Ultrasound Elastography in Temporomandibular Disorders: A Narrative Review

A class of intricate musculoskeletal diseases known as temporomandibular disorders (TMDs) affects the temporomandibular joint (TMJ) and its supporting structures. The majority of individuals will at some point in their lives experience some degree of TMD symptoms, as these diseases are highly prevalent in the general population. TMDs are multifactorial and are attributed to various physical and biopsychosocial factors. The TMD patients typically experience preauricular pain, tenderness of masticatory muscles, and joint sounds, and these in turn affect their quality of life. To carry out the appropriate course of treatment, it is critical to make an accurate and timely diagnosis. The TMDs are classified as myofascial pain, internal disc derangement, and degenerative disorders of TMJ. Myofascial pain, which is identified by palpating the affected muscles of mastication and tenderness, is one of the most common findings. The muscles in this condition become stiff due to the contraction of myofibrils and are known as trigger bands. The diagnosis of trigger bands involving the masticatory muscles commonly involving the masseter muscle in myofascial pain to date is subjective, and palpation is the only tool used for its diagnosis. An objective assessment of the masticatory muscles is desirable for accurate diagnosis and treatment planning. Various tools like electromyography and hardness meters have been for assessing muscle stiffness, but their application in TMJ muscle disorders has not yielded valuable results. A novel diagnostic method called ultrasound elastography evaluates muscle stiffness both qualitatively and quantitatively using an elastogram and the muscular elasticity index. In this paper, we will review the ultrasound elastographic techniques utilized for the diagnosis and management of TMDs.