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Effect of gypsum separating media on the appearance of stone cast surfaces
Tae Hyung Kim1, Tae Jun Ahn2, Reyes Enciso3
1Assistant Professor of Clinical Dentistry, Division of Restorative Science, Chair of Removable Section, Ostrow School of Dentistry of USC, University of Southern California, Los Angeles, Calif.
Statement Of Problem:
Several well-known parameters influence the appearance of the denture base surface, including proper isolation of the dental stone. There is lack of data describing the influence of this parameter on the appearance of the denture base surface.
Purpose:
The purpose of this study was to evaluate the effectiveness of 2 dental stone separating media on the surface of the denture base.
Material And Methods:
A conventional flasking technique for fabricating a denture base was used. Twenty casts were poured with Type III yellow dental stone to produce 20 identical denture bases. Each cast was sectioned into halves. One half of the cast was treated with Al-Cote (control group) and the other half with Iso-K separating material. Once the denture base was finished, a single examiner, blinded to the experiment, visually compared the 2 surfaces of each cast (right and left part of the cast) under natural light to determine which surface was glossier. The McNemar test (.05 significance level) was used to compare the discordant pairs (20 discordant pairs).
Results:
Two pairs (10%) were glossier than the Iso-K treatment, and 18 pairs (90%) within the Iso-K treatment were glossier than the treatment with Al-Cote. A statistically significant difference was found between the 2 treatments (P<.001). The odds ratio was 9.00, with a 95% confidence interval of 2.155 to 79.981.
Conclusions:
When used according to the manufacturer's instructions, denture surfaces treated with Iso-K appeared glossier than when treated with Al-Cote separating material.
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