Classifications

• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61C—DENTISTRY; APPARATUS OR METHODS FOR ORAL OR DENTAL HYGIENE
  • A61C8/00—Means to be fixed to the jaw-bone for consolidating natural teeth or for fixing dental prostheses thereon; Dental implants; Implanting tools
  • A61C8/008—Healing caps or the like
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61C—DENTISTRY; APPARATUS OR METHODS FOR ORAL OR DENTAL HYGIENE
  • A61C8/00—Means to be fixed to the jaw-bone for consolidating natural teeth or for fixing dental prostheses thereon; Dental implants; Implanting tools
  • A61C8/0048—Connecting the upper structure to the implant, e.g. bridging bars
  • A61C8/005—Connecting devices for joining an upper structure with an implant member, e.g. spacers
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61C—DENTISTRY; APPARATUS OR METHODS FOR ORAL OR DENTAL HYGIENE
  • A61C8/00—Means to be fixed to the jaw-bone for consolidating natural teeth or for fixing dental prostheses thereon; Dental implants; Implanting tools
  • A61C8/0048—Connecting the upper structure to the implant, e.g. bridging bars
  • A61C8/005—Connecting devices for joining an upper structure with an implant member, e.g. spacers
  • A61C8/0066—Connecting devices for joining an upper structure with an implant member, e.g. spacers with positioning means
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61C—DENTISTRY; APPARATUS OR METHODS FOR ORAL OR DENTAL HYGIENE
  • A61C8/00—Means to be fixed to the jaw-bone for consolidating natural teeth or for fixing dental prostheses thereon; Dental implants; Implanting tools
  • A61C8/0048—Connecting the upper structure to the implant, e.g. bridging bars
  • A61C8/005—Connecting devices for joining an upper structure with an implant member, e.g. spacers
  • A61C8/006—Connecting devices for joining an upper structure with an implant member, e.g. spacers with polygonal positional means, e.g. hexagonal or octagonal
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61C—DENTISTRY; APPARATUS OR METHODS FOR ORAL OR DENTAL HYGIENE
  • A61C8/00—Means to be fixed to the jaw-bone for consolidating natural teeth or for fixing dental prostheses thereon; Dental implants; Implanting tools
  • A61C8/0048—Connecting the upper structure to the implant, e.g. bridging bars
  • A61C8/005—Connecting devices for joining an upper structure with an implant member, e.g. spacers
  • A61C8/0069—Connecting devices for joining an upper structure with an implant member, e.g. spacers tapered or conical connection

