Related Experiment Video
Updated: Mar 17, 2026
In Vivo Functional Assessment of Rat Masseter Muscle Following Surgical Creation of a Volumetric Muscle Loss (VML) Injury
Published on: November 15, 2024
Patients with myogenic temporomandibular disorders have reduced oxygen extraction in the masseter muscle
Claudia Lúcia Pimenta Ferreira1, Giuseppe Bellistri1,2, Stefano Montagna3
1Department of Biomedical Sciences for Health, Functional Anatomy Research Center (FARC), Università degli Studi di Milano, via Luigi Mangiagalli 31, 20133, Milan, Italy.
Objective:
The objective of the present study is to investigate if changes in the oxygen saturation of masseter muscle during a chewing task can differentiate patients with myogenic temporomandibular disorders (TMD) from healthy subjects and if these differences are related to the gravity of the disorder and to the orofacial myofunctional status.
Materials And Methods:
Twelve women with moderate TMD (TMD group; 37 ± 16 years) and ten healthy control women (CTRL group 24 ± 5 years) participated. Validated protocols were used to evaluate the severity of TMD and the orofacial myofunctional status. Oxygen saturation in the masseter muscle was measured using near-infrared spectroscopy (NIRS) during unilateral chewing of a silicon device. Data were compared using Student's t test, Mann-Whitney test, and Spearman's rank correlation coefficient.
Results:
The women of the TMD group showed higher total score of severity of symptoms of TMD, lower total score of the orofacial myofunctional status, and lower oxygen extraction capacity during mastication than healthy control subjects (p < 0.01). Moreover, percentage O2 extraction was significantly related to the severity of signs/symptoms of TMD and of orofacial myofunctional disorders (p < 0.01).
Conclusion:
Women with TMD had a lower muscle oxygen extraction capacity than healthy subjects: the higher the signs and symptoms' severity, the lower the O2 extraction. NIRS proposes as an important instrumental method to assess the metabolic alterations in the muscles of patients with TMD.
Clinical Relevance:
The findings could be useful to complement clinical assessments, favoring the diagnosis and providing extra data for planning the rehabilitation of TMD patients, especially those with associated myofunctional orofacial disorders.
Related Concept Videos
01:28Disorders of the Skeletal Muscle
Musculoskeletal disorders
Musculoskeletal disorders involve injuries and conditions affecting the skeletal muscles and associated connective tissues. These disorders can arise from acute biomechanical stresses or chronic overuse and can occur across different age groups. Common injuries include sprains, fractures, and muscular strains, often resulting from...
01:14Muscles for Facial Expressions
01:29Relaxation of Skeletal Muscles
When an action potential reaches the axon terminal, it depolarizes the membrane and opens voltage-gated sodium channels. Sodium ions enter the cell, further depolarizing the presynaptic membrane. This depolarization causes voltage-gated calcium channels to open....
01:28Classification of Skeletal Muscle Relaxants
Peripherally acting skeletal muscle relaxants interfere with the neurotransmission at the neuromuscular end plate to induce paralysis during...
01:26Directly Acting Muscle Relaxants: Dantrolene and Botulinum Toxin
The binding of dantrolene to the RYR1...
01:21Mechanism of Breathing III: The Accessory Muscles
The respiratory system is a complex network that relies on primary respiratory muscles like the diaphragm, but also involves accessory muscles to enhance lung expansion and airflow during both inhalation and exhalation.
Enhancing Inhalation with Accessory Muscles:
Accessory muscles such as the sternocleidomastoid, scalene, intercostal, and abdominal muscles are crucial when additional respiratory effort is required, such as during deep...