, head protrusion recess 175 is circular in cross-section and body 81 is hexagonal in cross-section.

[00107] Unlike the supporting post 10 of the first embodiment, supporting post 310 of the fourth embodiment does not have a screw thread 70 at proximal end 65. Instead, second head 66 is provided at proximal end 65 of body 81. Second head 66 has a diameter larger than that of body 81 and such that it can be inserted into intermediate section 45 of recess 25 of implant root 305. As shown in Figure 15, second head 66 has a hexagonal cross-section. In addition, in this embodiment intermediate section 45 of recess 25 of implant root 305 has a hexagonal cross-section. Thus, second head 66 can engage intermediate section 45 in a way that limits the relative rotation of the implant root 305 and the supporting post 310.

[00108] Spring 190 is provided for placement in intermediate section 45 of recess 25 of implant root 305 between proximal end 65 of supporting post

310 and recess base 32 of root recess 25. Spring 190 is for absorbing some of the deflection forces experienced by the dental prosthesis mounting 315 during use. Because the supporting post 310 is not secured to implant root 305, the spring 190 permits micro movement in several directions, including along axis A. [00109] Dental prosthesis mounting 315 of the fourth embodiment of the invention comprises prosthesis base 95 which sits on connector 320, connector 320 being mounted on supporting pillar 390. Thus, the prosthesis base 95 and the connector 320 are formed as separate components .

[0011O] In the version of the fourth embodiment shown in Figures 9 and 10, the major axis of prosthesis base 95 is substantially parallel with vertical line A. Figure 11 shows a version of the fourth embodiment in which the implant has an alternative prosthesis base 95 to that of Figures 9 and 10. This version is shown in dashed lines in Figure 9. The prosthesis base 95 of Figure 11 has a major axis D provided at an angle of approximately 40 degrees to major axis A of the implant 300.

[0011I] As shown in Figure 14, supporting pillar 390 of dental prosthesis mounting 315 has a cylindrical external cross-section and has screw thread 92 formed on its curved outer surface. The shape of screw thread 92 of supporting pillar 390 is such that it will mate with screw thread 41 of distal section 40 of recess 25 of implant root 305.

[00112] Connector 320 comprises curved face 111 on its distal side, curved face 111 being shaped so as to seat a corresponding curved face on prosthesis base 95. Curved face 111 curves downwards from major axis A towards edges 112 such that curved face 111 has an arcuate cross- section.

[00113] Connector 320 also comprises curved face 105 from which supporting pillar 390 extends. Curved face 105 has an arcuate cross- section such that it will seat on lip 51 of implant root 305. [00114] At proximal end 150 of prosthesis base 95 is formed curved face 151. Curved face 151 of prosthesis base 95 has an arcuate cross-section such that it will seat on curved face 111 of connector 320.

[00115] Aperture 115 is formed in dental prosthesis mounting 315 along axis A. Aperture 115 extends from pillar opening 130 at proximal end 91 of supporting pillar 390 to dental prosthesis opening 96 in prosthesis base 95.

[00116] The part of aperture 115 that is formed in prosthesis base 95 comprises distal section 125 which has a circular cross-section and has a diameter such that head 80 of supporting post 310 can be inserted into it. The part of aperture 115 that is formed in prosthesis base 95 also comprises proximal section 98 extending approximately 1/8 of the way from proximal end 150 of prosthesis base 95, proximal section 98 being narrower that distal section 125. Proximal section 98 has a diameter such that it will allow body 81 of supporting post 310 to be inserted into it, but is too narrow to accept head 80 of supporting post 310. As shown in Figure 17, proximal section 98 of aperture 115 has a hexagonal cross- section. This is so that it can engage the hexagonal cross-section of body 81 in a way that limits relative rotation of the supporting post 310 and the dental prosthesis mounting 315. Since the relative rotation of the supporting post 310 and the implant root 305 is similarly limited, the relative rotation of the implant root 305 and the dental prosthesis mounting 315 is also limited.

[00117] The part of aperture 115 that is formed in supporting pillar 390 and connector 320 has a diameter such that when body 81 of supporting post 310 is inserted into aperture 115 there is a gap between the curved outer surface of the body 81 and the curved inner surface of aperture 115. This gap allows the supporting post 310, and the prosthesis base 95, to deflect relative to the implant root 305 and the connector 320. The diameter of this section of aperture 115 is such that second head 66 cannot be inserted into it.

[00118] During implantation, the implant root 305 is secured in the patient's jaw. The spring 190 is then inserted into intermediate section 45 of root recess 25. Body 81 and second head 66 of supporting post 310 are then inserted into root recess 25 such that second head 66 rests on top of spring 190.

[00119] Connector 320 is then inserted into distal section 40 of root recess 25 such that screw thread 92 of supporting pillar 390 contacts screw thread 41 of distal section 40, ensuring that body 81 is inserted into aperture 115 of connector 320. Connector 320 is then screwed into root recess 25 such that proximal end 91 of supporting pillar 390 contacts - second head 66, thereby securing body 81 in the root recess 25.

