Effects of Muscular Temporomandibular Disorder on Masticatory Muscles’ Thickness

This study analyzed the impact of muscular temporomandibular disorder (TMD) on masseter and temporalis muscles’ thickness. Eighty subjects (aged 21–60, both male and female) with complete dentition were divided into study (those with muscular temporomandibular disorder, n=40) and control (healthy individuals, n=40) groups. TMD classification was done using the Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD) questionnaire. Ultrasound images (via Sonosite Titan) were used to measure the thickness of masticatory muscles. Images were acquired in two conditions: with the mandibular muscles at rest and with dental clenching at maximum voluntary contraction. Muscle thickness data was tabulated and statistically analyzed (SPSS 22.0; t student test; (p ≤ .05). There were significant statistical differences in temporalis muscle thickness between the two study groups, with lower temporalis muscle thickness in the muscular TMD group. Our findings indicate that muscular TMD changed the morphology of subjects’ temporalis muscles.