Comparative Evaluation of Microtensile Bond Strengths of Posterior Composite With Different Liners- An in Vitro Study

Abstract

BACKGROUND Aim-The objective of this study is to evaluate the bond strengths of two different liners under the posterior composite restoration. MATERIALS AND METHODS Forty-five freshly extracted human mandibular molars were divided into three groups, (n = 15 each) of 15 specimens each. Standardised MOD cavities were prepared, etching and bonding procedure was performed in all the teeth. In Group A, the flowable liner Z-350 was placed and in Group B, the resin modified glass ionomer liner, Vitrebond was placed and cured. The final restoration was done with Z-250 hybrid composite in incremental pattern. In Group C, composite restoration was placed without any liner. Then the tooth samples were sectioned with a hard tissue microtome into slices of about 1 mm 2 and were subjected to microtensile bond strength testing in a universal testing machine, at a cross head speed of 0.5 mm/min. The values were analysed with one-way ANOVA and Newman-Keuls Post-Hoc test. RESULTS The results indicated statistically significant higher mean bond strength for Flowable Liner Group and Control Group when compared to the resin modified glass ionomer Liner Group. CONCLUSION It can be concluded that in the clinical setting, Z-350 flowable liner provides better bond strengths when compared to the RMGIC liner.