A Comparative Evaluation of the Shear Bond Strength of Three Different Fifth Generation Dentin Bonding Agents

Purpose: To compare and evaluate the shear bond strength of three different fifth generation dentin bonding agents used with composite resin and to determine the mode of bond failure in each case. Materials and methods: Forty-five freshly extracted human permanent molars were used and the specimens were divided into three test groups (N = 15) namely group A = Excite, group B = single Bond, group C = Prime and Bond NT. The occlusal surfaces of the specimens were ground to expose the superficial dentin and mounted in self cure acrylic resin. The surface was etched with 37% phosphoric acid gel and bonding agents were applied to etched surface. A composite button of 5.3 × 3 mm (Z 100) was bonded to the test specimens and subjected to shear load using United Universal Testing Machine at the cross-head speed of 0.5 mm/min. The nature of bond failure was determined using a stereomicroscope at ×8 magnification. Results: Mean shear bond strength values in MPa of groups A, B, C were 21.483, 16.881 and 14.116 respectively. Group A showed 73.3% cohesive and 26.6% adhesive, Group B showed 66.6% adhesive, 20% cohesive and 13.33% mixed, group C showed 73.3% adhesive 6.6% cohesive and 20% mixed bond failures. Conclusion: Excite dentin bonding agent exhibited highest shear bond strength values as compared to single Bond and Prime and Bond NT, this difference was statistically significant. There was no statistically significant difference between the shear bond strength values of Single Bond and Prime and Bond NT. Maximum number of cohesive bond failure were observed in dentin with Excite. Single Bond and Prime and Bond NT exhibited maximum number of adhesive bond failure.