BRACKET FOR CORRECTING SET OF TEETH

Abstract: A bracket for correcting a set of teeth, which comprises a substrate (1), a wire insertion groove (3) for receiving slidably a correcting wire and a wire support (2) having a pair of anchor pawls (10a) and (10b) for a ligature wire each on each of both of its side portions. At least one of the anchor pawls is formed without both end portions in its longitudinal direction so that the ligature wire can be run from one of the anchor pawls to the other through the upper surface of the end portion of the wire support and the correcting wire is not directly pressed by the ligature wire, thus ensuring a smooth sliding motion of the correcting wire.

Description: TECHNICAL FIELD The present invention concerns a bracket used for correcting set of teeth. BACKGROUND ART Heretofore, the bracket of this type, as shown in Fig. 14, comprises a base plate 14 and two wire supports 15, 15 disposed along both ends of the base plate 14, in which square sectioned wire passage grooves 16, 16 are formed in the center of the wire supports 15, 15, respectively. For correcting irregular set of teeth (state of set of teeth in an irregular arrangement), for instance, by using the brakket C, the following method is usually adopted. That is, as shown in Fig. 16, after the first premolar 17 is extracted, the bracket C is bonded and fixed to the surface of each of teeth at first (refer to Fig. 15). Then, a round wire 6 of a circular cross section is extended under tension along the wire passage grooves 16, 16 of the individual bracket C (refer to Figs. 14, 15), to correct the arrangement of the teeth along the backward and forward directions, as well as improve the twisting of the teeth and, while on the other hand, the gap after extracting the tooth is closed by moving a canine 19 toward a first molar by the resiliency of a rubber band (not illustrated). In this case, the canine 19 is moved by the sliding movement, on the round wire 6 of the wire passage grooves 16, 16 of the bracket C bonded and fixed to the canine 10. However, in a case of using the bracket C, since the wire passage grooves 16, 16 are in a line-to-line contact with the round wire 6, a frictional force between them is large and, as a result, it takes a considerably long period of time for the correction. There have been related for the related prior art U.S. 4,838,786, JP 45-37639, and U.S. 4,260,375. A teeth straightening bracket is known from U.S. 4,838,786, comprising a base portion, that is integrally formed with a tiewing having a surface for attachment to a tooth, while the base portion is having at least one longitudinally extending groove across the bracket, that is extending from the surface into the base portion. The JP 45-37639 describes a teeth bracket, comprising a wire support being disposed on a base, having substantially the same length as the base and engaging gains, which is formed at both ends of the wire support. The engaging gains are preventing a binding wire from contact with the round wire by winding the binding wire thereon, while the wire passage grooves are in a line-to-line contact with the round wire. In the U.S. 4,260,375 an orthodontic spring clip is described, comprising at least one elongated rear groove being formed in a rear surface portion of the body member. In view of the above, with an aim of shortening the correction period, the present applicant has previously filed "Teeth Straightening Bracket" in Japanese Patent Application Hei 1-18345. The invention of the above-mentioned application provides, as shown in Fig. 11, a teeth straightening bracket comprising a base plate 11, two wire supports 12, 12 disposed along both ends of the base plate 11 and wire passage grooves 13, 13 formed respectively to the wire supports 12, 12, in which both side walls 13a, 13b of each of the wire passage grooves 13 are formed each in a semi-cylindrical shape and protruding to each other, as well as the bottom surface 13c of the passage groove 13 is formed as a semi-cylindrical convex shape extending from one side wall 13a to the other side wall 13b. In the bracket B of such a constitution, the wire passage grooves 13, 13 are in point-to-point contact with the round wire 6 and, as a result, since the frictional force can be reduced as compared with the line-to-line contact in the conventional bracket C, the period required for the correction can be shortened. By the way, when the round wire 6 is extended under tension along with the wire passage grooves 13, 13 of the individual brackets B, it is necessary that the round wire 6 is not detached out of the wire passage grooves 13, 13. For this purpose, a hooked engaging finger 21 is disposed at both upper ends of the wire support 12 (Fig. 11), and a binding