Definitions

• the invention relates to a direct connected bone anchoring element for prosthetic structures
• a direct connected bone anchoring element for prosthetic structures comprising an implant to be inserted into bone tissue the end surface of the implant which is the outer end surface of the implant in the implanted position thereof, being arranged for attaching the prosthetic structure.
• implants are inserted by a separate surgical operation and are completely covered by the mucous membrane. After a minimum critical ingrowth period a further surgical operation is effected in order to connect the implants to the actual prosthetic structure via said exten- sion pieces of suitable length.
• This so called two-step method is utilized in order to reduce the failure frequency which is considered too high in a one-step method wherein the implant is allowed to penetrate the mucous membrane covering the bone, already at the installation of the implant.
• the higher failure frequency in the one-step method is due to the load transferred to the sensitive interface between bone tissue and implant via the portion of the implant which is located in the oral cavity above the mucous membrane, already during the initial period of the ingrowth phase.
• the implant is located in the bone tissue so that the most superficial portion thereof will be at the same level as or slightly above the bone surface where ingrowth is allowed to take place with the implant covered by soft tissue and unloaded for a period which is sufficiently long in order that the implant shall be intimately anchored, "get firmly rooted", in surrounding bone tissue.
• a second surgical operation is effected in order to uncover the implant by punching an aperture in the covering mucous membrane or by cutting through said membrane and to connect extension pieces to the implant.
• the purpose of the present invention is to provide a more rational and cheaper method, an improved ingrowth into the most superficial portion of the bone and the periosteal and connective tissue located on the bone surface.
• the bone anchoring element of the kind referred to above has been given the characterizing features of claim 1.
• the implant described herein can integrate with complete covering by mucous membrane and nevertheless be uncovered without applying extension elements, which provides several advantages : - Reduction of costs and simplification of the manufacture by elimination of the spacer screw (and spacer socket) .
• the implant is suitable for one-step technique as well as two-step technique.
• the diameter of the implant can be considerably reduced without increased risk of fracture due to the fact that the blind hole for the fastening screw has considerably smaller diameter than the hole for a spacer screw. This increases the indication domain considerably as far as yaws having a small bucko-lingual width are concerned.
• the thickness of the soft tissue can be controlled during ingrowth by the shape of the covering element being controlled. - Considerably smaller critical height of the prosthetic structure by connection thereof directly to the implant, which facilitates the prosthetics and increases the indication domain. - Minimal risk of buccal screw apertures through angled passages.
• the implant is made of a material which has a sufficient degree of biocompatibility and strength in order to be permanently implanted as anchoring element for prostheses, crowns, or bridges. It can consist of ceramics, metal, or tissue tolerant plastics or combinations thereof.
• a suitable metal is pure titanium which is prepared so that the surface thereof is completely free from organic material and which has been given a suitable surface roughness by turning, blasting or in another way. It can also be coated on the surface thereof with a material which optimizes the ingrowth thereof to the most intimate connection with surrounding bone, e.g. titanium, which is applied by so called plasma spraying, or hydroxyl apatite.
• the implant is screw-shaped.
• FIG. 1 is a side view, partly a vertical cross-sectional view, of a prior art screw implant in the embodiment which at present is most commonly appearing on the market,
• FIG. 2 is a side view, partly a vertical cross-sectional view, of an implant according to the invention
• FIG. 3 is a side view, partly a vertical cross-sectional view, of the implant according to the invention pro- vided with a cover element,
• FIG. 4 is a side view, partly a vertical cross-sectional view, of the implant in FIG. 3 after an aperture having been punched in covering soft tissue and the cover element having been removed
• FIG. 5 as a side view, partly vertical cross-sectional view, of the implant in FIG. 3 after the soft tissue having been laid down around the neck of the implant
• FIG. 6 is a side view, partly a vertical cross-sec- tional view, of the implant according to the invention provided with a cover element of another embodiment
• FIG. 7 is a fragmentary perspective view of an embodiment of the end surface of the implant according to the invention
• FIG. 8 to 11 are views illustrating different embodiments of the connection surface of the implant according to the invention.
• the prior art implant disclosed in FIG. 1 comprises a screw which is made of or coated with titanium or another biocompatible material. It has a screw threaded portion 10 which is screwed into a hole which has been drilled in the bone 11, so that the end surface 12 thereof will be placed substantially at the same level as the surface of the bone.
• the implant has a hexagonal portion on the end surface 12 in order that a tool can be engaged therewith when the implant is to be screwed into the bone the implant also having a threaded blind hole 14 for the attachment of an extension piece or spacer when the two-step method described above is applied.
• the implant is pro- vided with a cover screw 13 which is screwed into the threaded blind hole 14.
• the implant according to the invention which is disclosed in FIG. 2 has a screw threaded portion 10 and a cylindrical neck portion 15 which has been made smooth by turning and may be polished.
• the neck portion can have a length of 1 to 10 mm but preferably of 1 to 3 mm.
• the curved surface of the neck portion at the transition from the threaded portion of the implant is flush with the crests of the threaded portion but preferably diverges slightly towards the end surface 12 of the implant .
• the diameter of the implant can vary from some tenths mm and upwards but in oral prosthetical function preferably ranges from 2,0 to 8,0 mm.
• the implant is made self-tapping.
• a threaded axial blind hole 19 the diameter of which can vary in dependence on the dimension of the fastening screw which shall retain the prosthetic struc- ture, and the diameter of the implant.
• an internal hexagonal portion 19A for engagement with a tool by means of which the implant shall be screwed into the bone.
• the end surface 12 also can be provided with supplementary means for lock- ing the prosthetic structure attached to the end surface against rotation.
• Such means can comprise one or more grooves 20 or blind holes 21 as shown in FIG. 7, corresponding ridges or cylindrical or conical projections on the prosthetic structure to be attached to the end surface of the implant engaging therewith.
• the rotational locking can also be provided by means of a raised or countersunk portion around the fastening screw with four or more walls wherein a corresponding patrix or matrix attached to the prosthetic structure is exactly fitted.
• the implant Due to a well adjusted neck length the implant can be implanted with covering mucous membrane and can integrate unloaded and without infectious contamination via the oral cavity while the implant by selection of correct neck length in relation to the thickness of the mucous membrane can be easily palpated and uncovered by punching or in another way, but in order to avoid the existing relatively great risk of perforation of the mucous membrane there is mounted to the implant according to the invention a cover element 22, FIG 3, which is attached by means of a screw 23 in the threaded hole 19 which is intended for the fastening screw of the prosthetic structure.
• This cover element has a gently rounded cupola shaped upper surface 24 and comprises a body of a tissue tolerant at least partly plastic material which is attached to the head of the screw 23.
• the screw and the head thereof can consist of titanium.
• the head engages the end surface 12 of the implant a washer 25 being located therebetween.
• the tissue tolerant plastics can comprise a non-resorbable or alternatively a partly or completely resorbable polymer.
• the cover element can be perforated in the portion thereof which is located outside the end surface of the implant. These perforations partly shown at 27, should have a size which allows the formation of new tissue, which contributes both to the nutrition of the mucous membrane and the ingrowth process in the bone tissue adjacent the neck portion of the implant.
• the plastics should have a consistence which is close to the consistence of the connective tissue in order that the risk of perforation of the mucous membrane within 3 to 6 months after implantation shall be prevented. It should also be so plastic at least at the periphery thereof that it can be deformed without elastic return and without cracking or fracturing. It should also be possible to reshape - reduce - the plastics by means of a pair of scissors or a scalpel.
• FIG. 3 discloses how the implant and the cover element thereof is covered by connective tissue 28.
• the mucous membrane When the implant has been anchored in the bone by ingrowth 3 to 6 months after the implantation the mucous membrane shall be perforated by a cut or a circular aperture in order to uncover the neck portion 15 of the implant.
• the upper end surface of the cover element can form an aperture or a depression which can be palpated by means of a sond or the like. Uncovering of the cover element by punching causes the smallest possible damage of the tissue and thus the best possible healing at the shortest possible time in the important "sealing region" around the portion of the implant which penetrates the soft tissue.
• the soft tissue is laid down and takes the place of that part of the cover element which surrounded the neck portion 15 of the implant as disclosed in FIG. 5 where a cover screw 29 of metal or plastics has been attached by screw to the implant.
• the described embodiment of the implant means that the spacer screw which is a necessary element in the two- step systems available on the market will be superfluous. As a consequence thereof the implant system is substantially rationalized and cheapened. Moreover, the manufac- ture of the implant will be simplified due to the fact that no threaded central hole for a spacer screw in the threaded portion of the implant will be necessary. This means also that the strength of the implant will be increased and that the implant can be given a smaller diameter, which in turn means that the implant can be inserted by surgery in regions having a smaller bone width than that required by implants available so far.
• FIG. 6 Another implant of the cover element 22 is disclosed in FIG. 6 wherein the central portion with the screw 23 surrounds the implant neck as a cap 34 which occupies the height of the neck substantially corresponding to the thickness of the mucous membrane. Above and outside the cap the plastic body of the cover element 22 is located said body consisting of plastics. Said latter material can be applied separately in relation to the central cap.
• the cap 34 can form an annular bead or projections on the inside surface thereof to engage an annular groove or depressions on the outside surface of the neck portion 15 for attachment of the cover element to the implant.
• the central fastening screw 23 can be dispensed with.
• the neck portion 15 can be so conical (diverging towards the end surface) that the end surface of the implant has a diameter which is substantially larger than the diameter of the rest of the implant in order that the neck portion shall harmonize with the overlaying prosthetic structure and in order that a sufficiently dimensioned fastening screw can be used for attaching said structure due to the fact that the threaded hole 19 can be made larger.
• the end surface 12 is bevelled at an angle ranging from 5° to 45°.
• the threaded central hole 19 in the end surface is perpendicular to the end surface.
• the self-tapping implants allow a tolerance which means that the implant can be tightened to a level which is in agreement with the desired direction of the bevelled end surface. This is particularly true if the implant has a small thread pitch.
• the bevelled oval end surface can be shorted in regions where the radius thereof is larger in order to harmonize with a circular end surface in the prosthetic structure.
• the bevelled end surface 12 faces buccally for aesthetic optimization by the joint between the prosthetic structure 35 and the implant being located at a sufficiently low level in relation to the buccal soft tissue surface said joint for the rest not being located too low.
• a shape exactly fitting the bevelled end surface is imparted to the prosthetic structure.
• FIG. 10 there is disclosed an embodiment wherein the bevelled surface comprises only a minor part 12a of the end surface 12 in the basic embodiment described and thus does not include that part of this surface which is occupied by the fastening screw 36.
• the prosthetic structure 35 also in this case is given a shape fitting exactly the end surface.
• the end surface as in the basic embodiment is perpendicular to the longitudinal axis of the implant but the central hole is angled between 5° and 45°.
• the surface of the structure 35 to be attached against the end surface 12 of the implant is angled at an angle corresponding to that of the central hole 19.

