| Gypsum-based die materials (dental stones) are used extensively for the accurate replication of missing or damaged tooth structure, upon which permanent restorations for the teeth are made. This study has focused on several different ideas related to scratch test methodology and resin-reinforced die stones. The primary goal was to develop an original, simple and reproducible laboratory test, using available equipment such as a microhardness tester to test the scratch resistance and fracture resistance of gypsum die materials used in dentistry. Using a microhardness tester, a test was developed to determine the edge fracture strength of die stone. The device was also used to determine the effects of resin additives on gypsum die stones and to determine which commercial resin-containing die stones are most scratch resistant.; Different mixing and vibration times were also used to determine what effects these variables had on the scratch resistance of ResinRock. Finally, the effect of impression orientation on the scratch resistance of resin-reinforced die stone was tested. (Abstract shortened by UMI.)... |