wire 8 is wound around the bracket B (also in the bracket C) so as to press it against the round wire 6, and the binding wire 8 is prevented from slip-off by the engaging finger 21 (refer to Figs. 12, 13). However, if the binding wire 8 is wound around the bracket B so as to press it against the round wire 6, the binding wire 8 presses the round wire 6 downward in Fig. 3. Therefore, when the canine 19 is moved toward the first molar 20 by the sliding movement of the wire passage groove 13 of the bracket B bonded and fixed to the canine 19 along the round wire 6 (refer to Fig. 16), the wire passage holes 13, 13 can not be smoothly moved under sliding along the round wire 6. As a result, an aimed object of shortening the period for the correction by reducing the frictional force exerting between the wire passage holes 13, 13 and the round wire 6 is hindered and can not be attained. DISCLOSURE OF INVENTION The present invention has an aim for dissolving the foregoing problem in the prior art, to fixate a round wire in a bracket by a binding wire without pressing the round wire and to minimize the area of the contact surfaces between a round wire and wire passage groove, and it provides, as a means therefor, a teeth straightening bracket, characterised in that protruding semi-cylindrical wire sliding contact portions are formed on both side walls and bottom of said wire passage groove, perpendicularly to the longitudinal direction, engaging fingers for a binding wire are disposed on both sides i. e. on the incisal and gingival side of said wire support along the longitudinal direction of the wire support such that the engaging fingers are disposed except for both ends thereof at least on one side. Advantageously, an engaging groove for a binding wire is disposed on the vestibular i. e. upper surface of the longitudinal ends of the wire support. In a preferred embodiment, engaging fingers are disposed on the incisal and gingival side of the wire support except for the both longitudinal ends of the wire support. Furthermore, engaging fingers on the incisal and gingival side can be disposed except for the both longitudinal ends of the wire support elongate rectangular shape. In a teeth straightening bracket in another embodiment of the present invention, protruding semi-cylindrical wire sliding contact portions are formed on both side walls and bottom of said wire passage groove, perpendicularly to the longitudinal direction, engaging fingers for a binding wire are disposed on the incisal and gingival side of said wire support along the longitudinal direction of the wire support such that the engaging fingers are disposed except for both ends thereof at least on one side and other engaging fingers are disposed at both longitudinal ends of the wire support respectively. The engaging groove for a binding wire is advantageously formed on the vestibular surface of the longitudinal ends of the wire support. In the teeth straightening bracket according to the present invention, a binding wire passes on the vestibular surface of each protruding ends of each sides of the wire support, via a side of each removed ends of engaging fingers. Therefore, the binding wire can be wound around the teeth straightening bracket without pressing the bonding wire directly to the round wire upon preventing the round wire from slipping-off by the binding wire, while the teeth straightening bracket bonded and fixed to individual teeth can smoothly move slidingly on the round wire upon moving a tooth along a set of teeth and, as a result, a frictional force exerted between the wire passage groove and the round wire can be reduced to shorten the period for the correction. As the binding wire does not press the round wire against the bottom and walls, the round wire is fixated properly in the bracket by the binding wire. Further, in a case where another engaging fingers are disposed on both longitudinal ends of the wire support, the round wire is necessarily pressed against the bottom and walls by the binding wire passing under the other engaging fingers thereby enabling to correct the set of teeth in the forward and backward directions and correct the twisting of a tooth. