A Modified Intrabony Defect Model of Periodontitis in Rat

OBJECTIVE: The aim of this study was to compare the radiographic depth of the periodontal bone defect, as well as clinical and histological outcomes, between the proposed ligated defect model and the current non-ligated defect model, which often heals spontaneously and fails to replicate the complexities of periodontitis. METHODS: The proposed model combined osteotomy to create controlled periodontal bone defects (depth of 1.5 mm) and ligature placement around the cervical region of the maxillary first molar to induce inflammation. Micro-CT analysis, clinical examinations, histological evaluations, and quantitative PCR were conducted to assess defect morphology, healing, and inflammatory marker expression over 6 weeks, compared with the non-ligated defect group, sham surgery group, and control. RESULTS: Bone defect in the ligated defect group remained unhealed after surgery (1.525 ± 0.068 mm in depth at 2 weeks and 1.543 ± 0.082 mm at 6 weeks), with inflammatory cell infiltration and elevated expression of IL-1β, IL-6, and TNF-α, contrasting with observed healing from 1.328 ± 0.075 mm (2 weeks) to 0.593 ± 0.118 mm (6 weeks) in the non-ligated defect group. CONCLUSIONS: This model not only simulates the pathological features of periodontitis but also provides a reliable platform for testing innovative regenerative strategies and could lead to the development of specialized models for other periodontal conditions.