Ok S.-M. et al. - Photobiomodulation and Burning Mouth Syndrome: A Systematic Review and Meta-Analysis of Randomized Trial Protocols

Share this article:

In this meta-analysis of 18 randomized trials, photobiomodulation is associated with reduced pain and improved oral health-related quality of life in burning mouth syndrome. There was no significant improvement in xerostomia or depression, and the data remain insufficient to establish an optimal protocol.

What this study measured

Burning mouth syndrome is characterized by a burning sensation in the mouth, often without any visible lesions on the mucous membrane. Several randomized trials have evaluated photobiomodulation, also known as low-intensity laser therapy, but their irradiation protocols vary widely from one trial to another.

Soo-Min Ok and Misoon Lee conducted a systematic review with a meta-analysis at the protocol level, in accordance with the PRISMA and Cochrane guidelines. The review protocol is registered on PROSPERO under number CRD420261329136. Eighteen randomized trials were included. Random-effects meta-analyses assessed pain, oral health-related quality of life (OHIP-14 questionnaire), xerostomia, anxiety, and depression. Exploratory subgroup analyses also examined wavelength, power, fluence, irradiation duration, frequency of sessions, treatment duration, and mode of application.

Key Findings

According to the authors, photobiomodulation reduces pain and improves quality of life related to oral health. The effects on associated symptoms are more mixed.

Pain: mean difference -1.09 (95% CI -1.60 to -0.57), with 89% heterogeneity
OHIP-14: mean difference -3.82 (95% CI -4.79 to -2.86), with 41% heterogeneity
Xerostomia: no significant improvement
Depression: No Significant Improvement
Anxiety: modest reduction
Protocol Variables: Some Nominal Signals in Exploratory Analyses

How photobiomodulation works for this indication

The study abstract does not detail any biological mechanisms. Generally speaking, it is proposed that red or near-infrared light is absorbed by mitochondrial cytochrome c oxidase, which could alter cellular energy production and the signaling of inflammation and pain. In burning mouth syndrome, damage to small nerve fibers is often cited. These theories remain hypotheses: this meta-analysis measures clinical effects and does not test the mechanism.

Limits You Should Know

Several caveats should be noted. The results regarding xerostomia and depression are not significant, and the result regarding anxiety is only modest. The heterogeneity of the results regarding pain is high (89%), meaning that the trials yield highly variable results. Subgroup analyses based on radiation parameters were exploratory and yielded only nominal signals, which should be interpreted with caution. The authors conclude that current evidence supports standardization of radiation protocols but remains insufficient to define an optimal protocol. The abstract does not provide the total number of participants, the risk of bias in the trials, or the duration of follow-up.

What This Means in Practice

For patients and healthcare professionals, this meta-analysis suggests that photobiomodulation could be a complementary approach for managing pain and improving quality of life in burning mouth syndrome. It does not allow for the recommendation of a specific wavelength, power, fluence, or number of sessions. It is not a substitute for the diagnostic process or follow-up by a healthcare professional. The authors advocate for standardizing protocols in future trials to ensure that results are comparable.

Frequently Asked Questions

Does photobiomodulation reduce the pain associated with a burning mouth?

In this meta-analysis of 18 randomized trials, it is associated with a reduction in pain, with a mean difference of -1.09 (95% CI -1.60 to -0.57). Heterogeneity among trials is high (89%), which calls for caution.

Does it also help with dry mouth or mood?

Xerostomia and depression did not improve significantly. Anxiety showed a modest reduction. Oral health-related quality of life (OHIP-14) improved, with a mean difference of -3.82.

Is there a standard irradiation protocol?

No. The authors note that the current evidence remains insufficient to establish an optimal protocol. The signals observed based on the irradiation parameters were exploratory and only nominal.

Reference

Ok S-M, Lee M. Photobiomodulation Irradiation Protocols for Burning Mouth Syndrome: A Systematic Review and Protocol-Level Meta-Analysis of Randomized Trials. Photobiomodulation, Photomedicine, and Laser Surgery, 2026. PMID 42765164. View the study on PubMed

This summary is provided for informational purposes only and does not constitute medical advice. Photobiomodulation is not a substitute for prescribed treatment. Consult a healthcare professional.