Chitosan–gelatin scaffold reinforced with carbonate hydroxyapatite enhances bone healing in rat extraction sockets: An immunohistochemical study

Background: Tooth extraction commonly leads to alveolar bone loss, which can compromise future prosthetic rehabilitation. Biomaterial-based socket preservation aims to support hard-tissue healing and stabilize the extraction site. Objective: To assess the effect of a chitosan-gelatin scaffold reinforced with carbonate hydroxyapatite (CG-CHA) on bone healing in Wistar rats extraction sockets by evaluating immunohistochemical expression of Bone morpogenetic protein 2 (BMP-2), Runt-related transcription factor 2 (RUNX2) and Receptor activator of nuclear κB (RANK). Materials and methods: A true-experimental randomized post-test only control group design was used with 24 male Wistar rats. Following maxillary molar extraction, rats were assigned to either a control group (extraction only) or a CG-CHA scaffold group (n = 12 each). Mandibles were collected on days 7, 14, and 21 (n = 4 per time point per group). Immunohistochemistry were performed to evaluate the expression of BMP-2, RUNX2, and RANK. Data were analyzed using independent t-tests with significance at p < 0.05. Results: The CG-CHA group showed greater bone formation and significantly higher BMP-2, RUNX2, and RANK expression at days 7, 14, and 21 compared to controls (p < 0.05). Conclusion: Placement of a CG-CHA scaffold in extraction sockets improved bone healing and increased osteogenic marker expression in rats. These findings indicate that CG-CHA supports favorable socket healing and may be useful for alveolar bone preservation strategies.