The effect of photodynamic therapy on postoperative pain in teeth with primary endodontic infection

Introduction: : The objective of this study was to investigate the action of photodynamic therapy on pain control after endodontic treatment in asymptomatic teeth with a primary infection, within a single visit. Methods: : Sixty (60) single-rooted teeth with pulp necrosis and periapical lesions were selected and randomly divided into two (2) groups (n = 30), according to the protocol; a control group (CG) and a group using photodynamic therapy (aPDT). The canals were instrumented with Reciproc files # 25 up to 40 along the entire length of the canal, using 2% chlorhexidine gel as the auxiliary chemical substance, followed by irrigation with sterile saline. aPDT consited of 0.005% methylene blue as photosensitizer, using AsGaAl diode laser, 660 nm wavelength, 100 mW of power and 9 J of energy, using optical fibers with 365 μm in diameter. The canals were filled with Endomethasone N cement. Results: : Pain intensity was assessed at 8, 12, 24, 48, 72 h and 1 week after endodontic treatment using a visual analogue scale. The level of pain was classified as none (0), mild (1–3), moderate (4–7) or severe (8–10). The data were at a significance level of 5%. There was a statistically significant difference (p<0.05) in the periods of 8, 12, 24, 48 and 72 h between the control group and the aPDT group. After 1 week, there was no statistically significant difference. Conclusions: : It is concluded that photodynamic therapy had a significant effect on decreasing post-endodontic treatment pain in teeth with necrotic pulp and asymptomatic periapical lesions.