US 2479543 A
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Description (OCR text may contain errors)
1949- I H. J. RussELL 2,479,543
DENTAL SHADE GUIDE Filed April 24, 1947 INVENTOR. HARRY J. RUSSELL Patented Aug. 16, 1949 DENTAL snaps some Harry J. Russell, Newark, N. J :assignor to Baker & Company, Inc., Newark, ,N. J, a corporation of New Jersey Application April 24, 194 Serial 4 13, 686 7 1 Claim. 1 This invention relates to :a dental :shade guide and more particularly to a :device for matchin dental shades.
Dental shade guides serve the purpose of assisting the dentist in selecting the proper shade for an artificial tooth or -a fillin in making a dental restoration. In assisting .him to thus select the proper shade of material, the dentist employs a shade guide carrying a number of artificial teeth of the various shades available, the procedure being that the dentist places the shade guide teeth in front of the patients natural 'teeth to select the shade most closely .approximating the coloringof the patients natural teeth.
Shade guides as heretofore known suffer, however, from a number of shortcomings. They are not normally adapted to assure accurate color matching because natural teeth are translucent and consequently the color efi'ect in matching depends on a number of critical factors, including light effects, thickness of the tooth, positioning of the tooth and so forth, factors which known tooth shade guides do not advantageously provide for.
In many cases when positioning the shade guide in front of the patients natural tooth, the lighting effect is disturbed and frequently a shadow is caused to fall upon the natural tooth, with the result that the tooth appears to have a different shade than it actually has. Also, most existing tooth shade guides tend to distort the true shade of a matching material due to metallic parts utilized in the assembly of the individual tooth shade guide, where such metallic parts, due to the translucency of the guide material, will tend to either cause shadow or distort the true shade of the shade guide.
It is, therefore, one object of this invention to provide a dental shade guide adapted to permit accurate matching of the color of the natural teeth with the corresponding color of the artificial tooth or filling material. It is another object of this invention to provide such a shade guide which shall not interfere noticeably with the color effects and light distribution affecting the apparent color of the translucent natural teeth. Other objects and advantages ofthe invention will appear from the description thereof hereinafter following.
The invention is illustrated in the drawings forming part hereof, in which:
Figure 1 is a front elevational view of a shade guide assembly,
Figure 2 is a front elevational view of an individual tooth shade guide,
Figure 8 is :a side view of the shade guide pl Figure 2 with the shade guide holder indicated in section, and
.Figure dis a side -view :of another embodiment of a :shade guide, likewise :with the holder indirated in section.
The shade guide assembly :as shown in Figure 1 comprises a holder 1, of circular shape, as i-ndisated, or of an other desired shape. Projecting from (this holder, radially in thecasesoi the circu- Jar holder of Figure 1, are a plurality of individual shade guides 2. The individual shade guide 2 is made of translucent material, ,preferably of plastic resin material, such as methyl methacrylate. It consists of a matching head 3 and a supporting means, such as the shank l. The head is shaped to simulate a natural tooth. The shank 4 is in the form of an elongated downwardly projecting stem recessed rearwardly from the incisal edge 5 of the tooth 3.
Referring more particularly to Figure 3, the recessed portion 6 extends rearwardly of the head 3 at an angle of preferably approximately or more but less than with respect to the substantially flat rear side of the simulated tooth 3. The downwardly projecting stem portion of the shank 4 extends in a direction substantially parallel to the surface of the rear wall of the tooth 3, preferably forming an angle of 90 or less with the recessed portion 6.
Figure 4 illustrates another embodiment of this invention comprising a stem 1 either in the shape of an are or provided with an arched portion, so that in View of the inherent resiliency of the plastic resin, the tooth shade guide is retained in a holder l without an added retaining means.
Some tooth shade guides are so constructed that in matching the artificial tooth of the tooth shade guide with the natural tooth, it is sometimes necessary to compress the patients lips with the stem of the tooth shade guide or the finers of the dentist in order to bring the artificial tooth into matching contact with the natural tooth. The tooth shade guide of this invention has a construction that is particularly advantageous in that in practice the stem does not compress the lips of the patient in order for the synthetic tooth to come into a close matching contact with the natural tooth. This advantage is more particularly illustrated in Figure 3 where the incisal edge 5 of the simulated artificial tooth 3 can be placed in close proximity with the incisal edge of a natural tooth while neither the shank 4 nor the end of the stem portion of the 3 shank 4 which is held in the fingers of the dentist comes in contact with the patients lips.
Other tooth shade guides are so constructed that an assembly portion appears on the back of the artificial simulated tooth and usually in the center of the rear wall, thereby interferring with the close matching of the artificial tooth with the natural tooth, making it impossible to place the rear wall of the artificial tooth against the front Wall of the natural tooth for close matching contact. In the tooth shade guide of this invention, there is no such interference as would be caused by an assembly means or other protuberance attached to the rear wall of the artificial tooth of the shade guide. Compared therewith the rear wall of the head 3 as illustrated in Figure 3 is smooth and flat and there is no protuberance or other obstacle which would prevent the tooth shade guide from close contact with the natural tooth while determining the corresponding shades between the natural tooth and the tooth shade guide.
The close contact of the synthetic tooth with the natural tooth eliminates any possible degree of error, such as is apt to occur when the objects to be compared are a greater distance apart and such greater distance between the matching objects enhances the possibility of error in matching with respect to color effect and light distribution. Also, there is no distortion of the true shade, such as is evident in translucent materials when materials of greater opaqueness are interposed between the transparent materials to inhibit transparency and cause unnatural coloration, e. g. in cases where metallic assembly parts 4 are attached to the back of the tooth shade guide.
Assembled tooth shade guides as heretofore known have a further disadvantage in that the mechanical assembly provides crevices which hinder speedy and effective sterilization. The tooth shade guide of this invention eliminates such crevices by being manufactured as an integral unit and consequently is adapted for easier manufacture and for speedier and more effective sterilization.
What I claimed is:
A dental shade guide consisting entirely of a translucent plastic material and comprising as an integral unit the combination of a matching head and an elongated support, said matching head being shaped to simulate a natural tooth having an incisal edge and a substantially flat rear wall, said rear wall being free of attachments and protuberances, said elongated support having a portion extending rearwardly at said incisal edge and then extending downwardly from said rearwardly extending portion.
HARRY J. RUSSELL.
REFERENCES CITED The following references are of record in the file of this patent:
UNITED STATES PATENTS Number Name Date 789,415 Dressel May 9, 1905 1,369,718 Steele Feb. 22, 1921 2,249,634 Myerson July 15, 1941 2,420,570 Shapiro May 13, 1947