Photobiomodulation therapy for salivary gland hypofunction: a preliminary human study

Salivary gland hypofunction (SGH) is associated with an increased risk of tooth decay, oral infections, halitosis, xerostomia, and impaired speaking and swallowing functions, leading to decreased quality of life. Several therapies have been used to increase saliva production, and photobiomodulation therapy (PBMT) has shown promising results in treating SGH. This preliminary study aims to evaluate the efficacy of PBMT in SGH and changes in the quality of life of these patients. Eight patients diagnosed with SGH (salivary flow ≤ 0.2 mL/min) who were on continuous systemic medication underwent ten sessions of PBMT applied to the major salivary glands. A follow-up appointment was performed 45 days after the last session. The effect of PBMT was evaluated in terms of quality of life (XeQoLS) and dysphagia (EAT-10). The Friedman and Wilcoxon tests were used to analyze sialometry and questionnaire data. A p ≤ 0.05 was considered statistically significant. The unstimulated whole saliva flow (UWSF) rate improved in the fifth and tenth PBMT sessions (p = 0.005; p = 0.003, respectively). This improvement was also present 45 days after therapy (p = 0.04), thus demonstrating a long-term effect of PBMT in SGH treatment. Thus, our study demonstrates the efficacy of PBMT in treating salivary gland hypofunction, with a significant and sustained increase in UWSF rate even after the end of treatment. These findings suggest that PBMT may effectively improve saliva production in patients diagnosed with salivary gland hypofunction, including those on continuous systemic medication.