Impact of an anti-inflammatory therapy and its withdrawal on the progression of experimental periodontitis in rats.

Background: Anti-inflammatory agents have been reported as a bone loss mediator in periodontitis. This study aimed to investigate in rats the impact of a selective cyclooxygenase-2 inhibitor (meloxicam) on bone loss in ligature-induced periodontitis and its post-treatment effect after administration withdrawal.

Methods: Seventy-five adult male Wistar rats were included. After anesthesia, a mandibular first molar was randomly assigned to receive the cotton ligature in the sulcular position, while the contralateral tooth was left unligated. The animals were randomly assigned to one of the following five treatment groups (15 animals each), including daily subcutaneous injections: 1) saline solution for 15 days; 2) saline solution for 45 days; 3) 3 mg/kg of meloxicam for 15 days; 4) 3 mg/kg of meloxicam for 45 days; or 5) 3 mg/kg of meloxicam for 15 days followed by saline solution for 30 days. The animals were sacrificed and the specimens routinely processed. The volume of bone loss was histometrically measured and statistical analysis performed.

Results: Intergroup comparisons demonstrated that the drug may significantly reduce periodontitis-related bone loss (group 3: 5.83 +/- 2.04); however, this effect is less evident when the drug is administered in a short period (group 4: 3.59 +/- 1.57). Moreover, after drug withdrawal, no residual effect was observed (6.86 +/- 3.59, 6.09 +/- 2.66, groups 2 and 5, respectively) (P > 0.05).

Conclusions: Within the limits of the present study, it can be concluded that selective cyclooxygenase-2 inhibitors may reduce bone loss associated with experimental periodontitis and that no remaining effect can be expected after its withdrawal.