Computer-based assessment of habitual mastication.

Area of Science:

• Biomechanics
• Neuroscience
• Physiology

Background:

• Understanding the complex mechanics of mastication is crucial for diagnosing and treating orofacial disorders.
• Previous methods for analyzing chewing patterns were limited in their ability to capture dynamic movements and muscle activity simultaneously.

Purpose of the Study:

• To develop and validate a computer-based system for assessing mandibular movements and electromyographic (EMG) activity of masticatory muscles during habitual chewing.
• To analyze the rhythmic nature and individual variability of chewing cycles.

Main Methods:

• A computer system integrated a Siemens Sirognatograph for mandibular movement recording and surface EMG electrodes for masseter and temporal muscle activity.
• Twelve healthy subjects chewed a standardized crisp bread bolus, with data analyzed for single cycles, mean displacements, velocities, and EMG patterns.
• Mandibular movement paths (clockwise and counterclockwise) and temporal EMG data were computed.

Main Results:

• Habitual mastication exhibits a characteristic rhythmic pattern with distinct, alternating envelopes of motion specific to each individual.
• Chewing cycles can be individualized, with patterns influenced by the distribution of different motion envelopes.
• Distinct isotonic and isometric phases were identified during the muscle contraction cycle.
• Group data showed non-random, typical patterns in mean movement and EMG activity, suggesting a well-balanced functional system.

Conclusions:

• The developed system effectively characterizes individual chewing patterns and muscle activity.
• Habitual mastication is a highly regulated and individualized rhythmic process.
• The masticatory system demonstrates a balanced functional design for load distribution.