Method:
To measure the transmission of vibration, a non-invasive surface vibration measurement system was constructed including a vibration isolated test bench, a scanning laser Doppler vibrometer (SLDV) (PSV-400, Polytec, Tustin, CA) and data acquisition and analysis system. Firstly, to study the transmission of vibration on dentition and skull, following the instruction manual, a dental vibrator – AcceleDent (OrthoAccel Inc.) was placed between the upper and lower dentitions of the dry skull. After the onset of vibration, surface vibrations were recorded at various representative anatomical locations on the dentition (e.g. incisor, cuspid and molar) and the skull (e.g. alveolar bone, condyle, mandibular angular area). The magnitudes and frequencies of these recorded vibrations were compared with that of the original vibration of the device. Secondly, to mimic clinical application, the same device was inserted into a volunteer’s mouth, and the surface vibrations under three different levels of biting forces were recorded at the corresponding spots on the skin of face, and compared with the original device from the device.
Result: On the dry skull, vibration was transmitted from the dental vibrator through the entire skull and NOT consistent by magnitude. In terms of magnitude, most of the distance sites showed a reduced level of vibration, however the mandibular molar region, “Xi” point as well as gonial angle area exhibited higher levels than the device magnitude. On human body, vibration was transmitted from the dental vibrator to the skin surface, far reaching the TMJ area. Biting forces drastically influenced the vibration’s transmission.
Conclusion:
The transmission of vibration from AcceleDent is transmissible and variable. Further studies need to be done to explain the phenomenon of vibration transmission, as well as its possible biological consequences.