Assistant Professor, Department of Prosthodontics, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
Associate Professor, Dental Research Center, Implant Research Center, Laser Research Center, Dentistry Research Institute, Tehran University of Medical Sciences and Department of Prosthodontics, School of Dentistry, Tehran University of Medical Sciences, Tehran, Iran.
J Oral Implantol. 2020 Dec 1;46(6):555-561. doi: 10.1563/aaid-joi-D-19-00029.
This study evaluated the effect of adding serration to the abutment-implant connection on torque maintenance before and after loading. Two implant systems with the same dimensions and connection design (internal 8° Morse taper octagon) were selected: one with nonserrated abutments (Simple line II) and the other one with serrated abutments (F & B). The removal torque value (RTV) was measured in 2 groups for each system: one group with one-piece abutments and the other group with 2-piece abutments, before and after cyclic loading (n = 10 in each group). The initial RTV of the abutment screw was measured with a digital torque meter. Each abutment received a cement-retained metal crown with 30° occlusal surface. Cyclic axial peak load of 75 ± 5 N was applied to the implants for 500 000 cycles at 1 Hz. The post-load RTV was then measured. Two-way and repeated-measures analysis of variance (ANOVA), and independent t test were applied to assess the effects of cyclic loading, connection design, abutment type, and their interaction on the percentage of torque loss (α = .05). Two-way ANOVA showed that serration of mating surfaces had a significant effect on torque maintenance before (P < .001) and after (P = .004) cyclic loading. Repeated-measures ANOVA also showed that loading had a significant effect on the torque loss percentage (P < .01). Comparison of the groups with t test showed that the torque loss of the serrated groups was lower than that of non- serrated groups. Despite the limitations of this study, the stability of the implant-abutment connection in the serrated design was higher than that of non-serrated group.
本研究评估了在加载前后，在基台-种植体连接上增加锯齿对扭矩维持的影响。选择了两种具有相同尺寸和连接设计（内部 8°莫氏锥八角形）的种植体系统：一种具有非锯齿基台（Simple line II），另一种具有锯齿基台（F & B）。对于每个系统，每组都测量了两种连接方式的去除扭矩值（RTV）：一种是一体式基台，另一种是分体式基台，分别在循环加载前后（每组各 10 个）进行测量。用数字扭矩计测量基台螺钉的初始 RTV。每个基台都用带 30°咬合面的金属烤瓷冠进行固位。在 1 Hz 下，每个种植体施加 75±5 N 的轴向峰值循环负荷 50 万次。然后测量加载后的 RTV。采用双向和重复测量方差分析（ANOVA）和独立 t 检验来评估循环负荷、连接设计、基台类型及其相互作用对扭矩损失百分比的影响（α=0.05）。双向 ANOVA 显示，配合面的锯齿对循环加载前后的扭矩维持有显著影响（P<0.001 和 P=0.004）。重复测量 ANOVA 还显示，加载对扭矩损失百分比有显著影响（P<0.01）。t 检验比较各组显示，锯齿组的扭矩损失低于非锯齿组。尽管存在本研究的局限性，但锯齿设计中种植体-基台连接的稳定性高于非锯齿组。
