An Experimental And Clinical Study Of Vital Pulp Conservative Therapy With Hydroxyapatite

In this study, the animal experiment and clinical observation were used to evaluate the value of application of synthetic hydroxyapatite(HAP) as a biological capping material.120 teeth of 6 monkeys were treated by vital pulpotomy with HAP, calcium hydroxide(CH), HAP paste or HAP-CH paste. The pulp reactions were observed by histological examination. The observation periodes were one week, one month, three months and one year after operation. The pulp reactions with HAP and HAP paste were the same in each observation period. One week postoperatively, the necrosis layer which was composed of blood cells, tissue fragments and HAP particles was formed over the surface of radicular pulp. One month postoperatively, there were some osteodentin around HAP particles. No hard tissue barrier was formed. Three months postoperatively, a complete or incomplete hard tissue barrier was formed. One year postoperatively, there was no inflammation and degeneration in the radicular pulp. The pulp reaction with HAP-CH paste was similar to that with CH saline paste, but no degeneration was seen in HAP-CH paste group one year postoperatively. The histological success rates were 83.33% in HAP group and 75.0% in CH group after one year of operation. No significant difference was observed.Scanning electron microscope(SEM) observation of hard tissue barriers after three months and one year showed that the hard tissue barriers induced by HAP were composed of HAP particles and osteodentin around them, which could close orifices of root canals completely or incompletely. The surface structure of the crown-side of hard tissue barriers was loose. The hard tissue barriers induced by CH were composed of osteodentin in the up layer and tubular dentin in the lower layer, which close the orifices of root canals completely, but many small holes existed on the surface of crown-side hard tissue barriers.The antibacterial activities of HAP, CH, HAP paste and HAP-CH paste on Staphylococcus aureus, Escherichia coli, Streptococcus pyogenes,...