Effectiveness of low-intensity laser photobiomodulation in reducing inflammatory events (pain, edema, and trismus) after orthognathic surgery: a systematic review and meta-analysis of randomized clinical trials

Objective This systematic review aimed to answer whether, in (P) individuals undergoing orthognathic surgery, (I) low-level laser therapy (LLLT) during or shortly after the surgical procedure compared to (C) pharmacologic therapy alone or no therapy for improvement of post-intervention complications relieves (O) postoperative inflammatory events in (S) randomized clinical trials.Material and methods A preliminary electronic search was conducted for references with language following a Latin (Roman) alphabet in seven databases index, and gray literature without restriction on language or publication period. Risk of bias was performed by RoB 2.0 tool, and meta-analysis used mean differences (MD) for edema and mouth opening and standardized mean differences (SMD) for pain scores (p < 0.05, Revman<(R)>).Results A total of 91 control patients and 114 LLLT patients were included. The wavelengths ranged from 660 to 940 nm, and the applied energy density was between 5 and 100 J/cm2 at mostly extraoral distributed points. LLLT significantly reduced edema (MD = - 4.27, CI95% - 5.13 to - 3.41 mm) in the period from 5 days to 2 weeks postoperatively (p < 0.001) and showed strongly reduced pain scores (SMD = - 1.37, I95% = - 1.99 to - 0.75) between 1 day and 5 weeks (p < 0.001), without significantly interfering with mouth opening (p = 0.110). Despite the low risk of bias, high heterogeneity among studies (I2 > 70%) and small sample sizes made the certainty of GRADE evidence low.Conclusion This SR demonstrated that LLLT effectively controls pain and edema after orthognathic surgery.Clinical relevanceSystematic review that summarizes the use of photobiomodulation on orthognathic surgery.