A tissue-implant reaction associated with subcutan implantation of alpha-tricalcium phosphate, dental ceramic and hydroxyapatite bioceramics in rats

Calcium phosphate ceramics are among the more commonly used and biocompatible ceramics. Recently, we have synthesized a new calcium phosphate ceramic, alpha tricalcium phosphate (aTCP). The aim of this study was to assess the biocompatibility of this original, in our laboratory modified, newly synthesized aTCP ceramic, by carefully evaluating the inflammatory reaction of soft tissue in response to its subcutaneous implantation, and by comparing this result with the results of already widely used virtually non-toxic, non-immunogenic, and almost chemically inert dental (DC) and hydroxy apatite (HAP) ceramics. Implants (diameter 5x2 mm) of aTCP, DC and HAP were implanted into 12 adult male rats subcutaneously. At 2 weeks and 12 weeks post-implantation, the animals were euthanized and the tissueimplant reactions were analyzed histologically. Evaluation of routine stained sections (5 _m, hematoxylin & eosin) of the cutis and subcutis surrounding the aTCP, DC and HAP ceramics revealed the following: 1) all the ceramic devices had fibrous connective tissue capsules; 2) there were significant differences in the tissue - implant reactions based on the estimated time, while there were no differences in the tissue-implant reaction based on the type of ceramic material; 3) two weeks after implantation hyperemia and cellular proliferation were the most expressive results, while twelve weeks after implantation extensive angiogenesis and collagen fibers production were the prominent findings for all types of implanted calcium phosphate ceramics