Micro-shear bond strength of adhesive resins to enamel at different relative humidity conditions

Abstract

This study tested whether exhaled humid conditions would affect the adhesion of etch-and-rinse, two-step and one-step self-etch adhesive resins to enamel. Enamel surfaces of human maxillary anterior teeth (N=240, n=20) were exposed to four humid conditions (H1: 63-68%, H2: 73-78%, H3: 93-98%, H4: 36-45% RH) during bonding with Adper Single Bond 2 (SB2), Clearfil SE Bond (CSE) and Adper Easy Bond (AEB). Specimens were stored in distilled water at 37ºC for 24 h and tested to failure using micro-shear bond strength (μSBS) test. Data were analyzed using two-way ANOVA and Tukey's test (p<0.05). The μSBS to enamel with SB2, CSE and AEB was not significantly affected by humidity parameters. AEB resulted in significantly lower μSBS in all conditions. The frequency of adhesive failures was the highest at H2, H3 for SB2, H3 for CSE and H1-4 for AEB indicating that humidity conditions may decrease adhesion quality to enamel.