过氧化脲漂白剂对牙齿颜色影响的实验研究

目的：研究不同增稠载体及浓度的过氧化脲（carbamide peroxide，CP）漂白剂对牙齿颜色的影响。方法：以卡波姆（carbopol）、聚乙烯吡咯烷酮（PVP）或泊洛沙姆（Poloxamer）为漂白剂的增稠载体，分别配制含有10％和20％CP的漂白凝胶。将60颗离体变色牙随机分为6组，每组10颗。1组牙冠用以Carbopol为增稠载体的10％CP凝胶漂白；2组牙冠用以Carbopol为增稠载体的20％CP凝胶漂白；3组牙冠用以PVP为增稠载体的10％CP凝胶漂白：4组牙冠用以PVP为增稠载体的20％CP凝胶漂白；5组牙冠用以Poloxamer为增稠载体的10％CP凝胶漂白；6组牙冠用以Poloxamer为增稠载体的20％CP凝胶漂白。各组在37℃、100％湿度条件下每天漂白6～8h，持续2周。分别在漂白前、漂白后1周和2周对牙冠的L＊a＊b＊值进行测定，并计算色差（△E），漂白前后自身对照。结果：以Carbopol为增稠载体，20％CP漂白2周组的漂白效果最明显（P〈0．01）；以PVP或Poloxamer为增稠载体的各组分析结果同Carbopol组。不同增稠载体的10％CP或20％CP漂白1周和2周，漂白效果没有显著差异（P〉0．05）。结论：同种增稠载体下，20％CP的漂白效果明显优于10％CP，漂白时间越长，漂白效果越明显；不同增稠载体对漂白效果没有影响。

The effect of carbamide peroxide bleaching agents on teeth color in vitro

Objective To evaluate the effect of carbamide peroxide （CP） bleaching agents of different concentrations and carriers on tooth color. Methods Sixty teeth were randomly assigned to six groups. Using Carbopol,PVP and Poloxamer as thickening carriers respectively, bleaching gels containing 10%,20% of CP were applied on the enamel surface for two weeks （6-8h/d,37℃,100% relative humidity）. Prior to the treatment, L＊a＊b＊ values of the every tooth surface were measured with Digital Imaging Camera （DIC）and General image analysis tool set （GIANT）. The L＊a＊b＊ values were obtained again 1 week and 2 week post treatment. Results Using carbopol, PVP, or poloxamer as thickening carriers respectively, the tooth whitening effect of 20% CP was most notable after 2weeks treatment （P〈0.01）. Conclusion With same thickening agent, the bleaching effect of 20% CP is significantly greater than 10% CP; the longer the treatment duration, the greater the bleaching result. The difference between thickening agents does not affect the bleaching result.