Research Associate, Dental Research Institute and Department of Prosthodontics, School of Dentistry, Seoul National University, Seoul, Republic of Korea.
Professor, Dental Research Institute and Department of Dental Biomaterials Science, School of Dentistry, Seoul National University, Seoul, Republic of Korea.
J Prosthet Dent. 2022 May;127(5):784.e1-784.e7. doi: 10.1016/j.prosdent.2022.01.024. Epub 2022 Feb 25.
Although 3-dimensional (3D)-printed resin prostheses are widely used, studies on the effects of the manufacturing parameters of 3D printing on the color stability and stainability of these prostheses are lacking.
The purpose of this in vitro study was to investigate the effects of layer thickness and printing orientation on the color stability and stainability of a 3D-printed resin. In addition, the influence of roughness and water contact angle was evaluated.
Color changes (ΔE) in tooth-colored resin specimens produced by 3D printing with 2 different layer thicknesses and 3 different printing orientations and immersed in 3 types of aging media (distilled water, coffee solution, and wine) were evaluated (n=10). The CIELab color values were measured with a spectrophotometer at baseline and different time points (1, 3, 7, 15, and 30 days). The surface roughness (Ra) of resin specimens was measured at various time points (baseline, 7, 15, and 30 days) by confocal laser scanning microscopy after immersion in coffee solution (n=15). The water contact angle was determined by using the sessile drop method (n=10). The ΔE values were analyzed by using the 3-way repeated measures ANOVA followed by the Bonferroni test and Dunnett T3 test (α=.05). Ra values were analyzed by 3-way repeated measures ANOVA (α=.05). The water contact angle data were analyzed by 2-way ANOVA (α=.05).
The 3-way repeated measures ANOVA showed that layer thickness, printing orientation, and storage time significantly influenced the ΔE values of the 3D-printed resin specimens in each aging medium (P<.001). The ΔE values in the 0-degree subgroups were significantly lower than those in the 45- and 90-degree subgroups (P<.05). The ΔE values in the 25-μm thick groups were significantly higher than those in the 100-μm thick groups (P<.05). The ΔE values demonstrated an increase up to 15 days in all aging media. In distilled water, the ΔE values of the specimens increased or decreased depending on the groups, whereas in the coffee solution, the values decreased after 15 days (P<.001); in red wine, the values demonstrated a continuous increase up to 30 days in all groups (P<.001). The 3-way repeated measures ANOVA showed that the Ra values did not change significantly with immersion time (P=.444). The 2-way ANOVA showed that the water contact angle was not significantly affected by layer thickness (P=.921) or printing orientation (P=.062).
Layer thickness and printing orientation affected the color stability and stainability of the 3D-printed resin. The discoloration of the 3D-printed resin differed with time, depending on the type of aging media used.
尽管 3 维（3D）打印树脂假体已被广泛使用，但关于 3D 打印制造参数对这些假体颜色稳定性和染色性影响的研究还很缺乏。
本体外研究的目的是探讨不同层厚和打印方向对 3D 打印树脂颜色稳定性和染色性的影响。此外，还评估了粗糙度和水接触角的影响。
使用两种不同层厚和三种不同打印方向的 3D 打印技术制作牙色树脂标本，并将其浸泡在三种老化介质（蒸馏水、咖啡溶液和葡萄酒）中，评估其颜色变化（ΔE）（n=10）。使用分光光度计在基线和不同时间点（1、3、7、15 和 30 天）测量 CIELab 颜色值。在将树脂标本浸泡在咖啡溶液后，使用共聚焦激光扫描显微镜在不同时间点（基线、7、15 和 30 天）测量树脂标本的表面粗糙度（Ra）（n=15）。使用静态液滴法确定水接触角（n=10）。使用三因素重复测量方差分析（ANOVA），然后使用 Bonferroni 检验和 Dunnett T3 检验（α=.05）分析 ΔE 值。使用三因素重复测量 ANOVA（α=.05）分析 Ra 值。使用双因素 ANOVA（α=.05）分析水接触角数据。
三因素重复测量 ANOVA 显示，层厚、打印方向和储存时间在每种老化介质中均显著影响 3D 打印树脂标本的 ΔE 值（P<.001）。0 度亚组的 ΔE 值明显低于 45 度和 90 度亚组（P<.05）。25 μm 厚组的 ΔE 值明显高于 100 μm 厚组（P<.05）。在所有老化介质中，ΔE 值在 15 天前持续增加。在蒸馏水中，各组的 ΔE 值会升高或降低，而在咖啡溶液中，15 天后值会降低（P<.001）；在红酒中，所有组的数值在 30 天内持续增加（P<.001）。三因素重复测量 ANOVA 显示，Ra 值随浸泡时间无显著变化（P=.444）。双因素 ANOVA 显示，层厚（P=.921）或打印方向（P=.062）对水接触角无显著影响。
层厚和打印方向影响 3D 打印树脂的颜色稳定性和染色性。3D 打印树脂的变色情况因使用的老化介质类型而异，随时间而变化。
