WO2011069226A1

WO2011069226A1 - Apparatus, method, and system for holding a denture

Info

Publication number: WO2011069226A1
Application number: PCT/CA2009/001798
Authority: WO
Inventors: Harold Robert Bergman
Original assignee: Harold Robert Bergman
Priority date: 2009-12-11
Filing date: 2009-12-11
Publication date: 2011-06-16

Abstract

An apparatus for holding a denture having a denture connector in a mouth of a patient is disclosed. The apparatus includes an elongate body having affixing means for affixing the apparatus in the mouth of the patient, and denture engaging means for engaging the denture. The denture engaging means include guiding means for guiding the denture connector in longitudinal movement along the elongate body. The guiding means is dimensioned to enable the denture connector to move and be guided in longitudinal movement along the elongate body in response to a load on the denture, to locate the denture connector in a position to facilitate transfer of the load to soft tissue adjacent the apparatus in the mouth of the patient and reduce vertical loading on the apparatus. The elongate body also has retaining means for receiving and retaining the denture connector on the guiding means.

Description

APPARATUS, METHOD, AND SYSTEM FOR HOLDING A DENTURE BACKGROUND OF THE INVENTION

1. Field of Invention

This invention relates generally to dentures, and more particularly to apparatuses, methods, and systems for holding a denture in a mouth of a patient.

2. Description of Related Art

A denture is a prosthetic device for replacing lost natural teeth in the mouth of a patient. Some conventional dentures are held in the mouth by suction or by adhesives, for example. These dentures generally transfer loads from biting or chewing, for example, to gums or soft tissue in the mouth of the patient.

Alternatively, a denture may be held in place by one or more dental implants that are affixed to jaw bone in the mouth of a patient. A denture of this type is commonly referred to as an "overdenture", and generally has cavities for receiving abutment portions of the dental implants. These dental implants are generally implanted in the jaw bone, and attached to the bone either through scar tissue in the bone or by a process known as osseointegration. The abutment portions of these dental implants are often received within resilient connectors such as flexible O-rings, plastic devices, or resilient soft lining materials, for example, in the cavities of the overdenture. The resilient connectors engage the abutment portions to facilitate holding the overdenture in place. These abutment portions are therefore often referred to as "O-ring abutments".

One conventional O-ring abutment has a peripheral channel that holds an O- ring of an overdenture in a generally fixed longitudinal position relative to the dental implant. As such, when the overdenture receives a load from biting or chewing, for example, the overdenture transfers at least a significant portion of that load to the O-ring, and the O-ring transfers the load to the implant. Load transfer from an overdenture to a dental implant may be referred to as "vertical loading". Vertical loading can damage the connection between the dental implant and bone in the mouth of the patient, which may damage osseointegration or other connections between the dental implant and the bone, and thus weaken the connection of the implant to the bone.

SUMMARY OF THE INVENTION

In accordance with one aspect of the invention, there is provided an apparatus for holding a denture having a denture connector in a mouth of a patient. The apparatus includes an elongate body having affixing means for affixing the apparatus in the mouth of the patient, and denture engaging means for engaging the denture. The denture engaging means includes guiding means for guiding the denture connector in longitudinal movement along the elongate body, the guiding means dimensioned to enable the denture connector to move and be guided in longitudinal movement along the elongate body in response to a load on the denture to locate the denture connector in a position to facilitate transfer of the load to soft tissue adjacent the apparatus in the mouth of the patient. The denture engaging means also includes retaining means for receiving and retaining the denture connector on the guiding means. In accordance with another aspect of the invention, there is provided a denture system. The denture system includes the affixing means of each of the at least one apparatus affixed in bone in a mouth of a patient, and a denture having at least one connector. Each connector is held by a corresponding denture engaging means of a respective apparatus. In accordance with another aspect of the invention, there is provided an apparatus for holding a denture having a denture connector in a mouth of a patient. The apparatus includes an elongate body having an affixing portion operably configured to affix the apparatus in the mouth of the patient, and a denture engaging portion operably configured to engage the denture. The denture engaging portion includes a guide operably configured to guide the denture connector in longitudinal movement along the elongate body, the guide dimensioned to enable the denture connector to move and be guided in longitudinal movement along the elongate body in response to a load on the denture to locate the denture connector in a position to facilitate transfer of the load to soft tissue adjacent the apparatus in the mouth of the patient. The denture engaging portion also includes a stop operably configured to receive and retain the denture connector on the guide.

In accordance with another aspect of the invention, there is provided a denture system. The denture system includes at least one of the apparatus, the affixing portion of each apparatus affixed in bone in a mouth of a patient, and a denture having at least one connector, each connector being held by a corresponding denture engaging portion of a respective apparatus.

In accordance with another aspect of the invention, there is provided a method of holding a denture having a denture connector in a mouth of a patient. The method involves retaining the denture connector on a guiding portion of an elongate body affixed in the mouth of the patient, and guiding the denture connector in longitudinal movement along the guiding portion in response to a load on the denture to locate the denture connector in a position on the guiding portion that facilitates transfer of the load to soft tissue adjacent the apparatus in the mouth of the patient.

Other aspects and features of the present invention will become apparent to those ordinarily skilled in the art upon review of the following description of specific embodiments of the invention in conjunction with the accompanying figures.

