Effect of photodynamic therapy on the healing of periapical lesions after root canal retreatment: 1-year follow up randomized clinical trial.

BACKGROUND: The aim of this randomized clinical trial was to evaluate the effects of photodynamic therapy (PDT) after traditional activated final irrigation protocol (ultrasonically activated irrigation, UAI) on periapical lesion healing after single-visit root canal retreatment. METHODS: We included 36 patients with asymptomatic chronic apical periodontitis with periapical lesions larger than 5 mm and teeth sensitive to percussion and palpation, who had previous root canal treatment. All patients who signed informed consent underwent cone-beam computed tomography (CBCT) to determine and calculate the preoperative volume of the periapical lesion. Patients were randomly distributed into two groups according to the final disinfection protocol: Group 1; UAI (NaOCl, EDTA, and NaOCl), Group 2; UAI + PDT. All patients underwent single-visit root canal retreatment using rotary instrumentation and standardized irrigation (3 %NaOCl) by the same endodontist. The root canals were filled with epoxy resin-based sealer and single-cone gutta-percha, followed by control radiography. After one year, a new CBCT scan of the teeth was performed to calculate the reduction in the initial periapical lesion as a measure of periapical healing. For the statistical analysis, the chi-square test variants, Fisher's exact test and the Fisher-Freeman-Halton test were used at the level of significance set at 5 %. RESULTS: There were no significant differences between the groups in terms of age, sex, preoperative and postoperative lesion volume (p > 0.05), and reduction of periapical lesion volume (median, 86.98 % for UAI and 79.72 % for UAI+PDT) (p = 0.970). Additional use of PDT after UAI did not contribute to the healing of periapical lesions. CONCLUSION: The UAI and UAI+PDT protocols had equal effects on healing of periapical lesion.

Influence of irrigation and laser assisted root canal disinfection protocols on dislocation resistance of a bioceramic sealer.

BACKGROUND: It is not yet clear how different irrigation protocols and intracanal laser irradiation effects bioceramic sealers. In this vitro study, we aimed to evaluate the dislocation resistance of a bioceramic root canal sealer after different laser-assisted disinfection protocols and irrigants. METHODS: Sixty extracted human straight single-canal teeth were instrumented, and randomly divided into five experimental groups (n=10) according to the disinfection protocol used: group 1, conventional needle irrigation (CI) with sodium hypochlorite (NaOCl)+ethylenediaminotetraacetic acid (EDTA)+NaOCl; group 2, Photon initiated photoacoustic streaming (PIPS) of NaOCl+EDTA+NaOCl; group 3, NaOCl+EDTA+diode laser; group 4, NaOCl+EDTA+photodynamic therapy (PDT); group 5, CI with NaOCl+EDTA+Chlorhexidine (CHX); and control group without any treatment. The root canals were filled with a bioceramic root canal sealer (BioRoot RCS) using the single-cone filling technique. After three weeks of storage, the samples from each canal thirds were transversely sectioned and the push-out test was performed. RESULTS: The PIPS group showed the lowest dislocation resistance values in the coronal third (p>0.05), and no difference was observed among the other groups (p<0.05). The dislocation resistance in the middle and apical thirds was the highest in the diode laser group (p<0.05). CONCLUSION: Final root canal irradiation with diode laser led to improved dislocation resistance of the bioceramic sealer. PDT did not adversely affect the dislocation resistance of BioRoot RCS. The PIPS reduced the dislocation resistance values in the coronal third, but not in the middle and apical thirds.