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.