Department of Paediatric Dentistry, Field of Developmental Medicine, Course for Health Sciences, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan.
J Oral Rehabil. 2010 Jan;37(1):26-33. doi: 10.1111/j.1365-2842.2009.02006.x. Epub 2009 Oct 27.
The purpose of this study was to clarify whether the reverse cycle during chewing is abnormal in children with primary dentition. Children with normal primary dentition (N = 23; 5.5 +/- 0.8 years) and female adults (N = 25; 20.7 +/- 1.9 years) participated in this study. Chewing movement was recorded using an opto-electronic analysis system with six degrees-of-freedom (TRI-MET, Tokyo-shizaisha; Tokyo, Japan). Each subject was given a stick of chewing gum (new TRIDENT, WARNER-LAMBERT CO., Morris Plains, NJ, USA) and instructed to chew it normally. Starting from the maximum intercuspal position, each chewing sequence was recorded over a period of 20 s. A custom computer program identified individual chewing cycles. Frontal views were used to distinguish seven types of cycle shapes according to Ahlgren (Acta Odontol Scand, 24, 1966, 1-109; Acta Odontol Scand, 25, 1967, 3-13). Multilevel statistical models evaluated differences between children and adults. In the adults, type II cycles that initially opened towards the balancing side and then moved towards the working side were the most common, and the closing pathway was lateral to the opening pathway. In the children, type V (reverse) cycles that opened towards the working side were most common, the closing pathway was medial to the opening pathway, and there was a smaller lateral component during opening and closing than in adults (P < 0.05). We conclude that the reverse cycle is not abnormal because normal children with primary dentition have a smaller lateral component and difficulty in controlling asymmetric muscle activity.
本研究旨在阐明儿童乳牙期咀嚼时反循环是否异常。本研究纳入了具有正常乳牙（N=23；5.5±0.8 岁）和成年女性（N=25；20.7±1.9 岁）的儿童参与。咀嚼运动使用具有六自由度的光电分析系统（TRI-MET，东京世扎沙；东京，日本）进行记录。每位受试者被给予一根咀嚼口香糖（新的 TRIDENT，华纳-兰伯特公司，莫里斯平原，新泽西州，美国），并被指示正常咀嚼。从最大牙尖交错位开始，每个咀嚼序列记录 20 秒。自定义计算机程序识别每个咀嚼周期。根据 Ahlgren（《牙科学杂志》，24，1966，1-109；《牙科学杂志》，25，1967，3-13），使用前视图根据 Ahlgren 区分七种类型的循环形状。多层次统计模型评估了儿童和成人之间的差异。在成年人中，最初向平衡侧开口然后向工作侧移动的 II 型循环最常见，闭合路径位于开口路径的外侧。在儿童中，最常见的是 V 型（反向）循环，开口朝向工作侧，闭合路径位于开口路径的内侧，并且在开口和闭合期间侧向分量比成年人小（P<0.05）。我们得出结论，反循环并不异常，因为具有正常乳牙的正常儿童侧向分量较小，控制非对称肌肉活动的能力也较差。