BRIEF DESCRIPTION OF THE DRAWINGS

In drawings that illustrate embodiments of the invention,

Figure 1 is a fragmented cross-sectional view of a denture system in accordance with a first embodiment of the invention, in a separated arrangement, Figure 2 is a cross-sectional view of the denture system of Figure 1 in the separated arrangement, taken along the line ll-ll in Figure 1,

Figure 3 is a fragmented cross-sectional view of the denture system of Figure

1 in the separated arrangement, showing a first dental implant of the denture system of Figure 1 ,

Figure 4 is an elevation view of the dental implant shown in Figure 3,

Figure 5 is a plan view of the dental implant shown in Figure 3,

Figure 6 is a side cross-sectional view of a dental implant in accordance with a second embodiment of the invention,

Figure 7 is a plan view of the dental implant shown in Figure 6,

Figure 8 is an elevation view of a dental implant in accordance with a third embodiment of the invention,

Figure 9 is an elevation view of a dental implant in accordance with a fourth embodiment of the invention,

Figure 10 is an elevation view of a dental implant in accordance with a fifth embodiment of the invention,

Figure 11 is an elevation view of an abutment of the denture system of Figure 1 ,

Figure 12 is a side cross-sectional view of an abutment assembly in accordance with a sixth embodiment of the invention, and

Figure 13 is a fragmented cross-sectional view of the denture system of Figure

1 , in an assembled arrangement.

DETAILED DESCRIPTION

Referring to Figures 1 and 2, a denture system in accordance with a first embodiment of the invention is shown generally at 100. The denture system 100 includes an overdenture (or more generally, a "denture") shown generally at 102, a first dental implant 122, and a second dental implant shown generally at 124.

Referring to Figure 2, the overdenture 102 includes a denture base 104 comprised of acrylic or methyl methacrylate, for example, and the denture base 104 includes lateral projections 101 and 103 that are shaped to define a channel 105 that fits over soft tissue (or gum tissue) 106 that surrounds bone 108 in the mouth of a patient. In the embodiment shown, the bone 108 is a mandible or lower jaw bone from which natural teeth of the patient have been removed to allow the denture base 104 to fit in a complementary fashion over the soft tissue 106.

Referring back to Figure 1 , the overdenture 102 includes prosthetic molars 110 and 112, prosthetic bicuspids 114 and 116, a prosthetic canine tooth 118, a prosthetic lateral incisor 120, and a prosthetic central incisor 121 secured to the denture base 104 to project away from the channel 105 to replace corresponding natural teeth of the patient. In alternative embodiments, the overdenture may be formed to fit over a maxilla or upper jaw, and may include prosthetic teeth to replace natural maxillary or upper-jaw teeth. Also, in alternative embodiments, the overdenture may replace all of the upper or lower natural teeth in the mouth of a patient, or the overdenture may replace only certain natural teeth that have been removed.

The denture base 104 includes first and second denture connector assemblies, shown generally at 130 and 132, secured therein when the denture base 104 is formed. The first and second denture connector assemblies 130 and 132 include first and second inserts 135 and 140 respectively, which are annular in the embodiment shown. The first and second inserts 135 and 140, together with the denture base 104, define first and second cavities 134 and 136 respectively. The denture base 104 also defines first and second openings 131 and 133 in communication with the first and second cavities 134 and 136 respectively. In the embodiment shown, the first and second openings 131 and 133 are generally circular, the first and second cavities 134 and 136 are generally cylindrical, and the first and second openings 131 and 133 are axially aligned with the first and second cavities 134 and 136 respectively. The first and second cavities 134 and 136 are bounded by respective end surfaces 142 and 144 of the denture base 104. In the embodiment shown, the denture base 104 includes first and second shoulder portions 139 and 141 , which surround the first and second openings 131 and 133 respectively and contact the first and second inserts 135 and 140 respectively. The first and second shoulder portions 139 and 141 facilitate holding the first and second denture connector assemblies 130 and 132 respectively in the first and second cavities 134 and 136 respectively. Referring to Figure 3, the insert 135 has an inner wall 137 having an inner diameter 143. In the embodiment shown, the first opening 131 also has an inner diameter 146 approximately equal to the inner diameter 143. The inner wall 137 defines a groove 145, which holds a denture connector 138 in the first cavity 134. In this embodiment, the denture connector 138 includes a compressible and resilient rubber ring (or O-ring). Alternatively, however, the denture connector 138 may include silicone or plastic or other resilient materials, for example. When the denture connector 138 is not compressed, an inner surface 147 of the denture connector 138 has an uncompressed diameter 149, which is less than the inner diameter 143. The second denture connector assembly 132 (shown in Figure 1) substantially resembles the first denture connector assembly 130.

Referring to Figure 4, the first dental implant 122 includes an elongate body shown generally at 150. The elongate body 150 has an affixing portion 152 for affixing the first dental implant 122 in the mouth of a patient, a denture engaging portion 154 for engaging the first denture connector assembly 130

(shown in Figure 3), and a transition portion 153 disposed between the affixing portion 152 and the denture engaging portion 154.

