RESUMO
PURPOSE: To evaluate the effect of different acid etching modes on bond strength between composite resin and non-carious sclerotic dentin, and to provide references for clinical application. MOTHODS: Thirty premolars with naturally-occurring non-carious cervical lesions were divided into 2 groups based on self-etch adhesive system AdperTM Easy one (AEO) and total-etch adhesive system AdperTM Single Bond2 (ASB2). Each group was further divided into 3 subgroups (ASB21, ASB22, ASB23, AEO1, AEO2, AEO3) and subjected to the following processing: ASB21 subgroup was etched for 15 s with 35% phosphoric acid and coated with binder for 15 s; ASB22 subgroup was etched for 30 s with 35% phosphoric acid and coated with binder for 15 s; ASB23 subgroup was etched for 15 s with 35% phosphoric acid and coated with binder for 30 s; AEO1 subgroup was only etched with binder for 20 s; AEO2 subgroup was etched with binder for 40 s; AEO3 subgroup was etched for 15 s with 35% phosphoric acid and coated with binder for 20 s. The samples were restored with composite resin; 24 h after saved in distilled water at room temperature, the teeth were cut into dumbbell-shaped specimens with surface areas of approximately 1.0 mm2. The microtensile bond strength (µTBS) was detected and evaluated by one-way ANOVA and SNK-q test using SPSS 17.0 software package. RESULTS: µTBS was given in MPa: AEO3>ASB22>ASB23>ASB21>AEO2>AEO1, AEO3 resulted in statistically highest bond strength and AEO1 had the lowest bond strength (P<0.05), ASB22 acquired bond strength just lower than AEO3 (P<0.05). CONCLUSIONS: Use of total-etch adhesive system increasing the etching time of phosphoric time can enhance bond strength. For self-etch adhesive system,both duplicated the time of adhesive treatment and use of phosphoric acid can improve the bond strength. Use of phosphoric acid to etch for 15 s and coated with self-etch adhesive system for 20 s achieved the highest bond strength. In either self-etch or total-etch adhesive system, use of phosphoric acid to etch for 15 s and coated with self-etch adhesive system for 20 s achieved optimal bond strength, there was the lowest bond strength when the self-etch adhesive system used as recommended time.