Influence of pre-endodontic filling bacterial load on periradicular repair: prospective longitudinal study.

The aim of this project is to investigate the influence of pre-filling bacterial load on the repair of periradicular lesions of endodontic origin. Eighty-four (84) patients with primary endodontic infection (pulp necrosis and apical periodontitis) will be selected and will undergo Endodontic Treatment (ET) at the Endodontics clinic of Galeão Air Force Hospital (Rio de Janeiro, Brazil). Bacterial samples will be collected to detect thepresence of microbial infection in the root canals before ET (S1) and after completion of the chemical-mechanical preparation (S2). The samples will be evaluated using the RT qPCR test, checking the prevalence and bacterial load of the most found species in primary endodontic infections, in addition to the total bacterial load. The microbiological data detected will be correlated with clinical, radiographic, and tomographic examinations pre- and post- ET, with follow-up every six months for up to two years. Initial and follow-up periapical radiographs and CBCT scans will be evaluated, and the periapical condition will be evaluated using the Periapical Index (PAI) and Cone Beam Computed Tomographic Periapical Volume Index (CBCTPAVI) tool, respectively. The determination of success or failure of endodontic treatment will be based on clinical symptoms and radiographic evaluation of the periapical tissues. A statistical analysis will be carried out and the significance level will be set at 5%. It is expected that with the results found, a maximum level of post-chemical-mechanical preparation contamination compatible with the repair of apical periodontitis will be established.