FR2623709A1 - 2nd generation endo-osseus tubular implant - Google Patents

Abstract

This system is intended to replace one or more absent teeth in order to avoid the use of a mobile prosthesis. It comprises two separate parts: the implant proper, intended to be embedded in the bone; it is a hollow, openworked b cylindrical tube, which is threaded on its upper part c. It is made of titanium or any other biocompatible material with equal mechanical strength. It is furthermore surfaced with a biologically active ceramic a. This tube is housed in a bone cut made by a special trepan (trephine), and remains fitted for several weeks, during which a post is fixed onto the upper threaded part. This post may either be of polyurethane or similar material, or of titanium, whose ovoid head receives a plastic connector included in the tooth. These two posts are designed to neutralise traumatising mechanical forces. By its usefulness, its harmless nature, and its simplified operational technique, this implant is destined for widespread professional use.

Description

2nd GEt I0N TUBULAR IMPLANT
The present invention relates to a dental implant intended to be inserted into the maxillary bone to replace a missing tooth or to serve as a bridge abutment in order to avoid a mobile prosthesis.

 Traditionally, practitioners have tried to replace the missing tooth (s) with grafts or heterogeneous systems.

 Let us quote among others, - at the beginning of the century, Greenfield who inserted a metal cage in an uninhabited cell; Duclos which armed dental roots to re-implant them in the maxilla or even Leger Dorez who invented a pivot with extensible blades. the results were disappointing. It was not until t946 to witness a resumption with Formiginni and Cherchève who experimented with a spiral screw, followed by Scialom and its needle implants, linkow, its blades and Benhalm and Achard, their tubular implant from which we were inspired (patent n2 1.228; 362 ).

Despite some successes, there were many failures and after a lull, other practitioners tried the experiment. Many implants were created, the improvements are certain, but current systems are not immune to many major drawbacks, namely
- Significant destruction of the receiving maxillary bone.

 - thermal necrosis by heating of the drilling tool.

 - bone-material incompatibility used.

- the bone-implant interface insufficient to balance the
mechanical stresses.

- implant and post in one piece, hence immediate mobility,
invagination of the mucosa and delayed healing.

 Our system according to the invention tries to remedy these drawbacks by its design, structure and technique of use.

It is made up of two separate parts
- an infrastructure intended to be buried in the bone.

 - a suprastructure which will receive the prosthesis.

 The infrastructure is a cylindrical hollow tube of variable size depending on the receiving bone site. This tube has on the upper third of its length, an internal thread; on the remaining two thirds, large side openings.

 It is currently made of titanium but can be realistic in any other bio-compatible material.

 In addition, its characteristic is to be covered with a film of hydroxyapatite or calcium phosphate ceramic, bioactive substances par excellence which bind to the receptor bone by chemical bonds to achieve true integration.

 - The characteristic of this tubular implant that we claim, is to be introduced not into a bone cavity like most similar systems, but completely embedded in a circular groove thus achieving the immediate fixation sought between the external bone wall and the bone trunk internal. The upper opening which is flush with the maxillary croatian is closed by a titanium screw which adapts to the thread of the tube.

This bleeding is performed by a cutting bit specially designed for the bone with helical relief threads and large lateral openings.

 The essential advantage of this technique consists in leaving the implant in the maxillary bone several weeks before it is put into function, to allow a cicatricial osteogenesis protected from any septic attack.

 At the end of this resting, the closure screw is undone and replaced by a false abutment or tenon which will support the tooth or the prosthetic abutment.

This suprastructure is characterized by different shapes and materials depending on the planned restoration
- either in polyurethane or similar. I1 includes a tapped cylindrical base adaptable to the thread of the implant, surmounted by a cup-shaped shoulder on which the gingival ring rests and a cylindrical truncated cone easily retouchable according to the occlusion or parallelism of the natural pillars.

 The choice of material was selected for its flexibility which makes it possible to reduce the mechanical forces and for its bio-compatibility.

 In the case of slightly mobile natural abutments, we have designed a titanium faux'moigaon composed of a threaded cylindrical foot which is screwed onto the implant, a notched neck surfaced with bio-active ceramic to accommodate the mucosa and an ovoid head which receives a plastic contactor integrated inside the prosthetic tooth.

