SHADE GUIDE FOR EVALUATING THE OPTICAL APPEARANCE OF A DENTAL RESTORATION

Abstract: The shade guide (1) consists of a coloured polymerised composite material for evaluating the optical appearance of a dental restoration. It has a wedge-like shape and the composite material of which it is built up has a homogeneous structure. It has the advantage that it allows to evaluate the coloration of a dental restoration to be made with a curable composite material in particular with a light curable composite material before the restoration is performed.

Description: Shade guide for evaluating the optical appearance of a dental restoration This invention concerns a shade guide for evaluating the optical appearance of a dental restoration in accordance with the pre-characterising portion of claim 1, a set of such shade guides according to the preamble of claim 14, and an assembly for dental restorations consisting of a curable dental composite material and such shade guides in accordance with the pre-characterising portion of claim 15. Conventional shade guides are known in the form of fan type plates of uniform thickness usually made from pre-manufactured plastics which correspond more or less to the dental composite to be used. One major drawback of these prior art shade guides is their uniform thickness which allows no gradual superposition of the single guides. Another known type of known shade guides consists of plastic sleeves filled with the dental composite to be used and subsequently hardened. The drawback of these know guides is their inhomogenity caused by the different material for the sleeve (polyethylene or polypropylene) and for the hardened core (sophisticated polymethacrylates and other polymers) . Both types of know shade guides lead to significant colour deviations if used together with dental composite materials and in particular with light cured composites. The invention as claimed aims at solving the above described problems . The present invention provides a shade guide as defined in claim 1, a set of such shade guides as defined in claims 14 and an assembly as defined in claim 15. The shade guides according to the invention have the advantage that they allow to evaluate the coloration of a dental restoration to be made with a curable composite material before the restoration is performed. To this effect the shade guides consist of the same but polymerised material as the curable dental composite material . The homogenous wedge-like shaped shade guide has a wedge angle a in the range of 1 to 10°, preferably in the range of 1,5° to 5°. More preferably the wedge angle α. is in the range of 1,8° to 3,5° and typically in the range of 2,0 - 3,0 ° which allows superposition of two or more shade guides of different colours over a relatively extended area of the shade guides. The shade guide has preferably the form of a frustum of a wedge. The thickness x of the shade guide measured at its thickest end is in the range of 2,0 to 4 , 5 mm, preferably in the range of 2,5 to 3,5 mm. The thickness y of the shade guide measured at its thinnest end is in the range of 0 , 5 to 2,5 mm, preferably in the range of 0,8 to 1,5 mm. The length of the shade guide is in the range of 10 to 60 mm, preferably in the range of 35 to 45 mm. The width z of the shade guide is in the range of 4 to 10 mm, preferably in the range of 6,5 to 8,0 mm. The composite material of the shade guides may be either chemically cured (two component material) or preferably light-cured. In the latter case either UV light or preferably light in the visible region can be used. In order to prevent discoloration of the shade guides they should preferably comprise a colour stabiliser. A number of further additives to the composite material of the shade guide may be used in order to reach maximum similarity to the dental restoration to be performed. Such additives may comprise fluorescent agents and opacifiers. In a preferred embodiment of an assembly consisting of a curable dental composite material and a shade guide according to the invention the dental composite material comprises a first dentine-type composite material for the dentine part of a tooth and a second enamel -type composite material for the enamel part of a tooth in order to copy as truly as possibly the natural dental structure and coloration. The system can be further elaborated by using A) a first set of n > 2 shade guides consisting of the same but polymerised material as the dentine-type composite material; and B) a second set of n ≥ 2 shade guides consisting of the same but polymerised material as the enamel-type composite material. The number n is chosen from the group of the integers 3, 9, 21, 23 or 26 and is preferably in the range of 4 to 30, typically in the range of 10 to 25. The various features of novelty which characterize the invention are pointed out with particularity in the claims annexed to and forming part of this disclosure. For the better understanding of the invention, its operating advantages and specific objects attained by its use, reference should be had to the accompanying drawings, examples and descriptive matter in which are illustrated and described preferred embodiments of the invention. In the drawings : Fig. 1 is a perspective view of two partially superimposed shade guides according to the invention. Figure 1 shows a shade guide 1 for evaluating the optical appearance of a dental restoration having the form of a frustum of a wedge and consisting of a homogenous coloured polymerised composite material. The composite material is light-cured so as to match as truly as possible the colour of the light curable dental composite material to be used for the dental restoration. The shade guide consists of the same but polymerised material as the light curable dental composite material. The angle of the wedge of the frustum of a wedge is 2,5°. The length of the frustum is 40 mm and its width is 7,2 mm. The thickness x of the shade guide measured at its thickest end is 3 mm the thickness y of the shade guide measured at its thinnest end is 1,1 mm. As shown in Fig. 1 an anterior shade guide 1 is partially superimposed with an posterior shade guide having a different colour in order to give an indication of the colour to be obtained by mixing two components corresponding to two shade guides of different colour. By using a system of different shade guides and of corresponding composite material a large variety of possible colour combination can be evaluated before performing the dental restoration. Claims 1. Shade guide (1) consisting of a coloured polymerised composite material for evaluating the optical appearance of a dental restoration , characterized in that the shade guide (1) has a wedge-like shape and that the composite material has a homogenous structure. 2. Shade guide according to claim 1, characterized in that its wedge angle α. is in the range of 1 to 10°, preferably in the range of 1,5° to 5°. 3. Shade guide according to claim 2, characterized in that wedge angle α. is in the range of 1,8° to 3,5°, preferably in the range of 2,0 - 3,0 °. 4. Shade guide according to one of the claims 1 to 3, characterized in that the shade guide has the form of a frustum of a wedge . 5. Shade guide according to one of the claims 1 to 4, characterized in that the thickness x of the shade guide measured at its thickest end is in the range of 2,0 to 4 , 5 mm, preferably in the range of 2,5 to 3,5 mm. 6. Shade guide according to one of the claims 1 to 5, characterized in that the thickness y of the shade guide measured at its thinnest end is in the range of 0 , 5 to 2 , 5 mm, preferably in the range of 0,8 to 1,5 mm. 7. Shade guide according to one of the claims 1 to 6, characterized in that the length of the shade guide is in the range of 10 to 60 mm, preferably in the range of 35 to 45 mm. 8. Shade guide according to one of the claims 1 to 7, characterized in that the width z of the shade guide is in the range of 4 to 10 mm, preferably in the range of 6,5 to 8,0 mm. 9. Shade guide according to one of the claims 1 to 8, characterized in that the composite material is chemically cured. 10. Shade guide according to one of the claims 1 to 8, characterized in that the composite material is light-cured, preferably with light in the visible region. 11. Shade guide according to one of the claims 1 to 10, characterized in that the composite material comprises a colour stabiliser. 12. Shade guide according to one of the claims 1 to 11, characterized in that the composite material comprises a fluorescent agent. 13. Shade guide according to one of the claims 1 to 12, characterized in that the composite material comprises an opacifier . 14. Set of at least n ≥ 2 shade guides according to one of the claims 1 to 13 , characterized in that the shade guides have different colours . 15. Assembly for dental restorations consisting of a curable dental composite material and shade guides according to one of the claims 1 to 14, characterized in that the shade guides consist of the same but polymerised material as the curable dental composite material. 16. Assembly according to claim 15, characterized in that the dental composite material is a two component chemically curable composite. 17. Assembly according to claim 15, characterized in that the dental composite material is a light-curable composite. 18. Assembly according to one of the claims 15 to 17, characterized in that the dental composite material comprises a first dentine-type composite material for the dentine part of a tooth and a second enamel -type composite material for the enamel part of a tooth. 19. Assembly according to claim 18, characterized in that it comprises A) a first set of n ≥ 2 shade guides consisting of the same but polymerised material as the dentine-type composite material; and B) a second set of n 2 shade guides consisting of the same but polymerised material as the enamel-type composite material. 20. Assembly according to claim 19, characterized in that the number n is chosen from the group of the integers 3, 9, 21, 23 or 26. 21. Assembly according to one of the claims 19 or 20, characterized in that the number n is in the range of 4 to 30, preferably in the range of 10 to 25.

