Does eugenol affect the microtensile bond strength of self-adhering composite? – An in vitro study

OBJECTIVES: The objective of the study is to evaluate the effect of eugenol-based temporary on microtensile bond strength of self-adhering composite at 1 day and 7-day time intervals. MATERIALS AND METHODS: Occlusal enamel of 24 human molars was removed. Zinc oxide eugenol (ZnOE) and noneugenol temporary cement (ZnONE) were placed on the dentin surfaces and left for different times (1 day, 7 days). After removal of temporary cement, teeth were randomly divided into eight subgroups: subgroup GE1S (n = 3): ZnOE cement + Self-adhering composite (SAC), subgroup GE1N (n = 3): ZnOE cement + adhesive system (one coat 7 universal) + nanohybrid composite, subgroup GE7S (n = 3): ZnOE cement + SAC, subgroup GE7N (n = 3): ZnOE cement + adhesive system + nanohybrid composite, subgroup GNE1S (n = 3): ZnONE cement + SAC, subgroup GNE1N (n = 3): ZnONE cement + adhesive system + nanohybrid composite, subgroup GNE7S (n = 3): ZnONE cement + SAC, subgroup GNE7N (n = 3): ZnONE cement + adhesive system + nanohybrid composite. Four sticks per tooth were obtained, resulting in 12 sticks per group with a cross-sectional area of 0.5 mm (2). The μTBS test was performed with a crosshead speed of 0.5 mm/min. STATISTICAL ANALYSIS: Kruskal–Wallis and Mann–Whitney U-test were used for analysis. RESULTS: Highest and lowest mean value of microtensile bond strength was observed in GNE7N (12.75MPa) and GE1S (1.42MPa), respectively. CONCLUSION: The presence of eugenol at early stage, i.e. 1 day, has a negative influence on microtensile bond strength of SAC. At 7 days, the negative effect of eugenol on microtensile bond strength gets nullified. Thus, a waiting period of 1 week is sufficient to overcome negative influence of eugenol-based temporaries on polymerization of SAC.