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 (μSBS) 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°C distilled water for 48 h and thermocycling, μSBS test was done. Data were analyzed

using analysis of variance, post hoc Tukey tests, paired samples t‑test, and Fisher exact test (α = 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°C washing than

5°C (P = 0.003) and 22°C (P = 0.019), but no significant difference was observed between SE groups.

The bond strength of SE was significantly higher at 22°C than that of SB (P = 0.031), whereas the

bond strength of SB was significantly higher at 50°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.

Key Words: Bond, strength, dentin‑bonding agents, temperature, washing water