Evaluation of Carbonate Apatite Cement in Inducing Formation of Reparative Dentin in Exposed Dental Pulp

摘要

Carbonate apatite (CO_3Ap) cement is a biocompatible material with the ability to induce osteogenesis and is widely studied as the bone substitute material. The similarity of bone to tooth structure in their organic and inorganic composition offers a good prospect of the application of CO_3Ap for regeneration of dentin and pulp tissue repair. This study is a sequel of the previous study in the development of CO_3Ap cement for dental application, particularly in pulp capping treatment. In this study, the CO_3Ap cement is used to cover an exposed dental pulp in rats and histological evaluation was carried out to evaluate the formation of reparative dentin, which is one of the signs of positive pulp capping treatment outcome. The CO_3Ap cement was made by combining 60% dicalcium phosphate anhydrous (DCPA) and 40% vaterite with 1 mol/L Na_2HPO_4 aqueous solution at liquid to powder ratio of 0.5 and conventional calcium hydroxide [Ca(OH)_2], which is the golden standard for pulp capping material was used for control. The coronal part of dental pulp in Wistar Rat was exposed with a small dental bur until bleeding were visible. The CO_3Ap cement was applied to the exposed pulp and covered with light cured glass ionomer cement. The same protocol was applied to the control groups using Ca(OH)_2. The Evaluation of formation of reparative dentin was done in 3 weeks after application by histological observation. Reparative dentin was histologically visible for all samples in CO_3Ap group, as well as in the Ca(OH)_2 groups. None of the dental pulps were necrotic and the pulp showed no heavy chronic inflammation. The CO_3Ap cement was able to maintain the vitality of the pulp with no sign of chronic inflammation. The formation of reparative dentin was observable in 3 weeks of evaluation. Investigation on other properties and in vivo studies in different types of perforation and animal are to be carried out for further development of this material in dental application.