Masseter Deoxygenation in Adults at Risk for Temporomandibular Disorders.

Area of Science:

• Biomedical Engineering
• Physiology
• Dental Research

Background:

• Muscular temporomandibular disorder (TMD) is associated with abnormal jaw muscle oxygenation.
• The deoxygenation patterns in healthy individuals at risk for TMD, specifically those with frequent wake-time tooth-clenching, remain understudied.

Purpose of the Study:

• To investigate and compare the deoxygenation patterns of the masseter muscle during standardized tasks in TMD-free individuals with high versus low self-reported frequency of wake-time tooth-clenching.

Main Methods:

• A case-control study involving 255 university students who completed the Oral Behavior Checklist.
• Fourteen female participants were categorized into high parafunctional (HP) and low parafunctional (LP) groups based on their scores.
• Near-infrared spectroscopy measured tissue oxygen saturation (StO2) and hemoglobin changes in the masseter during maximum voluntary contraction (MVC) and prolonged low-intensity clenching tasks.

Main Results:

• Significant interaction effects between task and study group were observed for all outcome measures, indicating distinct deoxygenation patterns between HP and LP groups.
• The HP group showed a significantly greater reduction in StO2 during MVC compared to the LP group.
• Blood flow increase during prolonged clenching was substantially higher in the LP group than in the HP group, suggesting impaired blood flow regulation in those at risk for TMD.

Conclusions:

• Healthy individuals with frequent wake-time tooth-clenching, a risk factor for TMD, demonstrate abnormal masseter muscle deoxygenation.
• These findings highlight potential physiological differences in at-risk individuals and warrant further investigation into their role in TMD development.