【摘要】 背景:颊侧多曲簧活动矫治器可以阻断性矫治多种青少年错牙合畸形,但在临床中颊侧多曲簧疲劳断裂的问题是不可避免的,如何延长其疲劳断裂周期以确保矫治顺利进行仍然处于研究阶段。目的:研究颊侧多曲簧弯制前、后进行不同温度加热处理,对其疲劳断裂周期(时间)的影响,从而选出一种能够增强颊侧多曲簧抗疲劳性能的最佳方法。方法:弯制左侧HL-2型颊侧多曲簧35个,根据曲簧弯制前、后热处理分为7组,5个试样为一组,分别为:原丝组、弯制前对牙用不锈钢丝进行加热处理组(320,420,520℃)3组、弯制成曲簧后行加热处理组(320,420,520℃)3组,低温热处理后,再用三维开闭口运动模拟测试仪测试其疲劳断裂周期(时间),通过扫描电镜观察断裂曲簧的断口形貌特征。结果与结论:曲簧疲劳断裂周期均值从大到小排列顺序为:弯制前520℃组>弯制前420℃组>弯制前320℃组>原丝组>弯制后520℃组>弯制后320℃组>弯制前420℃组,说明在曲簧弯制前对牙用不锈钢丝进行加热处理可延长曲簧的疲劳断裂周期,其中520℃低温退火工艺可有效提高曲簧抗疲劳断裂的机械性能;在曲簧弯制完成后进行加热处理不能延长曲簧的疲劳断裂周期。扫描电镜下观察弯制前520℃组断口裂纹伸展区域有扩大趋势,延缓瞬断过程的形成,组织结构更加均匀。更多还原

【Abstract】 BACKGROUND: Buccal Multiloop Removable Appliance can interceptively correct mutiple adolescent malocclusions. But the clinical problem of Buccal Multiloop fatigue fracture is not solved yet. How to prolong the fatigue fracture cycle is still in the research stage.OBJECTIVE: To study the effect of different temperature of heat treatment on the Buccal Multiloop fatigue fracture cycle, thereby to select a relatively optimal method to enhance the fatigue fracture cycle.METHODS: Thirty-five left HL-2 Buccal Mltiloops were divided into seven groups according to different ways of heat treatment. Each group consisted of five samples. They were an untreated group, three pre-bending groups(320, 420, 520 ℃ heat treatment before bending) and three post-bending groups(320, 420, 520 ℃ heat treatment after bending). The dental stainless steel wires and Buccal Multiloop were respectively treated by low-temperature annealing. The data were recorded and evaluated after the samples tested by the 3D Simulating Movement of TMJ Testing Machine. The features of fatigue fracture were observed by scanning electron microscope.RESULTS AND CONCLUSION: The mean values of the Buccal Multiloop fatigue fracture cycle from largest to smallest were as follows: 520 ℃ pre-bending group > 420 ℃ pre-bending group > 320 ℃ pre-bending group >untreated group > 520 ℃ post-bending group > 320 ℃ post-bending group > 420 ℃ post-bending group. The fatigue fracture cycle of Buccal Multiloop made of the dental stainless steel wires after 520 ℃ annealing treatment was longer than others. By the observation of scanning electron microscope, the fracture crack extension area had the tendency to expand, transient interruption was delayed and the tissue structure became more uniform.更多还原