Prosthodontic and Periodontology Department, Piracicaba Dental School, University of Campinas, Piracicaba, Brazil.
Department of Biomaterials and Biomimetics, College of Dentistry, New York University, New York, NY.
J Prosthodont. 2018 Aug;27(7):659-664. doi: 10.1111/jopr.12540. Epub 2016 Nov 18.
To evaluate the reliability of narrow diameter dental implants (NDIs) with similar macrogeometry and 3 implant-abutment connection designs.
Eighty-four NDIs (3.5 × 10 mm) were selected and divided into 4 groups (n = 21/group) according to implant-abutment connection design, as follows: EH - external hexagon, IH - internal hexagon, IC - internal conical, and IC-M - internal conical connected to a monolithic titanium abutment. 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. Use of level probability Weibull curves, and reliability for a mission of 50,000 cycles at 75 N and 200 N were calculated.
The beta (β) values were: 1.48 for IC, 1.40 for IC-M, 8.54 for EH, and 1.98 for IH, indicating that damage accumulation was an acceleration factor for failure of all groups. At 75 N the probability of survival was not significantly different between groups. A decrease in reliability was observed for all groups at 200 N with no significant differences between IC (81.71%) and IC-M (94.28%), or between EH and IH (0%) which presented the lowest values. EH failures were primarily restricted to the screw, while IH involved screw and implant fracture. IC and IC-M were restricted to prosthetic failures (fracture and bending).
Narrow implants with external or internal hexagon connections presented the lowest reliability at high loads compared to internal conical connections. Failure modes differed among connections.
评估具有相似宏观几何形状和 3 种种植体-基台连接设计的细径种植体（NDIs）的可靠性。
选择 84 个 NDIs（3.5×10mm），根据种植体-基台连接设计分为 4 组（每组 n=21）：EH-外六角、IH-内六角、IC-内锥形和 IC-M-连接到整体式钛基台的内锥形。相同的基台被拧紧到种植体上，并将标准化的上颌切牙冠粘接到一起，然后在水中进行步进应力加速寿命测试（SSALT）。使用水平概率威布尔曲线和在 75N 和 200N 时 50,000 次循环的任务可靠性进行计算。
β值分别为：IC 为 1.48、IC-M 为 1.40、EH 为 8.54 和 IH 为 1.98，表明所有组的失效都是损伤积累的加速因素。在 75N 时，各组的存活率没有显著差异。在 200N 时，所有组的可靠性都有所下降，IC（81.71%）和 IC-M（94.28%）之间没有显著差异，EH 和 IH（0%）之间也没有显著差异，EH 和 IH 的可靠性最低。EH 失效主要限于螺钉，而 IH 涉及螺钉和种植体断裂。IC 和 IC-M 仅限于修复体失效（断裂和弯曲）。
与内锥形连接相比，具有外六角或内六角连接的细径种植体在高负荷下可靠性最低。连接方式的失效模式不同。
