Effect of Direct Pulp Capping with MTA Containing BMP

Abstract

Bone morphogenetic protein (BMP) is known to stimulate the differentiation of pulpal cells into odonto-blasts and the formation of reparative dentin. This study was conducted to investigate the ability of hard tissue formation after direct pulp capping with mineral trioxide aggregate (MTA) containing BMP. Cavities with an exposed pulp area were prepared in the first molars of Wistar rats. After irrigation using alternating solutions of 10% sodium hypochlorite and 3% hydrogen peroxide (chemical surgery), the pulps were capped with either MTA containing 5wt/wt% BMP (BMP-MTA) or MTA alone, and these cavities were sealed with Super Bond (Sun Medical). After 7, 14 and 21 days, the rats were euthanized and the jaws removed. The samples were fixed in 10% neutral-buffered formalin solution, decalcified in Plank-Rychlo, embedded in paraffin and sectioned. The teeth were stained with hematoxylin-eosin for histological examination of pulpal changes. Histopathological evaluation demonstrated thicker dentinal bridge with BMP-MTA than MTA. The hard tissue formations with BMP-MTA had irregular or unclear dentinal tubules and had bone-like matrix formations including cells. No severe inflammation was observed underneath the bridges of any of the samples. The result suggests that MTA may release BMP sustainedly and be suitable as a carrier of BMP. The MTA containing BMP can be a biologically-functional direct pulp capping material.