摘要：OBJECTIVE: The purpose of this study was to evaluate the effect of thermocycling on the sealing ability of White Mineral Trioxide Aggregate (WMTA) after application for management of furcation perforation. MATERIALS AND METHOD: Thirty two human permanent mandibular molar teeth were chosen and after root amputation, the coronal parts were further trimmed and conventional access cavities were prepared. Furcation perforations were made with diamond bur and Peeso drills. Samples were divided into 3 experimental groups (n=10) and two control groups (n=1). The perforations were filled with WMTA in the experimental groups; in the control groups samples remained unfilled. Samples in the first group remained without further treatment, while in the second and third groups, teeth were thermocycled 500 and 800 times between 5 to 55 °C prior to leakage testing. Microleakage testing was done by using bovine serum albumin for 90 days. The number of days for color change was used as an indicator of protein leakage. Data were analyzed by using one-way analysis of variance and a post hoc Tukey test at a significance level of p<0.05. RESULTS: Non-thermocycled teeth showed significantly the longest time necessary for protein leakage to occur in comparison with the other two thermocycled groups (p < 0.0001). The samples after 800 cycles showed the lowest resistance to protein leakage, while samples after 500 cycles indicated significantly more resistance against leakage (p < 0.0001). CONCLUSION: Thermocycling can remarkably influence the microleakage property of WMTA. Thermal changes occurring inside the oral cavity might jeopardize the sealing property of the applied cement, which can lead to microleakage and possible failure of treatment in a clinical scenario.
