Comparison of dynamic occlusal contacts during chewing between children with primary dentition and normal adult females

Objective: Investigation of dynamic occlusal contacts when food particles are being pulverized during chewing is of interest for many researchers and clinicians. However, measurement of dynamic occlusal contacts during chewing is difficult, and differences between children and adults have not been established. The purpose of this study is to test the hypothesis that dynamic occlusal contacts of children differ from those of adult females. Subjects: and methods: Thirteen healthy children (4-6 years of age; mean age 5 years, 7 months) and thirteen adult females (18-26 years of age; mean age 20 years, 7 months) with normal occlusion participated in this study. Occlusal contact area (OCA) was estimated with a developed measurement system combining 3-D digitization of tooth shape with 3-D tracking of mandibular movements (1) during the closing stroke, (2) at the maximum closing position (MCP), and (3) during the opening stroke. OCA at static maximum intercuspation (ICP) was also estimated. Results: At the MCP, the children's OCA was less than 76.4% of the contact area seen at the ICP. The timing of maximum OCA in children was shifted more towards the opening stroke compared with adults, and the OCA remained greater during opening in children than adults. The occurrence of the MCP was less stable in children than in adults, both between subjects and within subjects. Conclusions: We conclude that both the amount of OCA and the pattern of occlusal contacts during the occlusal phase of chewing completely differ between children and adult females. (C) 2019 Japanese Society of Pediatric Dentistry. Published by Elsevier Ltd. All rights reserved.