Clinical evaluation of single and repeated sessions of photobiomodulation with two different therapeutic wavelengths for reducing postoperative sequelae after impacted mandibular third molar surgery: a randomized, double-blind clinical study

J Appl Oral Sci. 2021 Nov 15:29:e20210383. doi: 10.1590/1678-7757-2021-0383. eCollection 2021.


Objective: The effects of the number of photobiomodulation (PBM) sessions on the postoperative inflammatory process remain controversial. The current literature comparing single and repeated PBM sessions is limited. This study aimed to compare the effects of single and repeated PBM sessions, applied at two different therapeutic wavelengths within the infrared spectrum, on postoperative inflammatory response after impacted third molar tooth extraction.

Methodology: This randomized, double-blind clinical study included 40 patients with bilateral impacted mandibular third molars (80 teeth). The patients were divided into two groups each including 20 subjects (40 teeth) to receive either single-session laser at 810 nm (20 teeth) and 940 nm (20 teeth) immediately after the surgery or repeated laser sessions at 810 nm (20 teeth) and 940 nm (20 teeth) (immediately after the surgery and on postoperative Day 1). Lasers at 940 nm (power density 0.5 Watt/cm2, energy density 4 J/cm2 for a time until the cumulative energy on the device screen reaches 50 J from 0 J, in continuous mode, spot size 2.8 cm2) and at 810 nm (power density 0.14 Watt/cm2, energy density 4 J/cm2, for 30 seconds, in continuous mode, spot size 2.1 cm2) were applied intra- and extra-orally. Pain, swelling, and trismus were evaluated postoperatively.

Results: No significant differences were determined between the groups on the evaluated parameters (p>0.05).

Conclusion: Within the study limitations, in PBM, the effects of 810 nm and 940 nm and those of single and repeated applications were similar regarding pain, swelling and trismus. Immediate postoperative PBM could be preferred to repeated applications performed by point application within a 24-hour period.

Publication types

  • Randomized Controlled Trial

MeSH terms

  • Double-Blind Method
  • Edema / etiology
  • Edema / prevention & control
  • Humans
  • Low-Level Light Therapy*
  • Molar, Third / surgery
  • Pain, Postoperative / prevention & control
  • Tooth Extraction / adverse effects
  • Tooth, Impacted* / surgery
  • Trismus / etiology
  • Trismus / prevention & control