Bordin Dimorvan, Bergamo Edmara T P, Fardin Vinicius P, Coelho Paulo G, Bonfante Estevam A
Prosthodontics and Periodontology Department, Piracicaba Dental School, University of Campinas, Piracicaba, SP, Brazil; University of Guarulhos, Guarulhos, SP, Brazil; Department of Biomaterials and Biomimetics, New York University, College of Dentistry, New York, NY, USA.
Prosthodontics and Periodontology Department, Piracicaba Dental School, University of Campinas, Piracicaba, SP, Brazil; Department of Biomaterials and Biomimetics, New York University, College of Dentistry, New York, NY, USA.
J Mech Behav Biomed Mater. 2017 Jul;71:244-249. doi: 10.1016/j.jmbbm.2017.03.022. Epub 2017 Mar 27.
To assess the probability of survival (reliability) and failure modes of narrow implants with different diameters.
For fatigue testing, 42 implants with the same macrogeometry and internal conical connection were divided, according to diameter, as follows: narrow (Ø3.3×10mm) and extra-narrow (Ø2.9×10mm) (21 per group). Identical abutments were torqued to the implants and standardized maxillary incisor crowns were cemented and subjected to step-stress accelerated life testing (SSALT) in water. The use-level probability Weibull curves, and reliability for a mission of 50,000 and 100,000 cycles at 50N, 100, 150 and 180N were calculated. For the finite element analysis (FEA), two virtual models, simulating the samples tested in fatigue, were constructed. Loading at 50N and 100N were applied 30° off-axis at the crown. The von-Mises stress was calculated for implant and abutment.
The beta (β) values were: 0.67 for narrow and 1.32 for extra-narrow implants, indicating that failure rates did not increase with fatigue in the former, but more likely were associated with damage accumulation and wear-out failures in the latter. Both groups showed high reliability (up to 97.5%) at 50 and 100N. A decreased reliability was observed for both groups at 150 and 180N (ranging from 0 to 82.3%), but no significant difference was observed between groups. Failure predominantly involved abutment fracture for both groups. FEA at 50N-load, Ø3.3mm showed higher von-Mises stress for abutment (7.75%) and implant (2%) when compared to the Ø2.9mm.
There was no significant difference between narrow and extra-narrow implants regarding probability of survival. The failure mode was similar for both groups, restricted to abutment fracture.
评估不同直径窄种植体的存活概率（可靠性）及失效模式。
为进行疲劳测试，将42颗具有相同宏观几何形状和内锥形连接的种植体按直径分为以下两组：窄种植体（Ø3.3×10mm）和超窄种植体（Ø2.9×10mm）（每组21颗）。将相同的基台扭紧至种植体上，并粘结标准化的上颌切牙冠，然后在水中进行阶梯应力加速寿命测试（SSALT）。计算使用水平概率威布尔曲线以及在50N、100N、150N和180N下50000次和100000次循环任务的可靠性。对于有限元分析（FEA），构建了两个虚拟模型，模拟疲劳测试中的样本。在牙冠处以离轴30°施加50N和100N的载荷。计算种植体和基台的冯·米塞斯应力。
β值分别为：窄种植体为0.67，超窄种植体为1.32，这表明前者的故障率不会随疲劳增加，而后者更可能与损伤累积和耗损失效相关。两组在50N和100N时均显示出高可靠性（高达97.5%）。两组在150N和180N时可靠性均降低（范围为0至82.3%），但两组之间未观察到显著差异。两组的失效主要涉及基台骨折。在50N载荷下，与Ø2.9mm相比，Ø3.3mm的基台（7.75%）和种植体（2%）显示出更高的冯·米塞斯应力。
窄种植体和超窄种植体在存活概率方面无显著差异。两组的失效模式相似，均局限于基台骨折。
