Inaudible temporomandibular joint vibrations

Area of Science:

• Biomechanics
• Biomedical Engineering
• Orthodontics

Background:

• Temporomandibular joint (TMJ) sounds are often associated with joint dysfunction.
• The energy content and frequency characteristics of TMJ vibrations are not fully understood, particularly in the inaudible spectrum.

Purpose of the Study:

• To investigate the presence and characteristics of inaudible vibrations in the temporomandibular joint (TMJ) area.
• To determine if vibration energy increases during jaw movements.
• To compare vibration patterns between subjects with and without audible TMJ sounds.

Main Methods:

• Utilized accelerometers to record vibrations in the TMJ area during jaw movements and rest.
• Employed power spectral analysis and t-tests to analyze vibration data across audible and inaudible frequency bands.
• Included subjects with and without audible TMJ sounds, assessed via conventional auscultation.

Main Results:

• Significant amounts of vibration energy were detected in the inaudible range (< 20 Hz) during both jaw movements and rest in all subjects.
• Vibration energy, both audible and inaudible, significantly increased during jaw movements in both groups.
• A higher percentage of signal energy above 20 Hz was observed in subjects with audible TMJ sounds, potentially due to decreased damping in damaged tissues.

Conclusions:

• Inaudible vibrations are a common finding in the TMJ area, irrespective of audible joint sounds.
• Increased vibration energy during jaw movement is a consistent observation.
• Further research is warranted to explore the diagnostic potential of these inaudible vibrations in TMJ disorders.