Zarif Najafi Hooman, Moshkelgosha Vahid, Khanchemehr Atefeh, Alizade Akram, Mokhtar Ali
Orthodontic Research Center, Dept. of Orthodontics, School of Dentistry, Shiraz University of Medical Sciences, Shiraz, Iran.
Student Research Committee, School of Dentistry, Shiraz University of Medical Sciences, Shiraz, Iran.
J Dent (Shiraz). 2015 Sep;16(3 Suppl):251-9.
Some studies have reported the bond strength to be significantly lower in fluorotic enamels than the non-fluorosed.
The purpose of this study was to evaluate the shear bond streongth of metallic brackets to non-fluorosed and fluorosed teeth after different enamel conditioning.
A total of 176 freshly extracted human premolars (88 non-fluorosed and 88 fluorosed teeth) were used in this study for bonding the metallic brackets. Teeth with moderate fluorosis were used according to Thylstrup and Fejereskov index (TFI). Eighty non-fluorosed and 80 fluorosed teeth (TFI=4-6) were randomly divided into 8 equal groups of 20 teeth each. The remaining 16 teeth were used for scanning electron microscopy observation. The enamel surface was conditioned by 4 methods: acid etching for 30 sec, acid etching for 120 sec, air abrasion followed by acid etching, and Er: YAG laser etching followed by acid etching. The morphology of etching patterns in different groups was studied under scanning electron microscope.
The shear bond strength of fluorosed teeth to the brackets was significantly lower than non-fluorosed ones (p= 0.003). The shear bond strength of laser-acid groups in both non-fluorosed and fluorosed teeth was significantly lower than other groups (p< 0.001). Weibull analysis indicated that the chance of failure under the applied force was different between fluorosed and non-fluorosed group. The scanning electron microscope observations revealed that the fluorosed teeth treated with phosphoric acid had fewer irregularities compared to non-fluorosed teeth. The most irregularities were detected in the teeth conditioned with phosphoric acid for 120 seconds.
Fluorotic enamel adversely affects the bond strength of orthodontic brackets. None of the conditioning methods tested in this study could significantly improve shear bond strength of metallic brackets. Er: YAG laser conditioning followed by acid further reduced the bond strength in non-fluorosed and fluorosed teeth.
一些研究报告称，氟斑牙釉质中的粘结强度显著低于非氟斑牙。
本研究的目的是评估在不同的牙釉质预处理后，金属托槽与非氟斑牙和氟斑牙之间的剪切粘结强度。
本研究共使用176颗新鲜拔除的人类前磨牙（88颗非氟斑牙和88颗氟斑牙）来粘结金属托槽。根据蒂尔斯楚普和费耶尔斯科夫指数（TFI）使用中度氟斑牙。80颗非氟斑牙和80颗氟斑牙（TFI = 4 - 6）被随机分为8个相等的组，每组20颗牙。其余16颗牙用于扫描电子显微镜观察。牙釉质表面采用4种方法进行预处理：酸蚀30秒、酸蚀120秒、空气喷砂后酸蚀以及铒：钇铝石榴石激光蚀刻后酸蚀。在扫描电子显微镜下研究不同组蚀刻图案的形态。
氟斑牙与托槽之间的剪切粘结强度显著低于非氟斑牙（p = 0.003）。非氟斑牙和氟斑牙中激光 - 酸组的剪切粘结强度均显著低于其他组（p < 0.001）。威布尔分析表明，在施加力作用下，氟斑牙组和非氟斑牙组的失败几率不同。扫描电子显微镜观察显示，与非氟斑牙相比，用磷酸处理的氟斑牙不规则之处更少。在酸蚀120秒处理的牙齿中检测到的不规则之处最多。
氟斑牙釉质对正畸托槽的粘结强度有不利影响。本研究中测试的任何预处理方法都不能显著提高金属托槽的剪切粘结强度。铒：钇铝石榴石激光预处理后再酸蚀进一步降低了非氟斑牙和氟斑牙的粘结强度。
