SUMMARY
Objective: To describe a methodology for evaluating the efficacy of intracanal medications in rats, by using cone beam computed tomography (CBCT) to follow-up periapical lesions.Methods: Six male Wistar rats were used, and periapical lesions were induced in 12 upper molars. The endodontic treatment was performed in all teeth and calcium hydroxide paste was applied inthe right molars (treated group, n=6), whereas no medication was used in left molars (control group, n=6). CBCT was performed 21 days after endodontic treatment, and the lesion area was determined in mm2. Unpaired Student t test was used to verify the differences between groups.Results: The lesion area was 9.38±0.68 mm2 in the control group and 7.08±0.44 mm2 in the treated group (P<0.05), according to CBTC evaluation. These data were confirmed by histological evaluation of maxillas, indicating the applicability of CBTC in the rat model of apical periodontitis.Conclusion: The rat model and CBCT was found to be a useful tool to study in vivo the effects of intracanal medications and their influence in periapical lesions healing.