WO1996027343A1

WO1996027343A1 - Method for setting prostheses to replace partial loss of teeth, and prostheses to implement said method

Info

Publication number: WO1996027343A1
Application number: PCT/HU1995/000004
Authority: WO
Inventors: Imre KERTÉSZ
Original assignee: Kertesz Imre
Priority date: 1995-03-08
Filing date: 1995-03-08
Publication date: 1996-09-12
Also published as: AU1859595A

Abstract

The invention relates to a method of setting prostheses to eliminate gaps in the row of teeth, and to a prostheses for implementing said method. A bridge body (2) constituting a bridge-type prosthesis is fixed by an adhesive (4) to the lateral surfaces of the existing pier teeth (5). The invented prosthesis comprises a bridge body (2) suitable for stockpiling and the two ends of it can be attached to the lateral surfaces of the pier teeth (5). These ends are shaped to form a tray-like part or trough having a near vertical direction or having dimensions permitting the formation of such a tray (3). The bridge body (2), after adjustment if necessary, is attrached to the lateral surfaces of the pier or supporting teeth (5) with an adhesive (4). The bridge-type prostheses to be built into the patient's mouth are either provided with a connecting support (2/a) preferably made of an acrylate material matched in color with the gum (6) and from said support also extensions bearing against the pier teeth (5) can be formed, or said support constitute an integral part with the bridge member (9) (1). The bridge body (2) generally made of its own material and having a reduced height, is inserted by leaving a distance to gap the removed tooth. This gap in the row of teeth can be filled up even right after extraction of the tooth. In the prostheses complying with the invention can be provided with metal clamps.

Description

Method for setting prostheses to replace partial loss of teeth, and prostheses to implement said method.

The invention relates to a method for setting prostheses to replace partial loss of teeth and describes various prostheses for implementing the method. The aim of the invention is to provide a very simple and quickly realizable structure suitable for provisional or durable replacement of lost teeth, instead of the prostheses conventionally used at present.

The field of application of the invention is primarily to replace quickly and simply one or two, or even more extracted incisors, cuspids or, even molars which are visible e.g. during speech. The invention provides further a solution to eliminate gaps in the row of teeth, due to the extraction of one or more teeth in the infant years, which result in a narrower or wider gap in the row of teeth remaining in adult age.

According present prosthetic dentistry the gaps occurring in the patients' row of teeth are eliminated by applying various prostheses, the most known of which - in the case of one or several teeth missing - is the ^• use of a fixed dental bridges, where the masticatory pressure acting on the replacement teeth are transferred to the jaw-bones by the remaining natural teoth, tooth stumps, referred to as supporting teeth. The other most common method of replacing missing teeth - in the case of a wide gap in the row of teeth - is the use of removable dentures, comprising artificial teeth fixed to a plate, where the masticatory pressure is transferred to softer surfaces of the mouth by providing a larger bearing surface to take up said pressure. These solutions are described in the books of Fabian-Huszar-Gϋtz: Introduction to Prosthetic Dentistry; and Jόzsef Bakk: Dental Mechanics.

The deficiency of a fixed dental bridge used in present practice for replacing missing teeth is associated with considerable mutilation of two existing healthy teeth, i.e. the supporting teeth due to the removal of dental enamel and part of the dentine by means of grinding tools. Although this operation is performed with alleviation of pain, full relief cannot be achieved in every case, let alone other uncomfortable and objectionable effects. Preparation of a prosthesis is a rather lengthy and very costly procedure, requiring separated treatments.

The time elapsing between loosing a tooth, extraction of already incurable teeth, healing of wounds and preparing a denture takes weeks, or even months, so that all mentioned drawbacks of a gap-toothed state become effective. Moreover, a gap-toothed patient is well aware of the fact that he has to reckon with deliberate mutilation of two sound teeth. The deficiencies and drawbacks mentioned give a clear explanation why many people are reluctant to have minor, yet conspicuous gaps in their row of teeth filled up.

In the early 1970-ies insertion of bridges without mutilating the supporting teeth was attempted. This is hinted at in the review

Stomatologia Hungarica [1986, title "Bridges and Splints Adhered to the

Enamel"]. The authors disclosed the experiences of using bridges and splints adhered to the enamel of teeth based upon Hungarian and foreign

^' professional literature, as well as the solutions just tested by the authors. In the Review of Dental Technics, May 1983 the article of Varga, J.: "Experiences with using the adhesive technics of Masuhara" discloses details of structure, manufacture and application of adhered (fixed by a cement) bridges, as well as preconditions and way of its use. The Review of Dental Technics includes further discussions of Hungarian and foreign authors. As examples articles of Varga, J. (September, 1983; August, 1987); Simonsen, Richard J. (January, 1989, published also in JADA, 1982); Dijkmann, A.G. and Arends, J. (August, 1987, published also in "Die Quintessenz", 1986, No. 2).

