THE RHYTHMS OF HUMAN PREMOLAR ERUPTION - A STUDY USING CONTINUOUS OBSERVATION

New optical technology now allows for precise observation of erupting human premolars. Continuous overnight tracking of an erupting tooth wi th a video microscope system shows that eruption occurs almost exclusi vely during the early evening. During the day, slight intrusion is lik ely to occur. When Moire magnification is used to provide extremely hi gh resolution (0.05 micrometer), slight movements of the erupting toot h in concert with the arterial pulse can be observed, and a previously unknown cyclic movement with a period of 20 to 50 seconds is seen con sistently. Rhythms in skeletal growth and tooth eruption suggest that treatment to influence jaw growth and move teeth may be most effective at specific times of the day.