The affixing portion 152 is connected directly to the bone 108 (shown in Figures 1 to 3), and in this embodiment is made with an alloy including titanium or another biocompatible material such as zirconium, for example, to facilitate osseointegration with the bone (108). In this embodiment, the affixing portion 152 includes a threaded portion 156 of the elongate body 150 for threadedly engaging the bone 108 (shown in Figures 1 to 3). The affixing portion 152 thus functions as a bone connector and is used to affix the first dental implant 122 in the mouth of a patient. In the embodiment shown, the affixing portion 152 also includes a shoulder portion 158 adjacent the denture engaging portion 154. Referring to Figures 3 and 4, the first dental implant 122 in this embodiment is positioned in the bone 108 such that the shoulder portion 158 is submerged approximately one to two millimeters below a gum-contacting surface 160 of the bone 108 such that the bone 108 may grow over the shoulder portion 158 to retain the affixing portion 152 in the bone 108, particularly against longitudinal movement of the first dental implant 122 relative to the bone 108. This process may be referred to as "platform switching". In general, platform switching advantageously strengthens the connection of the first dental implant 122 in the bone 108. Still referring to Figure 4, the denture engaging portion 154, which may also be referred to as an "abutment portion", includes a guide 162 and a stop 164. The guide 162 in the embodiment shown is disposed adjacent the transition portion 153 and the stop 164 is disposed adjacent the guide 162. The guide 162 includes an elongate surface portion 175 on the elongate body 150. In the embodiment shown, the elongate surface portion 175 has a first width 176 adjacent the stop 164, and a second width 177 adjacent the affixing portion 152. The first width 176 is less than the second width 177, such that the elongate surface portion 175 tapers inwardly in a direction away from the affixing portion 152. The stop 164 in the embodiment shown has an annular concaved stop surface 166 generally facing the guide 162, an end surface 168 generally opposite the stop surface 166, and a peripheral region 170 between the stop surface 166 and the end surface 168. The end surface 168 in this embodiment is gently curved convex, and forms a truncated spherical cap in the embodiment shown. The stop 164 has a diameter 172 defined by the peripheral region 170, and the end surface 168 rises a height 174 above the peripheral region 170. In the embodiment shown, the height 174 is less than half of the diameter 172.

Referring to Figures 4 and 5, the peripheral region 170 in the embodiment shown also includes a peripheral torque transfer surface 178 which is generally hexagonal (or more generally, generally polygonal) in the embodiment shown. More particularly, the peripheral torque transfer surface 178 includes six generally planar faces 180, 182, 184, 186, 188, and 190, and six rounded edges 192, 194, 196, 198, 200, and 202. The rounded edges 192, 194, 196, 198, 200, and 202 advantageously avoid sharp edges between the generally planar faces, as such sharp edges could cause damage to tissue in the mouth, for example. The peripheral torque transfer surface 178 facilitates engagement by a tool (not shown) for applying a torque to the first dental implant 122 to cause the first dental implant 122 to rotate, thereby causing the threaded portion 156 to threadedly engage with the bone 108 (shown in Figures 1 to 3) to a desired depth in the bone (108). In the embodiment shown, torque is applied to the peripheral torque transfer surface 178 until the shoulder portion 158 is approximately one to two millimetres below the gum-contacting surface 160 (shown in Figures 1 to 3) to facilitate platform switching as described above. Referring to Figure 6, a dental implant in accordance with a second embodiment of the invention is shown generally at 300. The dental implant 300 is substantially the same as the first dental implant 122, except that an end surface 302 of a stop 304 defines a recessed torque transfer surface 306. Referring to Figures 6 and 7, the recessed torque transfer surface 306 in the embodiment shown is centrally located and generally hexagonal (or more generally, generally polygonal) and includes six generally planar faces 308, 310, 312, 314, 316, and 318. It will be appreciated that dental implants may include one or both of a peripheral torque transfer surface (such as the peripheral torque transfer surface 178 shown in Figures 4 and 5) and a recessed torque transfer surface such as the recessed torque transfer surface

306, and it will be appreciated that the recessed torque transfer surface 306 facilitates engagement by a tool (not shown) to accomplish substantially the same functions as the peripheral torque transfer surface (178).

Referring to Figure 8, a dental implant in accordance with a third embodiment of the invention is shown generally at 210. The dental implant 210 includes an elongate body shown generally at 212. The elongate body 212 has an affixing portion 214 for affixing the dental implant 210 in the mouth of a patient, and a denture engaging portion (or "abutment portion") 216 for engaging a denture such as the overdenture 102 (shown in Figure 1). The denture engaging portion 216 is substantially the same as the denture engaging portion 154 shown in Figure 4. Although only a peripheral torque transfer surface (such as the peripheral torque transfer surface 178 shown in Figures 4 and 5) is shown, it will be appreciated that the dental implant 210 may additionally or alternatively include a recessed torque transfer (such as the recessed torque transfer surface 306 shown in Figures 6 and 7). Alternatively, the denture engaging portion 216 may not include any torque transfer surface, as the dental implant 210 may be positioned in bone by applying an axial force to the dental implant 210 without necessarily applying any torque. In such alternative embodiments, the denture engaging portion 216 may instead include a smooth peripheral region around the stop.

The affixing portion 214, has a shape similar to that of the affixing portion 152 (shown in Figure 4), although in this embodiment the affixing portion 214 includes a wedge portion 218 of the elongate body 212 for connecting directly to bone (such as the bone 108 shown in Figures 1 to 3) by frictionally engaging the bone. To facilitate osseointegration, the wedge portion 218 in this embodiment is made with an alloy including titanium or another biocompatible material such as zirconium, for example, and may be coated with hydroxyl appetite (not shown) to produce a rougher surface, or the surface of the wedge portion 218 may otherwise be roughened. In this embodiment, the affixing portion 214 includes a shoulder portion 220 adjacent the denture engaging portion 216 to facilitate platform switching as described above. The affixing portion 214 thus functions as a bone connector and is used to affix the dental implant 210 in the mouth of a patient.