According to professional literature adhesive bridges represent a solution for replacing one or two teeth, wherein a metal frame is adhered to non grinded surfaces of teeth by an adhesive resin. Preconditions of this kind of replacement are the following: etching by an acid; a high- -strength adhesive resin; a high-strength metal alloy (Ni-Cr, Co-Cr), a very precise imprersion, and high precision of metal casting to form adhesion wings, which should be repeated if the desired form is not achieved, because the cast can not be corrected. The adhesive technics currently used suffers from the following deficiencies: any contamination (by saliva, humidity, etc.) of the etched surface of the enamel of the tooth causes a defect bound between the polymer and the enamel, which will lead to the total deterioration of the etched tooth in the foreseeable future. Only an intact enamel surface is capable to provide a support. If amalgam filling is contained in the enamel surface, is should be replaced by a composite filling. A wider acceptance of the adhesive technics currently used in essentially hindered by the above drawbacks accompanying some obvious advantages.

All the above have led to the idea that a filling up of gaps without mutilation of the pier or supporting teeth, and selection of a denture from the assortment available at the dentist would provide a possibility for immediately eliminating such a gap. The motivation of the present invention is the very adverse psychological effect on the persons concerned, to whateven age they belong, caused by gaps in the their row of teeth becoming apparent when moving their mouth for any reason (e.g. while speaking) in many cases. The mental bunden of the negative aesthetical impression exerted on himself or others gives rise to very grave behavioral disadvantages. This effect especially impedes the performance and success of work in numerous professions, firstly of all persons suffering of a conspicuous gap in their row of teeth.

The invention is based on the recognition that there is a need to extend or improve the methods and means available at present for replacing missing teeth, and to offer a solution of the problems of persons suffering from conspicuously visible gaps in their row of teeth often, for several years. By the use of the invented method and the product prepared in compliance with it, (KERDENT system) the fear from seeing the dentist to replace teeth can be overcome, which is a consequence of its painless, simple and quickly performable procedure and, as a result, being considerably cheaper than the methods used so far. This applies also to the advantages of the invention over the prosthetic method using adhesive technics and disclosed in the above reference.

The aim of the invention is to eliminate the deficiencies of the present tooth replacement methods when opportunity arises. Its application is justified where the drawbacks to be encountered and its numerous obvious advantages can be brought into harmony with the requirements. To these drawbacks belongs the reduced load carrying capacity of the replacement teeth as compared to the teeth of conventional fixed bridges, when several, say up to three, missing teeth are to be replaced mainly in the case of cuspids and incisors. Therefore biting while eating should be limited. Further, the fixing by cementing, beside its simplicity, but having a reduced loadability, may have to be repeatedly carried out after shorter or longer periods of time. The invented method for replacing teeth and the invented article is based on the recognition that the gap of missing teeth can be very simply filled up by a fixed dental bridge, comprising a plastic prosthesis of suitable size and form cementing said bridge to the cleaned and, if necessary, roughened lateral surfaces of the supporting teeth without their mutilation.

To achieve the aim set, i.e. to maintain the advantages and to eliminate the drawbacks of the known adhesion based technics of prosthetic dentistry, which is not widely accepted. To assist wider acceptation of adhesive prosthetic technics in replacing partial loss of teeth by using a fixed bridge comprising one or more members or false teeth and a corresponding coupling support to form said bridge, said coupling support is made of the false teeth or another material having the same color as the gum, preferably of acrylate. A dental prosthesis of the suitable shade of color and size can be simply manufactured and its two sides have a connecting part formed of the material of the coupling support and leaning against the internal (posterior) lingual and/or external/anterior/oral part of the supporting or pier teeth.

This dental prosthesis should resist both vertical and horizontal stresses. This is achieved mainly by a troughed shape of the side of the prosthesis adjacent to the existing supporting teeth.

