Amaral Marina, Cesar Paulo Francisco, Bottino Marco Antonio, Lohbauer Ulrich, Valandro Luiz Felipe
Department of Dental Materials and Prosthesis, Dentistry School, Sao Paulo State University, Av. Eng Franscisco José Longo, 777, Sao Jose dos Campos, Brazil.
Department of Dental Materials, Dentistry School, Sao Paulo University, Av. Prof Lineu Prestes, 2227 Sao Paulo, Brazil.
J Mech Behav Biomed Mater. 2016 Apr;57:149-56. doi: 10.1016/j.jmbbm.2015.11.042. Epub 2015 Dec 15.
The aim of this study was to evaluate the effect of three surface treatments on the biaxial flexural strength before and after mechanical cycling, and fatigue limit of a Y-TZP ceramic.
Disc-shaped specimens were produced and three surface conditions were tested: CT (as-sintered, untreated), GL (thin layer of porcelain glaze), and AA (air abrasion with 30µm silica particles). Profilometric and phase transformation analyses were performed. Disks were submitted to biaxial flexural strength (BFS) before and after mechanical cycling (100N, 2×10(6) cycles) and staircase approach (n=20). The flexural fatigue limits (FFLs) were obtained at 10(2), 10(3), 10(4) and 10(5) cycles.
Tetragonal to monoclinic transformation was only observed for AA group (9.46% of monoclinic phase). Glazed group presented the highest Ra values. Flexural strength was higher for AA group; CT and GL groups were similar. The reliability was similar between groups. The mechanical cycling at 100N did not affected flexural strength. FFLs were higher for AA group, and the three surface treatments presented decrease in strength according to the increase in number o cycles.
本研究旨在评估三种表面处理对Y-TZP陶瓷在机械循环前后的双轴弯曲强度以及疲劳极限的影响。
制作盘状试样，并测试三种表面条件：CT（烧结态，未处理）、GL（薄瓷釉层）和AA（用30μm二氧化硅颗粒进行空气研磨）。进行了轮廓测定和相变分析。圆盘在机械循环（100N，2×10⁶次循环）前后接受双轴弯曲强度（BFS）测试以及采用阶梯法（n = 20）。在10²、10³、10⁴和10⁵次循环时获得弯曲疲劳极限（FFL）。
仅在AA组观察到四方相向单斜相的转变（单斜相占9.46%）。釉面组的Ra值最高。AA组的弯曲强度更高；CT组和GL组相似。各组之间的可靠性相似。100N的机械循环未影响弯曲强度。AA组的FFL更高，并且三种表面处理的强度均随循环次数增加而降低。
