Polydorou Olga, Hellwig Elmar, Hahn Petra
University Medical Center Freiburg, Dental School and Hospital, Department of Operative Dentistry and Periodontology, Freiburg, Germany.
Oper Dent. 2008 Sep-Oct;33(5):579-86. doi: 10.2341/07-148.
This in vitro study evaluated and compared the efficacy of three in-office bleaching systems and investigated their effect on enamel microhardness. Three groups of 12 teeth (third molars) each were bleached as follows: Group A: Opalescence Xtra Boost (38% HP), Group B: Easywhite Ready (30% HP) with plasma unit and Group C: Zoom2 system (25% HP with the Zoom2 unit). The teeth were stained with tea for 24 hours, followed by the appropriate bleaching procedure. Each bleaching cycle was conducted for 15 minutes. The bleaching procedure was repeated until a shade change of six tabs (VITA shade guide) was obtained. The shade of the teeth was evaluated before, immediately after bleaching and one month later, both visually and digitally. Additionally, the "change of shade tabs per minute" was calculated. For the digital evaluation, the photos were taken under the same circumstances and the Lab* values were calculated using Photoshop. Five additional enamel samples for each group were prepared, and Knoop microhardness was evaluated before and after 15 minutes of bleaching. According to the visual shade evaluation, the treatment cycles required to reach the defined level of bleaching were: 1.58 for Group A (23.7 minutes), 1.02 for Group B (16.2 minutes) and 1.25 for Group C (18.7 minutes). Immediately after bleaching, a significant difference was found between Groups A and B (p = 0.0094). However, one month after the bleaching procedure, no significant difference could be observed among the three groups. According to the digital evaluation, no significant differences were found among the three bleaching systems for each of the Lab* values and the three times tested (p > 0.05). No significant difference (p = 0.055) was noticed among the three groups regarding microhardness after bleaching.
这项体外研究评估并比较了三种诊室美白系统的疗效，并研究了它们对牙釉质显微硬度的影响。将三组，每组12颗牙齿（第三磨牙）进行如下漂白：A组：Opalescence Xtra Boost（38%过氧化氢），B组：配备等离子体装置的Easywhite Ready（30%过氧化氢），C组：Zoom2系统（25%过氧化氢搭配Zoom2装置）。将牙齿用茶染色24小时，然后进行适当的漂白程序。每个漂白周期持续15分钟。重复漂白程序，直到牙齿颜色变化达到六个色阶（VITA比色板）。在漂白前、漂白后即刻以及一个月后，通过视觉和数字方式评估牙齿颜色。此外，计算“每分钟色阶变化”。对于数字评估，在相同条件下拍摄照片，并使用Photoshop计算Lab值。每组额外制备五个牙釉质样本，在漂白15分钟前后评估努氏显微硬度。根据视觉比色评估，达到规定漂白水平所需的治疗周期为：A组1.58个周期（23.7分钟），B组1.02个周期（16.2分钟），C组1.25个周期（18.7分钟）。漂白后即刻，A组和B组之间存在显著差异（p = 0.0094）。然而，在漂白程序一个月后，三组之间未观察到显著差异。根据数字评估，对于每个Lab值以及三次测试时间，三种漂白系统之间均未发现显著差异（p > 0.05）。在漂白后，三组之间在显微硬度方面未发现显著差异（p = 0.055）。
