The buccinator during mastication: A functional and anatomical evaluation in minipigs

Area of Science:

• Oral anatomy and physiology
• Biomechanics of mastication

Background:

• The buccinator muscle forms the oral cavity's lateral wall.
• Its role in mastication, particularly bolus control and potential effects on occlusion, is presumed but not demonstrated.
• Buccinator deformation and pressure effects on alveolar bone remain unquantified.

Purpose of the Study:

• To evaluate buccinator electromyography (EMG) during feeding.
• To assess buccinator length and thickness changes.
• To measure pressure exerted on the buccinator's alveolar attachment in miniature pigs.

Main Methods:

• Fine-wire electrodes for buccinator and oral muscle EMG.
• Sonomicrometry crystals for muscle length and thickness.
• Pressure transducers at the mandibular origin.
• Recordings during feeding and muscle stimulation, with postmortem histology.

Main Results:

• Buccinator EMG peaked before jaw closers during mastication, with distinct patterns for working and balancing sides.
• The buccinator shortened and thickened upon contraction.
• Positive pressures were detected at the mandibular attachment, increasing with muscle activity.
• Histology revealed complex fiber interweaving associated with salivary tissue.

Conclusions:

• Buccinator contraction thickens the cheek, initiating just before the jaw closing stroke.
• The muscle likely aids in bolus control and may influence salivation.
• Despite muscle tension, positive pressure is exerted on the alveolar bone attachment.