ligning both upper and lower posterior teeth with the principal direction of muscle contraction produces the greatest resistance to masticatory forces and creates the inclinations that form the curve of Wilson (wilson 曲线)。
There are two reasons for the inclination倾斜 of posterior teeth后牙. One has to do with resistance to loading; second has to do with masticatory function. If the buccolingual颊舌侧 inclination of posterior teeth is analyzed in relation to the dominant direction of muscle force against them, it will be apparent that the axial alignment of all posterior teeth is nearly parallel with the strong inward pull of medial pterygoid muscles翼内肌. The strongest component of lateral横向的 function occurs nearly parallel with the direction of medial pterygoid muscles翼内肌, which bilaterally双侧 pull the condyles髁突 medially to the midmost position of centric relation.双侧拉髁突向正中关系位的正中位置 Aligning both maxillary 上颌and mandibular posterior teeth 下颌后牙with the principal direction of muscle contraction produces the greatest resistance to masticatory forces and creates the inclinations that form the curve of Wilson wilson曲线.
When the curve of Wilson is made too flat平, ease of masticatory function may be impaired because of the increased activity required to get the food onto the occlusal table.合平面 The greater the relative height of mandibular lingual cusps下颌舌尖, the greater the problem of chewing efficiency may become. If the lingual cusps of mandibular posteriors assume a position above the optimum level, the thrusting of food bolus by the tongue toward the occlusal table合平面 will be impaired. Furthermore, if the buccal cusps of maxillary posteriors were to assume a position below the optimum level, the action of the buccinator muscle to push the food bolus toward the occlusal table, would be similarly affected. In both these conditions, the curve of Wilson gets altered, and masticatory efficiency is jeopardized. With a large lateral occlusal curvature (substantial lingual inclination of the mandibular molars), the inclinations of the inside slope of the mandibular buccal cusp against the horizontal plane increases, making interfering occlusal contacts of the nonworking side possible. Thus, during mandibular movement, abnormal periodontal sensation, and muscle tension could be caused by a geometric limitation, especially at the distal of the arch.
The fourth key is related to the curve of Wilson,describing the posterior inclination of the crowns of the posterior upper teeth as a concave curve, setting the mo-lars with a lingual torque.
第一单词是Aligning