Southard T E, Southard K A, Stiles R N
Department of Orthodontics, University of Tennessee, Memphis 38163.
J Biomech. 1990;23(12):1199-207. doi: 10.1016/0021-9290(90)90377-f.
We hypothesized that the anterior component of occlusal force (ACF) generated by mandibular molars was a function of molar inclination, height of the transverse condylar axis above the occlusal plane, steepness of the occlusal plane, gape, molar root dimensions, interproximal tooth contact force when not biting, and bite force. Our research aim was to identify those biomechanical factors which determine ACF. Mandibular second molars were axially loaded with a 90 N force (10 mm second molar gape) in 15 subjects, and the resulting ACF was measured at the mandibular first molar-second premolar contact using a recording technique based on interproximal frictional forces. Morphologic measurements were obtained from lateral cephalometric radiographs of each subject and included: Frankfort mandibular plane angle, occlusal plane angle, angles formed by the longitudinal axis of the second molar and the occlusal and mandibular planes, perpendicular distance from the top of the condyle to the occlusal plane, and second molar root width and root length. For ten subjects, ACF resulting from axial loads of 50, 100, 150, and 200 N was measured. For ten subjects, ACF resulting from an axial load of 50 N and second molar gapes of 10 mm, 14 mm, 18 mm, and 22 mm were measured. ACF increased with increasing gape and increased proportionally to increasing bite force. Correlation and stepwise regression analyses revealed that ACF varies with interproximal tooth contact force when not biting (contact 'tightness') and molar root width (model R2 = 0.71, p less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)
我们假设下颌磨牙产生的咬合力前向分量（ACF）是磨牙倾斜度、髁突横轴高于咬合平面的高度、咬合平面的陡度、张口度、磨牙牙根尺寸、非咬合时邻牙间接触力以及咬合力的函数。我们的研究目的是确定那些决定ACF的生物力学因素。在15名受试者中，对下颌第二磨牙施加90 N的轴向力（第二磨牙张口度为10 mm），并使用基于邻牙间摩擦力的记录技术在下颌第一磨牙 - 第二前磨牙接触点测量由此产生的ACF。从每位受试者的头颅侧位X线片获取形态学测量数据，包括：法兰克福下颌平面角、咬合平面角、第二磨牙纵轴与咬合平面和下颌平面形成的角度、髁突顶部到咬合平面的垂直距离以及第二磨牙牙根宽度和长度。对10名受试者测量了50、100、150和200 N轴向载荷产生的ACF。对10名受试者测量了50 N轴向载荷以及10 mm、14 mm、18 mm和22 mm第二磨牙张口度产生的ACF。ACF随张口度增加而增加，且与咬合力增加成比例。相关性和逐步回归分析表明，ACF随非咬合时邻牙间接触力（接触“紧密度”）和磨牙牙根宽度而变化（模型R2 = 0.71，p小于0.01）。（摘要截断于250字）
