新型带环固位性能：3个方向抗剪切强度及其玻璃离子的黏结**

背景：由于磨牙带环的固位强度高,所以在正畸过程中起着重要的支抗作用,但是传统的磨牙带环存在着诸多弊端。目的：观察比较新型磨牙带环与传统磨牙带环的固位性能。方法：将拔除的人第三恒磨牙随机分为2组,对照组设计为玻璃离子水门汀黏结传统带环,对带环垂直加载;实验组设计为树脂加强型玻璃离子水门汀黏结新型带环,于电子万能材料测试机上从3个方向(垂直向、近中向及远中向)对带环加载,使用超精密形状与尺寸测量仪测量两种带环的表面积,计算带环完全脱落的最大载荷值。结果与结论：实验组的抗剪切强度高于对照组(P < 0.05)。实验组带环3个方向的抗剪切强度近、远中向组高于垂直组(P < 0.05)。结果证实,新型带环使用树脂加强型玻璃离子黏结,凸显了新型带环的优点,且其固位性能优于传统带环使用传统玻璃离子黏结,新型带环与磨牙黏结可发挥其支抗作用。

Retention performance of new type molar bands: Shear bond strengths and bonding of glass ionomer in three directions

BACKGROUND: Molar band has important anchorage capacity during orthodontic process based on its high fixation strength. However, traditional molar band has many disadvantages.OBJECTIVE: To compare the retention performance between new type molar bands and traditional molar bands. METHODS: Extracted human lower third molars were collected and randomly divided into two groups, the control group was designed for traditional bands bonding with glass ionomer cements, and then the bands were subjected to vertical directional load; the experimental group was designed for new type bands bonding with resin-modified glass ionomer cements, and then the bands were subjected to three directional load (vertical, mesial and distal). The surface areas of the two types of bands were tested to calculate their maximum load of complete loss. RESULTS AND CONCLUSION: Shear bond strengths of the experimental group were significantly stronger than those of the control group (P < 0.05). Shear bond strengths in mesial and distal directions were stronger than that in the vertical direction of the experimental group (P < 0.05). The combination of new type bands with resin-modified glass ionomer cements highlight the advantages of new type bands, and their retention performances are superior to the traditional bands bonding with glass ionomer cements. New type bands bonding to molars can produce a anchorage capacity.