Abstract
Cement cylinders were prepared by mixing tetracalcium phosphate or α-tricalcium phospate powder with citric acid or malic acid, and then implanted subcutaneously in the rats. Systemic and local responces of the rats to these newly developed cements were examined biochemically and histologically. The cements were also analyzed according to their morphological and chemical changes in the rat tissue.
The results were as follows:
1. There was no diffrence in body weight during the experimental period between rats receiving the cement implantation and not being implanted. Twelve weeks after the implantation, the systemic effects of the cements were studied by hematologic or biochemical examination of the blood and histological study of liver, kidney and spleen. Since these studies of the test animals showed essentially the same findings as the control, it was considered that implantation of these cements had evoked little systemic adverse effects in the rats.
2. Histopathological examinations of the rat tissue surrounding the cement cylinder showed that inflamatory cells had infiltrated into the tissue in contact with the cement made from α-tricalcium phospate and malic acid. However, in the case of the other cements tested, similar histological findings of the tissue affinity were obtained to those seen in the hydroxyapatite cylinder.
3. During whole experimental period, there was no change in the shape or radiopacity of the cement cylinders. It was shown by X-ray diffraction analysis that a larger part of α-tricalcium phospate had converted to hydroxyapatite and a small amount of α-tricalcium phospate still remained after the experimental period of 12 weeks. On the other hand, it was found that tetracalcium phospate cement had converted completely to hydroxyapatite in the same period.
