Fixed partial dentures and operative dentistry

Contouring and staining ceramic-metal restorations in the mouth Joseph T. Richardson, D.D.S., M.A.T.,* and F. Michael Gardner, D.D.S.** Medical University of South Carolina, College of Dental Medicine, Charleston, S. C.

Never before has such emphasis been pIaced on esthetics as in today's restorative procedures. Tile patient is no longer satisfied with a dental restoration that merely restores function. He insists that his prosthesis have a vital, natural appearance. Since necessity is the mother of invention, we now have more materials which enhance the esthetics of restorations better than ever before, and as research continues, each day brings the promise of newer and better materials. It is, therefore, necessary that both the dentist and the technician be skilled in the manipulation of these materials in order to achieve the best results. Unfortunately, the laboratol3, technician, armed with only a work authorization and diagnostic cast, is at a disadvantage in achieving maximum contours and characterization for esthetics. Only the dentist working directly in the mouth can achieve the proper end result of shading, contouring, and individualization of the restoration. Many restorations have been inserted just as they come from the lahoratory, without a few simple procedures having been done which would greatly improve the appearance of the prosthesis. A simple technique for characterization in the office is within the range of all dentists making porcelain restorations. The preparation, impression, and laboratory procedures leading up to the trial of the restoration will not be discussed, since we are concerned with finishing touches to be applied by the dentist in his office. We are assuming that the restoration is returned from the laboratory in the biscuit-bake form for trial.

IMPROVING THE ANATOMY After function and fit are achieved, the dentist should next turn his attention to esthetics, Pontics should be shaped to afford adequate embrasures, light tissue contact, and convex cleanable surfaces, while still presenting a natural lifelike rel,'itionship with the alveolar ridge? The restoration should complement the contours and "~Assoeiate Professor, Department of Crown and Bridge Dentistry. ~'~Associate, Department of Crown and Bridge Dentistry. 637

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J. Prosthet. Dent. June, 1975

Fig. 1. Upper right lateral incisor crown (a) at the biscuit bake and (B) at the final cementation.

Fig. 2. T w o upper right premolar crowns tation.

(A)

at the biscuit bake and

(B)

at the final cemen-

light-reflection properties of the adjacent teeth. Usually, with minimal selective grinding of the labial surfaces, light reflection and highlights, similar to those in adjacent teeth, can be created. The technician using"a stone working cast does not have this opportunity. Viewing the restoration from all angles, special attention should be paid to the proximolabial lind angles, the concavities and convexities of the labial surface, the angle of emergence from the gingiva, and the thickness of the incisaI edge. Changes in contour can alter the long-axis inclination of the tooth. Smoothing the labial surface gives an impression of larger size, and conversely, irregularities give an impression of smaller size. Vertical highlights create an illusion of greater length, while accentuated horizontal striations create a tooth that appears to be wide. A tooth can be made to appear wider by moving the labioproximal line angles lingually or narrower by moving these line angles labially (Figs. 1 to 4, A). The biscuit-baked restoration should be continually wetted to reflect light, as will the eventual glazed surfaces.'-', 3 All contouring should be done with special stones to avoid contamination of the porcelain. STAINING

Once all the necessary or allowable contouring has been done, attention should be turned to staining. Staining can be used to darken a shade, but it is practically impossible to lighten shades through staining. 3 Color can be changed in hue (base color), brightness (degree between white and

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Contouring and staining ceramic-metal restorations 6 3 9

Fig. 3. A ceramic-metal restoration

(A) before characterization and (B) after characterization.

Fig. 4. A three-unit pinledge prosthesis (A) before characterization and (B) after characterization.

