Mandibular border movements: The two envelopes of motion

Area of Science:

• Biomechanics
• Dental Mechanics
• Human Movement Analysis

Background:

• The envelope of motion diagrams mandibular border movements, classically performed eccentrically.
• Concentric development of mandibular border movements has not been previously explored.
• Understanding these movement limits is crucial for defining actual mandibular movement boundaries.

Purpose of the Study:

• To compare the geometric characteristics of eccentric and concentric mandibular border movements in healthy individuals.
• To analyze differences in trajectories, ranges, and areas of mandibular movement envelopes.

Main Methods:

• Sixteen healthy young adults (18-27 years) without temporomandibular disorders participated.
• 3D electromagnetic articulography recorded eccentric and concentric mandibular movements.
• MATLAB processed data to analyze maximum mouth opening, trajectories, displacement ranges, and polygon areas.

Main Results:

• Significant differences were found in all evaluated parameters on the frontal plane.
• Concentric movements showed higher values in the border movement envelope area and trajectories.
• Statistical differences were noted in sagittal plane polygon areas and horizontal plane ranges.

Conclusions:

• Concentric mandibular movements exhibit significant three-dimensional trajectory differences in the frontal plane.
• This research provides new insights into the geometric properties of mandibular border movements.