Calcium phosphate precipitation method for the treatment of dentin hypersensitivity

Purpose: To evaluate the feasibility of the calcium phosphate precipitation (CPP) method as a treatment for dentin hypersensitivity using vital teeth of beagle dogs. Also, gingival tissue response to two types of CPP methods was examined histologically. Materials and Methods: Dentin tubules of the dogs' vital teeth were exposed by shallow cavity preparation followed by etching with 50% citric acid to simulate the condition of hypersensitive dentin. After CPP treatment was applied to the vital tooth, the dentin surface and longitudinal sections were observed by SEM to evaluate the occluding ability of the CPP method. The precipitate was also analyzed by energy-dispersive X-ray microanalysis to obtain compositional information. The gingival tissue before and after CPP method was examined histologically with light microscopy. Results: Dentin tubules were occluded homogeneously and completely with an apatitic mineral after application of the CPP treatment in vital teeth. However, the depth of the precipitate in dentin tubules from the dentin surface was approximately half that seen in extracted teeth. No histological change was observed in gingival tissues when NaHCO3 was used as a post-treatment solution of the CPP method, whereas another CPP method using NaOH solution resulted in atrophy and degeneration of the epithelium of gingival tissue.