A modified bioassay system for measuring bone resorption in tissue culture and a study of the effects of a hypoglycemic agent 5-bromo-2-thisphenecarboxaldhyde on prostaglandings E2 and parathyroid hormone induced bone resorption
Date
1983
DOI
Authors
Sun, Arthur Fang-Shuo
Version
OA Version
Citation
Abstract
Opaque modifiers have been widely used in the intrinsic staining technique to enhance the esthetics of ceramometal restorations. The opaque modifiers are especially useful when adequate reduction of tooth structure for ceramometal restorations is not feasible. Despite the fact that opaque modifiers have become an indispensable part of ceramometal technology very little is known as to their color behavior and effect on the ceramometal bond.
The object of this research was to study the color stability of the opaque modifiers and their effect on the ceramometal bond after repeated firings. Two types of alloys, a noble alloy (Eclipse)* and a base alloy (Neydium+Be)*, were used to fabricate the samples. A ten-time repeated firings (Table 2, page 81) were conducted to fire the samples.
The opaque modifiers (SMO and SMBG)** to be tested were applied to the samples according to the two methods described below. These two methods are simulations of the practical methods employed by most dentists and dental technologists.
Method I. The opaque modifiers were applied on a layer of regular opaque.
Method II. The opaque modifiers were applied and fired directly to the metal castings.
The experimental design of this research was to provide information regarding the following issues which have long been a concern to the dental profession:
(1) Do the repeated firings affect the color stability of the opaque modifiers and the ceramometal bond of the ceramometal restoration?
(2) Do the methods (methods I & II described above) for applying the opaque modifiers affect the color stability of the opaque modifiers and the stability of the ceramometal bond?
(3) Do the metal alloys (noble & base alloys) for casting the metal substructures of ceramometal restorations affect the color stability of opaque modifiers and the stability of the ceramometal bond?
The spectrophotometric result of this research indicated a significant trend of color (Hue, Value & Chroma) shift of the ceramometal samples during repeated firing procedures. The color shift could be attributed to the combined effect of the firings, the metal alloys and the methods for applying the opaque modifiers. There was a significant interaction among the effects from the firings, the metal alloys and the methods of opaque modifier application. This interaction was very complicated since the magnitude of the individual affect on the color shift from all three factors was not only inconsistent but also interrelated.
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Description
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Thesis (M.Sc.D.)--Boston University, Henry M. Goldman School of Graduatr Dentistry, 1983 (Prosthodontics)
Bibliography : leaves 108-147.
Thesis (M.Sc.D.)--Boston University, Henry M. Goldman School of Graduatr Dentistry, 1983 (Prosthodontics)
Bibliography : leaves 108-147.
License
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.