Soniya Yaghoubi - Department of Physiotherapy, University of Social Welfare and Rehabilitation Sciences, Tehran, Iran.
Zahra Mosallanezhad - Department of Physiotherapy, University of Social Welfare and Rehabilitation Sciences, Tehran, Iran.
Hamid Reza Mokhtarinia - Department of Physiotherapy, University of Social Welfare and Rehabilitation Sciences, Tehran, Iran.
Charles Philip Gabel - Access Physiotherapy, Coolum Beach, Australia.

Objectives: A sonographic approach can be used to quantify joint movement, muscle thickness, and available joint space. This study aimed to compare the amount of mouth opening, joint articular distance, and both anterior and inferior translation of the mandibular condyle between healthy participants and individuals with temporomandibular joint (TMJ) disorders. Methods: A cross-sectional study design was used with ۵۲ participants (control: ۲۶ healthy and TMJ: ۲۶ symptomatic individuals) recruited using convenience sampling. The joint space distance and the anterior and inferior condylar translation on both sides were evaluated using sonography during maximum mouth opening and closing. Mouth opening was measured with a graduated ruler. Reliability was performed on a subgroup (n=۱۰) with an interval of ۳-۷ days. Results: The reliability was good to excellent (ICC=۰.۵۷-۰.۹۴). The highest reliability was related to the joint space distance. The mean values for mouth opening were ۴۳.۱ and ۳۵.۳mm, respectively for healthy and TMJ patients. The anterior condylar translation was ۷.۱۴-۷.۵۷mm, inferior condylar translation was ۲.۳۵-۲.۶۶mm, and the joint space distance was ۴۹.۴-۰.۴۴mm. No significant differences were found between the left and right sides in either group. The mouth opening and joint space values were significantly higher in the healthy group while the rate of anterior transition movement was higher but not significant. Furthermore, there was a significant negative relationship between pain, mouth opening, and joint distance. Discussion: Sonography can be considered an accurate tool for the assessment of joint space and condylar translation in individuals with symptomatic TMJ disorders.

Ultrasonography, Reliability, Temporomandibular joint disorders, Translatory motions