A review of rat models of periodontitis treated with natural extracts

Objective: To review treatment methods using natural extracts applied in rat models of periodontitis to establish a direction for the design of future experiments. Methods: An electronic search of PubMed was carried out using the keywords “periodontitis,” “natural”, “extracts”, “herb∗”, “plants” and “rats.” Articles were screened against inclusion and exclusion criteria by two independent researchers. Data describing the characteristics of rats, method of periodontitis inducement, extract administration, and outcome measures were extracted and analyzed by more than two authors manually. Results: Of the 864 articles identified, 33 studies were included. The use of Sprague–Dawley rats (51.2%) and male rats (90.9%) was preferred. The most common experimental methods were ligature placement (72.7%) and oral administration (66.7%). Alveolar bone loss was evaluated mainly by photography (51.5%) and micro-computed tomography (39.4%). Factors related to bone remodeling and inflammatory processes, such as interleukin-1β, tumor necrosis factor-α, receptor activator of nuclear factor-κB, and osteoprotegerin, were also measured. Conclusion: Many diverse experimental periodontitis models have been used. However, few articles observed bone formation, immune responses, antibacterial effects, and toxicity. Future studies to assess natural extracts for the treatment of periodontitis should be robust and well-designed.