Efficacy of 660 nm Photobiomodulation in Burning Mouth Syndrome Management: A Single-Blind Quasi-Experimental Controlled Clinical Trial.

Background: Burning mouth syndrome (BMS) is characterized by a burning sensation of the oral mucosa without any evidence of clinical signs or underlining condition. Several treatment modalities have been utilized with various results and levels of evidence. Lately, photobiomodulation (PBM) has emerged as a noninvasive effective therapy due to its anti-inflammatory and biostimulatory effects, especially the low-power laser setting of red wavelength. Objective: This single-blind quasi-experimental controlled clinical trial aimed to evaluate the PBM effectiveness at a low level of red laser light in patients with BMS compared with sham control. Materials and methods: Thirty patients diagnosed with BMS were consecutively assigned to intervention (PBM therapy) and control (sham) groups. The protocol for PBM dosimetry was as follows: laser 660 nm; spot size: 0.04 cm2; power output: 100 mW; emission mode: continuous wave; power density: 6 J/cm2; irradiation time: 10 sec per point within 1 cm2 surface area of the symptomatic area. The treatment protocol was based on once a week for a total of 10 sessions. Results: Our results showed no statistically significant difference in reduction of pain intensity between the two groups at all the evaluated timepoints during the course of treatment. However, in both groups, we observed a statistically significant reduction of maximum pain intensity of 50% compared with patient-self reporting before the treatment. Conclusions: Further randomized clinical trials to validate our positive results with a large sample size with a long-term follow-up and understanding further the sham placebo effect are warranted.

Voltage-gated sodium channels gene expression in Burning Mouth Syndrome: a case-control study

Abstract Burning mouth syndrome (BMS) is a condition characterized by painful symptoms of the oral mucosa, despite the absence of any clinical signs. Its etiology is unknown, and there is still no effective treatment to date. Current evidence has shown neuropathic impairment in BMS patients. Neuropathic pain can be related to the dysfunction of voltage-gated sodium channels, considering that these receptors regulate the induction of action potentials in nociceptive neurons. This study evaluated the gene expression of voltage-gated sodium channels Na v 1.7, Na v 1.8 and Na v 1.9 in these patients. The gene expressions of these channels were assessed by real time RT-PCR analysis of fresh-frozen tongue biopsies in a case-control study composed of 12 patients with BMS, and 5 healthy control patients, proportionally matched by sex and age, and analyzed using the 2^(-Delta Delta CT) method. There was no statistically significant difference between the analyzed groups, despite the increase in Na v 1.7 (fold-change = 3.13, p = 0.52) and decrease in Na v 1.9 (fold-change = 0.45, p = 0.36) gene expression in the BMS group. The Na v 1.8 gene was not expressed in any of the samples analyzed. Although the gene expression in the voltage-gated sodium channels in BMS under study seems to be comparable with that of the normal oral mucosa, the functionality of these channels in BMS has not yet been identified, thus suggesting that further research is needed to better understand these voltage-gated sodium channels.