Delayed direct pulp capping in permanent incisors of monkeys

Summary. The effect of preoperative oral contamination for either 4 or 48 hours on pulpal response to direct pulp capping was studied. Four young monkeys provided a contralateral experimental series of 16 pairs of incompletely developed permaent incisors. Radiographic examination, labelling in vivo, and conventional histological observations at 6 months postoperatively indicated no difference between the two series. All incisors in either series showed continued apical development, and all but one demonstrated increase in cervical dentine. All but two teeth in each series showed apparently fully bridged pulpal wounds. Full bridging generally correlated with normal pulpal conditions; however, in three teeth of the 48‐hour and one of the 4‐hour series, full bridging occurred along with moderate or dense coronal infiltrates of chronic inflammatory cells. All these teeth were mandibular and showed a large denticle formed around dentine chips. Failed bridging seen in two teeth of each series correlated with severe inflammation in the adjacent pulpal tissue. No consistent adverse effect of coronal pulpal inflammation on cervical increase in dentine was recorded.