In Vivo Evaluation of S-Chitosan Enhanced Calcium Phosphate Cements

Calcium phosphate cements (CPC), made from dicalcium phosphate dihydrate and calcium hydroxide and reinforced with water soluble S-chitosan, were investigated in vivo. Cylinders of these cements were prepared and prehardened before implantation into preformed radial defects in rabbits. Histological observations after 1, 4, 14 and 22 weeks, respectively, were performed on thin decalcified sections. No inflammation or other negative response was found in the S-chitosan containing cements (S-CPCs). After 4 weeks, newly formed trabeculae contacted with the implant directly in the lower S-chitosan sample, while a thin layer of fibers had formed between the newly formed bone and the implant in the higher S-chitosan samples. The degradation rates of the S-CPCs were significantly lower than the original CPC cement alone. Most of the S-chitosan cements were still present at the end of the 22 weeks. The implant material and the surrounding infiltrated fluid layer were examined by back scattered scanning electron microscopy and X-ray energy-dispersive spectrometry.