The aim of this study is: a) to monitor the microbiological load (UFC/mL) and the microbiological profile (checkerboard DNA-DNA hybridization test); lipopolysaccharides (LPS) (UE/mL) and lipoteichoic acid (LTA)/mL) levels in teeth with secondary endodontic infection submitted to single-visit (SV) and multiple-visit (MV) endodontic retreatment; b) to correlate the microbiological profile, CFU/mL, UE/mL, LTA/mL and with clinical signs and symptoms and the volume of periapical lesion (mm³) using cone beam computed tomography (CBCT); c) to compare volume of the periapical lesion (mm³) before and after eighteen months follow up in case of single-visit and multiple-visit endodontic retreatment; d) to compare the healing of the periapical lesion after eighteen months of treatment with UE/mL, LTA/mL and CFU/mL and microbial profile before and after root canal filling; e) to compare the success rate found after eighteen months of treatment between SV and MV retreatments; d) to compare the CBCT and radiography exam in the diagnosis and treatment decision. After clinical examination, following the criteria of inclusion and non-inclusion pre-established, will be selected thirty teeth with the need of endodontic retreatment. Patients will be submitted to CBCT. Root canal samples will be collected after removal of the obturator material (S1), after instrumentation with Reciproc® file (S2) and after of calcium hydroxide and physiological saline solution paste (S3). The contents will be assessed by microbiological culture (CFU/mL), the microbial profile by the Checkerboard DNA-DNA hybridization test, the EU/mL levels by the Limulus Amebocyte test and lipoteichoic acid (LTA/mL) by ELISA kit. The periapical bone destruction by CBCT analysis will be performed using Nemotec® software. The control of the endodontic retreatment will be accomplished, in order to compare the treatments regarding the repair process of the periapical lesion, relating the volume of the lesions with the clinical, radiographic findings and the CBCT exam. The data will be analyzed statistically.
News published in Agência FAPESP Newsletter about the scholarship: