Influência do alargamento apical no reparo das periodontites apicais : estudo em ratos

Abstract

Introduction: Instrumentation is considered one of the most important steps in endodontic treatment. The literature is controversial with regards to the optimal apical enlargement, especially as to the repair of periapical lesions, proposing different protocols and instrumentation techniques. This study aimed to evaluate the influence of apical enlargement in the process of apical repair in rats. Methods: 24 Wistar rats were divided into 03 experimental groups. Periapical lesion of the first molars on both sides was induced, leaving the root canals exposed to the oral cavity for three weeks. Group 01 consisted of preparation until a #20 file, Group 02 until #25 and Group 03 until #30 file. One molar has been instrumented, while the opposite side was a negative control for apical repair. Root canals were filled 0.5 mm from the apex, with single cone technique of gutta-percha and sealer. After three weeks, the animals were euthanized. Periapical repair was evaluated by digital radiographs and optical microscopy of histological sections (HE) and the data were analyzed using ANOVA test and Kruskal-Wallis test, aiming to establish whether the progressive increase of apical preparation provides an additional benefit in apical repair. Results: Periapical repair was evaluated using digital radiographs. Radiographic limits of the lesions were marked, finding a significant difference (p ≤ 0.05) in the repair in favor of all groups compared to their respective controls. These results were supported by histological analysis. There was a trend towards improvement in the periapical healing for the larger apical enlargement (group 3). Conclusion: No significant difference was found between the three experimental groups, but it was possible to appreciate radiographically an improving trend for the group of more instrumentation (third group: #30).