Referring to Figure 9, a dental implant in accordance with a fourth embodiment of the invention is shown generally at 230. The dental implant 230 includes an elongate body shown generally at 232. The elongate body

232 has an affixing portion 234 for affixing the dental implant 230 in the mouth of a patient, and a denture engaging portion (or "abutment portion") 236 for engaging a denture such as the overdenture 102 (shown in Figure 1).

The affixing portion 234 includes a wedge portion 238 of the elongate body 232 for connecting directly to bone in the mouth of a patient (such as the bone

108 shown in Figures 1 to 3) by frictionally engaging the bone. Again, to facilitate osseointegration, the wedge portion 238 in this embodiment is made with an alloy including titanium or another biocompatible material such as zirconium, for example, and may be coated with hydroxyl appetite (not shown) or otherwise roughened. However, the wedge portion 238 in this embodiment includes longitudinal projections (or "fins") 240 and 242 for engaging bone in the mouth of a patient (such as the bone 108 shown in Figures 1 to 3) to prevent rotation of the dental implant 230. Alternative embodiments may include one or more projections and recesses (such as grooves or indentations, for example) and the projections and/or recesses may be longitudinal, peripheral, or otherwise oriented to engage the bone and prevent movement of the dental implant 230 relative to the bone. Although two longitudinal projections 240 and 242 are shown, a greater or lesser number of projections and/or recesses may be used. The affixing portion 234 also includes a shoulder portion 244 adjacent the denture engaging portion 236 to facilitate platform switching as described above. The affixing portion 234 thus functions as a bone connector and is used to affix the dental implant 230 in the mouth of a patient.

In the embodiment shown, the denture engaging portion 236 is substantially the same as the denture engaging portions 154 (shown in Figure 4) and 216

(shown in Figure 8). Again, only a peripheral torque transfer surface (such as the peripheral torque transfer surface 178 shown in Figures 4 and 5) is shown, although it will be appreciated that the dental implant 230 may additionally or alternatively include a recessed torque transfer surface (such as the recessed torque transfer surface 306 shown in Figures 6 and 7). Alternatively, the denture engaging portion 236 may not include any torque transfer surface, and may instead include a smooth peripheral region around the stop, particularly in embodiments where one or more projections or recesses are configured to prevent rotation of the dental implant relative to bone. Referring to Figure 10, a dental implant in accordance with a fifth embodiment of the invention is shown generally at 330. The dental implant 330 includes an elongate body shown generally at 332. The elongate body 332 has an affixing portion 334 for affixing the dental implant 330 in the mouth of a patient, and a denture engaging portion (or "abutment portion") 336 for engaging a denture such as the overdenture 102 (shown in Figure 1 ). The denture engaging portion 336 is substantially the same as the denture engaging portion 154 shown in Figure 4. Again, only a peripheral torque transfer surface (such as the peripheral torque transfer surface 178 shown in Figures 4 and 5) is shown, although it will be appreciated that the dental implant 330 may additionally or alternatively include a recessed torque transfer surface (such as the recessed torque transfer surface 306 shown in Figures 6 and 7). Alternatively, the denture engaging portion 336 may not include any torque transfer surface, and may instead include a smooth peripheral region around the stop, particularly in embodiments where one or more projections or recesses are configured to prevent rotation of the dental implant relative to bone.

The affixing portion 334 includes a generally cylindrical portion 338 of the elongate body 332 for connecting directly to bone in the mouth of a patient (such as the bone 108 shown in Figures 1 to 3) by frictionally engaging the bone. The affixing portion 334 also includes a rounded end portion 340.

Again, to facilitate osseointegration, the affixing portion 334 in this embodiment is made with an alloy including titanium or another biocompatible material such as zirconium, for example, and may be coated with hydroxyl appetite (not shown) or otherwise roughened. The affixing portion 334 includes a shoulder portion 342 adjacent the denture engaging portion 336 to facilitate platform switching as described above. The affixing portion 334 thus functions as a bone connector and is used to affix the dental implant 330 in the mouth of a patient. The affixing portion 334 may further include one or more projections or recesses (such as the longitudinal projections 240 and 242 shown in Figure 9, for example), to prevent movement of the dental implant 330 relative to the bone.

The first dental implant 122 (shown in Figures 3 to 5), and the dental implants 300 (shown in Figures 6 and 7), 210 (shown in Figure 8), 230 (shown in Figure 9), and 330 (shown in Figure 10), are, in those embodiments, unitary dental implants that directly engage bone, such as the bone 108 (shown in Figures 1 and 2), for example.

