Date of Graduation
School of Dentistry
Mark W. Richards
Keith E. Kinderknecht
When accuracy and strength are required in fabricating working casts improved dental stones are recommended. The main variable affecting this accuracy is linear setting expansion. In this research study the linear setting expansion of three commonly used improved dental stones were compared over an extended 2-week period. Hard Rock, Silky Rock and Prima-Rock were vacuum mixed following manufacturers instructions. Five specimens of each stone were measured for linear expansion using a SAM EMI100 Expansion measuring Device. Expansion measurements were made at 10 and 30 minutes, 2, 24, 48, 72, and 120 hours. The gathered data were subjected to a two way ANOVA and the Tukey Multiple Range Test. The ADA specification #25 measures expansion over a 2-hour span. Continued dimensional changes may affect the accuracy of the final cast. The final fit of a restoration is determined by the accurate duplication of important oral structures and tooth preparations.
Cid Galano, Marcos, "Linear expansion of dental stone after its final set and beyond two hours" (2003). Graduate Theses, Dissertations, and Problem Reports. 1722.