Zidi Zhai, Chao Qian, Ting Jiao, Chun Xu, Jian Sun
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引用次数: 0
Abstract
Purpose: The mechanical and fatigue properties of zirconia specimens printed by vat photopolymerization (VPP) were evaluated and compared with those of zirconia specimens milled by computer numerical control (CNC).
Materials and methods: Bar-shaped specimens were printed by stereolithography (SL) and digital light processing (DLP). CNC-milled specimens were used as control samples. The fracture toughness, hardness, and flexural strength properties of the zirconia specimens were evaluated via single edge V-notch beam tests, Vickers hardness tests, and 3-point bending tests. Dynamic fatigue tests were carried out in distilled water using a step-stress test. After static bending and dynamic step-stress testing, fractography analysis was performed. Statistical analysis was carried out to compare the fracture toughness, hardness, flexural strength, and fatigue cycle results of each group (α = 0.05).
Results: The fracture toughness values did not significantly differ among the groups (p > 0.05). The flexural strength was 894.10 MPa for SL, 831.46 MPa for DLP, and 1140.39 MPa for CNC. The flexural strength of CNC was greater than that of SL and DLP (p < 0.01). The mean fatigue cycles were 23498.07 for SL, 19858.60 for DLP, and 31566.80 for CNC. The mean fatigue failure strength was 643.13 MPa for SL, 530.63 MPa for DLP, and 903.75 MPa for CNC. The fatigue failure strength of CNC was greater than that of SL and DLP (p < 0.05). Fractography analysis revealed material defects at the fracture origin for each group. A partially fused structure of the incompletely debonded resin could be observed in SL, and a porous region of incompletely sintered zirconia grains could be observed in CNC.
Conclusions: The fracture toughness and hardness of zirconia printed by VPP are comparable to those of zirconia milled by CNC. However, zirconia milled by CNC has superior static flexural strength and dynamic fatigue resistance. Further studies are needed to explore the clinical applications of VPP-printed zirconia.
期刊介绍：
The Journal of Prosthodontics promotes the advanced study and practice of prosthodontics, implant, esthetic, and reconstructive dentistry. It is the official journal of the American College of Prosthodontists, the American Dental Association-recognized voice of the Specialty of Prosthodontics. The journal publishes evidence-based original scientific articles presenting information that is relevant and useful to prosthodontists. Additionally, it publishes reports of innovative techniques, new instructional methodologies, and instructive clinical reports with an interdisciplinary flair. The journal is particularly focused on promoting the study and use of cutting-edge technology and positioning prosthodontists as the early-adopters of new technology in the dental community.
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