Exploring Photobiomodulation Therapy for Long COVID Xerostomia: A Randomized Controlled Pilot Trial

Aims: To investigate the effects of a photobiomodulation protocol in the treatment of long COVID-19 xerostomia

Study Design: This is a single-center, randomized, controlled, double-blind pilot clinical trial.

Methodology: 10 patients with long COVID-19 xerostomia are randomized into two groups. The participants receive a standard xerostomia treatment and also a low-intensity photobiomodulation therapy or placebo photobiomodulation therapy on the cutaneous topography of the salivary glands (a RED LED cluster, 2 J/cm2, 108 J per session, twice a week for six weeks). The outcomes measured using the Oral Health Impact Profile (OHIP-14), Xerostomia Inventory (XI) Scale, Brazilian version of SF-36 Quality of Life Scale, Brazilian Version of Functional Independence Measure (FIM), sialometry and salivary pH before and after the therapeutic period of six weeks of intervention.

Results: there were no significant differences between the photobiomodulation and placebo groups in the baseline or post-intervention moments for evaluated outcomes. In the individual analysis of the OHIP-14 and XI items, a difference was observed in the values of the PBM group comparing the pre-intervention baseline moment with the post-intervention PBM moment, not founded in the placebo group. No adverse effects are reported.

Conclusion: This PBM protocol was not superior to placebo in treating long COVID xerostomia for the evaluated outcomes. This study has limitations such as the small sample size and unblinding issues, which may have leading to a lack of significant results for primary outcomes in both the PBM and placebo groups. PBM irradiation of the salivary glands could be studied as a future approach to improving salivary production in patients with xerostomia due to long COVID.