Southard T E, Southard K A, Tolley E A
Department of Orthodontics, University of Tennessee, Memphis 38163.
J Dent Res. 1990 Nov;69(11):1776-9. doi: 10.1177/00220345900690111301.
In order to investigate the role played by posture in determining posterior dental contact tightness, we measured contact tightness of maxillary and mandibular posterior teeth in ten adult subjects, while each was initially seated upright, after each had assumed a supine posture for two h, and finally after each had returned to an upright posture for two h. The technique used for measurement of contact tightness was based on frictional force concepts and consisted of the recording of the force required to withdraw a 0.038-mm-thick stainless-steel strip that had been slipped into each contact. A decreased mean tightness of all maxillary and mandibular contacts followed the change from an upright to a supine posture. The most significant decrease (-32%) occurred at the mandibular first molar-second premolar contact, and the smallest decrease (-10%) occurred at the mandibular first premolar-canine contact. An increased mean tightness of all maxillary and mandibular contacts followed a return to an upright posture. The most significant increase (20%) occurred at the maxillary first molar-second premolar contact, and the smallest increase (8%) occurred at the maxillary first premolar-canine contact. We conclude that posterior dental contact tightness, generally regarded by dentists as a static feature of occlusion, varies significantly as a function of posture.
为了研究姿势在确定后牙接触紧密性方面所起的作用，我们测量了10名成年受试者上颌和下颌后牙的接触紧密性，测量时间分别为每位受试者最初直立坐姿时、仰卧姿势两小时后以及最终再次恢复直立姿势两小时后。用于测量接触紧密性的技术基于摩擦力概念，包括记录将一条0.038毫米厚的不锈钢条滑入每个接触点后抽出所需的力。从直立姿势变为仰卧姿势后，所有上颌和下颌接触点的平均紧密性均降低。最显著的降低（-32%）发生在下颌第一磨牙-第二前磨牙接触点，最小的降低（-10%）发生在下颌第一前磨牙-尖牙接触点。恢复到直立姿势后，所有上颌和下颌接触点的平均紧密性增加。最显著的增加（20%）发生在上颌第一磨牙-第二前磨牙接触点，最小的增加（8%）发生在上颌第一前磨牙-尖牙接触点。我们得出结论，后牙接触紧密性，通常被牙医视为咬合的静态特征，会随着姿势的变化而显著改变。
