بررسی تأثیر چرخه‌های حرارتی و فشاری بر استحکام شکست دندان‌های ثنایای فک فوقانی ترمیم شده با یک پست گلاس‌ فایبر ایرانی و دو نوع پست مشابه خارجی

  Background and Aims: The aim of this study was to evaluate the fracture strength of restored teeth with three different types of E glass-fiber posts after thermo-mechanical loading.   Materials and Methods: Sixty extracted upper central incisor human teeth, with similar size, were selected and divided into three groups (n=20). Endodontic treatment was done in all groups and crowns were sectioned from 2 mm above CEJ. Then one type of posts in each group (Anthogyr, Svensk, Hetco) cemented using Panavia cement and the crowns were restored with a composite. The specimens in each group were thermocycled for 6000 cycles (5-55°C) and subjected to 1200000 cycles of mechanical loadiong in an artificial mouth machine. Then the fracture strength was measured and data were analyzed using ANOVA and T-student test (α=0.05).   Results: The mean fracture strengths in Hetco group before and after thermomechnical loading were 581.098 ± 192.742 N and 564.74±213.59 N, in Anthogyr group were 664.358 ± 135.878 N and 629.12±390.3 N and, in Svensk group were 780.258 ± 379.133 N and 779.84±282.59 N, respectively. There was no significant difference between groups and also there was no significant difference in each group before and after thermo-mechanical loading (P>0.05).   Conclusion: Restored teeth with Hetco fiber glass post were similar in terms of the fracture strength with that of two other posts after thermo-mechnical loading.