Assistant Professor and Assistant Program Director AEGD Program, College of Dentistry, Texas A&M University, Dallas, Texas; Affiliate Faculty, Graduate Prosthodontics, University of Washington, Seattle, Wash; Researcher, Revilla Research Center, Madrid, Spain.
Assistant Professor, Department of Biological Sciences, College of Dentistry, Texas A&M University, Dallas, Texas.
J Prosthet Dent. 2020 May;123(5):754-760. doi: 10.1016/j.prosdent.2019.06.001. Epub 2019 Oct 23.
Interim dental restorations can be fabricated by using additive manufacturing (AM) technologies. Although dental restoration contours can be easily and accurately fabricated by using computer-aided design (CAD) procedures, protocols for creating predictable color dimensions of AM interim restorations are lacking.
The purpose of this in vitro study was to measure and compare color dimensions of different AM and conventional interim restorative materials.
Disks (N=420) were fabricated by using either conventionally (CNV group) or additively manufactured (AM group) materials. The CNV group was further divided into the subgroups CNV-1 (Protemp 4; 3M ESPE) and CNV-2 (Anaxdent new outline dentin; Anaxdent). AM subgroups included AM-1 (FreePrint temp; Detax), AM-2 (E-Dent 400; Envisiontec), AM-3 (NextDent C&B; NextDent), AM-4 (NextDent C&B MFH; NextDent), and AM-5 (Med620 VEROGlaze; Stratasys). Color measurements in the CIELab coordinates were made by using a spectrophotometer (VITA EasyShade Advance 4.0; VITA) with a standardized photography gray card as a background under room light conditions (1003 lux). Color difference (ΔE*) values were calculated by using the CIE76 and CIEDE2000 formulas. The data were analyzed by using the Kruskal-Wallis test with nonparametric pairwise comparisons.
Owing to a software error, the spectrophotometer was unable to measure the color of any specimens in the AM-5 subgroup, which was consequently excluded from further analysis. Significant differences (P=.001) between 2 manufacturing groups were found based on the L* variable. All subgroups were significantly different from each other for all 3 variables (P<.001). Pairwise comparisons revealed that all groups were significantly different from each other, except for the AM-1 and AM-2 subgroups, compared with the CNV-1 subgroup for the L* color dimension. The ΔE* values calculated by using the CIE76 formula varied from 6.63 to 23.1 and by using the CIEDE2000 formula from 3.43 to 10.21, suggesting a perceptible and unacceptable color mismatch between the CNV and AM groups.
None of the additively manufactured interim materials tested matched the conventional interim materials in all 3 CIELab color dimensions.
临时牙修复体可以通过增材制造（AM）技术来制作。虽然通过计算机辅助设计（CAD）程序可以轻松、准确地制作牙修复体轮廓，但缺乏用于创建可预测的 AM 临时修复体颜色维度的方案。
本体外研究的目的是测量和比较不同 AM 和传统临时修复材料的颜色维度。
通过传统方法（CNV 组）或增材制造方法（AM 组）制作圆盘（N=420）。CNV 组进一步分为 CNV-1（Protemp 4；3M ESPE）和 CNV-2（Anaxdent new outline dentin；Anaxdent）亚组。AM 亚组包括 AM-1（FreePrint temp；Detax）、AM-2（E-Dent 400；Envisiontec）、AM-3（NextDent C&B；NextDent）、AM-4（NextDent C&B MFH；NextDent）和 AM-5（Med620 VEROGlaze；Stratasys）。使用分光光度计（VITA EasyShade Advance 4.0；VITA）在室内光照条件（1003 勒克斯）下，使用标准化摄影灰卡作为背景，对 CIELab 坐标中的颜色进行测量。使用 CIE76 和 CIEDE2000 公式计算颜色差（ΔE*）值。使用 Kruskal-Wallis 检验和非参数两两比较对数据进行分析。
由于软件错误，分光光度计无法测量 AM-5 亚组中任何样本的颜色，因此该亚组被排除在进一步分析之外。基于 L变量，发现 2 个制造组之间存在显著差异（P=.001）。所有亚组在 3 个变量上彼此均存在显著差异（P<.001）。两两比较显示，除 AM-1 和 AM-2 亚组与 CNV-1 亚组的 L颜色维度外，所有组彼此之间均存在显著差异。使用 CIE76 公式计算的 ΔE值在 6.63 到 23.1 之间，使用 CIEDE2000 公式计算的 ΔE值在 3.43 到 10.21 之间，表明 CNV 和 AM 组之间存在可感知且不可接受的颜色不匹配。
在所测试的所有 3 个 CIELab 颜色维度中，没有一种 AM 临时材料与传统临时材料完全匹配。
