Int J Oral Maxillofac Implants. 2024 Feb 27;39(1):119-126. doi: 10.11607/jomi.10341.
This in vitro study investigated the effect of implant geometry and diameter on the rotational load fatigue performance of an implant system with an internal conical connection with microthreads.
Regular (4.2 mm) and wide-diameter (4.8 mm) Astra Tech EV implants with straight (S) and conical (C) geometries were tested with their corresponding titanium abutments, comprising four test groups: 4.2-mm S (Group 1), 4.2-mm C (Group 2), 4.8-mm S (Group 3), and 4.8-mm C (Group 4). Five samples were included in each group. Customized brass implant holders and abutment holders were machined. A rotational load fatigue machine was used to apply a sinusoidally varying load to the implant-abutment interface at an angle of 45 degrees to produce an effective bending moment of 35 Ncm at a frequency of 14 Hz (air temperature: 20°C). The number of cycles to failure was recorded, with the upper limit set at 5 × 106 cycles. Results were analyzed using ANOVA. Failed samples were examined with a scanning electron microscope to evaluate the mode of failure.
Of the 20 total samples, 2 failed, with Groups 1 and 2 each reporting one failure. Abutment and abutment screw fracture were observed in the failed sample in Group 1, while implant and abutment screw fracture occurred in the failed sample in Group 2. All wide-diameter implants ran beyond the cut-off without failure, but abutment screw loosening was noted in one sample in Group 3. No significant difference was found between implant groups of different geometries and diameters. Damage to the abutments and the implant internal surface were noted in all failed samples.
While no significant differences were found between the test groups, failures were observed only in the regular-diameter group. The abutment and abutment screw fractured deep within the implant, and the implant fractured below the simulated bone level. These modes of failure may pose a significant clinical challenge during retrieval of these components.
本体外研究旨在探讨具有内锥形连接和微螺纹的种植体系统中，种植体几何形状和直径对旋转负载疲劳性能的影响。
使用直（S）和锥形（C）几何形状的常规（4.2mm）和宽直径（4.8mm）AstraTech EV 种植体及其相应的钛基台进行测试，包括四个测试组：4.2mm S（第 1 组）、4.2mm C（第 2 组）、4.8mm S（第 3 组）和 4.8mm C（第 4 组）。每组包含 5 个样本。定制的黄铜种植体保持器和基台保持器被加工。使用旋转负载疲劳机以 45 度角向种植体-基台界面施加正弦变化的负载，以产生 35Ncm 的有效弯曲力矩，频率为 14Hz（空气温度：20°C）。记录失效的循环次数，上限设置为 5×106 次循环。使用 ANOVA 进行结果分析。使用扫描电子显微镜检查失效样本，以评估失效模式。
在总共 20 个样本中，有 2 个样本失效，第 1 组和第 2 组各报告 1 个失效。在第 1 组失效样本中观察到基台和基台螺钉断裂，而在第 2 组失效样本中观察到种植体和基台螺钉断裂。所有宽直径种植体均在截止点之前运行而未失效，但在第 3 组的一个样本中观察到基台螺钉松动。不同几何形状和直径的种植体组之间没有发现显著差异。所有失效样本均观察到基台和种植体内部表面损坏。
虽然测试组之间没有发现显著差异，但仅在常规直径组中观察到失效。基台和基台螺钉在种植体内部深处断裂，种植体在模拟骨水平以下断裂。这些失效模式可能在这些部件的取出过程中带来重大临床挑战。