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a perspective view showing a teeth straightening bracket according to the present invention, Fig. 2 is a front elevational view showing a state of winding a binding wire so as not to press a round wire, Fig. 3 is a cross sectional view taken along lines I-I in Fig. 2, Fig. 4 is a cross sectional view taken along lines II-II in Fig. 2, Fig. 5 is a perspective view illustrating another embodiment of a teeth straightening bracket according to the present invention, Fig. 6 is a front elevational view illustrating the state of winding a binding wire so as to press the round wire, Fig. 7 is a cross sectional view taken along lines III-III in Fig. 6, Fig. 8 is a perspective view illustrating a further embodiment of a teeth straightening bracket according to the present invention, Fig. 9 is a front elevational view showing a state of winding a binding wire so as not to press the round wire, Fig. 10 is a cross sectional view taken along lines V-V in Fig. 9, Fig. 11 is a perspective view illustrating an embodiment of the prior art, Fig. 12 is a front elevational view illustrating a state of winding a binding wire around the bracket in Fig. 11, Fig. 13 is a cross sectional view taken along lines IV-IV in Fig. 12, Fig. 14 is a perspective view illustrating another embodiment of the prior art, Fig. 15 is a front elevational view illustrating a state of bonding and fixing the bracket in Fig. 14 to the surface of a tooth and Fig. 16 is a schematic view illustrating the state of correction, Fig. 17 is a perspective view illustrating a more practical embodiment according to the present invention, Fig. 18 is a plan view of the bracket in Fig. 17, Fig. 19 is a cross sectional view taken along lines VI-VI in Fig. 18 and Fig. 20 is a cross sectional view taken along lines VII-VII in Fig. 18. BEST MODE FOR CARRYING OUT THE INVENTION The present invention will hereinafter be described by way of its preferred embodiments with reference to the drawings. Fig. 1 is a perspective view showing a teeth straightening bracket according to the present invention. As shown in Fig. 1, a teeth straightening bracket A comprises a base plate 1 for bonding and fixing to the surface of a tooth, and a wire support 2 disposed to the upper surface of the base plate 1 and formed with a wire passage groove 3 along the longitudinal direction thereof (direction of the set of teeth). The base plate 1 is entirely curved so that it can fit against the surface of the tooth. In the wire passage groove 3 of the wire support 2, semi-cylindrical wire sliding contact portions 4a, 4b and 4c, 4d protruded to each other are disposed, to both ends of the both side walls 4, 4, so that the circumferential surface of the round wire 6 is brought into point-to-point contact with that of the both side walls 4, 4 of the wire passage groove 3 when the correcting round wire 6 of a substantially circular cross section is inserted through the wire passage groove 3. Further, as shown in Fig. 4, which is a cross sectional view taken along lines II-II in Fig. 2, in the wire passage groove of the wire support 2, semi-cylindrical wire sliding contact portions 5a, 5b protruding upward are disposed at both longitudinal ends of the bottom surface 5 being in perpendicular to the longitudinal direction thereof respectively, so that the circumferential surface of the round wire 6 is brought into point-to-point contact with the circumferential surface 5 of the bottom surface 5 of wire passage groove 3 when the round wire 6 is inserted through the wire passage groove 3 (refer to Fig. 4). On both longitudinal ends at the vestibular surface of the wire support 2, engaging grooves 9, 9 are disposed in parallel with the wire sliding contact portions 5a, 5b (perpendicular to the longitudinal direction). Each of the engaging grooves 9 is formed as a semi-cylindrical shape having substantially the same diameter as the binding wire 8. Further, downwarding hook-shaped engaging fingers 10a, 10b are disposed along the longitudinal direction on the incisal and gingival side of the wire support 2 except for both longitudinal ends. That is, the engaging fingers 10a, 10b situates between the engaging grooves 9, 9 disposed in parallel with each other to the vestibular surface of the wire support 2. Accordingly, when the round wire 6 is extended under tension along the wire passage groove 3 of the individual bracket A, the binding wire 8 can be wound around the bracket A in a state along the engaging groove 9 and can be prevented from slipping-off by the engaging fingers 10a, 10b (refer to Figs.2 and 3). Then, since the round wire 6 is not pressed in this state by the binding wire 8, the wire passage grooves 3 of the bracket A bonded and fixed to the canine 19 can smoothly slide on the round wire 6 and, as a result, the period for the correction can be shortened by reducing the frictional force exerted between the wire passage groove 3 and the round wire 6. In another embodiment shown in Figs. 5 to 7 (members in Figs. 5 to 7 corresponding to the respective members in the embodiment shown in Figs. 1 to 4 are shown by corresponding reference numerals), second engaging fingers 7a, 7b and 7c, 7d are disposed on both longitudinal ends of the wire support 2 being situated to the outside of the wire passage grooves 3 respectively. In