Abstract
This study investigated the role of N-AAsp on the adhesion to dentin. The electric dissociation exponent (pKa) of two carboxyl groups in N-AAsp and pH change on the dentin surface treated with N-AAsp were measured. We also tried to identify the reaction products of hydroxyapatite and N-AAsp, because particle-like react products were observed on the treated dentin.
The pKa of the carboxyl group was 3.67 at the main chain of N-AAsp and 4.19 at the side chain. The pH value on the dentin surface treated with N-AAsp increased slowly with time from 4.1 at 1-minute to 4.9 at 5-minute. N-AAsp formed the corresponding salt with hydroxyapatite. These results suggested that react products of hydroxyapatite and N-AAsp were left in the decalcified dentin layer affecting dentin adhesion.
