Kinematics of the tooth tapping movement

Area of Science:

• Biomechanics
• Neurophysiology
• Dental Mechanics

Background:

• Understanding the dynamics of jaw movements during mastication and parafunctional activities is crucial.
• The interplay between muscle electrical activity, jaw kinematics, and tooth contact is complex.

Purpose of the Study:

• To analyze the effects of different tooth tapping frequencies on masseter muscle electrical activity and jaw movement phases.
• To investigate how tapping frequency influences jaw velocity, contact duration, and muscle electrical activity cessation.

Main Methods:

• Simultaneous recording of masseter muscle electrical activity and tooth contact vibrations.
• High-speed cinephotography used for kinematic analysis.
• Analysis of distinct phases: tooth contact phase (TCP), opening phase (OP), and closing phase (CP).

Main Results:

• Increased tapping frequency reduced the durations of TCP, OP, and CP.
• Jaw velocity immediately preceding tooth contact did not increase with frequency.
• Electrical activity duration post-contact was significantly shorter at higher frequencies.
• Average jaw speed increased due to a more abrupt transition from OP to CP.

Conclusions:

• Higher tooth tapping frequencies alter the temporal characteristics of jaw muscle activity and movement.
• The cessation of electrical activity and subsequent jaw opening are influenced by masseter muscle relaxation time.
• Findings provide insights into the neuromuscular control of rapid jaw movements.