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The Effect of Four Surface Treatment Methods on the Shear Bond Strength of Metallic Brackets to the Fluorosed Enamel | ||
| Journal of Dentistry | ||
| مقاله 5، دوره 16، Supplement 3- September 2015، آذر 2015، صفحه 251-259 اصل مقاله (874.89 K) | ||
| نوع مقاله: Original Article | ||
| نویسندگان | ||
| Hooman Zarif Najafi1؛ Vahid Moshkelgosha* 1؛ Atefeh Khanchemehr2؛ Akram Alizadeh2؛ Ali Mokhtar3 | ||
| 1Orthodontic Research Center, Dept. of Orthodontics, School of Dentistry, Shiraz University of Medical Sciences, Shiraz, Iran. | ||
| 2Student Research Committee, School of Dentistry, Shiraz University of Medical Sciences, Shiraz, Iran. | ||
| 3School of Dentistry, Tehran Islamic Azad University of Medical Sciences, Tehran, Iran. | ||
| چکیده | ||
| Statement of the Problem: Some studies have reported the bond strength to be significantly lower in fluorotic enamels than the non-fluorosed.Purpose: The purpose of this study was to evaluate the shear bond strength of metallic brackets to non-fluorosed and fluorosed teeth after different enamel conditioning.Materials and Method: 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.Results: 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.Conclusion: 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. | ||
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