Date of Graduation
2000
Document Type
Thesis
Degree Type
MS
Committee Chair
Mark W. Richards
Abstract
The purpose of this study was to investigate the effect of time on dimensional changes of polysulfide impression materials over time. A stainless steel die fabricated according to the ADA, Standards Specification No.19 was used. Measurements were carried out at 15 minutes intervals up to 3 hours and at 6, 12, and 24 hours. Results, the mean, and the percentage dimensional changes were reported. All collected data was based on a repeated measure design. Split plot analysis of variance at P< 0.05 was used to calculate any statistically significant dimensional changes over time among the three impression materials. All three impression materials tested could produce replicas with clinically acceptable dimensional changes up to 24 hours after making the impression. However, after 3 hours, there were significantly greater dimensional changes approaching our standard of 40 µm acceptability. It is therefore recommended that polysulfide impression materials be poured within 3 hours of making the impression.
Recommended Citation
Zeiaei-Nafchi, Saeid, "Dimensional changes of polysulfide impression materials over time." (2000). Graduate Theses, Dissertations, and Problem Reports. 10476.
https://researchrepository.wvu.edu/etd/10476