DENTAL MATRIX IN A FLEXIBLE STRIP WITH TIGHTENER CONNECTED TO IT

Abstract: The matrix consisting of a thin flexible strip of plastic comprises a loop 1 to be placed around the tooth to give the desired shape to the filling material. It is permanently connected to an annular tightener (2) made of material permanently deformable by pressure with the fingers and dentist's forceps, for example, of annealed aluminum sheet. It exhibits, in the front, a slit (3) through which pass the two terminal extensions (1′, 1″) of flexible strip (1) and, in the back, tabs (2′, 2″) between which are permanently fastened the ends of said terminal extensions (1, 1″) of said strip, so that by compressing said annular tightener (arrows 4, 5) it determines the slipping of slit (3) like a slider on the extensions (1′, 11″) of the strip, the narrowing of loop (1) and the perfect adherence of the loop of the strip to the tooth.

Description: Matrixes in a flexible strip, for example of plastic, to be placed around the tooth during filling to give the filling material the desired shape, are known. Tighteners are also known which are suitable for holding said strip against the tooth to avoid slipping during filling. Said known tighteners are very complex and bulky and involve a considerable loss of time for thier application to the strip for each filling. According to the invention, the tightener is connected to the strip so as not to involve any loss of time by the dentist for each filling and is so simple, effective and inexpensive as to achieve a real advance relative to the known art, for example, relative to the tightener according to US patent No. 3.383.769 which is bulky and does not give a complete guarantee of holding the matrix against the tooth during filling without slipping. Subject of the present invention is a dental matrix comprising a flexible strip in the shape of a loop to be placed around the tooth to give the desired shape to the filling material and an annular tightness (2) connected to the loop-shaped strip (1), the tightener being made of material permanently deformable by pressure of the fingers or dentist's forceps and having, at the front, at least a slit (3) through which may pass two terminal extensions (1′, 1″) of flexible strip (1) and, at the back, tabs (2′, 2″) between which are permanently fastened the ends of said terminal extensions (1′, 1″) of said strip (1), since that by compressing said annular tightener at the sides (arrows 4, 5), slit (3) slides along the extensions (1′, 1″) of the strip so as to tighten the matrix, characterized in that said annular tightener (2) has, above and below the slit (3) a projection (2″′, 2″″) to avoid slipping. According to a preferred embodiment as said, the annular tightener exhibits, above and below the slit, a projection so that the two projections assure the perfect adherence of the matrix to the tooth, at the same time avoiding slipping. The accompanying drawing represents said preferred embodiment of the invention in a nonlimiting and nonbinding way. -- Figure 1 represents the lateral view of only the strip constituting the matrix. -- Figure 2 the top plan view of the strip of fig. 1. -- Figure 3 the top plan view of only the tightener. -- Figure 4 the front view of the tightener of fig. 3. -- Figure 5 the side view of the tightener of fig. 3. -- Figure 6 the development in a plane of only the tightener. -- Figure 7 the unit of the matrix and tightener. With reference to figures 1 and 2: the matrix, made up of a strip of thin plastic, is shaped in a loop 1 to surround the tooth during filling and ends in two extensions 1′ an d 1″. To strip 1, 1′, 1″ is permanently applied tightener 2 (figs. 3, 4, 5, 6) made, for example, of thin annealed aluminum sheet to be able to be easily and permanently deformed if pressed with the fingers or the dentist's forceps in the direction of arrows 4 and 5 (fig. 7). For this purpose, the two extensions 1′, 1″ of the strip are made to go through slit 3 (fig. 4) of tightener 2 and fastened at their ends to tabs 2′, 2″ of tightener 2, for example, by means of heat-setting and then bending of the tabs to avoid injuring the cheek. Projections 2″′, 2″″, which may be obtained, for example, by drawing, assure the perfect adherence of loop 1 of the matrix to the tooth, avoiding slipping. It is clear that the ends of extensions 1′, 1″ of the strip being fastened in 2′, 2″ (fig. 7), by pressing the tightener according to arrows 4, 5 to go from a circular shape to an elliptic shape, slit 3 slips like a slider on extensions 1′, 1″ forcing loop 1 to become smaller and fit the tooth perfectly so as to give the filling material the desired perfect shape. Tightener 2 being permanently and not elastically deformed, the return of loop 1 to the enlarged shape is impossible. The cost of the tightener in question is negligible in comparison with the advantages that flow from it. It is provided that the shape of the strip and of the tightener in question and the nature of the material that constitutes them can, however, vary without going outside the scope of protection of the patent as defined in the appended claims.

Claims: 1. Dental matrix comprising a flexible strip in the shape of a loop to be placed around the tooth to give the desired shape to the filling material and an annular tightness (2) connected to the loop-shaped strip (1), the tightener being made of material permanently deformable by pressure of the fingers or dentist's forceps and having, at the front, at least a slit (3) through which may pass two terminal extensions (1′, 1″) of flexible strip (1) and, at the back, tabs (2′, 2″) between which are permanently fastened the ends of said terminal extensions (1′, 1″) of said strip (1), since that by compressing said annular tightener at the sides (arrows 4, 5), slit (3) slides along the extensions (1′, 1″) of the strip so as to tighten the matrix, characterized in that said annular tightener (2) has, above and below the slit (3) a projection (2″′, 2″″) to avoid slipping. 2. Matrix according to claim 1, wherein the flexible strip is of plastic and the annular tightener is of aluminum.

Inventors: VON WEISSENFLUH, HANS
Applicants: HAWE-NEOS DENTAL DR. H. VON WEISSENFLUH S.A.
Application year: 1988
Main classification: A61C5
IPC codes: A61C5, A61C3