[00120] Prosthesis base 95 is then placed on top of connector 320 such that curved surface 151 of prosthesis base 95 contacts curved surface 111 of connector 320.

[00121] Head 80 of supporting post 310 is then inserted into distal section 125 of aperture 115 so that head protrusion 160 is inserted through narrowed section 98 and screw thread 165 of head protrusion 160 contacts screw thread 180 of supporting post recess 175.

[00122] An Allen key (not shown) is then inserted into head recess 85 of supporting post 310 and the Allen key is used to screw head 80 of supporting post 310 into body 81 of supporting post 310. Because head 80 is too large to pass through narrowed section 98 of prosthesis base 95, and body 81 of supporting post 310 is held in root recess 25 by connector 320, this secures prosthesis base 95 to implant root 305.

[00123] The gap provided between the outer surface of the body 81 of supporting post 310 and the section of aperture 115 formed in supporting pillar 390 and connector 320 allows prosthesis base 95 to deflect relative to implant root 305 and connector 320. In addition, spring 190 allows implant 300 to absorb forces from a vertical direction F shown in Figure 9.

[00124] During the deflection of the prosthesis base 95 relative to implant root 305, curved face 111 of connector 320 of dental prosthesis mounting 315 slides over curved face 151 of prosthesis base 95 of dental prosthesis mounting 315. Curved faces 111,151 maintain contact such that aperture 115 is not exposed, thereby inhibiting ingress of foreign matter into root recess 25.

Claims

1. A dental implant comprising:

(a) a dental prosthesis mounting comprising a dental prosthesis base for supporting a dental prosthesis,

(b) an implant root for securing the dental implant to a patient's jaw, and

2. A dental implant as claimed in claim 1 , wherein the dental prosthesis mounting defines an aperture that is alignable with the root recess, the supporting post comprising a head that is receivable by an end of the aperture that is proximal to the patient's jaw and a screw that screws into a recess in the head, and the aperture comprising a section that is shaped such that the head cannot pass through it so that the head is securable in the aperture using the screw.

3. A dental implant as claimed in claim 1, wherein the dental prosthesis mounting defines an aperture that is alignable with the root recess such that the supporting post is receivable by the root recess through the aperture.

4. A dental implant as claimed in claim 3, wherein the supporting post comprises a body and a head, the head having a larger diameter than the body, and the aperture comprising a section that is shaped such that the head cannot pass through it and into the root recess.

5. A dental implant as claimed in any one of the preceding claims, wherein the root recess has an opening that is surrounded by a lip having an arcuate cross-section that in use is contacted by a complementarily shaped curved face on the dental prosthesis mounting.

6. A dental implant as claimed in any one of the preceding claims, wherein the dental prosthesis mounting comprises a connector on which the dental prosthesis base is mountable and that is shaped to abut the implant root.

7. A dental implant as claimed in claim 6, wherein the dental prosthesis base is releasably couplable to the connector.

8. A dental implant as claimed in claim 6 or claim 7, wherein the connector comprises a supporting pillar that is shaped to be received by the root recess.

9. A dental implant as claimed in claim 8, wherein a gap is provided between the root recess and the supporting pillar.

10. A dental implant as claimed in any one of the preceding claims, wherein the root recess comprises a screw thread that is shaped to receive a screw thread on the supporting post.

11. A dental implant as claimed in any one of claims 1 to 8, wherein the implant comprises a resiliently deformable member shaped to be received by the root recess and to contact the supporting post.

12. A dental implant as claimed in claim 11, wherein the dental prosthesis mounting comprises a supporting pillar that is shaped to be received by the root recess, the supporting pillar having a screw thread on its external surface that is shaped to be received by a screw thread in the root recess.

13. A dental implant as claimed in either claim 11 or claim 12, wherein the dental prosthesis mounting defines an aperture that is alignable with the root recess such that the supporting post is receivable by the root recess and the aperture.

14. A dental implant as claimed in claim 13, wherein a gap is provided between the aperture defined by the dental prosthesis mounting and the supporting post.

15. A dental implant as claimed in either claim 13 or claim 14, wherein the supporting post comprises two heads separated by a body, the heads having a larger diameter than the body and at least one head being releasably couplable to the body, and . the aperture comprising a section that is shaped such that the heads cannot pass through it.

16. A dental implant as claimed in any one of claims 11 to 15, wherein the dental prosthesis mounting comprises a connector on which the dental prosthesis base is slidably mountable and that is shaped to abut the implant root, wherein the connector comprises a curved face having an arcuate cross-section that in use is contacted by a complementarily shaped curved face on the dental prosthesis base.

17. A method of cosmetic dental treatment comprising the steps of:

(a) providing a dental implant according to any one of the preceding claims,

(b) securing the implant. root to a patient's jaw, (b) securing the dental prosthesis mounting to the implant root using the supporting post, and

(c) mounting a dental prosthesis on the dental prosthesis mounting.