black), or saturation (intensity of a given hue).a The basis of color change is the interaction of the primary colors red, yellow, and blue--and their secondary colors-green, violet, and orange. As more of a secondary color is added, the intensity and brightness of the primary color diminish, approaching gray. 4 In addition to color changes, various stains can be used to individualize restorations. An increase in incisal translucency can be obtained by addition of gray, blue, or purple stain at the incisal edge. Cracks and checks can be mimicked with brown or brown-orange stain (Figs. 1 and 2, B). Worn incisal edges showing dentin can be created. Decalcification can be produced with gray or white stain. Silicate fillings can be duplicated (Figs. 3 and 4, B). An appearance of a narrow tooth can be created by interproximal staining with brown-black or brown-orange. Also, interproximal staining is practically essential to give an illusion of separation of units of a bridge veneered in one piece. Brownish root surface or pink gingivae can be simulated on overly long crowns or pontics, a' 5 It is preferable to apply the stains at the biscuit bake. They are applied bv mixing the properly pigmented porcelain powder with the liquid medium and painting this on with a very fine red sable brush, e If the desired effect is not created, the stain can be simply wiped off and the staining begun again. If applied at the biscuit bake, *Delta's Permapoint, style 520, No. 000 and No. 0000, Delta Brush Manufacturing Con> pany, New York, N. Y.

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Richardson and Gardner

J. Prosthet. Dent.

June, 1975

Fig. 5. Staining kit with palette---Ceramco Color System Kit and Manual. Fig. 6. A simple air-firing furnace--Ney Barkmeyer multipurpose furnace, model 310.

the final glaze is applied in the usual manner, thus sealing the stain under the final glaze and creating a good effect of depth. However, if the restoration received a final glaze before staining, a low-fusing overglaze may be evenly brushed on in one direction and glazed to seal the stain to the surface. This technique does not quite produce the quality of depth produced by the first one. The stain having been apIilied, the restoration is dried in front of an open muffle at 1,200 ° F. until a dry, chalky appearance is produced. Then the prosthesis is carried into the furnace and the temperature increased at a rate of 75 ° to 100 ° F. per minute until the final glaze temperature is reached for the porcelain or low-fusing glaze material, whichever was applied. The maturity of the glaze must be visually ascertained by looking into the furnace at the glaze temperature until the desired result is obtained. The fired porcelain is cooled under glass. Proficiency in staining may be easily obtained by sandblasting a porcelain shade guide and practicing different modifications? The described procedures require only a selection of stones reserved for porcelain grinding, one of several staining kits "x" currently available, and an air-fired porcelain oven,t which sells for less than $150.00 (Figs. 5 and 6). The satisfaction obtained by both patient and dentist from a truly individualized restoration should rapidly pay for the minimal cost in time and money. SUMMARY

An office technique has been described whereby the dentist, using minimal time and money, may produce an individualized and esthetic result with ceramic-metal restorations. This result can only be obtained by the dentist working with the patient; ~'Ceramco Color System Kit and Manual, Ceramco, Inc., Long Island City, N. Y.; Steele's Technic Manual and Kit for Porcelains, Super-Stains, and Super-Glaze, Columbus Dental Manufacturing Company, Columbus, Ohio. tNey Barkmeyer multipurpose furnace, model 310, The J. M. Ney Company, Bloomfield, Conn.

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Contouring and staining ceramic-metal restorations 641

it cannot be obtained by the laboratory technician working with only models and casts.

References 1. Stein, R. S.: Pontic Residual Ridge Relationship: A Research Report, J. PROSTHET. DENT. 16: 251-284, 1966. 2. Johnston, J. F., Mumford, G., and Dykema, R. W.: The Porcelain Veneered Crown, Dent. Clin. North Am., Nov., 1963, pp. 853-864. 3. Johnston, J. F., Mumford, G., and Dykema, R. W. : Modern Practice in Dental Ceramics, Philadelphia, I969, W. B. Saunders Company, pp. 23-34. 4. Ceramco Color System, revised edition, Ceramco Equipment Corporation, Long Island City, N. Y., 1968. 5. Aeziman, H. T.: Use of Surface Stains for Ceramic Restoration, Northwest Dent. 50: 215220, 1971. DR. RICHARDSON MEDICAL UNIVERSITY OF SOUTH CAROLINA COLLEGE OF DENTISTRY 80 BARRE ST. CHARLESTON, S. C, 29401 DR. GARDNER 556 ASHBURN

FT. BLrSS, ~rEXAS 79916

Contouring and staining ceramic-metal restorations in the mouth.

Fixed partial dentures and operative dentistry Contouring and staining ceramic-metal restorations in the mouth Joseph T. Richardson, D.D.S., M.A.T.,*...
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