Photobiomodulation versus stabilization splint, both combined with self-management, for acute temporomandibular myalgia: 48-week outcomes of a partially randomized controlled study

Background Photobiomodulation (LLLT) is used for myogenous temporomandibular disorders (TMD), but longer-term comparative evidence versus stabilization splints alongside structured self-management remains limited. This study aims to compare pain reduction and maximum painless mouth opening after photobiomodulation+self-management (PBM + SM) versus stabilization splint+self-management (OS + SM), with an additional self-management–only comparator (SM), over 48 weeks. Methods This partially randomized controlled study enrolled 66 patients with DC/TMD-diagnosed acute masticatory muscle pain. Forty-four participants consenting to intervention were randomized 1:1 to PBM + SM (660-nm diode laser, twice weekly, 10 sessions) or OS + SM (maxillary stabilization splint worn at night, 8 h/day for 2 months). Both intervention groups received the same SM programme (education, habit modification, and jaw exercises for 2 months). A non-randomized convenience group received SM alone (n = 22). Assessments were performed at baseline and weeks 2, 4, 12, 24, and 48. Primary outcomes were VAS pain (0–10) and maximum painless mouth opening (MPMO, mm). Secondary outcomes included masticatory muscle tenderness and Patient Global Impression of Change (PGIC). Longitudinal analyses used linear mixed-effects models. Results All groups improved over time, with earlier improvement in both intervention arms. In the randomized comparison, PBM + SM and OS + SM showed comparable week-48 outcomes for VAS pain and MPMO. No significant between-group difference in masticatory muscle tender points was observed at week 48 after Holm adjustment. Comparisons involving the SM-only group were exploratory. Conclusions Over 48 weeks, PBM + SM and OS + SM produced comparable improvements in pain and maximum painless mouth opening, with no significant between-group difference in masticatory muscle tender points at week 48. Trial Registration ClinicalTrials.gov ID: NCT06419738