The delay time of tooth vibration signal recorded at facial skin surface

The onset of a tooth vibration signal with a mini acceleration pickup attached to the skin on the forehead was delayed by 0.1788 ms on average after the actual tooth impact. When the signal was recorded at the zygomatic arch, the delay time was 0.1008 ms on average, which was significantly shorter than that obtained from the forehead (P less than 0.001). The difference due to a transposition of the vibrated tooth was also smaller (0.025 less than P less than 0.05) and had almost no effect on the intensities of the tooth flipping force. The delay time was even more prolonged when a poor frequency specification pickup and/or low pass filter were applied.