Evaluation of the effect at various stages of porcelain baking and post soldering of multiple unit facially butted porcelain ceramometal restorations
Date
1991
DOI
Authors
Ezaki, Tomohiro
Version
OA Version
Citation
Abstract
Various investigators have reported on the 'fit' of facial butted porcelain ceramometal crowns. Most of the studies have been confined to single unit crowns. Originally, the technique for a facial porcelain shoulder was based on the use of platinum foil (0.001mm) burnished to the replica (die) of tooth preparation. Due to the unpredictability of the platinum foil technique (technique sensitivity), other methods have been developed. Foremost of these alternative techniques has been the direct lift off approach.
From a practical everyday clinical viewpoint, it is quite common to use anterior multiple unit crown restorations with facially butted joints in order to achieve a cosmetic result. The multiple units may be obtained by one piece castings or soldering.
West et al. (1985) compared the marginal integrity of porcelain butt joints of individual ceramometal crowns fabricated by two different techniques; the platinum foil and direct lift off method. They directed their research to the quality and fit of the marginal gap. They reported that although no significant differences were found in the overall marginal porcelain adaptation of the two techniques, the platinum foil method consistently produced the sharpest marginal delineation (less rounding) and was less porous. In comparison, the direct lift off technique which is more complex caused greater marginal discrepancies.
It has been noted that marginal distortion occurs when a single unit crown is subjected to additional firing such as for glazing after clinical correction or for color modification (staining). Thus, it is quite apparent that all previous investigations failed to evaluate the distortional effect on single units when joined by post soldering which is a common clinical procedure.
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Thesis (M.Sc.D.)--Boston University, Henry M. Goldman School of Graduate Dentistry, 1991 (Prosthodontics)
Bibliography: leaves 150-161.
Thesis (M.Sc.D.)--Boston University, Henry M. Goldman School of Graduate Dentistry, 1991 (Prosthodontics)
Bibliography: leaves 150-161.
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This work is protected by copyright. Downloading is restricted to the BU community. If you are the author of this work and would like to make it publicly available, please contact open-help@bu.edu.