Department of Prosthodontics, Oral Science Research Center, College of Dentistry, Yonsei University, Seoul, the Republic of Korea.
Research Institute of Agriculture and Life Sciences, College of Agriculture & Life Sciences, Seoul National University, Seoul 08826, the Republic of Korea; Graphy, Inc. 6th Fl, Ace GasanFORHU, 225 Gasan digital 1-ro, Geumcheon-gu, Seoul 08501, the Republic of Korea.
Dent Mater. 2023 Jul;39(7):648-658. doi: 10.1016/j.dental.2023.05.007. Epub 2023 May 18.
This study aimed to assess the effects of airborne-particle abrasion (APA) on the flexural strength of two types of 3D-printing resins for permanent restoration.
Two types of 3D printing resins (urethane dimethacrylate oligomer; UDMA, ethoxylated bisphenol-A dimethacrylate; BEMA) constituting different components were printed. The specimen surfaces were subjected to APA using 50 and 110 µm alumina particles under different pressures. The three-point flexural strength was measured for each surface treatment group, and a Weibull analysis was performed. Surface characteristics were analyzed via surface roughness measurements and scanning electron microscopy. Dynamic mechanical analysis and nano-indentation measurements were limited to the control group.
The three-point flexural strength according to the surface treatment was significantly lower in the UDMA group for large particle sizes and at high pressures; the BEMA group demonstrated low flexural strength for large particle sizes regardless of the pressure. After thermocycling, the flexural strengths of UDMA and BEMA significantly decreased in the group subjected to surface treatment. The Weibull modulus and characteristic strength of UDMA were higher than those of BEMA under different APA and thermocycling conditions. As the abrasion pressure and particle size increased, a porous surface formed, and the surface roughness increased. Compared with BEMA, UDMA featured a lower strain, greater strain recovery, and a negligible increase in modulus according to strain.
Thus, surface roughness increased with the sandblasting particle size and pressure of the 3D-printing resin. Hence, a suitable surface treatment method to improve adhesion can be determined by considering physical property changes.
本研究旨在评估气固喷射研磨（Airborne-Particle Abrasion，APA）对两种用于永久修复的 3D 打印树脂的弯曲强度的影响。
打印两种不同成分的 3D 打印树脂（聚氨酯二甲基丙烯酸酯低聚物；UDMA、乙氧化双酚 A 二甲基丙烯酸酯；BEMA）。使用 50 和 110μm 氧化铝颗粒在不同压力下对试件表面进行 APA 处理。对每种表面处理组进行三点弯曲强度测量，并进行威布尔分析。通过表面粗糙度测量和扫描电子显微镜分析表面特性。动态力学分析和纳米压痕测量仅限于对照组。
根据表面处理的三点弯曲强度，UDMA 组在大粒径和高压力下显著降低；BEMA 组在大粒径下无论压力如何，弯曲强度均较低。热循环后，经表面处理的 UDMA 和 BEMA 组的弯曲强度显著降低。在不同的 APA 和热循环条件下，UDMA 的威布尔模数和特征强度均高于 BEMA。随着研磨压力和颗粒尺寸的增加，形成了多孔表面，表面粗糙度增加。与 BEMA 相比，UDMA 的应变较低，应变恢复较大，应变下的模量增加可忽略不计。
因此，3D 打印树脂的喷砂颗粒尺寸和压力会增加表面粗糙度。因此，可以通过考虑物理性能变化来确定改善附着力的合适表面处理方法。
