Healing following tooth extraction in cyclosporine-fed rats

Healing after tooth extraction was studied in rats treated with cyclosporine-A (CSA) for four weeks. Sixty male Sprague-Dawley rats were assigned to one of three groups of 20 rats each. The maxillary right molars were extracted from two groups; the third group served as a non-extraction control. The non-extraction group and one extraction group (vehicle control) received the solvent mineral oil daily, and the other extraction group received 15 mg/kg CSA in mineral oil. Five rats from each group were killed 5, 10, 14 and 28 days after extraction and samples analyzed histologically. On days 5 and 10, bone volume was significantly lower and marrow volume significantly higher in both extraction groups than in the non-extraction group. The fractional-formation surfaces were significantly lower in the extraction groups than in the non-extraction group on day 5 only. Osteoid volume was significantly higher in the extraction vehicle control group than in the other two groups on days 10 and 14; however, the osteoid volume was higher in the CSA group than in the other two groups on day 28. On days 14 and 28, bone volume was lower and marrow volume higher in the CSA group than in the extraction vehicle control and non-extraction groups. On day 28, bony surface areas were significantly greater in the CSA group than in the extraction vehicle control and non-extraction groups. Soft-tissue evaluation showed significantly greater epithelial areas, connective tissue areas and total tissue areas in the CSA group than in the extraction vehicle control group on day 28, but not on day 14. These data suggest that CSA may influence healing of both the gingival tissue and the alveolar bony sockets in the tooth-extraction wound. Further detailed study is needed to identify the mechanisms responsible.