Bédouin Yvan, Lefrançois Etienne, Salomon Jean-Pierre, Auroy Pascal
Associate Professor, CHU Rennes, Univ Rennes, INSA Rennes, CNRS, ISCR (Rennes Institute of Chemical Sciences), Rennes, France.
Assistant Professor, CHU Rennes, Univ Rennes, INSA Rennes, CNRS, ISCR (Rennes Institute of Chemical Sciences), Rennes, France.
J Prosthet Dent. 2023 Mar;129(3):433-439. doi: 10.1016/j.prosdent.2021.04.027. Epub 2021 Jul 5.
Information regarding the rotational freedom of internal connection implants is sparse.
The purpose of this in vitro study was to compare the rotational freedom of different internal conical and internal nonconical connections.
Thirty implants, 30 straight manufactured standard abutments, and 30 standard abutment screws were obtained for each of the 5 implant systems tested. Three implant systems had indexed internal conical connections with different antirotational geometries: hexagon (Naturall+), cam-groove (ID CAM M), and octagon (Bone Level). Two implant systems had internal nonconical connections with hexagonal antirotational geometry (Tapered Screw-Vent and Seven). The implants were mounted in a steel plate, and a metal reference arm was attached to the abutment. Before tightening the standard abutment screw, a modified torque wrench was used to rotate the abutment clockwise until reaching the clockwise rotational endpoint. This modified torque wrench was connected to the abutment's outer surface. It allowed free access to the standard abutment screw for a second torque wrench, specific to each implant system. The modified torque wrench applied a controlled torque of 5 Ncm, which held the abutment at the clockwise rotational endpoint. The standard abutment screw was then tightened to the manufacturer's specified torque value with the second torque wrench. Angle value corresponding to the clockwise endpoint was measured microscopically between a fixed reference point on the steel plate and the reference arm. The abutment was then unscrewed and removed. The same procedure was carried out to rotate the abutment counterclockwise and measure the angle value corresponding to the counterclockwise rotational endpoint. The rotational freedom was finally determined from the differences in the angles between the clockwise and counterclockwise rotational endpoints. Rotational freedom angle values were summarized as descriptive statistics (means, standard deviations). The normality test (Kolmogorov-Smirnov) was applied, and the Kruskal-Wallis test was performed. The Wilcoxon signed-rank test was used to isolate the implant system differences from each other (α=.05).
The lowest mean rotational freedom angles were obtained for Bone Level (conical connection, 0.17 degrees) and Tapered Screw-Vent (nonconical connection, 0.05 degrees). These systems were followed in increasing order by ID CAM M (conical connection, 0.50 degrees), Seven (nonconical connection, 1.98 degrees), and Naturall+ (conical connection, 2.49 degrees). Compared with each other, all implant systems had significant statistical differences in rotational freedom angles (P<.05).
Significant differences were found among the 5 implant systems. The lowest mean rotational freedom angles were obtained both with a conical connection (Bone Level) and a nonconical connection (Tapered Screw-Vent).
关于内部连接种植体旋转自由度的信息较少。
本体外研究的目的是比较不同内部锥形和非锥形连接的旋转自由度。
对测试的5种植体系统，每种均获取30颗种植体、30个直的标准基台以及30个标准基台螺丝。3种植体系统具有带不同抗旋转几何形状的索引式内部锥形连接：六边形（Naturall+）、凸轮槽（ID CAM M）和八边形（骨水平型）。2种植体系统具有带六边形抗旋转几何形状的内部非锥形连接（锥形螺纹孔和Seven）。将种植体安装在钢板上，并在基台上连接一个金属参考臂。在拧紧标准基台螺丝之前，使用改良扭矩扳手顺时针旋转基台，直至到达顺时针旋转终点。该改良扭矩扳手连接到基台的外表面。它允许另一个特定于每种种植体系统的扭矩扳手自由接近标准基台螺丝。改良扭矩扳手施加5 Ncm的受控扭矩，将基台保持在顺时针旋转终点。然后用第二个扭矩扳手将标准基台螺丝拧紧至制造商规定的扭矩值。在钢板上的固定参考点与参考臂之间，通过显微镜测量对应于顺时针终点的角度值。然后拧松并移除基台。以相同程序逆时针旋转基台并测量对应于逆时针旋转终点的角度值。最终根据顺时针和逆时针旋转终点之间的角度差确定旋转自由度。旋转自由度角度值汇总为描述性统计量（均值、标准差）。应用正态性检验（柯尔莫哥洛夫-斯米尔诺夫检验），并进行克鲁斯卡尔-沃利斯检验。使用威尔科克森符号秩检验来区分各种植体系统之间的差异（α = 0.05）。
骨水平型（锥形连接，0.17度）和锥形螺纹孔（非锥形连接，0.05度）获得的平均旋转自由度角度最低。按升序排列，这些系统之后依次是ID CAM M（锥形连接，0.50度）、Seven（非锥形连接，1.98度）和Naturall+（锥形连接，2.49度）。相互比较时，所有种植体系统在旋转自由度角度上均有显著统计学差异（P < 0.05）。
在5种植体系统之间发现了显著差异。锥形连接（骨水平型）和非锥形连接（锥形螺纹孔）均获得了最低的平均旋转自由度角度。
