Clelland Nancy L, Dorosti Yassamin, Seghi Robert R
Ohio State University College of Dentistry, Columbus, OH 43218-2357,USA.
J Prosthodont. 2002 Jun;11(2):81-5.
This study evaluated the effects of a simulated 1- and 2-week night guard bleaching technique using various bleaching gel concentrations on wear resistance and color change of human enamel opposing a feldspathic porcelain substrate.
VMK 68 feldspathic porcelain was formed into 15-mm disks (n = 63) and fired according to manufacturer's recommendations. Enamel cusps were formed and shaped from extracted third molars and treated with 1 of 3 bleaching materials for 7 or 14 days. Specimens were kept at 37 degrees C in 100% humidity. The control group was subjected to identical conditions but with water replacing the bleaching gel between and during bleaching treatments. After simulated bleaching, the enamel cusp specimens were subjected to 3-body wear testing opposite a highly polished porcelain substrate. Enamel wear was evaluated using optical scanning methods, and color was measured with a small-aperture colorimeter. Data were subjected to a one-way repeated- measure analysis of variance and various post hoc statistics.
Results indicated that the within effect of treatment time (7 or 14 days) did not significantly affect (p = 0.13) the size of the resulting enamel wear facet, whereas the between effect of bleaching concentration was significant (p = 0.01). Statistical analysis of unbleached control groups suggests that between-group differences can be explained by variations in wear rates of the 3 enamel groups, not by the concentration differences in bleaching gels. All bleaching treatments resulted in significant color changes (p = 0.04) compared to the unbleached control, but the bleach concentration did not significantly influence the magnitude of color change (p = 0.81).
A simulated night guard vital bleaching treatment of 1 or 2 weeks had no significant effect on the wear resistance of human enamel in vitro. The increased bleaching treatment time and concentration did not significantly affect the amount of enamel color change.
本研究评估了使用不同浓度漂白凝胶的模拟1周和2周夜间护齿漂白技术对与长石质瓷基底相对的人牙釉质耐磨性和颜色变化的影响。
将VMK 68长石质瓷制成15毫米的圆盘（n = 63），并按照制造商的建议进行烧制。从拔除的第三磨牙上制作并塑形牙釉质尖，并使用3种漂白材料之一处理7天或14天。标本在37摄氏度、湿度100%的条件下保存。对照组在相同条件下，但在漂白处理期间和之间用水代替漂白凝胶。模拟漂白后，将牙釉质尖标本与高度抛光的瓷基底进行三体磨损测试。使用光学扫描方法评估牙釉质磨损，并使用小孔径色度计测量颜色。数据进行单向重复测量方差分析和各种事后统计分析。
结果表明，处理时间（7天或14天）的组内效应未显著影响（p = 0.13）最终牙釉质磨损面的大小，而漂白浓度的组间效应显著（p = 0.01）。未漂白对照组的统计分析表明，组间差异可由3个牙釉质组磨损率的差异解释，而非漂白凝胶浓度的差异。与未漂白对照组相比，所有漂白处理均导致显著的颜色变化（p = 0.04），但漂白浓度并未显著影响颜色变化的幅度（p = 0.81）。
1周或2周的模拟夜间护齿活髓漂白处理在体外对人牙釉质的耐磨性没有显著影响。增加漂白处理时间和浓度并未显著影响牙釉质颜色变化的量。