Referring to Figure 1 , as an alternative to the unitary implants shown in Figures 2 to 10, a two piece dental implant may be employed, and the second dental implant 124 is an example of a two-piece dental implant. This type of implant includes a fixture 126 attached directly to the bone 108, and an abutment 128 connected to the fixture 126. In the embodiment shown, the fixture 126 is made with an alloy including titanium or another biocompatible material such as zirconium, for example, to facilitate osseointegration, and is submerged about one to two millimetres below the gum-contacting surface 160 (shown in Figure 1 ) to facilitate platform switching as described above. Referring to Figure 11 , the abutment 128 (also shown in Figure 1 ) includes an elongate body shown generally at 250. The elongate body 250 has an affixing portion 252, which in this embodiment may be referred to as a "fixture connector", for connecting the abutment 128 to the fixture 126, which is attached directly to the bone 108 (as shown in Figure 1). The affixing portion 252 is thus used to affix the abutment 128 in the mouth of a patient. Referring to Figures 1 and 11 , the affixing portion 252 includes a threaded portion 254 of the elongate body 250 for threadedly engaging a complementary portion 256 of the fixture 126. The affixing portion 252 also includes a mating surface, which in the embodiment shown includes a tapered portion 258 of the elongate body 250 for engaging a complementary receptacle 260 of the fixture 126. The tapered portion 258 of the elongate body 250 in the embodiment shown may be referred to as a "Morse taper", and the cooperation of the tapered portion 258 and the complementary receptacle 260 of the fixture 126 has been found to facilitate a secure connection between the affixing portion 252 of the abutment 128 to the fixture

126.

The abutment 128 also includes a denture engaging portion 262 that is substantially the same as the denture engaging portions 154 (shown in Figure 4), 216 (shown in Figure 8), 236 (shown in Figure 9), and 336 (shown in Figure 10) although again, a stop 263 of the denture engaging portion 262 may include one or both of a peripheral torque transfer surface such as the peripheral torque transfer surface 178 (shown in Figures 4 and 5) and a recessed torque transfer surface (such as the recessed torque transfer surface 306 shown in Figures 6 and 7). Referring to Figure 12, an abutment assembly in accordance with a sixth embodiment of the invention is shown generally at 350, and includes an abutment shown generally at 352 and a fastener shown generally at 360. The abutment 352 includes an elongate body that has an affixing portion 354 having a fixture end 370. The affixing portion 354 in the embodiment shown includes a mating surface 356 for contacting a complementary surface on a fixture, such as the complementary receptacle 260 of the fixture 126 shown in Figure 1 , for example. In the embodiment shown, the mating surface 356 is a tapered portion that may be referred to as a "Morse taper" to facilitate a secure connection between the affixing portion 354 of the abutment 352 to the fixture. Alternatively, the mating surface 356 may have an internal or external polygonal cross-section, such as a triangular, square, or hexagonal cross- section, for example.

The abutment 352 also includes a denture engaging portion 358 that is substantially the same as the denture engaging portions 154 (shown in Figure 4), 216 (shown in Figure 8), 236 (shown in Figure 9), 336 (shown in Figure

10), and 262 (shown in Figure 11 ). However, in the embodiment shown, a stop 359 of the denture engaging portion 358 may not include any torque transfer surface, and may instead include a smooth peripheral region around the stop, as the fastener 360 facilitates holding the abutment 352 in a fixture (such as the fixture 126 shown in Figure 1 , for example).

In the embodiment shown, the abutment 352 defines a through-channel 362 for receiving the fastener 360. The fastener 360 includes a head 363 that defines a retaining surface 364 for contacting a complementary surface 366 of the abutment 352 in the through-channel 362. When the fastener 360 is received within the through-channel 362, the retaining surface 364 contacts the complementary surface 366, and a threaded portion 368 of the fastener 360 protrudes through the fixture end 370 of the abutment 352. The threaded portion 368 is threadedly received in a complementary threaded portion of a fixture (such as the complementary portion 256 of the fixture 126 shown in Figure 1 , for example), thereby holding the mating surface 356 against a complementary surface of the fixture (such as the complementary receptacle 260 of the fixture 126 shown in Figure 1 , for example). The affixing portion 354 is thus used to affix the abutment 352 in the mouth of a patient.

Unitary dental implants such as the first dental implant 122 (shown in Figures 3 to 5), and the dental implants 300 (shown in Figures 6 and 7), 210 (shown in

Figure 8), 230 (shown in Figure 9), and 330 (shown in Figure 10), for example, generally have a maximal diameter (shown respectively at 204 in Figure 4, at 320 in Figure 6, at 222 in Figure 8, at 246 in Figures 9, and at 344 in Figure 10) of their respective bone-engaging portions that is less than about three millimeters, although some unitary dental implants may have maximal diameters of their bone-engaging portions in excess of three millimetres. In contrast, a two-piece dental implant such as the second dental implant 124 (shown in Figure 1) generally has a maximal diameter of its bone-engaging portion (shown at 264 in Figure 1) of greater than about three millimetres.

Unitary dental implants such as the first dental implant 122 may thus be referred to as "minis". Generally, a suitable dental implant will have a bone- engaging portion having a maximal diameter that leaves at least about two millimeters of bone surrounding the bone-engaging portion. Therefore, unitary dental implants are more frequently used in regions of a mouth where bone is generally relatively narrow and deep, whereas two-piece dental implants such as the second dental implant 124 may be more suitable for use in regions of a mouth where bone is generally relatively thick and shallow. For example, bone width in the mouth of a patient is known to diminish over time in regions of the mouth where natural teeth are missing, and thus narrower unitary dental implants such as the first dental implant 122, for example, may be more frequently used in such regions.

