Subcutaneous tissue reaction to castor oil bean and calcium hydroxide in rats

Castor oil bean cement (cob) is a new material that has been used as an endodontic sealer,and is a candidate material for direct pulp capping. objective: the purpose of this study was to evaluate the biocompatibility of a new formulation of cob compared to calcium hydroxide cement (ch) and a control group without any material,in the subcutaneous tissue of rats. material and methods: the materials were prepared,packed into polyethylene tubes,and implanted in the rat dorsal subcutaneous tissue. animals were sacrificed at the 7th and 50th days after implantation. a quantitative analysis of inflammatory cells was performed and data were subjected to anova and tukey's tests at 5% significance level. results: comparing the mean number of inflammatory cells between the two experimental groups (cob and ch) and the control group,statistically significant difference (p=0.0001) was observed at 7 and 50 days. there were no significant differences (p=0.111) between tissue reaction to ch (382 inflammatory cells) and cob (330 inflammatory cells) after 7 days. after 50 days,significantly more inflammatory cells (p=0.02) were observed in the ch group (404 inflammatory cells) than in the cob group (177 inflammatory cells). conclusions: these results demonstrate that the cob cement induces less inflammatory response within long periods.