Maino B Giuliano, Di Blasio Alberto, Spadoni Davide, Ravanetti Francesca, Galli Carlo, Cacchioli Antonio, Katsaros Christos, Gandolfini Mauro
Department of Biomedical, Biotechnological and Translational Science, University of Parma.
Private practice.
Eur J Orthod. 2017 Oct 1;39(5):519-527. doi: 10.1093/ejo/cjw069.
Orthodontic miniscrews are an increasingly popular choice to achieve absolute anchorage. The temporary use of miniscrews and their recent introduction have limited the debate over the biological aspect of the materials to that of the surface that permeates the field of dental implants. The aim of the present study was to investigate the integration of grade 5 titanium mini-implants with machined or sand blasted acid etched surface (SAE) under mechanical load in a rabbit tibia model of implant integration.
A total of 64 miniscrews (Ti6Al4V) of 1.5 mm diameter and 6.5 mm length were inserted in the proximal medial surface of each tibia in eight male rabbits aged 6 months. Each tibia received four miniscrews. A 100 g nickel-titanium coil spring (Neosentalloy) was applied between two miniscrews along the main axis while two miniscrews were left unloaded. The removal torque was measured for loaded and unloaded miniscrews after 12 weeks. Two miniscrews were harvested for histology.
Removal torque was significantly higher for SAE mini-implants than for machined screws, under both loading conditions. Although no difference in bone to implant contact was observed among the groups, cortical area significantly decreased with both surfaces under loading.
Our data indicate that SAE miniscrews have higher bone retention than MA miniscrews, although the effects of mechanical loading of these devices on cortical bone require further investigations.
正畸微螺钉是实现绝对支抗越来越受欢迎的选择。微螺钉的临时使用及其最近的引入，将关于材料生物学方面的争论局限于渗透到牙种植领域的表面方面。本研究的目的是在种植体整合的兔胫骨模型中，研究机械负荷下具有机加工或喷砂酸蚀表面（SAE）的5级钛微种植体的整合情况。
将总共64枚直径1.5mm、长度6.5mm的微螺钉（Ti6Al4V）植入8只6个月大雄性兔子每只胫骨的近端内侧表面。每只胫骨植入4枚微螺钉。在两枚微螺钉之间沿主轴施加一个100g的镍钛螺旋弹簧（Neosentalloy），同时让两枚微螺钉不加载负荷。12周后测量加载和未加载微螺钉的去除扭矩。收获两枚微螺钉用于组织学检查。
在两种加载条件下，SAE微种植体的去除扭矩均显著高于机加工螺钉。尽管各组之间在骨与种植体接触方面未观察到差异，但在加载情况下，两种表面的皮质面积均显著减小。
我们的数据表明，SAE微螺钉比机加工微螺钉具有更高的骨保留能力，尽管这些装置的机械负荷对皮质骨的影响需要进一步研究。
