The effect of warm air-blowing on the microtensile bond strength of one-step self-etch adhesives to root canal dentin.

PURPOSE: The use of warm air-blowing to evaporate solvents of one-step self-etch adhesive systems (1-SEAs) has been reported to be a useful method. The purpose of this study was to evaluate the effect of warm air-blowing on root canal dentin. METHODS: Four 1-SEAs (Clearfil Bond SE ONE, Unifil Core EM self-etch bond, Estelink, BeautiDualbond EX) were used. Each 1-SEA was applied to root canal dentin according to the manufacturers' instructions. After the adhesives were applied, solvent was evaporated using either normal air (23+/-1 degrees C) or warm air (80+/-1 degrees C) for 20s, and resin composite was placed in the post spaces. The air from the dryer, which could be used in normal- or hot-air-mode, was applied at a distance of 5cm above the root canal cavity in the direction of tooth axis. The temperature of the stream of air from the dryer in the hot-air-mode was 80+/-1 degrees C, and in the normal mode, 23+/-1 degrees C. After water storage of the specimens for 24h, the muTBS were evaluated at the coronal and apical regions. The muTBSs were statistically analyzed using three-way ANOVA and Student's t-test with Bonferroni correction (alpha=0.05). RESULTS: The warm air-blowing significantly increased the muTBS of all 1-SEAs at the apical regions, and also significantly increased the muTBS of two adhesives (Estelink and BeautiDualBond EX) at coronal regions. CONCLUSIONS: The muTBS of 1-SEAs to root canal dentin was improved by using warm air-blowing.