Statement of problem

Information related to the optical and surface properties, including health compatibility, surface roughness, and esthetics, of 3D-printed dental materials is scarce.

Purpose

The purpose of this in vitro study was to compare the physical and surface properties of a 3D-printed resin with those of materials used for interim restorations.

Material and methods

A 3D-printed resin (PR) (NextDent C&B MFH; 3D Systems), an autopolymerizing interim material (BA) (Protemp 4; 3M ESPE), and a composite resin (Z350) (Filtek Z350XT; 3M ESPE) were tested for degree of color change (ΔE) (n=7) at different timepoints—24 hours after polishing/baseline (P0), 8 days after polishing (P1), and after artificial aging in water at 60 °C for 24 hours (P2)—by using a CIELab-based colorimeter; flexural strength (σ) (n=10) with a 3-point bend test; Knoop hardness (H) (n=8); and surface roughness (Ra) (n=7) with a profilometer. All specimens were polished 24 hours after polymerization, except for the additional group for surface roughness (BA) without polishing (BANP). A statistical analysis was performed by using 2-way repeated-measures ANOVA followed by the Fischer test for ΔE and 1-way ANOVA followed by the Fisher test for microhardness and surface roughness (α=.05).

Results

The Z350 showed the highest values for σ and H, followed by PR. BA showed the lowest results for both tests (P<.05). Considering roughness, the Z350 showed similar values to those of BA but lower than PR; PR showed similar roughness when compared with BA. PR showed the highest color variation among the groups at all timepoints, followed by BA. The Z350 was the most color stable material at all timepoints.

Conclusions

The 3D-printed composite resin had adequate mechanical and surface properties for an interim restorative material. It has the potential to be a low-cost workflow in dentistry, although its color stability could be a concern for long-term use.

中文翻译：

---

用于数字工作流程的3D打印复合树脂的物理和表面特性。

问题陈述

与3D打印牙科材料的光学和表面特性（包括健康兼容性，表面粗糙度和美观度）有关的信息很少。

目的

这项体外研究的目的是比较3D打印树脂的物理和表面性能与用于临时修复的材料的物理和表面性能。

材料与方法

测试了3D打印树脂（PR）（NextDent C＆B MFH; 3D Systems），自动聚合中间材料（BA）（Protemp 4; 3M ESPE）和复合树脂（Z350）（Filtek Z350XT; 3M ESPE）的程度不同时间点的颜色变化（ΔE）（n = 7）-抛光/基线（P0）后24小时，抛光（P1）后8天以及在60°C的水中人工老化24小时（P2）之后的变化-通过使用基于CIELab的色度计；抗弯强度（σ）（n = 10）进行三点弯曲测试; 努氏硬度（H）（n = 8）; 用轮廓仪测定表面粗糙度（Ra）（n ＝ 7）。聚合后24小时对所有样品进行抛光，除了另外一组表面粗糙度（BA）没有抛光（BANP）。

结果

Z350的σ和H值最高，其次是PR。BA在两个测试中均显示最低的结果（P <.05）。考虑到粗糙度，Z350显示出与BA相似的值，但低于PR。与BA相比，PR表现出相似的粗糙度。PR在所有时间点的组中显示出最高的颜色变化，其次是BA。Z350在所有时间点都是最稳定的颜色。

结论

3D打印的复合树脂对临时修复材料具有足够的机械和表面性能。尽管它的颜色稳定性可能是长期使用的问题，但它有可能成为牙科的低成本工作流程。