Effectiveness of Photodynamic Therapy in the Disinfection of Root Canals in Patients With Apical Lesion

The object of the present study is to compare the effectiveness of conventional endodontic treatment with that of endodontic treatment combined with PDT in patients with apical lesion. A randomized, clinical, superiority trial will be carried out, controlled, blinded and masked, with 3 parallel arms. The patient sample will be randomized in 3 treatment groups: the first is the placebo group which will receive conventional endodontic treatment (ET) and a simulated treatment with the equipment in which no radiation will be emitted; the second group will receive conventional ET associated with PDT with diode laser at 660 nm, fluence 10 s/canal; and the third group will receive conventional ET associated with PDAT with laser at 660 nm, 20 s/canal. The photosensitizer used in the PDT will be methylene blue. Clinical and radiographic examination of all the patients will be used to obtain baseline values (T0) and values 6 months post-treatment (T1). The presence and size of apical lesion will be assessed at T0 and T1, the percentage reduction of the lesion will be calculated and the PAI index will be used as a scoring system to assess the lesion. The success rate will be assessed for each group 6 months after completion of the treatment. Disinfection of the root canals will be assessed by analysis of colony formation (ufc/ml); biological samples will be taken with paper cones inserted into the root canals to the apical region at two moments: Baseline (before treatment, T0); after instrumentation with PDT (experimental groups) and without PDT (placebo group). Adverse events will be analysed; a serious adverse event for this study is any unfavourable odontological event that the investigators believe to bear a causal relation with the experimental intervention.