title: 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.
  
  
  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).
  
  
  CONCLUSIONS
  The use of high-temperature washing water is an appropriate method to enhance bond strength in etch-and-rinse systems.
authors.affiliation: Department of Operative Dentistry, Faculty of Dentistry, Islamic Azad University, Isfahan (Khorasgan) Branch, Isfahan, Iran.
authors.forename: Mohammad Reza
authors.initials: MR
authors.lastname: Malekipour
authors.affiliation: Dental Materials Research Center and Department of Operative Dentistry, Faculty of Dentistry, Isfahan University of Medical Sciences, Isfahan, Iran.
authors.forename: Farzaneh
authors.initials: F
authors.lastname: Shirani
authors.affiliation: Dentist, Faculty of Dentistry, Isfahan University of Medical Sciences, Isfahan, Iran.
authors.forename: Mehrnoush
authors.initials: M
authors.lastname: Ebrahimi
keywords: Bond; dentin-bonding agents; strength; temperature; washing water