In a preferred embodiment of the method of the invention, the connecting surfaces at the extremities of the prosthesis consisting of a bridge body comprising one or several bridge members depending on the width of the gap are shaped to fit to the existing plier teeth. Now, mixing the acrylate material of the linking support of the bridge body made either of a slowly setting acrylate or of the same material as the body the bearing extensions are attached. After its partial setting, but still in plastic state, the dental bridge thus prepared is slided between the plier teeth. After the adjustment the extensions still in their plastic state are pressed against the widening-out rear and front surfaces of the plier teeth. The dental bridge thus shaped within the mouth is taken out before attaining its full rigidity, and a final adjustment is made. After all this, the bridge is cemented with a quick-setting adhesive to the lateral connecting surfaces of the plier teeth.

To eliminate partial gaps of missing teeth and to render the tooth replacement procedure as effective as possible, the set task has been solved on the basis of the outlined recognition by means of a bridge construction (an article) providing improved fixability, said structure, having troughs at its connecting side surfaces or having dimensions suitable for subsequent shaping of a trough like portion, said article is partly or fully prefabricated as regards shade of color, size and form, further lending itself to assemble an assortment, which enables easy composition of a prosthesis and requiring but minor adjustments before insertion, if needed.

In a possible embodiment of the product complying with the invention the bridge body is fully made of the same material as the bridge member(s), or of the same material as the coupling support having a color harmonizing with that of the gums and serving for fixing the bridge members to each other make them bear on the rear and/or front parts of the pier teeth.

In another possible embodiment of the invention the body of the bridge is provided with one or more lingual and/or oral supporting or backing protrusions leaving on the pier teeth. Larger supporting protrusions can be formed subsequently by using preferably an acrylate material of the same color as the gum. The lateral surface of the body of the bridge is preferably provided with a goove, recess or trough having a near vertical orientation and broadening downwards so as to fit to the pier teeth. The bridge body having a connecting support made of the same material as the bridge members (false or artificial teeth) or of one matched to the color of the gums is shaped to have a free gap between the gum and bridge body to facilitate cleaning.

In the following, a detailed description of the invention is given, referring to the attached drawings showing a few preferred examples of the invented KERDENT-system tooth replacement and its design details.

In the drawings:

Figure 1 is a vertical cross-section along line A of Fig. 3 of a substitute incisor in accordance with the invention; Figure 2 is the horizontal cross-section along line B of the tooth replacement of Figure 1 ;

Figure 3 is a combined elevation of frontal and rear/lingual side of the prosthesis of Figure 1 , with the buccal elevation on the left side; Figure 4 is the vertical cross-sectional drawing along line C of an incisor replacement according to the invention showing a variant with a broadened lower part;

Figure 5 is a combined buccal (on the left side) and lingual (to the right) elevation of the bridge of Figure 4; Figure 6 is a horizontal section along line D of the bridge shown in Figure 5; Figure 7 is a horizontal section along line E of the prosthesis shown in Figure 8; Figure 8 is the front and rear view of a prosthesis filling a gap of two missing teeth; Figure 9 is the vertical section of a tooth substitute of reduced height, built in right after extraction of the own tooth, said section taken along line F of Fig. 10; Figure 10 is the buccal front view of the incisor replacement of Figure 9; Figure 11 is the front view of the completion of a broken incisor; Figure 12 is the horizontal section of the broken incisor shown in Figure 11 ; Figure 13 is the vertical section of a cuspid replacement according to the invention, with a bridge body made of material of the replacement teeth itself and adopting a tooth plate; Figure 14 is a horizontal section of the embodiment shown in Figure 13, taken along line H.

The tooth replacement procedure essentially consists of selecting a preferably prefabricated prosthesis from the stock available at the dentist which should matching in size and shape to the gap and have the desired color shade, said prosthesis or bridge comprises a bridge member 1 and a bridge body 2 and is provided preferably with a trough 3 on either side. After performing minor adjustments (grinding), if required, said bridge is inserted between the two pier teeth 5 and is fixed with an adhesive 4.

To enable a selection of a proper prosthesis a suitable assortuent of bridges should be available at the dentist and said selection is carried out with respect to the geometry of the defect of the row of teeth. To fill the gap, i.e. to insert the prosthesis same minor adjustments may be needed, e.g. said trough 3, or protrusions being a part of connecting support 2a should be adjusted, in case supplemented to fit properly to supporting teeth 5. In lack of a proper assortment or for other reasons said bridge body 2 assembling said bridge members or artificial teeth 1 by using said connecting support 2a can be manufactured by using common technics of prosthetic dentistry, i.e. taking an impression and making a mould (model), whereby said trough 3 and/or said protrusions can be formed to fit to said supporting teeth 5. The size and extension of said protrusions on the lingual side are determined by the expectable load of said supporting teeth, while on the buccal side first of all by esthetic aspects.

