分光光度比色仪对牙齿漂白效果的分析

摘要

Objective To analyze the changes in CIE L*, a*, and b* at cervical, body, and incisal sites after tooth bleaching by using a spectrophotometer. Methods Sixty-seven intact and healthy maxillary central incisors were in-vestigated. These incisors were darker than A3 according to the Vita Classical shade guide. The CIE tooth shade parameters L*, a*, and b* were simultaneously recorded at three tooth areas (cervical, body, and incisal) with a spectrophotometer before and after tooth bleaching (35%H2O2 coordinating with Beyond whitening accelerator irradiating). The shade dif-ferential (ΔE) was calculated. ANOVA, paired t-test, and Pearson correlation analysis were used for data analysis. Results The efficacy rates of tooth bleaching were satisfactory, with 86.6%, 86.6%, and 85.1% in the cervical, body, and incisal sites, respectively. The average values ofΔE were 5.09, 4.44, and 4.40 in the cervical, body, and incisal sites. Tooth bleaching significantly increased L* and significantly decreased a* and b* in all tooth areas (P<0.01). The decreasing range ofΔb* was more than the increasing range ofΔL* at the cervical site; opposite results were observed at the incisal site. A positive correlation was detected between baseline b*andΔE. Conclusion The spectrophotometer could objectively evaluate the whitening effect of tooth bleaching at the different tooth sites. The tooth bleaching system (35%H2O2 coordinating with Beyond whitening accelerator irradiating) exerts powerful bleaching actions in most of the tooth areas investigated. The order of tooth bleaching effectiveness is cervical>body>incisal. Yellow coloration is decreased mainly at the cervical site, and brightness was increased mostly at theincisal site. The effectiveness of tooth bleaching increases as the baseline b* value increases.%目的：采用分光光度比色仪分析牙齿漂白后不同部位颜色CIEL*、a*、b*值的变化。方法选择67个健康完整的上颌中切牙，颜色大于A3（Vita经典比色板）。分光光度比色仪比色，记录颈部、体部、切端牙色。进行诊室漂白治疗（35%H2O2协同冷光漂白仪）后再次记录各部位牙色，计算ΔE、ΔL*、Δa*、Δb*和治疗有效率。对数据进行方差分析、配对t检验和Pearson相关分析。结果治疗有效率分别为：颈部86.6%，体部86.6%，切端85.1%。ΔE均值：颈部5.09，体部4.44，切端4.40。漂白后L*值升高，a*和b*值降低，均有统计学差异（P<0.01）。颈部和体部基线b*值与ΔE成正相关。结论35%H2O2协同冷光漂白仪照射有较好的牙齿漂白效果，顺序为颈部>体部>切端。颈部黄色降低幅度最大，切端明度增加最多。基线b*值越高，色差越大。