Decreased chewing activity during mouth breathing

Area of Science:

• Dentistry
• Physiology
• Biomechanics

Background:

• Mouth breathing is common and can influence craniofacial development and dental occlusion.
• The functional impact of mouth breathing on masticatory forces and their effect on posterior teeth is not fully understood.

Purpose of the Study:

• To investigate the effects of mouth breathing on the strength and duration of the vertical effect on posterior teeth during gum chewing.
• To compare masticatory functional parameters between nasal and mouth breathing.

Main Methods:

• 39 healthy nasal breathers underwent a 3-minute gum chewing protocol.
• Electromyographic (EMG) activity of the masseter muscle was recorded during nasal breathing and with occluded nostrils (simulating mouth breathing).
• Strength and duration of the vertical effect were quantified using integrated EMG activity, chewing stroke count, chewing cycle variation, and EMG activity duration.

Main Results:

• Mouth breathing led to a significant decrease in integrated EMG activity and EMG activity duration above baseline.
• Chewing stroke count and chewing cycle duration were significantly reduced during mouth breathing.
• Chewing cycle variance increased significantly during mouth breathing compared to nasal breathing.

Conclusions:

• Mouth breathing diminishes the vertical effect on posterior teeth.
• Reduced masticatory forces and altered chewing patterns associated with mouth breathing may negatively affect the vertical position of posterior teeth.
• This could be a contributing factor to the development of malocclusion.