The preferably trough-shaped 3 bridge body 2 performed of one or more bridge members 1 is properly prepared for insertion if trough 3 permits some limited movement of the bridge pushed in place without applying any adhesive, but so as to prevent its tipping-out. The bridge is fitted to the gum so as to make the bridge body 2 lean on the thicker lingual and/or buccal part of the supporting pier teeth 5 and at the middle section leaving a free interspace between the bridge and the gum 6. If the dental bridge available on stock has not any leaning protrusions, or the size or form of its protrusions is not suitable, then the leaning protrusions are formed by mixing an acrylate material and adhering it to the coupling support 2a of the bridge body having a color matching the gum. After a partial setting of this acrylate material but still in its plastic state the bridge prepared this way is slided in-between the supporting teeth 5. The proper position of the bridge is adjusted and the protrusions being in plastic state are pressed against the surface of the thicker parts on the lingual and buccal sides of the supporting teeth 5. Similar procedure is carried out if an impression is taken to produce a mould (model), and the bridge adjusted inside the mouth of the patient or using the mould is removed before complete setting of the leaning or supporting protrusions. After complete setting some adjustment might be necessary, which, as well as finishing (polishing) of surfaces not subjected to adhering are also effected. After for preparing, cleaning and roughening, if necessary the contacting surfaces of pier teeth 5, an adhesive 4 (tooth cement etc.) of preferably matching color is applied to the contacting surfaces of the bridge body 2 provided with troughs 3 and of pier teeth 5, then said bridge body 2 is placed into its final position by sliding and tilting. For a period depending on the solidification time of the adhesive 4, the bridge body 2 is kept in its proper place with the rows of teeth closed, or additionally with a plastic or metal tray slipped or pulled over the arch of the row of teeth. After partial solidification of adhesive 4, its parts extruded to the surfaces of the teeth is removed before hardening. (Figure 1 to 3). A suitable quick- -binding, preferably two-component adhesive 4 (tooth cement, acrilates, etc.) should be used.

A bridge body 2 of increased interspace and of reduced height offers the advantage of avoiding undesirable aesthetic effects and the associated very unfavorable psychical consequences resulting in all cases from the exposed gaps in the row of teeth after having had one or two adjacent front teeth lost or extracted, until the crater 7 heals and the lost teeth are finally replaced. With the proposed method, between the lower plane of bridge body 2 and the injured gum 6 an interspace increased by a few millimeters is left, where said bridge body 2 consists of one or several bridge members 1 , preferably provided with trough 3 and fixed by an adhesive 4, preferably a dental cement (Figures 9 and 10.). Following the healing of the wound the provisional bridge body 2 is removed, then a final bridge body 2 is inserted in the way described in the foregoing.

Making use of the invention a broken tooth 10 having a sound root can be simply be repaired with complementary tooth 9. In that case the complementary tooth 9 mating with the broken tooth 10 is preferably provided with a trough 3 at its lateral side contacting an adjacent tooth 5. The broken surface of broken tooth 10 is ground off when required (Figures 11 , 12).

A favorable effect can be achieved by employing a linking or connecting support 2/a made of a material (e.g. acrylate) harmonizing in color with the gum 6 for clamping the tooth substitute to form a bridge body 2, in the case of one or two bridge members 1 are needed.

From the material of said coupling support 2/a extensions or protrusions may be formed constituting a surface bearing against the lingual and or buccal part of pier teeth 5. By preliminary or subsequent provision of clamps used in dentists' practice the firmness of keeping the tooth substitute in position can be improved. Of course, on the bottom part forming the bridge body 2 and having the same color as gum 6, on either side of the connections to the pier teeth 5, preferably similar troughs or tray-like formations are provided also in that parts of the artificial gum. For better support of the tooth substitute the sidewise extending lower part of the bridge body 2 is shaped to bear against the thickened rear- and/or front-side oblique part of the adjacent pier teeth 5 (Figures 4 to 8). In order to improve the formal, aesthetical appearance of the tooth substitute, the outer surface of the bridge body 2 with its tray-like lower part 3, generally made acrylate, but slightly differing in color from the existing teeth, can be covered with an acrylate, porcelain, etc. tooth plate of proper shade of color, said tooth plate is cemented to the bridge body subsequently or, preferably, in the course of its manufacture (Figure 13, 14).

