An evaluation of three sprue designs for titanium cast removable partial denture frameworks
Date
1997
DOI
Authors
Al-Mesmar, Hamda S
Version
OA Version
Citation
Abstract
Although titanium has been used to cast removable-partial-denture frameworks, the casting process is arduous and requires specialized equipment. The objective of this study was to evaluate the ability of three different sprue designs (tree, ball, circular) to produce complete, void-free castings for removable partial-denture frameworks made from commercially pure titanium.
A cast with a Kennedy Class III, modification I partially edentulous pattern was used for this study. The blocked-out cast was modified to facilitate assessment of the completeness of the casting of the clasp arms. Thirty refractory casts were made (Titavest PP, J, Morita Corp., Osaka, Japan). Ten wax patterns for each sprue design were fabricated and invested with ethyl silicate investment (Titavest PS, J Morita Corp.). Castings were made with an arc-type automatic casting machine in an argon atmosphere (Cyclarc, J. Morita Corp.).
The castings were examined with radiographic equipment (General Electric Co., Milwaukee, Wisconsin) to detect the presence of voids in the castings, and the completeness of each casting was visually verified. Data were tabulated and statistically analyzed by using a oneway analysis of variance (ANOVA) followed by student Newman-Keuls test. Results indicated no statistically significant differences in the total number of porosities between the three sprue designs (p=0.51). Results of completeness of the castings were evaluated by using chi-square test, which revealed a statistically significant deference between the three sprue designs (P=0.008).
Currently, the manufacturer recommends a sprue design similar to the tree sprue. Addition of a ball reservoir to each tree sprue will produce a sprue design similar to the one used in this study and should improve the reliability of the casting technique. This study evaluated the different sprue systems with only one framework design, namely, a maxillary tooth-borne casting with a palatal-strap major connector. Results may be different for other framework designs.
Description
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Thesis (M.Sc.D.)--Boston University, Henry M. Goldman School of Dental Medicine, 1997 (Restorative Sciences).
Includes bibliographical references: (leaves 119-125).
Thesis (M.Sc.D.)--Boston University, Henry M. Goldman School of Dental Medicine, 1997 (Restorative Sciences).
Includes bibliographical references: (leaves 119-125).
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.