Referring to Figures 1 and 13, the denture system 100 is shown in different arrangements. Figure 1 shows the denture system 100 in a separated arrangement, wherein the denture base 104 is spaced apart from the soft tissue 106, and the first and second dental implants 122 and 124 are not received in the first and second cavities 134 and 136. Figure 13 shows the denture system 100 in an assembled arrangement. In the assembled arrangement, the soft tissue 106 is received within the channel 105 (shown in Figure 1), the denture base 104 is seated against the soft tissue 106, the denture engaging portion 154 of the first dental implant 122 is received within the first cavity 134, and the denture engaging portion 262 of the second dental implant 124 is received within the second cavity 136. As shown, a mixture of different types of dental implants may be used in the mouth of one patient, depending upon the thickness and depth of available bone, for example, at various locations the mouth of the patient.

The second denture connector assembly 132 substantially resembles the first denture connector assembly 130, and the denture engaging portion 262 of the second dental implant 124 is substantially the same as the denture engaging portion 154 of the first dental implant 122. Therefore, for simplicity, the functions of the first denture connector assembly 130 and the denture engaging portion 154 of the first dental implant 122 are described below, although it will be appreciated that the second denture connector assembly

132 and the denture engaging portion 262 of the second dental implant 124 function in substantially the same way.

Referring back to Figure 3, the diameter 172 of the stop 164 is less than the inner diameter 146 of the first opening 131 , and less than the inner diameter 143 of the inner wall 137, so that the stop 164 can pass through the first opening 131 and into the first cavity 134, as shown in Figure 13.

In order to configure the denture system 100 in the assembled arrangement shown in Figure 13, the overdenture 102 is positioned in the mouth of a patient as shown in Figure 1 , such that the first dental implant 122 is generally aligned with the first opening 131 , and the denture engaging portion 262 of the second dental implant 124 is generally aligned with the second opening 133. The overdenture 102 is then pressed onto the soft tissue 106 such that the denture engaging portion 154 of the first dental implant 122 is received within the first cavity 134, and the denture engaging portion 262 of the second dental implant 124 is received within the second cavity 136.

Referring to Figure 3, in response to an increase in force on the overdenture 102 towards the soft tissue 106, the denture connector 138 is urged against the convex end surface 168, which bears on the inner surface 147 of the denture connector 138. This force on the overdenture 102 causes the convex end surface 168 to deform the resilient denture connector 138, expanding the inner surface 147 from the uncompressed diameter 149 to at least the diameter 172 of the stop 164, thus urging the denture connector 138 over the peripheral region 170. The convex shape for the end surface 168 thus advantageously facilitates positioning the denture connector 138 in the retained position on the guide 162. When the denture engaging portion 154 is received within the first cavity 134, as shown in Figure 13, the denture connector 138 is positioned on the guide 162.

Still referring to Figures 3 and 13, the diameter 172 of the stop 164 is greater than the uncompressed diameter 149 of the inner surface 147 of the denture connector 138, so that the stop surface 166 retains the denture connector 138 in the assembled arrangement on the guide 162, as shown in Figure 13. The first dental implant 122 thus functions as an apparatus to hold the overdenture 102 in the mouth of a patient.

Although in the embodiment shown, the denture connector 138 includes a resilient ring, it will be appreciated that alternatively, the denture connector

138 may include a silicone lining, or plastic or other resilient materials, for example, that function as a cushion and that can be resiliently deformed or compressed as the denture connector 138 is positioned against the guide 162 and thereby retained by the stop 164. Referring back to Figure 3, the first width 176 of the elongate surface portion

175 in the embodiment shown is approximately equal to, or slightly greater than, the uncompressed diameter 149 of the inner surface 147 of the denture connector 138, and thus the elongate surface portion 175 is dimensioned to slidably contact the denture connector 138 to enable the denture connector 138 to move longitudinally along the elongate surface portion 175 between the stop 164 and the affixing portion 152.

When the denture system 100 is in the assembled arrangement shown in Figure 13, the overdenture 102 is pressed against the soft tissue 106 in response to a load on the overdenture 102 resulting from biting or chewing, for example, and the denture connector 138 is therefore guided by the guide

162 in longitudinal movement along the elongate body 150 in a direction towards the soft tissue 106. Advantageously, because the denture connector 138 can move longitudinally along the elongate body 150, at least a greater portion of load on the overdenture 102 is transferred to the soft tissue 106 instead of to the first dental implant 122, when compared to other dental implants that hold a guide in a fixed longitudinal position relative to the dental implant. The overdenture 102 may therefore be referred to as a "soft-tissue- supported overdenture". By facilitating transfer of load on the overdenture 102 to the soft tissue 106 adjacent the first dental implant 122, a reduced load (also known as "vertical load") may be transferred to the first dental implant

122, thus advantageously reducing load transferred to the affixing portion 152 that may loosen or otherwise weaken the connection of the first dental implant 122 to the bone 108.

As indicated above, the denture connector 138 in the embodiment shown is a rubber O-ring, having a resilient tendency to push inwards on the guide 162.

Because the first width 176 is less than the second width 177, the denture connector 138 exerts a greater inward force on the elongate surface portion 175 as the denture connector 138 is displaced along the guide 162 away from the stop 164. Therefore, in the assembled arrangement shown in Figure 13, a load on the overdenture 102 from biting or chewing, for example, may displace the denture connector 138 away from the stop 164, but the inward force of the denture connector 138 on the elongate surface portion 175 urges the denture connector 138 back along the guide 162 towards the stop 164.

In order to reduce vertical loading, contact between the end surface 142 of the denture base 104 to the end surface 168 is preferably reduced or eliminated.

