Healing of tooth extraction sockets in experimental diabetes mellitus

Purpose: This study was undertaken to examine the healing of molar tooth extraction sockets in the streptozotocin-treated, diabetic rat. Materials and Methods: Insulin-dependent diabetes mellitus was induced in a group of mature Sprague-Dawley rats by injecting streptozotocin. Control animals were injected with citrate buffer only. A third group of rats were also injected with streptozotocin, but the diabetes was controlled by daily injections of insulin. After 2 weeks, all of the rats underwent extraction of the right maxillary molar teeth under general anesthesia. The rats were killed at varying intervals and the maxilla and calvaria recovered in continuity. Tissue sections were stained with hematoxylin-eosin and periodic acid-Schiff (PAS), the latter to identify diabetic microangiopathy. Results: At 10 days after tooth extraction in the control and insulin-streptozotocin-treated rats, thick collagen fiber; formed a pretrabecular scaffold that dictated the direction of the forming trabeculae. The collagen fibers in the diabetic socket were thin and scanty, and formed a narrow layer in the apical part. There was no evidence of diabetic microangiopathy in the extraction sockets of diabetic, insulin-treated diabetic, or normal rats. Conclusion: These histologic observations suggest that in uncontrolled, insulin-dependent diabetes, the formation of the collagenous framework in the tooth extraction socket is inhibited, resulting in delayed healing and increased alveolar destruction.