A comparison of centric relation with maximum intercuspation based on quantitative electromyography

Area of Science:

• Dental Science
• Biomechanics
• Neuromuscular Dentistry

Background:

• The relationship between jaw position and muscle activity is crucial in dentistry.
• Maximum intercuspation and centric relation are key maxillo-mandibular positions.
• Understanding muscle activity variations is essential for effective clinical therapy.

Purpose of the Study:

• To investigate alterations in muscle activity during the shift from maximum intercuspation to centric relation.
• To quantify muscle activity changes in masseter and temporal muscles.
• To assess the clinical implications of using centric relation as a reference position.

Main Methods:

• Electromyography (EMG) using an integrator-averager to measure micro V average amplitude.
• Assessment of masseter and temporal muscles in two jaw positions: centric relation and maximum intercuspation.
• Data collection across three functional modes: first contact occlusion, chewing, and swallowing.

Main Results:

• A statistically significant increase in micro V (muscle activity) was observed in all centric relation positions.
• Analysis of variance yielded an F value of 5.88258 (p=0.005).
• Quantification of horizontal deviation from maximum intercuspation to centric relation was performed.

Conclusions:

• Centric relation positions demonstrate significantly altered muscle activity compared to maximum intercuspation.
• The findings indicate potential limitations in relying solely on centric relation for clinical dental therapy.
• Further research may be needed to refine the use of jaw relation positions in treatment planning.