اثر تعداد چرخه‌های مکانیکی بر ریزنشت حفرات کلاس V ترمیم شده با کامپوزیت و ادهزیو Etch & Rinse

Introduction: Characteristics of Dental materials may be examined under stimulated oral conditions like loadcycling and Thermocycling. The aim of this study was to evaluate the effect of loadcycling on microleakage of class V cavity preparations restored with composite and total etch adhesives. Methods: One hundred class V preparations (5mm×3 mm and 2.5mm axial Depth) with incisal margin in enamel and gingival margin in dentin, were prepared in the anterior bovine teeth. The teeth were randomly divided into two groups which restored with single Bond (3M-USA) or excite (Ivaclar/viva dent/Lichtenstein). Each group was further divided into five subgroups. The numbers of used loadcycles involved respectively 0, 50k, 100k, 200k, 300k. [K=1000] Then, all the teeth were covered with sticky wax except 1mm around the samples and were immersed in 2% methylene blue for 24 hours. Then all the teeth were sectioned longitudinally and the scores of Dye penetration were registered under stereomicroscope. The study data were analyzed using kruskal Wallis and Mann Whitney and wilcoxon tests. Results: All the dentin margins showed higher microleakage than enamel margin (P=0.0001). There was no significant difference between the microleakage of single bond and Excite(P>0/05). The effect of the number of loadcycles on the microleakage of the single bond and Excite in dentin and enamel margin was not significant. Conclusion: Enamel margins showed less microleakage than dentin margins. This study did not show any increase in microleakage after increasing the number of loadcycles