Ichihashi M
Department of Pedodontics, Asahi University, School of Dentistry.
Shoni Shikagaku Zasshi. 1990;28(2):432-48.
The purpose of this study was to investigate the changes of the mandibular movement during chewing-gum chewing in subjects ranging from children with deciduous dentition to adults with permanent dentition, and also to analyze the influences of malocclusion on the mandibular movement in children. The subjects were divided into three groups based on the developing stage of the dentition: ie., i) 7 children; mean age 4.6 yrs-with deciduous dentition, ii) 9 children; mean age 9.0 yrs with mixed dentition and iii) 10 adults; mean age 22.9 yrs with permanent dentition. In addition, 17 subjects who have malocclusion were also examined, who were subdivided into the cross-bite group (mean age 7.9 yrs) and progenia group (mean age 7.3 yrs). The mandibular movements were recorded with Saphon Visi-Trainer CII during chewing-gum chewing and the traces of mandibular movement recorded on the sagittal plane were then analyzed. The results obtained in the present study are summarized as follows; 1) The chewing pattern of children with deciduous dentition was characterized by narrow width and large posterior deviation of the opening and closing pathway. During growth, the width of the pathways increased and their posterior deviation decreased. The narrow width of the opening and closing pathways form the majority of the type of chewing pattern in children with deciduous dentition. On the other hand, the types of reversed and crossed pathways form the majority in adults. 2) The chewing pattern in children with malocclusion was characterized by small posterior deviation in the pathway. The type of reversed cycle was ranked first among the chewing patterns of progenia patients, while there were no significant differences of chewing types between cross-bite patients and children with normal occlusion. As far as the results of the present study is concerned, the changes of the mandibular movement on the sagittal plane following the dentitional growth were characteristic indicated. In addition, malocclusion such as cross-bite and progenia observed in the children may influence the chewing pattern.
本研究的目的是调查从乳牙列儿童到恒牙列成人在咀嚼口香糖过程中下颌运动的变化，并分析错牙合对儿童下颌运动的影响。根据牙列发育阶段，将受试者分为三组：即，i）7名儿童，平均年龄4.6岁，乳牙列；ii）9名儿童，平均年龄9.0岁，混合牙列；iii）10名成人，平均年龄22.9岁，恒牙列。此外，还检查了17名有错牙合的受试者，他们被细分为反牙合组（平均年龄7.9岁）和前突组（平均年龄7.3岁）。在咀嚼口香糖过程中，使用Saphon Visi-Trainer CII记录下颌运动，然后分析矢状面上记录的下颌运动轨迹。本研究获得的结果总结如下：1）乳牙列儿童的咀嚼模式特点是开合路径宽度窄且后向偏移大。在生长过程中，路径宽度增加，后向偏移减小。开合路径窄是乳牙列儿童咀嚼模式的主要类型。另一方面，反向和交叉路径类型在成人中占多数。2）错牙合儿童的咀嚼模式特点是路径后向偏移小。在前突患者的咀嚼模式中，反向循环类型排名第一，而反牙合患者与正常咬合儿童之间的咀嚼类型没有显著差异。就本研究结果而言，表明了随着牙列生长矢状面上下颌运动的变化具有特征性。此外，儿童中观察到的反牙合和前突等错牙合可能会影响咀嚼模式。
