Effect of hybridization on bond strength and adhesive interface after acid-base challenge using 4-META/MMA-TBB resin

The purposes of this study were twofold, namely to evaluate: (1) the effect of hybridization on microtensile bond strength (mu TBS) to dentin, and (2) the ultrastructure of the dentin-adhesive interface with 4-META/MAM-TBB resin after acid-base challenge. Dentin surfaces, which received no treatment (NT), 65% phosphoric acid (PA), or 10% citric acid-3% ferric chloride (10-3), were bonded with a 4-META/MMA-TBB resin. To evaluate dentin bond strength, mu TBS test was performed at a crosshead speed of 1 mm/min. For ultrastructural evaluation of the adhesive interfaces, SEM was used to examine the interfaces of the bonded specimens after acid-base challenge. The mu TBS of NT was not determined, while that of 10-3 was significantly higher than that of PA (p<0.05). With PA and 10-3, the hybrid layer was clearly observed, but no so for the acid-base resistant zone. Wall lesion was found in NT only. In conclusion, hybridization is vital to improving mu TBS to dentin and enhancing resistance at the adhesive interface against acid-base challenge.