Yamaguchi Yoko, Shiota Makoto, Munakata Motohiro, Kasugai Shohei, Ozeki Masahiko
Department of Implant Dentistry, Showa University School of Dentistry, 2-1-1 Kitasenzoku Ota-ku, Tokyo, 145-8515, Japan.
Oral Implantology and Regenerative Dental Medicine, Department of Masticatory Function Rehabilitation, Division of Oral Health Sciences, Graduate School, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo, 113-8510, Japan.
Int J Implant Dent. 2015 Dec;1(1):21. doi: 10.1186/s40729-015-0024-0. Epub 2015 Aug 8.
Primary stability following implant placement is essential for osseointegration and is affected by both implant design and bone density. The aim of this study was to compare the relationships between torque-time curves and implant designs in a poor bone quality model.
Nine implant designs, with five implants in each category, were compared. A total of 90 implants (Straumann: Standard RN, Bone Level RC, Tapered Effect RN; Nobel Biocare: Brånemark MKIII, MKIV) were placed in type IV artificial bone. Torque-time curves of insertion and removal were recorded at the rate of 1000 samples/s by a torque analyzer.
The torque-time curves were divided into initial, parallel, tapered, and platform areas. The mean torque rise rate of the parallel area was smallest at 0.36 N · cm/s, with a significant difference from those of the other areas (p < 0.05). Values of 2.14, 2.33, and 2.65 N · cm/s were obtained for the initial, tapered, and platform areas, respectively. The removal torque for six of the implant designs (Bone Level RC 8, 10, and 12 mm; Tapered Effect RN 10 mm; Brånemark MKIII 10 mm, MKIV 10 mm) was significantly smaller than the corresponding insertion torque (p < 0.05). However, the removal torque for ST6, 8, and 10 was almost the same as or slightly greater than the corresponding insertion torque.
The insertion torque-time curves and design features of the implants were accurately transferred. Increasing implant taper angle appeared to increase the torque rate. Torque was mainly generated from the superior surface to the valley of the thread and the inferior and axial surfaces of the platform, while the inferior and axial surfaces of the thread did not significantly affect torque generation.
种植体植入后的初期稳定性对于骨结合至关重要，且受种植体设计和骨密度的影响。本研究的目的是在骨质较差的模型中比较扭矩-时间曲线与种植体设计之间的关系。
比较了九种种植体设计，每种设计有五颗种植体。总共90颗种植体（士卓曼：标准RN、骨水平RC、锥形效应RN；诺贝尔生物保健：布伦马克MKIII、MKIV）被植入IV型人工骨中。通过扭矩分析仪以1000样本/秒的速率记录植入和取出时的扭矩-时间曲线。
扭矩-时间曲线分为初始、平行、锥形和平台区域。平行区域的平均扭矩上升速率最小，为0.36N·cm/s，与其他区域有显著差异（p<0.05）。初始、锥形和平台区域的扭矩上升速率分别为2.14、2.33和2.65N·cm/s。六种种植体设计（骨水平RC 8、10和12mm；锥形效应RN 10mm；布伦马克MKIII 10mm、MKIV 10mm）的取出扭矩显著小于相应的植入扭矩（p<0.05）。然而，ST6、8和10的取出扭矩与相应的植入扭矩几乎相同或略大。
种植体的植入扭矩-时间曲线和设计特征被准确传递。种植体锥角增加似乎会提高扭矩速率。扭矩主要从螺纹的上表面至谷底以及平台的下表面和轴向表面产生，而螺纹的下表面和轴向表面对扭矩产生没有显著影响。
