Histological evaluation of odontoblast-like cells response after capping application of calcium hydroxide and hydroxilapatite in dog’s pulp

This study was conducted to observe the response of dog's dental pulp to hydrpxylapatite (Hap) and calcium hydroxide when used as pulp capping materials. After the pulps of 22 teeth were exposed, they were capped with either Hap or calcium hydroxide. Histological analysis was performed 8 weeks after treatment. Results showed that pulp exposure caused irreversible injury of odontoblasts, which were subsequently replaced by similar, odontoblast-like cells. These cells were able for reparative dentin bridge formation in 6 cases treated with calcium hydroxide and almost all the cases treated with hydroxylapatite. The presence of odontoblast-like cells seemed to be crucial for reparative dentinogenesis. The capping material was of less importance. In conclusion neither calcium hydroxide nor hydrxylapatite had completely satisfied all the requirements of an ideal capping material, although Hap can be recognized as a superior alternative to calcium hydroxide.