Background

The effects of HP-based products upon dental enamel are inconclusive.

Purpose

The purpose of this study was to evaluate the colour and mineral changes caused by the bleaching agent applications at different durations on the enamel surface.

Basic Procedures

60 caries-free lower central incisor extracted for periodontal reasons were standardized for enamel and dentin thickness after cone-beam computed tomography (CBCT) measurements in terms of mineral (n = 24) and colour change (n = 36). All teeth were divided into 3 groups according to different bleaching durations for colour (n = 12) and mineral change (n = 8) measurements. The samples for mineral change were examined with the -energy scattering X-ray (EDX, JSM-6390 LV, Jeol Inc., Japan) device before and 2 weeks after the application. For colour change, the measurement of the samples was performed with spectrophotometer device (VITA EasyShade 4.0, Germany). Opalescence Boost PF 40% (Ultradent Products, USA) was applied for 20 minutes (min) in Group 1, 40 minutes in Group 2 and 60 minutes in Group 3. In order to determine the efficacy of bleaching, colour measurements were repeated at 24 hours, 7 and 14 days after the application. In the intragroup comparison, Friedman and Wilcoxon tests were used for non-normally distributions, while repeated variance analysis and paired t test were used for normally distributions in dependent variables. In the intergroup comparison, ANOVA and LSD tests were used for normally distributions, while Kruskal-Wallis and Dunn tests were used for non-normally distributions in independent variables. p < 0.05 was considered significant.

Main Findings

In the study, statistically significant difference was observed between all groups in terms of colour change at different measurement times (p < 0.05). The highest ΔE₀₀ values were observed in Group 3 (ΔE₀₀₃ = 8.37 ± 2.15); the lowest value was observed in Group 1 (ΔE₀₀₁ = 4.74 ± 1.26). Ca values were similar increase among all groups (p > 0.05). The highest Ca values were observed in Group 3 (69.91 ± 5.34); the lowest value was observed in Group 2 (66.08 ± 1.50). P values were similar increase among all groups (p > 0.05). The lowest P values were observed in Group 3 (26.54 ± 5.92); the highest value was observed in Group 2 (29.86 ± 2.26).

Principal Conclusions

Effective whitening was achieved in all study groups. When the results are evaluated as versatile in terms of bleaching effectiveness and mineral change, the most ideal bleaching duration was determined as 40 minutes (Group 2).

中文翻译：

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不同漂白时间对牙齿颜色和矿物质改变的影响。

背景

基于 HP 的产品对牙釉质的影响尚无定论。

目的

本研究的目的是评估漂白剂在牙釉质表面使用不同持续时间引起的颜色和矿物质变化。

基本程序

在锥形束计算机断层扫描 (CBCT) 测量后，根据矿物质 (n = 24) 和颜色变化 (n = 36)，对因牙周原因提取的 60 颗无龋下中切牙的牙釉质和牙本质厚度进行标准化。根据颜色 (n = 12) 和矿物质变化 (n = 8) 测量的不同漂白持续时间，将所有牙齿分为 3 组。在应用前和应用后 2 周，用 β-能量散射 X 射线（EDX，JSM-6390 LV，Jeol Inc.，日本）设备检查矿物变化的样品。对于颜色变化，使用分光光度计装置（VITA EasyShade 4.0，德国）进行样品的测量。Opalescence Boost PF 40%（Ultradent Products，美国）在第 1 组中使用 20 分钟（分钟），在第 2 组中使用 40 分钟，在第 3 组中使用 60 分钟。为了确定漂白效果，在施用后 24 小时、7 天和 14 天重复颜色测量。在组内比较中，非正态分布采用Friedman和Wilcoxon检验，因变量的正态分布采用重复方差分析和配对t检验。在组间比较中，ANOVA 和 LSD 检验用于正态分布，而 Kruskal-Wallis 和 Dunn 检验用于自变量的非正态分布。p < 0.05 被认为是显着的。ANOVA 和 LSD 检验用于正态分布，而 Kruskal-Wallis 和 Dunn 检验用于自变量的非正态分布。p < 0.05 被认为是显着的。ANOVA 和 LSD 检验用于正态分布，而 Kruskal-Wallis 和 Dunn 检验用于自变量的非正态分布。p < 0.05 被认为是显着的。

主要发现

在研究中，在不同测量时间的颜色变化方面，所有组之间都观察到了统计学上的显着差异（p < 0.05）。在第 3 组中观察到最高的 ΔE ₀₀值（ΔE ₀₀₃  = 8.37 ± 2.15）；在第 1 组中观察到最低值 (ΔE ₀₀₁  = 4.74 ± 1.26)。Ca 值在所有组中都有相似的增加（p > 0.05）。在第 3 组中观察到最高的 Ca 值 (69.91 ± 5.34)；在第 2 组中观察到最低值 (66.08 ± 1.50)。P 值在所有组中都有相似的增加（p > 0.05）。在第 3 组中观察到最低 P 值 (26.54 ± 5.92)；在第 2 组中观察到最高值 (29.86 ± 2.26)。

主要结论

所有研究组均实现了有效美白。当结果在漂白效果和矿物质变化方面被评估为通用时，最理想的漂白持续时间被确定为 40 分钟（第 2 组）。