Department of Masticatory Function Rehabilitation, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8549, Japan.
Arch Oral Biol. 2013 Jun;58(6):674-80. doi: 10.1016/j.archoralbio.2012.12.006. Epub 2013 Jan 4.
Occlusal curvatures such as the curve of Spee, curve of Wilson and Monsons's sphere exist in the human adult mandibular arch. A previous study showed that human young adults with flatter occlusal curvatures had higher ability of food comminution and mixing. The aim of this study was to clarify functional significance of occlusal curvatures in terms of masticatory movements. This study investigated the association between occlusal curvature and mandibular movements while chewing a variety of food items.
Forty-six young adults with complete dentitions (mean age, 25.0 years) participated in the study. Sphere radius of occlusal curvature was determined by a three-dimensional analysis of the mandibular arch based on the Broadrick flag method. Mandibular movements during unilateral chewing of six test food items (chewing gum, cheese, kamaboko, boiled beef, gummy jelly and raw carrot) until the subjects felt ready to swallow were recorded using a six-degrees-of-freedom mandibular movement recording system, and 11 parameters for masticatory movements of a lower incisal point of the mandible were analysed.
Linear regression analyses identified the sphere radius as a significant predictor for closing velocity in all test food items, occluding/cycle duration in 3 items, opening velocity, closing duration and chewing time in 2 items, and opening duration in 1 item (P<0.01). The results suggest that subjects with larger sphere radius (flatter occlusal curvature) in the mandibular arch could prepare food bolus effectively for swallowing.
Occlusal curvature seems to be associated with masticatory movements in young adults with permanent dentition.
人类下颌弓存在诸如 Spee 曲线、Wilson 曲线和 Monson 球等咬合曲线。先前的研究表明，咬合曲线较平坦的年轻成年人具有更高的食物粉碎和混合能力。本研究旨在从咀嚼运动的角度阐明咬合曲线的功能意义。本研究调查了咀嚼各种食物时咬合曲率与下颌运动之间的关系。
46 名具有完整牙列的年轻成年人（平均年龄 25.0 岁）参加了这项研究。根据 Broadrick 标志法，通过对下颌弓的三维分析确定了咬合曲率的球半径。使用六自由度下颌运动记录系统记录了 6 种测试食物（口香糖、奶酪、鱼糕、煮牛肉、胶状果冻和生胡萝卜）单侧咀嚼时下颌的运动，直到受试者感觉可以吞咽为止，并分析了下颌切牙点的 11 个咀嚼运动参数。
线性回归分析确定球半径是所有测试食物的闭合速度、3 种食物的闭牙/循环时间、2 种食物的开口速度、闭合时间和咀嚼时间、1 种食物的开口时间的显著预测因子（P<0.01）。结果表明，下颌弓中球半径较大（咬合曲线较平坦）的受试者可以有效地为吞咽准备食物团块。
在具有恒牙列的年轻成年人中，咬合曲率似乎与咀嚼运动有关。
