Effect of thermocycling on the fracture strength of intact third molars stored for two different time periods.
OBJECTIVE
This study investigated the effect of thermocycling on the fracture strength of intact, extracted molars stored for two different intervals before testing.


METHODS
Thirty-eight recently extracted molars and 38 molars stored for 1 to 5 years were each randomly separated to create four subgroups. One subgroup from each storage interval was thermocycled 1,000 times from 5 to 55 degrees C using 30-second dwell times, and then all teeth were fractured using a universal testing machine.


RESULTS
Thermocycled recently extracted molars had significantly lower mean fracture strengths than nonthermocycled recently extracted molars (p < 0.001). No other pairwise comparisons were statistically significant.


CONCLUSIONS
Thermocycling significantly reduced the fracture strength of recently extracted third molars. However, no significant differences in fracture strength were seen with molars stored for 1 to 5 years before thermocycling.
Department of Restorative Dentistry, University of the Pacific School of Dentistry, San Francisco, CA 94115, USA.
Mark S
MS
Hagge
James S
JS
Lindemuth
D006358:Hot Temperature / Q000009:adverse effects*; D006801:Humans; D008422:Materials Testing / Q000379:methods; D008964:Molar, Third; D013048:Specimen Handling; D013997:Time Factors