Summers Andrew, Kao Elizabeth, Gilmore Jeffrey, Gunel Erdogan, Ngan Peter
Department of Restorative Dentistry, West Virginia University School of Dentistry, Morgantown 26506, USA.
Am J Orthod Dentofacial Orthop. 2004 Aug;126(2):200-6; quiz 254-5. doi: 10.1016/j.ajodo.2003.06.013.
The objectives of this study were (1) to compare the in vivo survival rates of orthodontic brackets bonded with a resin-modified glass ionomer adhesive (Fuji Ortho LC; GC America, Alsip, Ill) after conditioning with 10% polyacrylic acid and a conventional resin adhesive (Light Bond; Reliance Orthodontic Products, Itasca, Ill) bonded with 37% phosphoric acid, (2) to compare the in vitro bond shear/peel bond strength between the 2 adhesives, (3) to determine the mode of bracket failure in the in vivo and in vitro tests according to the adhesive remnant index (ARI), and (4) to compare the changes in surface morphology of enamel surface after etching or conditioning with 10% polyacrylic acid, with scanning electron microscopy. In the in vitro study, 50 extracted premolars were randomly divided into 4 groups: brackets bonded with Fuji Ortho LC or Light Bond adhesive that were debonded after either 30 minutes or 24 hours. Bond strengths were determined with a testing machine at a crosshead speed of 1 mm/min. Data were analyzed with analysis of variance and a paired Student t test. The in vivo study consisted of 398 teeth that were randomly bonded with Fuji Ortho LC or Light Bond adhesive in 22 subjects with the split-mouth technique. Bracket survival rates and distribution were followed for 1.3 years. Data were analyzed with Kaplan-Meier product-limit estimates of survivorship function. The in vitro study results showed significant differences (P <.05) among the adhesives and the debond times. Light Bond had significantly greater bond strengths than Fuji Ortho LC at 24 hours (18.46 +/- 2.95 MPa vs 9.56 +/- 1.85 MPa) and 30 minutes (16.19 +/- 2.04 MPa vs 6.93 +/- 1.93 MPa). Mean ARI scores showed that Fuji Ortho LC had significantly greater incidences of enamel/adhesive failure than Light Bond adhesive (4.9 vs 4.1). For the in vivo study, no significant differences in failure rate, sex, or location in dental arch or ARI ratings were found between the 2 adhesives. These results suggest that, compared with conventional resin, brackets bonded with resin-modified glass ionomer adhesive had significantly less shear bond strength in vitro. However, similar survival rates of the 2 materials studied after 1.3 years indicate that resin-reinforced glass ionomers can provide adequate bond strengths clinically. The weaker chemical bonding between the adhesive and the enamel might make it easier for clinicians to clean up adhesives on the enamel surface after debonding.
（1）比较用10%聚丙烯酸预处理后用树脂改性玻璃离子黏合剂（Fuji Ortho LC；美国GC公司，伊利诺伊州阿尔西普）黏结的正畸托槽与用37%磷酸处理后用传统树脂黏合剂（Light Bond；美国信赖正畸产品公司，伊利诺伊州伊塔斯卡）黏结的正畸托槽在体内的存留率；（2）比较两种黏合剂的体外黏结剪切/剥离强度；（3）根据黏合剂残留指数（ARI）确定体内和体外试验中托槽脱落的模式；（4）用扫描电子显微镜比较用10%聚丙烯酸酸蚀或预处理后釉质表面的形态变化。在体外研究中，50颗拔除的前磨牙被随机分为4组：用Fuji Ortho LC或Light Bond黏合剂黏结的托槽，分别在30分钟或24小时后脱黏。用试验机以1 mm/min的十字头速度测定黏结强度。数据用方差分析和配对学生t检验进行分析。体内研究包括22名受试者的398颗牙齿，采用分口技术随机用Fuji Ortho LC或Light Bond黏合剂黏结。随访托槽存留率和分布情况1.3年。数据用Kaplan-Meier生存函数乘积限估计法进行分析。体外研究结果显示，黏合剂和脱黏时间之间存在显著差异（P<.05）。Light Bond在24小时（18.46±2.95 MPa对9.56±1.85 MPa）和30分钟（16.19±2.04 MPa对6.93±1.93 MPa）时的黏结强度明显高于Fuji Ortho LC。平均ARI评分显示，Fuji Ortho LC釉质/黏合剂脱落的发生率明显高于Light Bond黏合剂（4.9对4.1）。在体内研究中，两种黏合剂在脱落率、性别、牙弓位置或ARI评级方面均未发现显著差异。这些结果表明，与传统树脂相比，用树脂改性玻璃离子黏合剂黏结的托槽在体外的剪切黏结强度明显较低。然而，两种材料在1.3年后的存留率相似，这表明树脂增强型玻璃离子体在临床上可以提供足够的黏结强度。黏合剂与釉质之间较弱的化学键合可能使临床医生在脱黏后更容易清理釉质表面的黏合剂。
