Muscular activity in class III dentofacial deformity

Area of Science:

• Dentofacial Orthopedics
• Biomedical Engineering
• Electromyography

Background:

• Class III dentofacial deformities involve significant morphological and myofunctional changes.
• Accurate diagnosis is crucial for effective surgical-orthodontic treatment planning.
• Understanding muscle electrical activity aids in assessing these deformities.

Purpose of the Study:

• To evaluate the electrical activity of masseter, temporal, and suprahyoid muscles in Class III patients.
• To assess electromyographic (EMG) characteristics using functional tests.
• To compare muscle activity between Class III subjects and a control group.

Main Methods:

• EMG recordings of masseter and temporal muscles during isometric and maximal isometric contractions.
• EMG assessment of suprahyoid and masseter muscles during maximal mouth opening and saliva swallowing.
• Comparison of EMG data between 20 Class III subjects and 10 controls.

Main Results:

• Class III subjects exhibited lower electrical potential in the masseter muscle during isometric contraction (significant difference).
• Maximal isometric contraction showed increased activity in both groups, but remained lower in the Class III group (no significant difference).
• Abnormal EMG tracings during saliva swallowing were frequent in both groups, unexpectedly including the control group.

Conclusions:

• Class III dentofacial deformities are associated with altered muscular activity, specifically reduced masseter potential during isometric contractions.
• No other significant electromyographic peculiarities were identified to differentiate the groups.
• Further investigation into swallowing EMG patterns is warranted, even in controls.