this modified embodiment, the binding wire 8 may be disposed along the engaging groove 9 in the same way as in the embodiment described previously or, if required, it may be passed below the second engaging fingers 7a-7d and then wound around the bracket A so as to press against the upper surface of the round wire 6 and prevented from slipping off by the second engaging fingers 7a, 7b and the 7c, 7d. Then, when it is bound in the latter way, since the bracket A bonded and fixed to each of teeth less slides on the round wire 6, this embodiment is more effective, for example, in a case of arranging the set of teeth in the forward and backward directions by the resiliency of the round wire 6 and then improving the twisting of a tooth. In each of the above-mentioned embodiments, the engaging groove 9 is disposed to the vestibular surface of the wire support 2, and the binding wire 8 is passed through the engaging groove 9 upon winding the binding wire 8 around the bracket A so as not to press the round wire 6, but such an engaging groove 9 is not always necessary but the wire 8 may be extended along the vestibular surface of the wire support 2. Further, although two engaging fingers 10a, 10b are disposed on the incisal and gingival side of the wire support 2 excepting for both longitudinal ends thereof, it is not always necessary for such a constitution, providing that the bonding wire rising from the engaging finger does not directly press the round wire. For instance, in Figs. 8 to 10 showing a further embodiment of the present invention (members in Figs. 8 to 10 corresponding to respective members in each of the embodiment described above are shown by corresponding reference numerals), the engaging finger 10a is disposed except for the both ends only on one side of the wire support 2, while the engaging finger 10c is disposed including the both ends thereof on the other side. Also in this case, when the round wire 6 is extended under tension in a state along the wire passage groove 3 of the individual bracket A, it is possible to wind the binding wire 8 around the bracket A in a state not to press the round wire 6 and along the vestibular surface of the wire support 2, and prevent it from slipping-off by the engaging fingers 10a, 10c (refer to Figs. 9 and 10). In a case of manufacturing and fabricating the tooth straightening bracket according to the present invention, it is preferred to make each of portions into a more smooth shape while considering actual feeling upon mounting, appearance or the like, and such a practical embodiment of the bracket is shown in Figs. 17 to 20. In the figures, identical members with those in each of the embodiments described above are shown by identical reference numerals, excepting for indicating only the portion corresponding to the engaging groove 9 in each of the examples as a more smoothed engaging recess 9a. INDUSTRIAL APPLICABILITY The teeth straightening bracket according to the present invention is suitable to the effective correction for irregular set of teeth in various states in a short period of time.

Claims: A teeth straightening bracket comprising: a base plate (1), a wire support (2) disposed on said base plate (1) and a wire passage groove (3) formed in said wire support (2), characterised in that protruding semi-cylindrical wire sliding contact portions are formed on both side walls (4a, 4b, 4c, 4d) and bottom (5a, 5b) of said wire passage groove (3), perpendicularly to the longitudinal direction; engaging fingers (10a, 10b, 10c) for a binding wire (8) are disposed on the incisal and gingival side of said wire support (2) along the longitudinal direction of the wire support (2) such that said engaging fingers (10a, 10b) are disposed except for both ends thereof at least on one side. A teeth straightening bracket according to claim 1 characterised in that an engaging groove (9) for a binding wire (8) is disposed on the vestibular surface of the longitudinal ends of the wire support (2). A teeth straightening bracket according to claim 1 characterised in that engaging fingers (10a, 10b, 10c) on the incisal and gingival side of the wire support (2) are disposed except for the both longitudinal ends of the wire support (2). A teeth straightening bracket according to claim 1 characterised in that other engaging fingers (7a, 7b, 7c, 7d) are disposed at both longitudinal ends of said wire support (2) respectively. A teeth straightening bracket according to claim 4 characterised in that an engaging groove (9) for a binding wire (8) is formed on the vestibular surface of the longitudinal ends of the wire support (2).

Inventors: SUYAMA HAJIME, SUYAMA, HAJIME
Applicants: JOBERT SUZANNE, SUYAMA, HAJIME
Application year: 1990
Main classification: A61C7
IPC codes: A61C7