Claims: AMENDED CLAIMS [received by the International Bureau on 13 February 2001 (13.02.01); original claims 1 and 2 amended; remaining claims unchanged (1 page)] 1. Shade guide (1) having a wedge-like shape consisting of a coloured polymerised composite material for evaluating the optical appearance of a dental restoration, characterized in that A) the wedge angle of the shade guide (1) is in the range of 1 to 10°; and B) the composite material has a homogenous structure. 2. Shade guide according to claim 1, characterized in that the wedge angle α is in the range of 1,5° to 5°. 3. Shade guide according to claim 2, characterized in that wedge angle α is in the range of 1,8° to 3,5°, preferably in the range of 2,0 - 3,0 ° . 4. Shade guide according to one of the claims 1 to 3, characterized in that the shade guide has the form of a frustum of a wedge . 5. Shade guide according to one of the claims 1 to 4, characterized in that the thickness x of the shade guide measured at its thickest end is in the range of 2,0 to 4,5 mm, preferably in the range of 2,5 to 3,5 mm.

Inventors: MICELI EUGENIO, NIEM THOMAS, VANINI LORENZO, MICELI, EUGENIO, NIEM, THOMAS, VANINI, LORENZO
Applicants: GDF GES DENTALE FORSCH, MICELI EUGENIO, MICERIUM S R L, NIEM THOMAS, VANINI LORENZO, GDF GESELLSCHAFT FUER DENTALE FORSCHUNG UND INNOVATIONEN GMBH, MICELI, EUGENIO, MICERIUM S.R.L., NIEM, THOMAS, VANINI, LORENZO
Application year: 2000
Main classification: A61C19
IPC codes: A61C19, B44D3