The effects of photodynamic therapy on postoperative pain in teeth with necrotic pulps

This study aimed to determine the effects of photodynamic therapy (PDT) on postoperative pain after treatments of teeth with necrotic pulps. This randomized clinical trial consisted of 60 patients who presented for treatment of asymptomatic teeth. The patients were randomly assigned into the Control Group (CG) or the PDT Group (PG). The canals were instrumented with a reciprocating instrument (50.05) under 2.5% NaOCL irrigation. After instrumentation was completed, the canals were flooded with 1.56 μM/mL of methylene blue (MB), the optical fiber was inserted to the working length and applied for 3 min (P =100 mW, t =3 min, E = 18 J). The device emitted PDT only for the PG. The operator and the patient were both masked to the treatment protocol. After PDT, the root canal treatment was completed and the canals were filled. A card was given to the patients to document their pain perception through the 0-10 visual analogue scale (VAS) at 24 h, 72 h, and 1-week intervals. The Mann-Whitney and Fisher´s exact tests were used for statistical analysis (P < .05). The average pain level for the CG was 1.33 at 24 -hs and 0.50 at 72 -hs; for the PG, the average pain level was 0.37 at 24 -h and 0 at 72 -h (P < .05). After 1-week there was no report of pain. PDT had a significant effect in decreasing postoperative pain at 24- and 72 -h intervals in treatment of single-rooted teeth with necrotic pulps performed in one visit.