Abstract
The quality of occlusal contact during chewing is thought to be critical for effective breakdown of food and numerous studies have used a variety of methods to determine that. Although those methods are relatively easy to apply and evaluate in a clinical setting, those contacts were measured in previous studies only in the maximum intercuspal position (ICP) rather than during masticatory function. Most clinicians consider that the maximum closing position (MCP) during chewing coincides with ICP, though that has not been tested, since it would be necessary to record occlusal contacts at all mandibular positions during mastication. In the present study, we examined the differences in mandibular position and occlusal contact area (OCA) between the MCP and ICP during chewing with use of a measurement system that combines 3-D tracking of mandibular movements with 3-D digitization of tooth shapes.We enrolled female children and adult subjects. The three-dimensional distance between the ICP and MCP at the incisor position in children was significantly larger than that in adults. At the MCP,the OCA in children was less than 77% of the contact area seen at the ICP. Also, the timing of maximum OCA in children was shifted more towards the opening stroke as compared with adults and the OCA remained greater during opening in children. Occurrence of MCP was less stable in children than in adults, both between and within the subjects. We concluded that both the amount of OCA and pattern of occlusal contacts during the occlusal phase of chewing are significantly different between children and adult females.
