[Histopathologic study on the application of synthetic hydroxyapatite and alpha-tricalcium phosphate for vital...

Hydroxyapatite (HAp) and alpha-Tricalcium phosphate (alpha-TCP) are generally known as materials biocompatible to human tissue. In this study, the adaptation of HAp and alpha-TCP as a pulpotomy agent was studied histopathologically. In this study, HAp granules with a sintering temperature of 1,200 degrees C and sieved through a 37 micron sieve, and APATITE LINER TYPE I (Sankin CO.) as alpha-TCP were used. Calcium hydroxide served as a control. The physical properties of these experimental materials were evaluated and the reaction of pulp tissue to the materials was examined histolongically in dogs. alpha-TCP mixed with saline solution showed more homogeneous and higher viscosity than HAp mixed with saline solution. When alpha-TCP was applied on the site of exposure of a pulp following pulpotomy, the mechanically harmed pulp tissue was healed earlier than when HAp was applied. A hard tissue was formed earliest when calcium hydroxide was used, and then in the order of alpha-TCP and HAp. When HAp was applied, osteodentin was formed and when alpha-TCP was applied, dentin was formed on the site of exposure of a pulp following pulpotomy. When HAp or alpha-TCP was applied, the calcification in the initial stage was not observed. The calcification in initial stage was observed when calcium hydroxide was applied. These results suggest that alpha-TCP is useful as a pulpotomy agent.