Interfacial micromorphology and shear bond strength of single-bottle primer/adhesives

Objectives This study was conducted 1) to characterize through SEM analysis the resin-dentin interface produced by single-bottle primer/adhesives and a three-component system [Scotchbond Multi-Purpose (3M Dental)] and 2) to evaluate the shear bond strength to dentin of these adhesive systems. Methods Single-bottle primer/adhesives [Bond 1 (Jeneric/Pentron), Single Bond, (3M Dental Products); One Step (Bisco Inc.), OptiBond Solo (Kerr Corp.), Prime & Bond 2.1(L.D. Caulk-Dentsply), Syntac Single-Component (Ivoclar-Vivadent), Tenure Quik with Fluoride (Den-Mat)] were used according to manufacturersʹ instructions to bond resin composite to flat dentinal surfaces of extracted human third molars (n=15). All samples were thermocycled 300x. Twelve specimens per group were used to measure shear bond strength and three specimens were used to evaluate the interfacial morphology under SEM. A one-way ANOVA and Tukeyʹs 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. The statistical analysis indicated that Single Bond produced significantly higher (p < 0.001) bond strengths than Syntac Single-Component, Prime & Bond 2.1, Bond 1 and Tenure Quik With Fluoride. Bond strengths for Syntac Single-Component were significantly lower than One-Step, OptiBond Solo, Scotchbond Multi-Purpose Plus and Single Bond. SEM examination 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 present in vitro bond strengths and hybrid layer formation similar to those found for the conventional three-component adhesive system tested.