The effect of washing water temperature on resin-dentin micro-shear bond strength

Abstract

BACKGROUND: The purpose of this study was to evaluate the effect of washing water temperature on the micro-shear bond strength (muSBS) of composite resin to dentin using a two-step etch-and-rinse system and a two-step self-etching system. MATERIALS AND METHODS: In this in vitro study, the intact dentins of buccal and lingual surfaces of healthy third molars were exposed. Dentin surfaces were rinsed with different temperatures of distilled water (20 s) before applying Single Bond (SB) or Clearfil SE Bond(SE). After applying the adhesive, composite cylinders (0.8 mm diameter and 1 mm length) were bonded to the teeth surfaces. After storing the specimens in 37 degrees C distilled water for 48 h and thermocycling, muSBS test was done. Data were analyzed using analysis of variance, post hoc Tukey tests, paired samples t-test, and Fisher exact test (alpha = 0.05). RESULTS: Temperature and interaction of temperature and type of bonding agent affected the bond strength. The bond strength of SB groups was significantly higher at 50 degrees C washing than 5 degrees C (P = 0.003) and 22 degrees C (P = 0.019), but no significant difference was observed between SE groups. The bond strength of SE was significantly higher at 22 degrees C than that of SB (P = 0.031), whereas the bond strength of SB was significantly higher at 50 degrees C than that of SE (P = 0.007). CONCLUSION: The use of high-temperature washing water is an appropriate method to enhance bond strength in etch-and-rinse systems.