Therefore, the first denture connector assembly 130 in the embodiment shown includes sufficient clearance above the end surface 168 to avoid such contact. A gently curved convex end surface 168 allows for reduced clearance within the first denture connector assembly 130 when compared to some known O-ring abutments, and reducing this clearance advantageously increases thickness and strength of the denture base 104, enabling a stronger overdenture 102.

Although the first dental implant 122 and the first denture connector assembly 130 are shown in Figures 2 and 8, the dental implants 300, 210, 230, and 330 (shown in Figures 6, 8, 9, and 10 respectively), the abutment 128 of the second dental implant 124 (shown in Figures 1 and 11 ), and the abutment 352 (shown in Figure 12) function in a similar manner with a denture connector assembly such as the first denture connector assembly 130. Therefore, the dental implants 300, 210, 230, and 330 (shown in Figures 8, 9, and 10 respectively) and the abutment 128 and 352 (shown in Figures 11 and 12 respectively) also function as apparatuses for holding an overdenture in the mouth of a patient.

While specific embodiments of the invention have been described and illustrated, such embodiments should be considered illustrative of the invention only and not as limiting the invention as construed in accordance with the accompanying claims.

Claims

What is claimed is:

1. An apparatus for holding a denture having a denture connector in a mouth of a patient, the apparatus comprising: an elongate body having: affixing means for affixing the apparatus in the mouth of the patient; and denture engaging means for engaging the denture, said denture engaging means including: guiding means for guiding the denture connector in longitudinal movement along said elongate body, said guiding means dimensioned to enable the denture connector to move and be guided in longitudinal movement along said elongate body in response to a load on the denture to locate the denture connector in a position to facilitate transfer of the load to soft tissue adjacent the apparatus in the mouth of the patient; and retaining means for receiving and retaining the denture connector on said guiding means.

2. The apparatus of claim 1 wherein said guiding means comprises an elongate surface portion on said elongate body, said elongate surface portion being disposed between said retaining means and said affixing means, and operably configured to slidably contact the denture connector to enable the denture connector to move longitudinally along said elongate surface portion between said retaining means and said affixing means.

The apparatus of claim 1 or 2 further comprising means for urging said denture connector along said guiding means towards said retaining means.

The apparatus of claim 2 wherein said elongate surface portion has a first width adjacent said retaining means and a second width greater than said first width adjacent said affixing means, to urge said denture connector along said guiding means towards said retaining means.

The apparatus of any one of claims 1 to 4 wherein said retaining means comprises a stop having a stop surface generally facing said guiding means for retaining the denture connector on said guiding means.

The apparatus of claim 5 wherein said stop has a peripheral torque transfer surface for receiving torque from a tool a first to affix said affixing means in the mouth of the patient.

The apparatus of claim 6 wherein said peripheral torque transfer surface has a generally polygonal shape.

The apparatus of claim 5, 6, or 7 wherein said stop has a recessed torque transfer surface for receiving torque from a second tool to affix said affixing means in the mouth of the patient.

The apparatus of claim 8 wherein said recessed torque transfer surface has a generally polygonal shape.

The apparatus of any one of claims 5 to 9 wherein said stop has an end surface generally opposite said stop surface, and a peripheral region between said end surface and said stop surface.

11. The apparatus of claim 10 wherein said end surface comprises a gently curved convex surface to facilitate urging the denture connector over said peripheral region and onto said guiding means.

12. The apparatus of claim 11 wherein said end surface includes a spherical cap portion.

13. The apparatus of any one of claims 1 to 12 wherein said affixing means comprises a fixture connector for connecting the apparatus to a fixture attached to bone in the mouth of the patient.

14. The apparatus of claim 13 wherein said fixture connector includes a threaded portion of said elongate body for threadably engaging a complementary portion in said fixture.

15. The apparatus of claim 13 or 14 wherein said fixture connector includes a mating surface on said elongate body for engaging a complementary receptacle of said fixture.

16. The apparatus of claim 15, wherein said mating surface is tapered to facilitate a Morse taper with said complementary receptacle.

17. The apparatus of any one of claims 1 to 12 wherein: said affixing means comprises a mating surface on said elongate body for contacting a complementary surface on a fixture attached to bone in the mouth of the patient; and said elongate body defines a through-channel for receiving a fastener for fastening the apparatus to said fixture.

18. The apparatus of any one of claims 1 to 12 wherein said affixing means includes a bone connector for connecting the apparatus directly to bone in the mouth of the patient.

19. The apparatus of claim 18 wherein said bone connector includes a threaded portion of said elongate body for threadably engaging said bone.

20. The apparatus of claim 18 wherein said bone connector includes a wedge portion of said elongate body for frictionally engaging said bone.

21. The apparatus of claim 18 wherein said bone connector includes a generally cylindrical portion.

22. The apparatus of claim 20 or 21 wherein said bone connector further includes at least one projection for engaging said bone to prevent movement of the apparatus.

23. The apparatus of claim 20, 21 , or 22 wherein said bone connector further includes at least one recess for engaging said bone to prevent movement of the apparatus.

24. The apparatus of any one of claims 18 to 23 wherein said bone connector includes a shoulder portion adjacent said denture engaging means to facilitate bone growth over said shoulder portion to retain said bone connector in said bone.

