Efeitos da administração do bisfosfonato tiludronato associado ou não à terapia peripdontal mecânica, na periodontite experimental em ratos

Abstract

Background and Objectives: The proven efficacy of bisphosphonates to inhibit the osteoclastic bone resorption has led to their use in the management of periodontal diseases. This dissertation, comprised by 2 manuscripts, aimed: (1) to histologically analyze the effects of systemic administration of Tiludronate (TIL) on ligature-induced periodontitis in rats; (2) to histologically analyze the effects of systemic administration of TIL as an adjunctive therapy to mechanical periodontal treatment on ligature-induced periodontitis in rats. Methods: In study 1, 32 adult male rats were divided into four groups (n=8): C, PD, PD-TIL5, PD-TIL15 (C–Control group, PD–Periodontitis groups). On PD groups, a ligature was placed in the cervical area of the right mandibular 1st molar of each rat. After 15 days, TIL solutions (Tildren®, Ceva Saúde Animal Ltda., Paulínia, SP, Brazil) at dosages of 5 mg/kg body weight (group PD-TIL5) or 15 mg/kg body weight (group PD-TIL15) were subcutaneously administered 5 times a week for 3 weeks. In study 2, 40 adult male rats were divided into five groups (n=8): C, PD, PDT, PDT-TIL 5, PDT-TIL 15. On PD groups, ligatures were placed as described. After 15 days, ligatures of the rats from groups PDT, PDT-TIL5 and PDT-TIL15 were removed and scaling and root planing were performed. TIL solutions at dosages of 5 mg/kg body weight (group PDT-TIL5) or 15 mg/kg body weight (group PDT-TIL15) were subcutaneously administered 5 times a week for 3 weeks. All animals were euthanized at the 36th day. Histometric and histologic analyses were performed. Data were statistically analyzed (ANOVA, Tukey, p<0.05). Results: In study 1, alveolar bone loss was significantly reduced in group PD-TIL5 (1.12 mm±0.24), when compared with groups PD (1.70 mm±0.32) and PD-TIL15 (1.47 mm±0.21). The animals from all PD groups presented more periodontal attachment loss than the ones from group C (0.12 mm±0.09). There were no differences in periodontal attachment loss among PD groups (PD: 0.53 mm±0.19; PD-TIL5: 0.37 mm±0.09; PD-TIL15: 0.52 mm±0.13). In study 2, there were no differences in alveolar bone losses among groups PDT (1.27 mm±0.15), PDT-TIL 5 (1.18 mm±0.10) and PDT-TIL 15 (1.26 mm±0.40). The alveolar bone losses found in these groups were slighter than the alveolar bone loss observed in group PD and did not statistically differ from the alveolar bone loss found in group C. Animals from all groups with periodontitis induction (group PD: 0.59 mm±0.16; group PDT: 0.39 mm±0.07; group PDT-TIL 5: 0.42 mm±0.05; group PDT-TIL 15: 0.48 mm ± 0.09) presented periodontal attachment losses statistically greater than the animals from group C (0.12 mm±0.09). Groups PDT and PDT-TIL 5 presented less periodontal attachment loss than group PD. Conclusions: Within the limits of this study, it can be concluded that (i) systemically-administered TIL solution reduced alveolar bone loss in established periodontitis in rats, (ii) dosage of TIL may influence its anti-inflammatory and anti-resorptive properties and (iii) systemically-administered TIL did not result in additional benefits to periodontal mechanical therapy in rats with experimental periodontitis.