Histological Evaluation of Connective Tissue Adhesion to Machined Grade III Titanium Discs in Albino Rats: An In Vivo Biocompatibility Study

Abstract Background: Titanium is widely used in implant dentistry, yet connective tissue adhesion to machined titanium surfaces requires further in vivo characterization to support biocompatibility evidence. Aim and Objective: To evaluate histological connective tissue adhesion and local tissue response to Grade III machined titanium discs implanted in albino Sprague Dawley rats. Materials and Methods: An in vivo experimental study was conducted using 11 rats (plus 2 pilot animals). A total of 20 Grade III machined titanium discs were implanted subcutaneously in the scapular region. Animals were housed under controlled conditions (23–25°C; 46–48% humidity) with standardized bedding, purified water, and balanced feed. General anesthesia was induced intraperitoneally with ketamine hydrochloride, followed by a small incision and disc insertion using a catheter, and wound closure with sutures. At predefined intervals, implants with surrounding tissue were harvested and fixed in 10% formalin for histopathological analysis. Blood was collected via cardiac puncture. Euthanasia was performed using sodium pentothal (50–70 mg/kg) followed by agent T33 to allow adequate tissue sampling depth. Results: Histological assessment showed fibroblasts, macrophages, and lymphocytes in close association with the titanium discs, with evidence of collagen fiber synthesis and extracellular matrix organization. No histological signs of infection or hypersensitivity were observed. Giant platelets were identified, consistent with a localized reparative response. Conclusion: Grade III machined titanium discs demonstrated favorable connective tissue adhesion and a localized repair response without evidence of infection or hypersensitivity, supporting their in vivo biocompatibility in this animal model.