Evaluation of internal echogenic pattern of masseter in subjects with myofascial pain/ myositis, oral submucous fibrosis, chewers, bruxers and healthy individuals- a preliminary ultrasonographic study

Statement of the Problem: The masseter is generally involved in myofascial pain, myositis, oral submucous fibrosis [OSMF], bruxism, and in subjects with habitual tobacco/arecanut chewing. In all the above conditions, changes in the internal echogenic pattern on ultrasonography of the muscle may be observed

Purpose: The present study aimed at evaluating the internal echogenic pattern of masseter by ultrasonography in subjects with various conditions affecting master muscle

Materials and Method: The study subjects were categorized into 5 groups consisting of 20 subjects each with the following conditions; Group 1: myofascial pain or myositis, Group 2: oral submucous fibrosis [OSMF], Group 3: habitual chewing of tobacco/arecanut without OSMF, Group 4: bruxism. Group 5 consisted of 20 healthy subjects. An ultrasonographic examination of masseter was performed in all subjects and the echogenic pattern was classified into Types I, II and III. The images were examined by two observers and inter-observer variability was assessed. Differences in internal echogenic pattern between study groups and control group was evaluated using Chi- square test

Results: A good inter observer agreement was noted [k value= 0.8]. An equal distribution of Types II and III echogenic pattern was noted in myofascial pain/myositis group. Type II was predominant in subjects with OSMF, habitual tobacco/arecanut chewing and bruxism. Type I was predominant in controls. The echogenic pattern differed significantly from controls in subjects with myofascial pain/myositis and OSMF [p=0.00001*, 0.0237* respectively], whereas in subjects with habitual tobacco/arecanut chewing and bruxism, it did not differ significantly from controls [p=0.2482, 0.1223 respectively]

Conclusion: Ultrasonographic examination of the echogenic pattern may help in understanding the nature of the disease process affecting the masseter muscle in various conditions

Evaluation of Efficacy of Ultrasonography in the Assessment of Transcutaneous Electrical Nerve Stimulation in Subjects with Myositis and Myofascial Pain

BACKGROUND: The study aimed to determine if ultrasonography of masseter can be used to evaluate the outcome of transcutaneous electrical nerve stimulation (TENS) in subjects with temporomandibular disorders (TMDs) such as myositis and myofascial pain. METHODS: Fifteen TMD subjects with myofascial pain/myositis who satisfied the RDC/McNeil criteria were included in the study. All the subjects were administered TENS therapy for a period of 6 days (30 minutes per session). The mouth opening (in millimeters) and severity of pain (visual analogue scale score) and ultrasonographic thickness of the masseter (in millimeters) in the region of trigger/tender areas was assessed in all the subjects both prior and post TENS therapy. A comparison of the pre-treatment and post-treatment values of the VAS score, mouth opening and masseter thickness was done with the help of a t-test. RESULTS: There was a significant reduction in the thickness of masseter muscle (P = 0.028) and VAS scores (P < 0.001) post TENS therapy. There was also a significant improvement in the mouth opening (P = 0.011) post TENS therapy. CONCLUSIONS: In the present study, ultrasonography was found to be an effective measuring tool in the assessment of TENS therapy in subjects with myositis and myofascial pain.