Histologic reactions to a newly developed calcium phosphate cement implanted in the periapical and periodontal...

A newly developed calcium phosphate cement (CPC), basically composed of tetracalcium phosphate, Ca4(PO4)2O and dicalcium phosphate dihydrate, CaHPO4.2H2O or anhydrous calcium phosphate, CaHPO4, was tested in this study. When combined with water, the cement hardens and produces hydroxylapatite resembling the principal mineral of teeth and bones. Therefore, the CPC should be highly compatible with the body. However, before its clinical application in dentistry, the biocompatibility of CPC in the potential environments of implantation needs confirmation. Eight monkeys were used in our study to test the material in the periapical and marginal periodontal regions. Surgically created periodontal defects were implanted with CPC and hydroxylapatite (HA) (Calcitite 4060). In another application, CPC was pushed into the periapical areas via overfilling of the root canals. Sargenti N2 served as the control material in the periapical test. Generally, only a limited inflammatory response to CPC was found after 6 weeks of implantation in the periodontal area. In the 16-week specimens, the adverse reaction was negligible, and bone regeneration was marked and directly surrounding the CPC. The bone formation activity and biocompatibility in general were found to be even better in the periapical region. The results suggest that the CPC may have a good potential in future clinical applications, although many issues remain to be investigated.