Abstract
The purpose of this study is to examine the mandibular movement during gum chewing of the children with deciduous dentition and to compare with those of adults, and also to analyze the influences of malocclusion on the masticatory movement of children.
The subjects were devided into three groups, based on the types of dentition, i) 10 children; mean age 4y7m with deciduous dentition (designated as d. d. ), ii) 10 children; mean age 8y4m with mixed dentition (designated as m. d. ) and iii) 10 adults; mean age 21y6m with permanent dentition (designated as p. d. ). In addition 20 subjects having malocclusion cross-bite; mean age 6y11m m and progenie; mean age 7y2m during mixed dentition. The mandibular movemenets was recorded with Saphon Visi-Trainer C II during gum chewing and the traces of mandibular movement recorded on the frontal plane were analyzed.
The results obtained in the present study are summarized as follows,
1) The chewing pattern of children with d. d. was characterized by large lateral deviation to working side and narrow width of opening and closing pathway. During growth, the lateral deviation of both the maximum opening position and the maximum lateral position of the mandibule is decreased, and the width of the opening and closing pathway is incresed. The type of chewing for children with d. d. was characterized by chopping, while the children with m. d. and adults was characterized by grinding.
2) The chewing pattren of the children with malocclusion was generally characterized by a midsagittal opening and closing pathway, and a narrow width of the opening and closing pathway. The children with cross-bite represent chopping type predominantly.
As far as the results of the present study is concerned, the alteration of chewing following the dentitional growth could be suggested. In addition, malocclusion such as crossbite or progenie observed in the children may affect the chewing pattern. The proposed method in the present study is considered to be appropriate to evaluate the mandibular movement in children.
