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Effect of exposure time of zinc oxide eugenol restoration on microtensile bond strength of adhesives to dentin

Abstract:

Objective: The purpose of this study was to evaluate the influence of different exposure times (24. h, 7 days and 45 days) of zinc oxide eugenol cement (ZOE) on microtensile bond strength (μTBS) of etch-and-rinse and self-etch adhesives. Methods: Occlusal enamel of 40 human molars was removed. Zinc oxide eugenol restoration was placed on the dentin surface and left for different times (24. h, 7 days or 45 days). After ZOE removal or over fresh dentin (control) were restored using Adper Single Bond 2 (SB2) or Clearfil S3 Bond (CS3). After 24. h, each tooth was longitudinally sectioned, to obtain bonded sticks that were tested under tension (0.5. mm/min). Two-way ANOVA and Tukey's test (α= 0.05) were used to compare μTBS. Results: A decrease in μTBS was observed for SB2 after 24. h (46.8. ±. 3.4. MPa) when compared to the control (60.4. ±. 5.2. MPa, p<. 0.05). Similarly, a decrease was observed for CS3 after storage for 24. h (20.4. ±. 2.2. MPa) and 7 days (18.1. ±. 2.1. MPa), when compared with a control group (39.1. ±. 4.2. MPa, p<. 0.05). After 45 days, both adhesives SB2 and CS3 show the same μTBS compared to controls. Under all conditions, SB2 showed higher μTBS values than CS3 (p<. 0.001). Conclusion: The results suggest that ZOE has negative effects on microtensile bond strength after 24. h. © 2013 Sociedade Portuguesa de Estomatologia e Medicina Dentária.