Positions of the mandible during chewing and swallowing recorded by light-emitting diodes.

The Selspot system has been developed to record mandibular movements with LED. The aim has been to make a system that is easy to manipulate and permits chewing performance with only minimal mechanical interferences. This study was performed to obtain information on the suitability of the Selspot system for collecting data on the cranial position of the mandible during chewing and swallowing. The results coincided with reports by others using different methods, and the suitability of the system was regarded as good for studying occlusal position during function. The following conclusions could be drawn from the results: 1. In the sagittal plane the chewing activity was performed in a more anterior position than the swallowing contact position. 2. The lateral and vertical cranial position is unstable in the beginning of the chewing period but stabilizes to the occlusal position in the latter half of the chewing period. 3. The occlusal position during chewing does not seem to be a single position but rather a three-dimensional occlusal zone.