An evaluation of exposure time and temperature in the thermocycling of dental restorative materials.

This study indicates that some current procedures used in thermocycling dental restorative materials would not produce the desired thermal gradient in the specimens. The shortfall in gradient depends on the size of the specimen, the dwell time in the baths and whether the baths are stirred or not. The desired thermal gradient of 50 degrees C can be approximated with a dwell time of 60 s in well-circulated water baths at 5 degrees C and 55 degrees C. For critical studies a dwell time of 90 s is recommended.