Resident, Advanced Prosthodontics Program, University of Tennessee Health Science Center, Memphis, Tenn.
Assistant Professor, Director of Implantology, Department of Prosthodontics, University of Tennessee Health Science Center, Memphis, Tenn.
J Prosthet Dent. 2023 Dec;130(6):877.e1-877.e7. doi: 10.1016/j.prosdent.2023.09.008. Epub 2023 Oct 14.
Three-mol% yttria-stabilized tetragonal zirconia polycrystal (3Y-TZP) has been commonly used for fixed prosthodontic restorations. The opacity of 3Y-TZP may be masked with external staining, although the longevity of extrinsic stains applied to monolithic zirconia is unclear.
The purpose of this in vitro study was to analyze the color and surface roughness of extrinsically stained zirconia specimens after thermocycling and toothbrushing.
Monolithic Ø12.5×1.25-mm zirconia disks were milled from 3Y-TZP blocks, sintered according to manufacturer instructions, and then divided into 3 groups (C, J, and O; n=16) for application of stain and glaze. All specimens underwent 10 000 thermocycles in distilled water before being further divided into 2 dentifrice groups (n=8): normal grit, low relative dentin abrasivity (RDA) (Subgroup N) and abrasive grit, high RDA (Subgroup A). Specimens were brushed in a multistation brushing machine under 1.47 N of force using a 5:8 toothpaste and distilled water slurry for 10 000 cycles with a straight (American Dental Association Standard) toothbrush to simulate 1 year of toothbrushing. Color and surface roughness measurements were obtained at 3 time points: baseline, after thermocycling, and after brushing. A 2-way repeated measures ANOVA was used to independently assess changes in color and surface roughness with respect to thermocycling and brushing (α=.05).
Group J displayed no significant change in color for either dentifrice system (P>.05). However, a significant change in surface roughness was observed for both dentifrice subgroups (P<.001). Group C specimens displayed significant changes in color (P<.001) and surface roughness (P<.001) for both dentifrice systems. Group O specimens displayed significant changes in color (P<.025) for both dentifrice systems and significant changes in surface roughness (P<.004) for subgroup A, but no significant changes for subgroup N (P=.075).
Artificial aging of monolithic zirconia resulted in changes in color and surface roughness that did not surpass the thresholds for perceptibility and acceptability. This study failed to establish durability limits for extrinsic stains applied to 3Y-TZP.
三氧化二钇稳定的四方氧化锆多晶（3Y-TZP）已广泛用于固定义齿修复体。虽然外源性染色剂应用于整体氧化锆的耐久性尚不清楚，但 3Y-TZP 的不透明度可以通过外部染色来掩盖。
本体外研究的目的是分析热循环和刷牙后外染色氧化锆试件的颜色和表面粗糙度。
从 3Y-TZP 块中铣削出直径为 12.5mm、厚 1.25mm 的整体氧化锆圆盘，按照制造商的说明烧结，然后分为 3 组（C、J 和 O；n=16）进行染色和上釉。所有试件在蒸馏水中进行 10000 次热循环，然后进一步分为 2 个牙膏组（n=8）：普通磨料，低相对牙本质磨损率（RDA）（亚组 N）和磨料，高 RDA（亚组 A）。在 1.47N 的力下，使用 5:8 的牙膏和蒸馏水浆，在多工位刷牙机上以直刷（美国牙科协会标准）刷牙 10000 次，模拟 1 年的刷牙时间。在 3 个时间点测量颜色和表面粗糙度：基线、热循环后和刷牙后。采用 2 因素重复测量方差分析分别评估热循环和刷牙对颜色和表面粗糙度的变化（α=.05）。
J 组对于两种牙膏系统的颜色均无显著变化（P>.05）。然而，两种牙膏亚组的表面粗糙度均有显著变化（P<.001）。C 组试件的颜色（P<.001）和表面粗糙度（P<.001）均有显著变化，两种牙膏系统均有显著变化。O 组试件的颜色（P<.025）对于两种牙膏系统和亚组 A 的表面粗糙度（P<.004）有显著变化，但亚组 N 无显著变化（P=.075）。
整体氧化锆的人工老化导致颜色和表面粗糙度发生变化，但未超过可察觉和可接受的阈值。本研究未确定应用于 3Y-TZP 的外源性染色剂的耐久性极限。
