In Vivo Evaluation of Root Canal Irrigation Systems

Method: Periapical lesions were induced in sixty root canals, which were subjected to a single-session endodontic treatment. The teeth were randomly assigned to three groups: Group I: apical negative pressure irrigation (ANP) with EndoVac (n=20 root canals); Group II: passive ultrasonic irrigation (PUI) (n=20 root canals); and Group III: apical positive pressure irrigation (PP - conventional irrigation) (control) (n=20 root canals). After 180 days, the animals were euthanized, and the maxillae and mandibles were removed and subjected to histotechnical processing. Histopathological and morphometric analyses of HE-stained sections were performed under conventional and fluorescence microscopy. Radiographic analysis of periapical lesions was performed by measuring them before and after 180 days. Kruskal-Wallis non-parametric test was employed to compare the different groups. A significance level of 5% was set.

Result: Regarding the histopathological evaluation, there was a significant difference between Groups I and III, with milder infiltrate inflammatory in Group I (p=0.02). Regarding the morphometric analysis of the extent of the periapical lesions, no significant difference was found between the groups (p=0.92). The radiographic examination revealed that, even though it has been a reduction in the size of lesions, a statistically significant difference was not found when comparing the results of the three groups (p=0.91).

Conclusion: It can be concluded that ANP caused milder inflammatory response than control group, but similar to passive ultrasonic irrigation. Regarding morphometric and radiographic analyses, the response of the apical and periapical tissues to all root canal irrigation systems was similar and do not promote the repair of the apical and periapical tissues, after a single-session endodontic treatment.