Pulp reactions to a synthetic hydroxyapatite and chlorhexidine in monkeys

Abstract

The study compared pulp reactions to a synthetic hydroxyapatite and to calcium hydroxide with either one percent chlorhexidine or distilled water as a mixing vehicle. Forty-seven permanent teeth of two monkeys were mechanically exposed under aseptic conditions. The pulps were then capped with one of the following: synthetic hydroxyapatite mixed with chlorhexidine; synthetic hydroxyapatite mixed with water; calcium hydroxide mixed with chlorhexidine; calcium hydroxide mixed with water. Small square sheets of gold foil were then placed over the capping material. A base of IRM was placed and the cavities were restored with amalgam. The teeth were extracted at 14 and 90 days after pulp capping. The specimens were fixed in 10% formalin and decalcified in 5% formic acid. Serial sections 7 microns thick were prepared and stained with hematoxylin and eosin. The synthetic hydroxyapatite mixed with one percent chlorhexidine or water was well tolerated by the dental pulp. Complete bridging occurred infrequently in the specimens capped with the hydroxyapatite, compared to those capped with calcium hydroxide, which usually showed complete bridging of the exposure.