Effect of photobiomodulation therapy on postoperative pain after endodontic treatment: a randomized, controlled, clinical study

Clin Oral Investig. 2019 Jan;23(1):285-292. doi: 10.1007/s00784-018-2435-9. Epub 2018 Apr 16.


Objective: The aim of this prospective, randomized, clinical study was to assess the effect of photobiomodulation therapy (PBM) with low-level laser irradiation (LLLI) on postoperative pain after endodontic treatment.

Materials and methods: Sixty patients, diagnosed with irreversible pulpitis in lower molar teeth, participated in the study. All treatments were performed by a single operator. Participants were randomly divided into two groups: in the experimental group (EG), endodontic treatment was performed with a reciprocating system, immediately followed by PBM with LLLI; and only endodontic treatment was performed in the control group (CG). Postoperative pain was assessed by a second examiner, who was blinded, using two scales: verbal rating scale (VRS) and numerical rating scale (NRS). Assessment was carried out at 6, 12, and 24 h after treatment. Data were analyzed using chi-squared, Fisher's exact, Mann-Whitney tests, ordinal, and non-parametric regression analyses.

Results: For the prevalence of pain, the difference between the groups was significant for the evaluations performed after 6 h (p = 0.04) and 24 h (p = 0.02). The difference after 24 h remained significant after stratification by sex and extrusion of filling material. Increased pain intensity was associated with extrusion of root canal filling material to the periapical region in the two scales used.

Conclusion: The effect of PBM therapy after endodontic treatment showed a significant decreasein prevalence of postoperative pain.

Clinical relevance: The PBM reduces the prevalence of postoperative pain and may benefit patients who need endodontic treatment.

Keywords: Clinical trial; Intervention study; Photobiomodulation therapy; Postoperative pain.

Publication types

  • Randomized Controlled Trial

MeSH terms

  • Adolescent
  • Adult
  • Brazil
  • Double-Blind Method
  • Female
  • Humans
  • Low-Level Light Therapy*
  • Male
  • Middle Aged
  • Pain Measurement
  • Pain, Postoperative / radiotherapy*
  • Prospective Studies
  • Pulpitis / therapy
  • Root Canal Therapy*
  • Treatment Outcome