The aim of this research was to assess the color differences (∆E₀₀), Vickers microhardness, whiteness index, and surface roughness values of different durations of bleaching the enamel. One hundred and eight teeth were utilized for color evaluation, roughness, and microhardness (n = 36). Teeth were assigned to three groups (n = 12) based on the durations of the bleaching application. Bleaching agent was applied for 20 minutes in group 1, 40 minutes in group 2, and 60 minutes in group 3. The color was measured with a Vita Easyshade Advance 4.0 spectrophotometer before applying the bleach, and 24 hours, 7, and 14 days after bleaching application. The CIEDE2000 and whiteness index for dentistry values were calculated. The microhardness and surface roughness values were obtained before application and 7 and 14 days after application. Data were analyzed using two-way ANOVA and post-hoc LSD tests Group 3 had the largest color and whiteness changes. The whiteness index for dentistry values were statistically significantly increased, considering baseline measurements within all groups (P < .05). For the Vickers micohardness values, in group 3, a statistically significant difference was observed among baseline, and 7 days after application (P < .05). However, the surface roughness values showed no significant difference in any measurement (P > .05). According to this research in all groups, effective whitening was accomplished. Based on the results evaluated for whiteness, color alteration, microhardness, and roughness, the optimal bleaching duration of application was in 40 minutes.

中文翻译：

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不同漂白持续时间对牙釉质牙齿颜色、显微硬度和表面粗糙度的影响

本研究的目的是评估颜色差异 (Δ E ₀₀)、不同漂白时间的牙釉质的维氏显微硬度、白度指数和表面粗糙度值。108 个牙齿用于颜色评估、粗糙度和显微硬度 (n = 36)。根据漂白应用的持续时间，牙齿被分为三组 (n = 12)。在第 1 组中使用漂白剂 20 分钟，在第 2 组中使用 40 分钟，在第 3 组中使用 60 分钟。使用 Vita Easyshade Advance 4.0 分光光度计在使用漂白剂之前和之后 24 小时、7 和 14 天测量颜色漂白应用。计算牙科值的 CIEDE2000 和白度指数。显微硬度和表面粗糙度值在应用前和应用后 7 天和 14 天获得。使用双向方差分析和事后 LSD 测试对数据进行分析，第 3 组的颜色和白度变化最大。考虑到所有组的基线测量值，牙科值的白度指数在统计学上显着增加（P  < .05）。对于维氏微硬度值，在第 3 组中，在基线和应用后 7 天之间观察到统计学上的显着差异 ( P  < .05)。然而，表面粗糙度值在任何测量中都没有显着差异（P  > .05）。根据所有组的这项研究，实现了有效的美白。根据对白度、颜色变化、显微硬度和粗糙度的评估结果，最佳漂白持续时间为 40 分钟。