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

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

Effectiveness of Photodynamic Therapy Combined With Conventional Endodontic Treatment in the Disinfection of Root Canals in Patients With Apical Lesion: a Randomized Clinical Trial

The object of the present study is to compare the effectiveness of conventional endodontic treatment with that of endodontic treatment combined with Photodynamic Therapy (PDT) in patients with apical lesion. Clinical and radiographic examination of the patients will be used to evaluate the presence of apical lesion, size of the lesion, and PAI index. Microbiological examination (evaluation of UFC/ml) will be carried out to assess the disinfection of the root canals. The success rate of the treatment will also be assessed. Endodontic treatment will be carried out in accordance with habitual standards and practices. PDT will be applied with diode laser (660 nm, 100 mW) and methylene blue will be used as photosensitizer (PS). Patients of the Endodontics Service of Universidad San Sebastián (Santiago campus) will be recruited for the study.

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.

routine endodontic treatment will be applied and the application of laser will be simulated with the equipment, but no radiation will be emitted

Conventional ET + PDT. PDT will be carried out with diode laser with optical fibre coupled to the equipment (660 nm, 100 mW, 10 s). The photosensitizer used will be methylene blue.

Conventional ET + PDAT. PDAT will be carried out with diode laser with optical fibre coupled to the equipment (660 nm, 100 mW, 20 s). The photosensitizer used will be methylene blue.

The lesion will be measured vertically and horizontally, and the size difference between the start of treatment and 6 months after treatment will be evaluated. The lesion will also be evaluated by the PAI index score. Interpretation of radiographs and PAI scores will be carried out by experienced endodontists.

Disinfection of the root canals will be evaluated by analysis of colony formation (ufc/ml). To assess colony formation (ufc/ml) in the root canal, 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). Three paper cones will be inserted into the root canals for 30 s. Routine microbiological analysis will be performed. Disinfection of the canal will be evaluated by comparing colony formation in each group at T0 and T1. Which treatment promotes the greatest disinfection will also be determined.

Success rate of the treatment, measured after 6 months, based on the clinical results (absence of clinical signs and symptoms) and on the radiographic results (diminution of the lesion and absence of root resorption, PAI index score). The analyses will be carried out by two calibrated researchers, who will be blinded to the patient's assignment to a treatment group. The success rate will be assessed for each group 6 months after completion of ET.

Primary inferential analysis will be based on intention to treat. A protocol will be used to analyse the result variable 'adverse effects' to avoid underestimation of its magnitude. All adverse events will be recorded that occur from entry into the study until completion of treatment. 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.

Inclusion Criteria: Patients eligible for this study must comply with the following for randomization: Adult patients of either sex No general biological risk At least 1 molar with pulp necrosis and apical lesion Exclusion Criteria: Pregnancy Patients requiring complex dental rehabilitation due to major coronal destruction Individuals with cognitive disability making conventional treatment impossible