Department of Pediatric Clinics, Preventive and Community Dentistry, Ribeirão Preto Dental School, University of São Paulo, Ribeirão Preto, SP, Brazil.
J Appl Oral Sci. 2011 Nov-Dec;19(6):662-7. doi: 10.1590/s1678-77572011000600020.
The purpose of this study was to evaluate in situ the occurrence of corrosion in the soldering point areas between the wire, silver brazing and band in Haas expanders.
Thirty-four 7-12-year-old patients who needed maxillary expansion with a Haas expander were randomly assigned to two groups of 17 individuals each, according to the oral hygiene protocol adopted during the orthodontic treatment: Group I (control), toothbrushing with a fluoride dentifrice and Group II (experimental), toothbrushing with the same dentifrice plus 0.12% chlorhexidine gluconate (Periogard®) mouthrinses twice a week. The appliances were removed after approximately 4 months. Fragments of the appliances containing a metallic band with a soldered wire were sectioned at random for examination by stereomicroscopy, scanning electron microscopy (SEM) and energy dispersive x-ray spectroscopy (EDS). Data were analyzed statistically by Fisher's test at 5% significance level.
The analysis by optical microscopy revealed areas with color change suggestive of corrosion in the soldering point areas joining the band and the wire in all specimens of both groups, with no statistically significant difference between the groups (p=1). The peaks of chemical elements (Ni, Fe, Cr, O, C and P) revealed by EDS were also similar in both groups.
Color changes and peaks of chemical elements suggestive of corrosion were observed in the soldering point areas between the wire, silver brazing and band in both control and experimental groups, which indicate that the 0.12% chlorhexidine gluconate mouthrinses did not influence the occurrence of corrosion in situ.
本研究旨在原位评估哈斯扩弓器中金属丝、银钎焊和带材焊接点处的腐蚀发生情况。
34 名 7-12 岁需要上颌扩张的患者，随机分为两组，每组 17 人，根据正畸治疗期间采用的口腔卫生方案：组 I（对照组），使用含氟牙膏刷牙；组 II（实验组），使用相同的牙膏加每周两次 0.12%葡萄糖酸氯己定（Periogard®）漱口。大约 4 个月后取下矫治器。随机从含有焊接金属丝和金属带的矫治器碎片中进行横切面检查，通过立体显微镜、扫描电子显微镜（SEM）和能谱分析（EDS）进行检查。数据以 Fisher 检验在 5%显著水平下进行统计分析。
光学显微镜分析显示，两组所有标本的焊接点区域均有颜色变化，提示存在腐蚀，两组间无统计学差异（p=1）。EDS 显示的化学元素（Ni、Fe、Cr、O、C 和 P）峰值也相似。
在对照组和实验组的金属丝、银钎焊和带材焊接点区域均观察到颜色变化和化学元素峰值提示腐蚀发生，表明 0.12%葡萄糖酸氯己定漱口液不会影响原位腐蚀的发生。
