【摘要】 目的:观察组合酸不同酸蚀时间对新鲜离体氟斑牙牙釉质超微结构的影响,寻找增强氟斑牙托槽粘接强度的方法。方法:选择5颗正常恒牙,用37%的磷酸酸蚀作为对照组。将中、重度氟斑牙25颗随机分为5组,用同一组合酸进行酸蚀,时间分别为1、2、3、4和5min,酸蚀后粘接托槽,24h后测定托槽的抗剪切强度,并通过扫描电镜观察去除托槽后树脂-牙釉质界面形态学改变。结果:对照组抗剪切强度为(3.33±2.03)MPa,氟斑牙酸蚀时间1～5min组抗剪切强度分别为(7.81±1.04)MPa,(10.71±2.96)MPa,(5.87±2.70)MPa,(4.02±1.86)MPa,(4.05±2.27)MPa。除氟斑牙酸蚀2min组与对照组比较差异无统计学意义(P>0.05),其余各组与对照组比较差异均有统计学意义(P<0.05)。除氟斑牙酸蚀1min时牙釉质超微结构改变不明显,酸蚀2min时有较明显的蜂窝状改变,随酸蚀时间延长釉质结构溶解破坏增多。结论:组合酸酸蚀氟斑牙2min可获得较理想的粘接强度和形态变化。更多还原

【Abstract】 Objective : To evaluate bonding strength of orthodontic bracket bonded to fluorotic teeth in vitro by using different etching times and investigate the effects of different etching times on the micro morphology of enamel to find a method to increase bonding strength of orthodontic bracket bonded to fluorotic teeth. Methods: Five normal teeth and 25 fluorotic teeth,freshly extracted from patients,were included in the study. Control group of five normal teeth was eroded by 37% phosphoric acid for 1 min. All of the fluorotic teeth were randomly divided into 5 groups. Each group of 5 teeth was eroded for 1 min,2 min,3 min,4 min,5 min with comose acid. After etching,brackets were bonded with a composite resin. Shear bond strength was measured 24 hours later. Then the etching patterns of enamel were observed by scanning electron microscope(SEM). Results: The shear bond strength of the normal teeth was(3.33 ± 2.03)MPa. The values of shear bond strength in different fluorotic teeth groups from 1 min to 5 min were(7.81 ± 1.04),(10.71 ± 2.96),(5.87 ± 2.70),(4.02 ± 1.86) and(4.05 ± 2.27)MPa respectively. There were significant differences in bond strength between each of the fluorotic teeth groups and control group(P < 0.05) except for the fluorotic teeth group of etching 2 min(P > 0.05). There were no significant SEM changes in fluorotic teeth with 1 min eroded but obvious honeycomb was appeared in 2 min group. The erosion of enamel became more serious with the time of etching. Conclusion: The result demonstrated that good shear bond strength and SEM changes were obtained in group of fluorotic teeth with 2 min comose acid.更多还原