Comparative Evaluation of the Effectiveness of Ultrasound Heat Therapy, Low-level Laser Therapy and Transcutaneous Electrical Nerve Stimulation in Symptomatic Temporomandibular Disorders: An In vivo Study

Abstract Introduction: Temporomandibular disorders (TMDs) are common musculoskeletal conditions affecting the masticatory system, leading to pain and restricted jaw movement. Various conservative modalities such as transcutaneous electrical nerve stimulation (TENS), low-level laser therapy (LLLT) and ultrasound heat therapy (UST) have shown potential in symptom management. However, direct comparative evidence on their relative efficacy remains limited. Materials and Methods: A prospective randomised study was conducted on 48 patients diagnosed with TMDs, who were equally divided into three groups: UST ( n = 16), LLLT ( n = 16) and TENS ( n = 16). Each participant underwent eight treatment sessions administered twice weekly. Pain intensity was assessed using the Visual Analogue Scale (VAS) and maximum mouth opening (MMO) was measured with a vernier calliper. Data normality was checked using the Shapiro–Wilk test. Repeated measures analysis of variance (ANOVA) evaluated intragroup changes, while one-way ANOVA with post hoc tests compared intergroup differences at a significance level of P < 0.05. Results: All three therapies produced significant improvements in pain reduction and MMO. LLLT demonstrated the greatest effectiveness (VAS: 0.5 ± 1.26; MMO: 40.4 ± 4.02 mm), followed by TENS (VAS: 2.38 ± 1.93; MMO: 38.25 ± 3.44 mm) and UST (VAS: 2.63 ± 1.89; MMO: 36.19 ± 5.62 mm). The differences between LLLT and the other two modalities were statistically significant ( P < 0.05). Conclusion: All non-invasive therapies improved pain and jaw function in TMD patients, but LLLT produced superior outcomes compared to TENS and UST. Hence, LLLT may be considered the preferred conservative treatment for TMD management, with TENS and UST serving as effective alternatives.