Abstract
This study aimed to determine the role of the 10-methacryloyloxydecyl dihydrogen phosphate (MDP) in dentin bond durability of universal adhesive in etch-&-rinse mode through bond strength tests after different degradation conditions. This study used the MDP-containing universal adhesive, Clearfil Universal Bond Quick (CU), and an experimental adhesive (NM) made with the same ingredients as CU, excluding MDP. Shear bond strength (SBS) to dentin were obtained in etch-&-rinse mode with or without MDP. CU in self-etch mode was used as a comparison. The groups were divided into three types: 1) subjected to thermal cycling; 2) subjected to long-term water storage; and 3) stored in water for 24 h, as a baseline. The discrepancies in the mean SBS of the CU and NM groups become prominent with prolonged degradation periods. This study indicates that the MDP in universal adhesive might play a key role in enhancing dentin bond quality even when etch-&-rinse mode is used.