Proposing an Optimal Occlusal Angle for Minimizing Masticatory and Cervical Muscle Activity in the Supine Position: A...

Area of Science:

• Biomechanics
• Ergonomics
• Physiology

Background:

• The occlusal angle (OA), influenced by pillow height, may impact head and neck muscle tension.
• Defining the optimal OA range for minimizing muscle activation is crucial but not well-established.

Purpose of the Study:

• To investigate the effects of OA on resting muscle activity in masticatory and cervical muscles.
• To identify an optimal OA range for reduced muscle activation using advanced statistical methods.

Main Methods:

• Muscle activities of masseter (MAS), temporalis (TEM), sternocleidomastoid (SCM), and posterior vertebral muscles (PVM) were measured.
• OA was modulated via pillow heights (0, 5, 10 cm) in the supine position.
• Statistical analyses included ANOVA, ROC curve analysis, k-means clustering, and linear mixed-effects models.

Main Results:

• Increased OA values significantly elevated MAS and TEM resting muscle activity ratio (RMR).
• SCM muscle activation decreased with larger OA values (p = 0.001).
• A low-activity cluster centered at 105°-111° OA was identified; 138° OA indicated potential muscular overload.

Conclusions:

• Pillow height-modulated OA is a modifiable factor influencing muscle activity.
• An OA range of 105°-111° may represent a practical comfort zone.
• This range could be particularly beneficial for individuals susceptible to temporomandibular disorders (TMDs).