 This cap, a real shock absorber, allows a slight rotational movement without risking to mobilize the implant.

We obeyed two major concerns
- reduce the stresses borne by the implant,
- induce, through the bio-active substance, physicochemical links with the mucosa which produces a real cervical crimp.

 The characteristics of our invention will emerge more clearly from the appended figures, the descriptions which will follow and the clinical implementation.

 - Figure 1 shows an implant perspective according to our invention.

- Figure 2 shows it in section along the axis Ak '
- Figure 3 shows it in plan along the axis BB '
- Figure 4 is a variant of this implant.

- Bes suprastructures are represented by figure 5
polyurethane post, seen in perspective and
- Figure 6, the post seen in section.

 - Figure 7 is a connecting stud according to our invention.

 - Figure 8 shows the drill bit modifies.

 - Figures 3 to II represent the placement of the implant.

 - Figure 12 shows in section, bone healing.

FIG. 13 represents the prosthetic tooth on the post in
plastic.

- Figure 14 shows the prosthetic tooth on the post
contactor.

 The implant presented (FIG. 1) is essentially constituted by a hollow cylindrical tube, made of titanium or any other bio-compatible metal, covered on its external face (a) with a bio-active ceramic.

Three lengths are available: 1 cm, 1.3 cm and 1.5 cm
and two external diameters: 0.55 cm and 0.65 cm.

The tube has on the inner upper third (Figure 2), a thread ge (c) and on the remaining two thirds, large openings of various geometric shapes (Figure 4 (d). The thickness of the tube is 0.04 cm and 0.05 cm in the threaded portion. (Figure 3t)
The implementation of the implant allows to better realize the advantages of the invention. After the opening of the gingival mucosa at the chosen site, a bone compartment is prepared, using a root drill, 0.3 cm deep (Figure 9).

Then with the bit (figure B) copious Irrigated Pent, turning to
less than 200 revolutions per minute, the circular groove is made to a depth sufficient to embed the chosen implant therein (FIG. 10). After having closed with a screw, the upper opening, the gingival flap is sutured over it (figure 11).

Two to three months later, this mucosa is released, the screw defeated and replaced by the false abutment selected for the future prosthesis. (Figures 13 and 14)
The originality of our technique allows the scutian bone tissue to heal and integrate into the tubular implant without any mobility.

 We can observe on a section (Figure 12), the osteogenesis between the internal bone 2) and the external bone (g).

 Given the success of certain prosthetic restorations such as: posterior molar edentulousness, long-term intermediate edentulousness, we believe that our invention can be of great service to practitioners, confronted daily with such problems.

 In addition, the simplicity of the tubular implant, compared to current complex systems, allows rapid manufacturing at reasonable costs.

Claims (7)

 1) Endosseous implant for the maxilla, intended to replace a tooth or serve as a bridge abutment, characterized in that its infrastructure consists of a cylindrical tube comprising large lateral openings (b) and having an internal thread (c) on its upper part for screwing a stud forming its suprastructure intended to receive the prosthesis.  2) Implant according to claim 1, characterized by a titanium structure covered with a hydroxyapatite film (a).  3) Implant according to claim I, characterized in that it is produced in a bio-compatible substance having mechanical properties of high resistance.  4) Implant according to claims 2 and 3, characterized in that it is preferably surfaced with calcium phosphate ceramic or another bioactive substance.  5) Implant according to any one of the preceding claims, characterized in that its suprastructure is formed by a non-integral stud made of polyurethane or similar flexible and biocompatible material, the threaded cylindrical base of which will not be screwed to the cylindrical tube embedded in the maxilla only after a period of time necessary for osteogenesis.  6) Implant according to any one of claims 1 to 4 characterized in that its suprastructure is formed by a connecting post of ovoid shape whose neck in contact with the gum, is coated with a surface layer of hydroxyapatite or d 'a  similar bioactive substance.  7) Tool for making a circular bone groove for embedding and fixing the tubular implant according to any one of claims 1 to 4, characterized in that it is constituted by a drill bit with special cutting blades for the bone with helical clearance nets and wide side openings.