ABSTRACT
Fourteen animal studies involving the implantation of beta-tricalcium phosphate ceramic (TPC) in rats, dogs, and primates have shown the material to be effective in repairing many types of bony defects. Histological examinations confirm that the implant is resorbed and concomitantly replaced by normal bone when firmly fixed to freshly cut and bleeding bone. Tissue compatibility has been shown to be superior to other synthetic materials. TPC has been used in human clinical studies to repair marginal and periapical periodontal defects, as well as apexification and miscellaneous alveolar bony defects. When used to repair marginal periodontal defects, degrees of repair equaled or exceeded those obtained using autogenous bone. Complete bone fill, as evidenced by radiography, was observed in the repair of two-and three-walled periapical defects. TPC afforded a better barrier than calcium hydroxide in the obturation of open apexes and provided equivalent repair. No adverse reactions attributable to TPC have been reported.
Subject(s)
Bone and Bones/surgery , Calcium Phosphates , Ceramics , Prostheses and Implants , Animals , Biocompatible Materials , Bone and Bones/physiology , Dogs , Haplorhini , Humans , Osteogenesis , Periapical Diseases/surgery , Periodontal Diseases/surgery , Rats , Root Canal Filling MaterialsABSTRACT
"Synthos" (beta-tricalcium phosphate) implants in bone are resorbed and replaced with endogenous bone. This investigation was conducted to study by continuous flow and static system techniques, whether or not resorption of synthos occurs by passive dissolution at 37 degrees C. Calcium and phosphates were released in a time dependent manner from synthos in calcium and phosphate free Tris-Hcl buffer (pH 7.4). Scanning electron micrographs (SEM) of buffer exposed ceramics indicated breakdown of grain structure. In contrast, levels of human plasma calcium and phosphate were not altered by ceramics. Significant amounts of 32p were absorbed by the ceramics in the first hour and 45Ca in the second hour of exposure to plasma containing the radioactive isotopes. Exposure of ceramics to plasma did not alter the levels of plasm isotopes significantly for the remaining duration of the experiment. However, breakdown of grain structure was evident in SEM's of ceramics exposed to plasma. It appears that in an acellular physiological environment, dissolution of synthos is diffusion dependent and is limited to a localized surface exchange phenonmenon.
