Statement of problem

Information regarding three-dimensional-printed (3D-printed) dentures, especially when using the additive manufacturing technique, and the repair strength of this type of denture is sparse.

Purpose

The purpose of this in vitro study was to assess the effect of different surface treatments on the surface roughness and flexural strength of repaired 3D-printed denture base.

Material and methods

One hundred and twenty 3D-printed bar-shaped specimens were fabricated from acrylic resin and divided into 6 groups (n=20). The positive control group consisted of intact specimens. The other specimens were sectioned in half with a 1-mm gap. Except for the specimens in the negative control group, the remaining specimens were treated with erbium: yttrium-aluminum-garnet (Er:YAG) laser, airborne-particle abrasion, a combination of laser and airborne-particle abrasion, and bur grinding. All sectioned specimens were repaired by autopolymerizing acrylic resin and thermocycled after measuring their surface roughness with a profilometer. The flexural strength test was performed with a universal testing machine. One specimen of each group was inspected under a scanning electron microscope. The data were analyzed with ANOVA, followed by the Games-Howell post hoc test or the Kruskal-Wallis test followed by the Mann-Whitney test with Bonferroni adjustment.

Results

The mean flexural strength of the PC group was significantly higher than that of all repaired groups (P<.001). All surface-treated groups showed significantly higher flexural strength (P<.05) and surface roughness (P<.004) than the negative control group. Bur grinding provided significantly higher flexural strength than other surface treatments (P<.001) and higher surface roughness than laser and airborne-particle abrasion plus laser (P<.001).

Conclusions

All surface treatments significantly increased the surface roughness and flexural strength, but none of them yielded a strength comparable with that of the intact group. Bur grinding provided the highest flexural strength.

中文翻译：

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不同表面处理对修复后的 3D 打印义齿基托表面粗糙度和抗弯强度的影响：一项体外研究

问题陈述

有关 3D 打印（3D 打印）假牙的信息，尤其是在使用增材制造技术时，此类假牙的修复强度很少。

目的

这项体外研究的目的是评估不同表面处理对修复后的 3D 打印义齿基托的表面粗糙度和弯曲强度的影响。

材料与方法

120 个 3D 打印的棒状试样由丙烯酸树脂制成，分为 6 组（n = 20）。阳性对照组由完整标本组成。其他样品被切成两半，间隙为 1 毫米。除阴性对照组标本外，其余标本均用铒处理：钇铝石榴石（Er：YAG）激光、空气颗粒磨蚀、激光和空气颗粒磨蚀相结合，以及车针研磨。所有切片样品均通过自聚合丙烯酸树脂进行修复，并在用轮廓仪测量其表面粗糙度后进行热循环。弯曲强度试验采用万能试验机进行。在扫描电子显微镜下检查每组一个样品。数据用ANOVA分析，

结果

PC组的平均抗弯强度显着高于所有修复组（P <.001）。所有表面处理组的抗弯强度（P <.05）和表面粗糙度（P <.004）均显着高于阴性对照组。车针磨削提供比其他表面处理显着更高的弯曲强度 ( P <.001) 和比激光和空气颗粒磨损加激光 ( P <.001)更高的表面粗糙度。

结论

所有的表面处理都显着增加了表面粗糙度和弯曲强度，但没有一个产生与完整组相当的强度。车针研磨提供了最高的抗弯强度。