Conservative Department, College of Dentistry, University of Sulaimani, Iraq.
Biomed Res Int. 2021 Apr 27;2021:6611173. doi: 10.1155/2021/6611173. eCollection 2021.
This study evaluates the effect of bleaching before or after veneer preparation and the depth of preparation on color masking ability of laminate veneers. Sixty extracted premolars were artificially stained to vita shade A4, verified by digital spectrophotometer (Vita Easy Shade V), and then divided into three groups: NB = nonbleached, BBP = bleaching before preparation, and BAP = bleaching after preparation. Based on the preparation depths, each group was further divided into two subgroups: S1 = 0.5 mm and S2 = 1.0 mm. BBP and BAP were subjected to one session of in-office bleaching using 35% hydrogen peroxide. IPS e-max CAD veneers of 0.5 and 1.0 mm thickness (corresponding to the preparation depths) of the same shade and translucency (HT A1) were cemented immediately to the bleached surfaces. Immediately after cementation, the color change Δ between the baseline (after staining) and the resulted shades was measured using the Vita Easy Shade V digital spectrophotometer and CIELab color system.
Bleached groups exhibited a significant Δ value compared to the nonbleached group ( < 0.05). BAP showed the highest Δ value. No significant difference was found between BBP and BAP. S2 revealed a significant Δ value than S1 ( < 0.05). No significant difference was found between S1of BAP and S2 of NB, BBP, and BAP ( > 0.05). Regarding the color coordinates, the difference between the tested groups was highly significant in lightness (ΔL∗) ( < 0.001), while no significant differences were found in green/red value (Δ∗) and yellow/blue value (Δ∗) ( > 0.05).
In cases of severe tooth discoloration, one session of in-office bleaching before or after veneer preparation and the preparation depth do not influence the color masking ability of laminate veneers.
本研究评估了贴面预备前或后漂白以及预备深度对贴面遮色能力的影响。将 60 颗离体前磨牙人工染色至 vita 比色 A4，通过数字分光光度计（Vita Easy Shade V）验证，并分为三组：NB = 非漂白组，BBP = 预备前漂白组，BAP = 预备后漂白组。根据预备深度，每组再分为两个亚组：S1 = 0.5mm 和 S2 = 1.0mm。BBP 和 BAP 采用 35%过氧化氢进行一次诊室漂白。即刻将厚度为 0.5 和 1.0mm（对应于预备深度）、同一比色和半透明度（HT A1）的 IPS e-max CAD 贴面粘接到漂白后的表面。粘固后即刻使用 Vita Easy Shade V 数字分光光度计和 CIELab 颜色系统测量从基线（染色后）到所得颜色的颜色变化 Δ。
与非漂白组相比，漂白组的 Δ 值有显著差异（<0.05）。BAP 组的 Δ 值最高。BBP 和 BAP 组之间无显著差异。S2 组的 Δ 值显著高于 S1 组（<0.05）。BAP 的 S1 组与 NB、BBP 和 BAP 的 S2 组之间无显著差异（>0.05）。在颜色坐标方面，各组之间的明度差异（ΔL∗）具有高度显著性（<0.001），而红/绿值（Δ∗）和黄/蓝值（Δ∗）无显著差异（>0.05）。
在严重牙齿变色的情况下，贴面预备前或后进行一次诊室漂白以及预备深度不会影响贴面的遮色能力。
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