INTERFACIAL MICROMORPHOLOGY AND SHEAR BOND STRENGTH OF SINGLE-BOTTLE PRIMER ADHESIVES/

Objectives. This study was conducted 1) to characterize through SEM an alysis the resin-dentin interface produced by single-bottle primer/adh esives and a three-component system [Scotchbond Multi-Purpose (3M Dent al)] and 2) to evaluate the shear bond strength to dentin of these adh esive systems. Methods. Single-bottle primer/adhesives [Bond 1 (Jeneri c/Pentron), Single Bond, (3M Dental Products); One Step (Bisco inc.), OptiBond Solo (Kerr Corp.), Prime & Bond 2.1 (L.D. Caulk-Dentsply), Sy ntac Single-Component (Ivoclar-Vivadent), Tenure Quik with Fluoride (D en-Mat)] were used according to manufacturers' instructions to bond re sin composite to flat dentinal surfaces of extracted human third molar s (n=15). All samples were thermocycled 300x. Twelve specimens per gro up were used to measure shear bond strength and three specimens were u sed to evaluate the interfacial morphology under SEM. A one-way ANOVA and Tukey's test were used to assess the results. Results. Mean shear bond strengths in MPa +/- SD for the groups ranged from 22.27 +/-:4.5 MPa for Single Bond to 7.6 +/- 3.9 MPa for Syntac Single-Component. Th e statistical analysis indicated that Single Bond produced significant ly higher (p < 0.001) bond strengths than Syntac Single-Component, Pri me & Bond 2.1, Bond 1 and Tenure Quik With Fluoride. Bond strengths fo r Syntac Single-Component were significantly lower than One-Step, Opti Bond Solo, Scotchbond Multi-Purpose Plus and Single Bond. SEM examinat ion clearly revealed the formation of a distinct hybrid layer for all adhesive systems; however, minor variations in ultrastructure existed among products. Significance. Some single-bottle primer/adhesives pres ent in vitro bond strengths and hybrid layer formation similar to thos e found for the conventional three-component adhesive system tested.