Neshandar Asli Hamid, Rahimabadi Samiye, Babaee Hemmati Yasamin, Falahchai Mehran
Professor, Department of Prosthodontics, Dental Sciences Research Center, School of Dentistry, Guilan University of Medical Sciences, Rasht, Iran.
General Practitioner, Dental Sciences Research Center, School of Dentistry, Guilan University of Medical Sciences, Rasht, Iran.
J Prosthet Dent. 2021 Oct;126(4):595.e1-595.e8. doi: 10.1016/j.prosdent.2021.07.005. Epub 2021 Aug 6.
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.
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.
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.
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).
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.
关于三维打印（3D打印）假牙的信息，尤其是在使用增材制造技术时，以及此类假牙的修复强度方面的信息很少。
本体外研究的目的是评估不同表面处理对修复后的3D打印义齿基托表面粗糙度和弯曲强度的影响。
用丙烯酸树脂制作120个3D打印的条形试件，并分为6组（n = 20）。阳性对照组由完整试件组成。其他试件被切成两半，中间留1毫米的间隙。除阴性对照组的试件外，其余试件分别用铒：钇铝石榴石（Er:YAG）激光、空气颗粒研磨、激光与空气颗粒研磨相结合以及车针打磨进行处理。所有切开的试件均用自凝丙烯酸树脂修复，并用轮廓仪测量其表面粗糙度后进行热循环处理。用万能试验机进行弯曲强度测试。每组取一个试件在扫描电子显微镜下检查。数据采用方差分析进行分析，随后进行Games-Howell事后检验，或采用Kruskal-Wallis检验，随后采用经Bonferroni校正的Mann-Whitney检验。
阳性对照组的平均弯曲强度显著高于所有修复组（P <.001）。所有表面处理组的弯曲强度（P <.05）和表面粗糙度（P <.004）均显著高于阴性对照组。车针打磨提供的弯曲强度显著高于其他表面处理（P <.001），且表面粗糙度高于激光和空气颗粒研磨加激光处理（P <.001）。
所有表面处理均显著提高了表面粗糙度和弯曲强度，但均未产生与完整组相当的强度。车针打磨提供了最高的弯曲强度。
