Associate Professor and Predoctoral Implant Program Director, Department of Restorative Dentistry, University of Illinois at Chicago, College of Dentistry, Chicago, Ill.
Assistant Professor, Department of Prosthodontics and Periodontology, Piracicaba Dental School, University of Campinas, San Paolo, Brazil.
J Prosthet Dent. 2018 Jun;119(6):1000-1006. doi: 10.1016/j.prosdent.2017.06.001. Epub 2017 Sep 29.
The effects of toothbrushing (B) and thermocycling (TC) on the surface texture of different materials with various fabrication processes have been investigated. However, studies of computer-aided design and computer-aided manufacturing (CAD-CAM) ceramic restorations are limited.
The purpose of this in vitro study was to evaluate the effect of B and TC on the color stability and surface roughness of extrinsically characterized and glazed CAD-CAM ceramic restorations.
Lithium disilicate CAD ceramic (n=90) and zirconia ceramic (n=90) were studied. All specimens were crystallized/sintered, characterized, and glazed following the manufacturer's recommendation. The specimens were divided into 9 different groups: B, TC, and a combination of B plus TC (B+TC). Brushing was performed at 50 000, 100 000, and 150 000 cycles, simulating an oral environment of 5, 10, and 15 years. Thermocycling was performed at 6000, 12 000, and 18 000 cycles, simulating an oral environment of 5, 10, and 15 years. Brushing plus TC was performed with the combination of the 50 000 cycles of B, then 6000 cycles of TC, and 10 000 cycles of B, then 12 000 cycles of TC, and 15 000 cycles of B, then 18 000 cycles of TC. The color and surface roughness of each specimen were measured before and after all interventions with simulated cycles. Color differences (ΔE) and surface roughness (ΔR) data were analyzed using 2-way ANOVA, followed by the least significant difference test (α=.05). The correlation between ΔE and ΔR was statistically analyzed using the Pearson correlation analysis.
Within the lithium disilicate CAD groups, intervention did not result in any significant differences in color change (P>.05). Within the zirconia groups, a 15-year clinical simulation revealed significantly higher ΔE values than a simulated 5-year exposure (P=.017). Increased simulated cycles showed significantly higher R values for all groups. Within the zirconia groups, B revealed significantly smoother surfaces than TC (P<.001) and B+TC interventions (P<.001). For the zirconia, simulating B+TC for15 years revealed significantly higher R values than the groups of B+TC for 5 years (P<.001) and B+TC for 10 years (P=.003). No correlation (lithium disilicate CAD, r=.079; P=.462; zirconia, r=.001; P=.989) was found between the color change and surface roughness.
For both lithium disilicate CAD and zirconia, color changes were below the selected clinical perceptible threshold (ΔE=2.6) after all intervention and simulated cycles. All mean surface roughness measurements were below 0.2 μm. Generally, the surface of both lithium disilicate CAD and zirconia became rougher. No correlation was found between color difference and surface roughness for either material.
已经研究了刷牙（B）和热循环（TC）对具有不同制造工艺的不同材料的表面纹理的影响。然而，关于计算机辅助设计和计算机辅助制造（CAD-CAM）陶瓷修复体的研究有限。
本体外研究的目的是评估 B 和 TC 对特征化和上釉的 CAD-CAM 陶瓷修复体的颜色稳定性和表面粗糙度的影响。
研究了锂硅 CAD 陶瓷（n=90）和氧化锆陶瓷（n=90）。所有样本均按照制造商的建议进行结晶/烧结、表征和上釉。将样本分为 9 个不同组：B、TC 和 B 加 TC（B+TC）的组合。刷牙在 50000、100000 和 150000 个循环下进行，模拟 5、10 和 15 年的口腔环境。热循环在 6000、12000 和 18000 个循环下进行，模拟 5、10 和 15 年的口腔环境。刷牙加 TC 是在 50000 次 B 循环后进行 6000 次 TC 循环，然后是 10000 次 B 循环后进行 12000 次 TC 循环，然后是 15000 次 B 循环后进行 18000 次 TC 循环。在所有模拟循环干预前后，使用模拟循环对每个样本的颜色和表面粗糙度进行了测量。使用 2 因素方差分析分析颜色差异（ΔE）和表面粗糙度（ΔR）数据，然后进行最小显著差异检验（α=.05）。使用 Pearson 相关分析统计分析 ΔE 和 ΔR 之间的相关性。
在锂硅 CAD 组内，干预并没有导致颜色变化有任何显著差异（P>.05）。在氧化锆组内，15 年临床模拟显示出比模拟 5 年暴露更高的ΔE 值（P=.017）。增加模拟循环会导致所有组的 R 值显著升高。在氧化锆组内，B 显示出比 TC（P<.001）和 B+TC 干预（P<.001）更光滑的表面。对于氧化锆，模拟 B+TC 15 年的 R 值比 B+TC 5 年（P<.001）和 B+TC 10 年（P=.003）的 R 值更高。未发现颜色变化与表面粗糙度之间存在相关性（锂硅 CAD，r=.079；P=.462；氧化锆，r=.001；P=.989）。
对于锂硅 CAD 和氧化锆，所有干预和模拟循环后，颜色变化均低于所选临床可察觉阈值（ΔE=2.6）。所有平均表面粗糙度测量值均低于 0.2μm。通常，两种锂硅 CAD 和氧化锆的表面都变得更粗糙。对于这两种材料，都没有发现颜色差异与表面粗糙度之间存在相关性。
