Effect of cyclosporin A on the mineral apposition rate of cementum and dentin in growing rats

Background: Since there is no direct information to verify whether cyclosporin A (CsA) can affect the mineralization of dental hard tissue, the formation of dentin and cementum in growing rats was recorded by labeling the mineral phase of these tissues with fluorochrome marker in this study. Methods: After the extraction of the right maxillary molars, 30 male 3-week-old Sprague-Dawley rats were assigned to two groups. Following a 2-week healing period, the experimental rats received 30 mg/kg CsA daily for 7 weeks, while the control rats received only mineral oil. The fluorescent markers, calcein and alizarin red, were given on alternate weeks for 7 weeks. At the end of study, the mandibles were obtained and undemineralized sections were processed. Serial sections, 8 mu m thick, were cut for the entire distal roots of the first molars. Five central sections were selected to determine the mineral apposition of cellular cementum and dentin at the apex and middle of root, respectively. Results: The apposition rates of apical cellular cementum were significantly influenced by CsA therapy, occlusal function, and observation duration. However, the dentin apposition rates were significantly influenced by the observation intervals only. Conclusions: In this study, CsA therapy and occlusal function significantly influenced the apposition rates of apical cementurn, but not the rates of mid-root dentin. Our hypothesis that CsA can induce oral hard tissue alterations, as well as gingival overgrowth, is demonstrated.