The loading of the adhesively fixed dental prosthesis according to the invention can be decreased by minimizing the width of the cutting edge of e.g. an incisor along the distance between the connection at troughs 3. If more than one bridge member 1 is included the loadability of the bridge can be improved by including reinforcing steel wires of sufficient strength into the connecting support 2a.

A further advantage of the invented method and article for replacing teeth consists in enabling the use of very simple means for eliminating gaps in the row of the teeth. This advantage becomes clear from a comparison with conventional bridges adhered to supporting teeth reduced by grinding. The invention essentially overcomes the drawbacks of recently developed and so called adhesive bridges hindering its wide acceptance. No metallic frame (bridge structure) has to be manufactured which needs high precision casting. The use of an extremely adhesive cement is not essential, neither the surface of the enamel should be etched by an acid, thereby the deterioration of the enamel can be avoided. Even teeth with non fully intact enamel can be used to support a bridge and incidental amalgam filling have not to be replaced by a composite filling. Thereby substantial time and cost can be saved.

Beside the numerous advantages outlined in the foregoing the invention offers the possibility of performing the replacement of teeth in a simple, quick and painless way even if the bridge has to be connected to not fully sound and slightly loose teeth. In such cases, also the stiffening, fixing, and retaining of loosened teeth for a prolonged period of time, and extension of their useful life are achieved.

Obviously, the application of the invention is not restricted to the examples described above, but beyond the outlined embodiments it can be implemented in numerous ways without departing from the scope defined by claims.

Claims

C l a i m s

1. A method of eliminating partial lack of teeth by installing a prosthesis, wherein a bridge body (2) is provided by connecting one or more bridge members (1) by a connecting support (2a), said connecting support (2a) consisting of the material of the bridge member (1) or an acrylate material having the same color as the gum (6) and the prosthesis is adapted to fit to adjacent side surfaces of supporting teeth (5) and is fixed by an adhesive (4).

2. The method of claim 1 wherein said bridge body (2) is provided with protrusions at its connection to said supporting teeth (5), said protrusions extending laterally and resting on at least one of the lingual and buccal parts of said supporting teeth.

3. The method of Claim 1 or 2 wherein the sides of the prosthesis connecting to said supporting teeth (5) is formed to have a trough (3) or groove thereon.

4. The method of tooth replacement as claimed in any of Claims 1 to 3 wherein said bridge body (2) consisting of one or several bridge members (1), constituting a prosthesis of reduced height is inserted at a distance above the injured gum (6) or crater (7) immediately after extraction of the tooth (teeth), after cessation of bleeding.

5. The method of tooth replacement as claimed in Claim 4 wherein the provisional tooth replacement built-in at an increased distance from the gum is removed, and a final bridge body (2) is installed.

6. The method of tooth replacement as claimed in Claim 1 to 3 wherein a supplementary tooth (9) is fitted between a slightly deficient broken tooth (10) and a pier tooth (5) located next to said broken tooth (10).

7. The method of tooth replacement as claimed in any of Claims 1 to 6, wherein the prosthesis is fixed by using an adhesive of a relatively short bonding time.

8. A prosthesis prefabricated for providing tooth replacements comprising a bridge body (2) consisting of one or several bridge members (1), said bridge body (2) is provided on its part adjoining to the existing pier teeth (5) either with a tray-like section or trough (3) or has a sufficient size to permit subsequent shaping of such a trough (3) fitting to said supporting teeth.

9. Prostheses as claimed in Claim 8, comprising further a connecting support (2a) for clamping together one or more bridge members (1) into a bridge body (2), said connecting support (2a) preferably matching in color to the gum (6).

10. Prostheses as claimed in Claim 9, wherein several bridge members (1) constitute a single, integral part.

11. Prostheses as claimed in any of Claims 9 or 10, wherein said prosthesis is provided at its connection to the pier teeth (5) with broadening protrusions is made of the material of the linking support (2/a) of said bridge body (2), said protrusions bearing against the lower lingual and/or buccal part of the two pier teeth (5).

12. Prostheses as claimed in Claims 8 and 10, wherein the bridge body (2) consisting of one or several bridge members (1) is provided at its connection to the pier teeth (5) with broadening protrusions bearing against the lingual and/or buccal part of the two pier teeth (5).

13. The method and prostheses as claimed in any of Claims 1 to

12, wherein a plate (8) preferably made of acrylate or porcelain and matched to the front-view shape of the replaced teeth is fixed to the visible, outer surface of the bridge body (2).

14. The method and prostheses as claimed in any of Claims 1 to

13, wherein metal clamps and/or wires are built into the bridge body (2).