[Effects of three self-etch adhesives and mild salivary contamination on the bonding durability of deciduous teeth].

OBJECTIVE: To compare the bonding durability of three different self-etch adhesives to primary enamel and dentin, and to investigate the effect of mild salivary contamination followed by air drying on the bonding durability. METHODS: Two hundred and forty enamel specimens were divided randomly into 16 groups (n=15/group)according to the adhesive system [self-etch adhesives: Clearfil SE Bond(SE), AdperTM Easy One (EO), Scotchbond Universal (SBU); total-etch adhesive: AdperTM Single Bond Plus(SL)], contamination status (non-contaminated vs. salivary-contaminated) and storage condition (stored in distilled water for 24 h vs. aging mode 5 000 thermal cycles in 5 ℃ and 55 ℃). Two hundred and forty dentin specimens were assigned in the same way. Shear bond strength for 12 specimens in each group were measured. The adhesive interface for the residual specimens in each group was observed by scanning electron microscopy(SEM). Data were analyzed by three-way analysis of variance and Tukey test(P < 0.05). RESULTS: For primary enamel, total-etch adhesive showed higher initial shear bond strength values (28.92±1.83) MPa and shear bond strength values (27.27±3.03) MPa after thermal cycles compared with the other groups, and the difference between the groups was statistically significant (P < 0.01). Shear bond strength values of EO decreased significantly in salivary-treated groups, regardless of storage conditions, and the difference was statistically significant (P < 0.01). For primary dentin, shear bond strength values of EO decreased significantly in salivary-treated groups after 24 h (P < 0.01). After 5 000 thermal cycles, total-etch adhesive showed significantly lower shear bond strength values (14.31±1.97) MPa compared with the other groups, and the difference between the groups was statistically significant (P < 0.01), and shear bond strength values of EO were significantly lower than those in SE and SBU groups (P < 0.01), regardless of contamination status. CONCLUSION: Total-etch adhesive SL has better bonding durability to primary enamel. SE and SBU have better bonding durability to primary dentin and have a certain resistance to salivary contamination, while the bonding performance of EO is compromised greatly by mild salivary contamination followed by air drying.