运动护齿器力的缓冲原理研究

Protective Mechanism of Sports Mouthguards from External Impact

目的:研究定制式运动护齿器(mouthguard,MG)的力的缓冲原理,为临床制作运动护齿器提供指导性意见。方法:热凝塑料制作标准上下颌模型并可通过中央螺丝固定,在标准石膏模型上利用真空层压的方法制作具有良好咬合关系、初始乙烯-醋酸乙烯酯共聚物(ethylene-vinylacetate,EVA)膜片厚度为2+4+2 mm的定制式运动护齿器。实验组佩戴具有良好咬合关系的运动护齿器;空白对照组分为未戴护齿器无对颌和未戴护齿器有对颌。通过从定制的滑道(长35 cm、高50 cm)上滑下的钢球(直径4 cm、质量260g)对其施行不同方向及位点(右侧上颌中切牙正面、右侧上颌第一磨牙侧向、颏部)撞击,利用薄膜电阻应变式传感器采集右侧上下颌中切牙区、第一前磨牙区、第一磨牙区牙齿的形变值,通过数据采集系统输入计算机。结果:佩戴运动护齿器后,各位点形变值显著降低,实验组与空白对照组之间差异具有统计学意义(P<0.05)。在受到不同方向及位点的撞击时,运动护齿器存在三类防护作用。当右侧上颌中切牙受到正前方的撞击时,运动护齿器的Ⅰ和Ⅲ防护作用显著;当右侧上颌第一磨牙受到侧向撞击时,运动护齿器的Ⅰ和Ⅱ防护作用显著;当颏部受到撞击时,运动护齿器的Ⅱ和Ⅲ防护作用显著。结论:运动护齿器可以有效防止牙外伤及骨折外伤的发生。

Objective To evaluate protective principle of sports mouthguards and provide some instructional advice for producing mouthguards in practical use. Methods Both phantom maxillary model and mandibular dentate model were fabricated and fixed together with a screw. The mouthguards were applied to the experimental model,while the control group simply kept jaw clenching without wearing the mouthguards. The two models were stricken by a steel ball（260g）from different directions and on different sites. Filmistor strain gauges were used to collect the data of right teeth deflection at the central incisor,first premolar and first molar when the two models were impacted and then the data was computed. The protective effects of the mouthguards were evaluated in accordance to Chapman：effect I absorbed the external force by the mouthguards materials itself,effect II was the dispersion of the external force to the same jaw dentition,and effect III was a buffer action of the external force through occlusal transmission between the mandible and maxilla,and between the skull and the mandible and maxilla. Results The deformation values at different sites during the impact from different directions were significantly lower in experimental model than in control model（P〈0.05）. Protective effects I and III of the mouthguards were significant when the impact was on the right maxillary central incisor,protective effects I and II of the mouthguards were significant when the impact was on the right maxillary first molar,and the protective effects II and III of the mouthguards were significant when the impact was on the chin. Conclusion Sports mouthguards could effectively prevent teeth trauma and jaw fracture.