Ramos G F, Ramos N C, Alves L M M, Kaizer M R, Borges A L S, Campos T M B, Melo R M
Department of Dental Materials and Prosthodontics, São Paulo State University (UNESP), Institute of Science and Technology, 777 Eng. Francisco José Longo Avenue, 12245-000, São José Dos Campos, SP, Brazil.
Department of Dental Materials and Prosthodontics, São Paulo State University (UNESP), Institute of Science and Technology, 777 Eng. Francisco José Longo Avenue, 12245-000, São José Dos Campos, SP, Brazil; College of Dentistry, Sao Francisco University (USF), 218 Sao Francisco de Assis Avenue, 12916-900, Bragança Paulista, SP, Brazil.
J Mech Behav Biomed Mater. 2021 Jul;119:104438. doi: 10.1016/j.jmbbm.2021.104438. Epub 2021 Mar 10.
To evaluate the failure probability and stress distribution of traditional and bioinspired porcelain-zirconia milled crowns, with and without silica infiltration (graded zirconia).
Traditional crown design had a zirconia infrastructure veneered with porcelain; Bioinspired, had a porcelain infrastructure with translucent-zirconia veneer; Graded and Graded Bioinspired crowns had their zirconia layer infiltrated by silica (n = 25). The cameo surface of each crown (porcelain or zirconia) was glazed. The restoration layers were fused by a vitreous connector and the crowns were adhesively cemented to dies. The specimens were then mechanically cycled in a sliding machine using 100 N load at 4 Hz. The specimens were tested until 2 × 10 cycles, and every 0.5 × 10 cycles the crowns were evaluated under stereomicroscopy for the presence of failures. The stress distribution was inspected with Finite Element Analyses.
The predominant failure modes for the Traditional and Graded crowns were delamination and cracking, respectively. The Weibull parameters beta and eta were, respectively: Traditional 1.30 and 2.3 × 10 cycles, and Graded 1.95 and 2.3 × 10 cycles. Thus, the Traditional and Graded crowns presented greater susceptibility to failure due to fatigue, while the Bioinspired and Graded Bioinspired crowns showed no fatigue effect using 100N load, showing beta = 1 and eta of approximately 17 × 10 cycles. Also, through finite element analyses, it was verified that the Bioinspired and Graded Bioinspired crowns presented the best stress distribution on both crowns and dental structures.
Bioinspired and Graded Bioinspired crowns had the lowest failure probability and better stress distribution and may be considered robust long lasting restorations.
评估传统及仿生氧化锆铣削全冠在有无二氧化硅渗透（梯度氧化锆）情况下的失效概率和应力分布。
传统全冠设计为氧化锆基底 veneered 有瓷层；仿生全冠有瓷基底和半透明氧化锆 veneer；梯度及梯度仿生全冠的氧化锆层有二氧化硅渗透（n = 25）。每个全冠（瓷或氧化锆）的浮雕面进行了上釉处理。修复层通过玻璃质连接体熔合，全冠用粘结剂粘结到代型上。然后将标本在滑动试验机中以4Hz的频率施加100N载荷进行机械循环。对标本进行测试直至2×10 次循环，每0.5×10 次循环在体视显微镜下评估全冠是否存在失效情况。用有限元分析检查应力分布。
传统全冠和梯度全冠的主要失效模式分别为分层和开裂。威布尔参数β和η分别为：传统全冠1.30和2.3×10 次循环，梯度全冠1.95和2.3×10 次循环。因此，传统全冠和梯度全冠因疲劳而失效的敏感性更高，而仿生全冠和梯度仿生全冠在使用100N载荷时未显示疲劳效应，β = 1且η约为17×10 次循环。此外，通过有限元分析证实，仿生全冠和梯度仿生全冠在全冠和牙齿结构上均呈现出最佳的应力分布。
仿生全冠和梯度仿生全冠具有最低的失效概率和更好的应力分布，可被视为坚固耐用的修复体。