Landscapes

• Health & Medical Sciences (AREA)
• Oral & Maxillofacial Surgery (AREA)
• Orthopedic Medicine & Surgery (AREA)
• Dentistry (AREA)
• Epidemiology (AREA)
• Life Sciences & Earth Sciences (AREA)
• Animal Behavior & Ethology (AREA)
• General Health & Medical Sciences (AREA)
• Public Health (AREA)
• Veterinary Medicine (AREA)
• Prostheses (AREA)
• Surgical Instruments (AREA)

Priority Applications (9)

Applications Claiming Priority (1)

Publications (1)

Family

ID=20405603

Family Applications (1)

Country Status (8)

Cited By (8)

Families Citing this family (23)

Citations (3)

Family Cites Families (4)

• 1997
  • 1997-02-25 US US09/367,999 patent/US6227858B1/en not_active Expired - Fee Related
  • 1997-02-25 WO PCT/SE1997/000314 patent/WO1998036701A1/en not_active Ceased
  • 1997-02-25 EP EP97919798A patent/EP0969776B1/en not_active Expired - Lifetime
  • 1997-02-25 AT AT97919798T patent/ATE304821T1/de not_active IP Right Cessation
  • 1997-02-25 JP JP53653298A patent/JP2001512348A/ja not_active Ceased
  • 1997-02-25 DE DE69734248T patent/DE69734248T2/de not_active Expired - Fee Related
  • 1997-02-25 AU AU24149/97A patent/AU733051B2/en not_active Ceased
  • 1997-02-25 CA CA002279526A patent/CA2279526A1/en not_active Abandoned

Patent Citations (3)

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