Effect of exposure time of eugenol containing temporary cement on tensile bond strength of permanent restorations luted with self-adhesive dual cure resin cement-an in vitro study

Purpose: To evaluate the effect of eugenol containing provisional luting agents on tensile bond strength and failure mode of self-adhesive resin cement system at different time intervals. Materials and Method: Sixty freshly extracted premolars having standardized mesiodistal width of 3mm, buccolingual dimension of 6mm and height of 3mm were randomly divided into 4 experimental groups (n=15) according to the exposure time to eugenol; no exposure-CG, 24hour(h) exposure-1G, 7days-7G and 14days-14G. Provisional crowns (DPI –self cure Tooth molding Powder) were fabricated for all specimens except the control group(CG), cemented using eugenol containing temporary cement (Kalzinol; DPI)and stored in a water bath for the allocated time period. Permanent crown were fabricated with Ni-Cr alloy (Wirolloy) and cemented with Self-Adhesive Resin Cement (RelyX U200). Universal testing machine (2mm/min) was used to determine the tensile load testing. The mode of fracture was analyzed at a magnification of 10 X using stereomicroscope. The results were analyzed with 1-way ANOVA (a=.05) followed by a Tukey B post hoc test. Results: Macrotensile bond strength for CG (5.61 Mpa ± 0.83) was significantly higher than 1G (3.03 Mpa±0.87) (p<.001).There was no significant difference between 7G (4.29 Mpa±0.69) and 14G (4.95 Mpa±0.75). The significant mode was adhesive failure for 1G (78.6%), other specimens demonstrated predominantly a mixed failure. Conclusion: The tensile bond strength is significantly reduced if the permanent cementation is carried out within 24 h of provisional cementation of eugenol containing temporary cement.