Nguyen Melissa V, Codrington John, Fletcher Lloyd, Dreyer Craig W, Sampson Wayne J
Department of Orthodontics, University of Adelaide, Adelaide, South Australia, Australia.
Department of Mechanical Engineering, University of Adelaide, Adelaide, South Australia, Australia.
Eur J Orthod. 2018 Jan 23;40(1):37-44. doi: 10.1093/ejo/cjx026.
The aim of this in vitro study was to evaluate the progressive development of surface microdamage produced following the insertion of orthodontic miniscrews (OMs) into 1.5 mm thick porcine tibia bone using maximum insertion torque values of 12 Ncm, 18 Ncm, and 24 Ncm.
Aarhus OMs (diameter 1.5 mm; length 6 mm) were inserted into 1.5 mm porcine bone using a torque limiting hand screwdriver set at 12 Ncm, 18 Ncm, and 24 Ncm. A custom rig equipped with a compression load cell was used to record the compression force exerted during manual insertion. A sequential staining technique was used to identify microdamage viewed under laser confocal microscopy. Virtual slices were created and stitched together to form a compressed two-dimensional composition of the microdamage. Histomorphometric parameters, including total damage area, diffuse damage area, maximum crack length, maximum damage radius, and maximum diffuse damage radius, were measured. Kruskal-Wallis Tests and Wilcoxon Rank-Sum Tests were used to analyse the generated data.
All OMs inserted using 12 Ncm failed to insert completely, while partial insertion was observed for two OMs inserted at 18 Ncm. Complete insertion was achieved for all OMs inserted at 24 Ncm. Histomorphometrically, OMs inserted using 24 Ncm produced a significantly larger diffuse damage area (P < 0.05; P < 0.05) and maximum diffuse damage radius (P < 0.05; P < 0.05), for both the entry and exit surfaces, respectively, compared with the 12 Ncm and 18 Ncm groups.
Insertion torque can influence the degree of OM insertion and, subsequently, the amount of microdamage formed following insertion into 1.5 mm thick porcine tibia bone. An increase in insertion torque corresponds with greater insertion depth and larger amounts of microdamage.
本体外研究的目的是评估在将正畸微螺钉（OMs）以12 Ncm、18 Ncm和24 Ncm的最大插入扭矩值插入1.5毫米厚的猪胫骨后表面微损伤的渐进发展情况。
使用设置为12 Ncm、18 Ncm和24 Ncm的扭矩限制手动螺丝刀将奥胡斯微螺钉（直径1.5毫米；长度6毫米）插入1.5毫米厚的猪骨中。使用配备有压缩测力传感器的定制装置记录手动插入过程中施加的压缩力。采用顺序染色技术识别激光共聚焦显微镜下观察到的微损伤。创建虚拟切片并拼接在一起以形成微损伤的压缩二维合成图像。测量组织形态计量学参数，包括总损伤面积、弥散损伤面积、最大裂纹长度、最大损伤半径和最大弥散损伤半径。使用Kruskal-Wallis检验和Wilcoxon秩和检验分析生成的数据。
使用12 Ncm插入的所有微螺钉均未完全插入成功，但观察到以18 Ncm插入的两个微螺钉部分插入。以24 Ncm插入的所有微螺钉均实现了完全插入成功。在组织形态计量学方面，与12 Ncm和18 Ncm组相比，以24 Ncm插入时，微螺钉在入口和出口表面分别产生了显著更大的弥散损伤面积（P < 0.05；P < 0.05）和最大弥散损伤半径（P < 0.05；P < 0.05）。
插入扭矩可影响微螺钉的插入程度，并进而影响插入1.5毫米厚猪胫骨后形成的微损伤量。插入扭矩的增加与更大的插入深度和更多的微损伤量相对应。
