Statement of problem

Vat-polymerization additive manufacturing (AM) technologies can be used to fabricate clear silicone indices for diagnostic trial restorations, interim restorations, and direct composite resin restorations. Different support parameters, including print orientation of the virtual design of the silicone index, need to be determined when a dental device is fabricated with AM. However, the optimal printing angulation for minimal surface texture remains unclear.

Purpose

The purpose of this in vitro study was to measure the surface roughness of the AM clear silicone indices manufactured by using a vat-polymerization 3D printer with different print orientations.

Material and methods

A virtual design of a facial silicone index was obtained, and the standard tessellation language file was exported and used to manufacture all the specimens using a vat-polymerization 3D printer. All the specimens were placed on the build platform with the same parameters, except for the print orientation which was selected as the only manufacturing variable. Therefore, the 5 different groups were 0, 25, 45, 75, and 90 degrees. To minimize variation in the procedure, all the specimens (N=50) were manufactured at the same time in the selected printer at a constant room temperature of 23°C. The printer had been previously calibrated following the manufacturer′s recommendations. Surface roughness was measured in the intaglio of the left central maxillary incisor using an optical profilometer with a magnification of ×20 and an array size of 640×480. Three measurements per specimen were recorded. The Shapiro-Wilk test revealed that the data were normally distributed, and the data were analyzed by using 1-way ANOVA, followed by the post hoc Sidak test (α=.05).

Results

The 0-degree angulation printing group reported the least mean ±standard deviation surface roughness (0.9 ±0.3 μm), followed by the 90-degree group (3.0 ±0.6 μm), the 75-degree group (12.4 ±1.0 μm), the 25-degree group (13.1 ±0.9 μm), and the 45-degree group (13.5 ±1.0 μm). However, no statistically significant difference was found in the surface roughness between the 25-degree and 45-degree print orientation groups (P=.296).

Conclusions

Print orientation significantly influenced the surface roughness measured on the intaglio of the facial AM silicone indices tested.

中文翻译：

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印刷角度对添加剂制造的透明有机硅指数的表面粗糙度的影响：一项体外研究

问题陈述

还原聚合增材制造（AM）技术可用于制造透明的有机硅指数，用于诊断性试验修复，中期修复和直接复合树脂修复。当使用AM制造牙科器械时，需要确定不同的支持参数，包括有机硅指数虚拟设计的印刷方向。然而，用于最小表面纹理的最佳印刷角度仍不清楚。

目的

这项体外研究的目的是测量通过使用具有不同打印方向的桶式聚合3D打印机制造的AM透明有机硅指数的表面粗糙度。

材料与方法

获得了面部有机硅指数的虚拟设计，并导出了标准镶嵌语言文件，并使用大桶聚合3D打印机将其用于制造所有标本。除了选择打印方向作为唯一的制造变量外，所有标本都以相同的参数放置在构建平台上。因此，这5个不同的组分别是0度，25度，45度，75度和90度。为了最大程度地减少过程中的差异，所有样品（N = 50）均在选定的打印机中同时在23°C的恒定室温下生产。打印机之前已按照制造商的建议进行了校准。使用光学轮廓仪将左上颌中切牙的凹版内的表面粗糙度放大倍数为20倍，阵列尺寸为640倍×480。记录每个样品三个测量值。Shapiro-Wilk检验显示数据呈正态分布，并使用1向ANOVA分析数据，然后采用事后Sidak检验（α= .05）进行分析。

结果

0度角印刷组的平均平均值±标准偏差最小（0.9±0.3μm），其次是90度组（3.0±0.6μm），75度组（12.4±1.0μm），其次是25度组（13.1±0.9μm）和45度组（13.5±1.0μm）。但是，在25度和45度打印方向组之间的表面粗糙度上没有发现统计学上的显着差异（P = .296）。

结论

印刷方向显着影响所测面部AM有机硅指数的凹版上测得的表面粗糙度。