Department of Endodontics, College of Dentistry, University of Tennessee Health Science Center College of Dentistry, Memphis, Tennessee.
Department of Bioscience Research, College of Dentistry, University of Tennessee Health Science Center College of Dentistry, Memphis, Tennessee.
J Esthet Restor Dent. 2018 Mar;30(2):E61-E67. doi: 10.1111/jerd.12335. Epub 2017 Aug 31.
To determine the effect of access design on intracoronal bleaching with 35% carbamide peroxide on discolored teeth.
Forty-two intact maxillary central incisors were selected, sectioned and artificially stained using whole blood. Color measurements were performed with a spectrophotometer: before staining (T1), after staining (T2), at 7 (T3), and 14 (T4) days postbleaching. After T1, specimens were stratified and divided randomly into two groups according to access design (N = 20): G1: contracted endodontic cavity (CEC) access performed with a #848-010M bur and G2: traditional endodontic cavity (TEC) access done with a #1157 bur. Canals were obturated, a cervical barrier was placed and 35% carbamide peroxide was sealed in the chamber for 7 days and replaced at 7 days for an additional 7 days. Data were collected based on CIELAB-CIE1976 (L a b ) system. Repeated measures SNK anova was used to evaluate the effects of access design and time on color change (ΔE ) and luminosity (L ) (α < 0.05).
For CEC, L was significantly different at all times points (P < .05). For TEC, L values were significantly different at all time points (P < .05) except for T0 and T4, which were similar (P > .05). There was no statistical difference for ΔE between CEC and TEC designs at any time point (P > .05).
In general, teeth accessed with CEC or TEC designs showed statistically similar bleaching when using 35% carbamide peroxide. However, lightness values were only reestablished with bleaching through a TEC access design.
Despite the current trend to conserve tooth structure when performing endodontic access cavities, the use of conservative access designs for bleaching discolored maxillary central incisors affected the acceptability threshold when compared with a traditional access design. These smaller accesses might not be an alternative treatment option when internal bleaching in the esthetic zone is anticipated.
确定不同的根管口设计对使用 35%过氧化脲对内源性牙齿着色进行漂白的效果。
选择 42 颗完整的上颌中切牙，用全血进行切片和人工染色。使用分光光度计进行颜色测量：染色前（T1）、染色后（T2）、7 天（T3）和 14 天（T4）后。在 T1 后，根据根管口设计将标本分层并随机分为两组（N=20）：G1：使用 848-010M 号球钻进行收缩性根管口（CEC）进入，G2：使用 1157 号球钻进行传统根管口（TEC）进入。根管填充后，放置颈缘封闭剂，将 35%过氧化脲封入根管内 7 天，7 天后更换并再封 7 天。数据基于 CIELAB-CIE1976（L a b）系统收集。采用重复测量 SNK 方差分析评估根管口设计和时间对颜色变化（ΔE）和明度（L）的影响（α<0.05）。
对于 CEC，所有时间点的 L 值均有显著差异（P<0.05）。对于 TEC，除 T0 和 T4 外，所有时间点的 L 值均有显著差异（P<0.05），T0 和 T4 之间无显著差异（P>0.05）。在任何时间点，CEC 和 TEC 设计之间的 ΔE 均无统计学差异（P>0.05）。
总体而言，使用 35%过氧化脲进行漂白时，采用 CEC 或 TEC 设计的牙齿在漂白效果上具有统计学上的相似性。然而，只有通过 TEC 进入设计才能重新建立亮度值。
尽管目前在进行根管口预备时存在保留牙齿结构的趋势，但与传统的根管口设计相比，使用保守的根管口设计进行漂白变色的上颌中切牙会影响可接受阈值。在预期进行内漂白的美观区域，这些较小的根管口可能不是一种替代治疗选择。
