Therapeutic Ultrasound for Pain Management in Temporomandibular Disorders: A Systematic Review of Clinical Evidence From Controlled and Prospective Studies.

Abstract

Temporomandibular disorders (TMDs) are a common source of persistent orofacial pain and are estimated to affect a substantial proportion of the population. Therapeutic ultrasound is a non-invasive modality frequently used in musculoskeletal rehabilitation, although its clinical effectiveness for TMD-related pain remains debated. This systematic review was designed and reported in accordance with the PRISMA 2020 recommendations. PubMed/MEDLINE, Scopus, and Web of Science were searched from database inception to April 2026. We included randomized controlled trials, prospective clinical studies, and comparative clinical designs evaluating therapeutic ultrasound for pain management in adults with TMDs. The primary outcomes were pain intensity, assessed using VAS, NRS, or VRS, and mandibular function, assessed mainly by mouth opening. Risk of bias was evaluated using the Cochrane RoB 2.0 tool for randomized trials and ROBINS-I for non-randomized studies. Because of substantial clinical and methodological heterogeneity, findings were synthesized narratively rather than pooled statistically. The search identified 143 records, of which 82 remained after duplicate removal and were screened. Thirty-seven full-text articles were assessed, and 23 studies involving 1256 participants (1226 of them with a temporomandibular disorder) met the eligibility criteria. Twenty-one of 23 studies reported a statistically significant reduction in pain relative to their own baseline; however, these are within-group changes rather than treatment effects, and the certainty of the evidence for pain reduction was very low (GRADE), with low certainty for mandibular function, pressure pain threshold and quality of life/disability. Reported reductions included VAS improvement from 42 to 18 when ultrasound was added to home exercise, compared with 40-26 with exercise alone, and VAS improvement from 4.90 to 1.70 after low-intensity ultrasound therapy in a large randomized trial. Compared with low-level laser therapy or photobiomodulation, four studies favored laser-based treatment, whereas one study favored low-intensity ultrasound combined with exercise. Ultrasound was superior to TENS in two studies, while one study found no meaningful difference among ultrasound, TENS, and LLLT. No consistent difference was observed between continuous and pulsed ultrasound modes. Among randomized trials, 8 studies were judged as low risk of bias, 8 raised some concerns, and 1 was judged as high risk of bias. Adverse events were reported by only 2 of the 23 studies, so the safety of the intervention could not be characterised. Therapeutic ultrasound may reduce pain and improve mandibular function in patients with temporomandibular disorders, particularly as an adjunct to multimodal rehabilitation; however, the certainty of the evidence is very low for pain and low for mandibular function, pressure pain threshold and quality of life/disability, and the optimal treatment parameters remain undetermined. These findings should not be interpreted as establishing clinical efficacy. Although some comparative studies reported greater pain reduction with LLLT/PBM than with ultrasound, this finding should be interpreted cautiously because the number of studies was small and treatment protocols were heterogeneous. Therefore, current evidence does not establish the superiority of LLLT/PBM over therapeutic ultrasound.