Buschang Peter H, Throckmorton Gaylord S, Austin Dawn, Wintergerst Ana M
Baylor College of Dentistry, Dallas, Tex, USA.
Am J Orthod Dentofacial Orthop. 2007 May;131(5):627-34. doi: 10.1016/j.ajodo.2005.06.037.
The notion that chewing cycle shape and cycle dynamics differ between subjects with and without malocclusion is largely based on qualitative studies that combined various types of malocclusion. The purpose of this prospective study was to determine whether chewing cycle kinematics of untreated young adults with deepbite malocclusion differ from those with normal occlusion.
Twenty-three deepbite subjects (>50% overbite) and 24 controls with normal occlusion chewed gum (right side only) while their jaw movements were recorded at 100 Hz by using an optoelectric jaw tracking system.
Differences in cycle duration between deepbite and control subjects were small and not significant (P >.05). The deepbite subjects showed significantly (P <.05) less maximum inferior excursion (7.7 vs 9.0 mm) and significantly greater maximum posterior excursion (5.1 vs 4.0 mm) than subjects with normal occlusion. In addition, the deepbite subjects had significantly smaller maximum vertical velocities than subjects with normal occlusion (49.2 vs 60.8 mm per second). Deepbite subjects also showed significantly (P <.05) less cycle-to-cycle variability in maximum velocities and excursions to the balancing side but significantly (P <.05) greater variability in cycle duration and maximum posterior excursions.
A deepbite malocclusion alters the shape of chewing cycles and the consistency of chewing cycle kinematics.
咬合不正与正常咬合个体之间咀嚼周期形状和周期动态存在差异这一观点，很大程度上基于对各种类型咬合不正进行综合研究的定性研究。这项前瞻性研究的目的是确定未经治疗的深覆合咬合不正的年轻成年人的咀嚼周期运动学是否与正常咬合者不同。
23名深覆合受试者（覆盖超过50%）和24名正常咬合对照者咀嚼口香糖（仅右侧），同时使用光电颌骨跟踪系统以100赫兹的频率记录他们的颌骨运动。
深覆合组与对照组之间的周期持续时间差异较小且无统计学意义（P>.05）。深覆合受试者的最大下颌向下运动幅度明显较小（7.7毫米对9.0毫米，P<.05），最大向后运动幅度明显较大（5.1毫米对4.0毫米）。此外，深覆合受试者的最大垂直速度明显低于正常咬合者（每秒49.2毫米对60.8毫米）。深覆合受试者在最大速度和向平衡侧运动幅度方面的周期间变异性也明显较小（P<.05），但在周期持续时间和最大向后运动幅度方面的变异性明显较大（P<.05）。
深覆合咬合不正会改变咀嚼周期的形状和咀嚼周期运动学的一致性。