25. Use of the apparatus of any one of claims 1 to 24 for holding the denture in the mouth of the patient.

26. A denture system comprising: at least one of the apparatus of any one of claims 1 to 24, said affixing means of each said at least one apparatus affixed in bone in a mouth of a patient; and a denture having at least one connector, each said at least one connector being held by a corresponding said denture engaging means of a respective one of said at least one apparatus.

27. The denture system of claim 26 wherein each said at least one denture connector comprises a cushion.

28. The denture system of claim 27 wherein each said cushion comprises a resilient ring.

29. An apparatus for holding a denture having a denture connector in a mouth of a patient, the apparatus comprising: an elongate body having: an affixing portion operably configured to affix the apparatus in the mouth of the patient; and a denture engaging portion operably configured to engage the denture, said denture engaging portion including: a guide operably configured to guide the denture connector in longitudinal movement along said elongate body, said guide dimensioned to enable the denture connector to move and be guided in longitudinal movement along said elongate body in response to a load on the denture to locate the denture connector in a position to facilitate transfer of the load to soft tissue adjacent the apparatus in the mouth of the patient; and a stop operably configured to receive and retain the denture connector on said guide.

30. The apparatus of claim 29 wherein said guide comprises an elongate surface portion on said elongate body, said elongate surface portion being disposed between said stop and said affixing portion, and operably configured to slidably contact the denture connector to enable the denture connector to move longitudinally along said elongate surface portion between said stop and said affixing portion.

31. The apparatus of claim 30 wherein said elongate surface portion has a first width adjacent said stop and a second width greater than said first width adjacent said affixing portion, to urge said denture connector along said guide towards said stop.

The apparatus of claim 29, 30, or 31 wherein said stop has a stop surface generally facing said guide, said stop surface operably configured to stop the denture connector from separating from said guide.

33. The apparatus of claim 32 wherein said stop has an end surface generally opposite said stop surface, and a peripheral region between said end surface and said stop surface.

34. The apparatus of claim 33 wherein said end surface comprises a gently curved convex surface to facilitate urging the denture connector over said peripheral region and onto the guide.

35. The apparatus of claim 34 wherein said end surface includes a spherical cap portion.

36. The apparatus of any one of claims 29 to 35 wherein said stop has a peripheral torque transfer surface for receiving torque from a first tool to affix said affixing portion in the mouth of the patient.

37. The apparatus of claim 36 wherein said peripheral torque transfer surface has a generally polygonal shape.

38. The apparatus of any one of claims 29 to 37 wherein said stop has a recessed torque transfer surface for receiving torque from a second tool to affix said affixing portion in the mouth of the patient.

39. The apparatus of claim 38 wherein said recessed torque transfer surface has a generally polygonal shape.

40. The apparatus of any one of claims 29 to 39 wherein said affixing portion comprises a fixture connector for connecting the apparatus to a fixture attached to bone in the mouth of the patient.

41. The apparatus of claim 40 wherein said fixture connector includes a threaded portion of said elongate body for threadably engaging a complementary portion in said fixture.

42. The apparatus of claim 40 or 41 wherein said fixture connector includes a mating surface on said elongate body for engaging a complementary receptacle of said fixture.

43. The apparatus of claim 42 wherein said mating surface is tapered to facilitate a Morse taper with said complementary receptacle.

44. The apparatus of any one of claims 29 to 39 wherein: said affixing portion comprises a mating surface on said elongate body for contacting a complementary surface on a fixture attached to bone in the mouth of the patient; and said elongate body defines a through-channel for receiving a fastener for fastening the apparatus to said fixture.

45. The apparatus of any one of claims 29 to 39 wherein said affixing portion includes a bone connector for connecting the apparatus directly to bone in the mouth of the patient.

46. The apparatus of claim 45 wherein said bone connector includes a threaded portion of said elongate body for threadably engaging said bone.

47. The apparatus of claim 45 wherein said bone connector includes a wedge portion of said elongate body for frictionally engaging said bone.

48. The apparatus of claim 45 wherein said bone connector includes a generally cylindrical portion.

49. The apparatus of claim 47 or 48 wherein said bone connector further includes at least one longitudinal projection for engaging said bone to prevent movement of the apparatus.

50. The apparatus of claim 47, 48, or 49 wherein said bone connector further includes at least one recess for engaging said bone to prevent movement of the apparatus.

51. The apparatus of any one of claims 45 to 50 wherein said bone connector includes a shoulder portion adjacent said denture engaging portion to facilitate bone growth over said shoulder portion to retain said bone connector in said bone.

52. Use of the apparatus of any one of claims 29 to 51 for holding the denture in the mouth of the patient.

53. A denture system comprising: at least one of the apparatus of any one of claims 29 to 51, said affixing portion of each said at least one apparatus affixed in bone in a mouth of a patient; and a denture having at least one connector, each said at least one connector being held by a corresponding said denture engaging portion of a respective one of said at least one apparatus.

54. The denture system of claim 53 wherein each said at least one denture connector comprises a cushion.

55. The denture system of claim 54 wherein each said cushion comprises a resilient ring.

56. A method of holding a denture having a denture connector in a mouth of a patient, the method comprising: retaining the denture connector on a guiding portion of an elongate body affixed in the mouth of the patient; and guiding the denture connector in longitudinal movement along said guiding portion in response to a load on the denture to locate the denture connector in a position on the guiding portion that facilitates transfer of the load to soft tissue adjacent the apparatus in the mouth of the patient. The method of claim 56 further comprising urging said connector along said guiding portion away from said soft tissue.