Effect of 2 years water aging on bond strength stability of adhesive systems to artificial caries-affected primary dentin

Abstract

PurposeTo evaluate the effect of 2 years of water aging on microtensile bond strength (μTBS) of an etch-and-rinse and a self-etch adhesive system to sound (S) and artificial caries-affected primary dentin (CAD). MethodsOcclusal cavities were prepared in 24 primary molars. Half of the specimens were submitted to a pH-cycling model to simulate artificial caries-affected dentin. Teeth were randomly restored either with two-step etch-and-rinse adhesive Adper Single Bond 2 (SB) or two-step self-etch system Adper SE Plus (SE). After 24h of storage, the teeth were sectioned into two halves. One half was sectioned into sticks (0.8mm2) to be tested immediately under μTBS testing. The same procedure was performed in the other half after storage in distilled water for 2 years (2y). Data were analyzed by three-way repeated measures ANOVA and Tukey tests (α=0.05). ResultsThe μTBS values of both adhesive systems significantly decreased after 2 years aging (SB: S – 38.4%, CAD – 23.9%; SE: S – 17.1%, CAD – 15.7%) (p<0.001). SE showed lower μTBS values compared with SB, regardless of storage period (p<0.001). Higher μTBS were detected in sound dentin, regardless of adhesive (p<0.001). ConclusionThe degradation of the resin-dentin bonds occurred after 2 years of water aging, regardless of the substrate condition or type of adhesive. However, the etch-and-rinse adhesive system is preferable due to the highest μTBS in both periods.