Department of Mechanical Engineering, University of Wisconsin-Madison, 3046 Mechanical Engineering Building, 1513 University Avenue, Madison, WI, 53706, USA.
Nobel Biocare Services AG, Balz-Zimmermann-Str.7, 8302, Kloten, Switzerland.
J Mech Behav Biomed Mater. 2020 Dec;112:103995. doi: 10.1016/j.jmbbm.2020.103995. Epub 2020 Aug 1.
Anchorage of dental implants is quantified with a mechanical engagement to insertion, for example maximum insertion torque (MIT) and insertion energy (IE). Good anchorage of dental implants highly correlates to positive clinical outcomes. However, it is still unclear how bone density, drill protocol, surface finish and cutting flute affect anchorage. In this study, effects of the insertion factors on both MIT and IE were investigated using a full-factorial experiment at two levels: bone surrogate density (0.32 g/cm versus 0.48 g/cm), drill protocol (Ø2.4/2.8 versus Ø2.8/3.2 mm), implant surface finish (machined versus anodized surface) and cutting flute (with versus without). Osteotomies were prepared on rigid polyurethane foam blocks with dimensions of 40 × 40 × 8 mm. Screw shaped dental implants with variable tapered body were consecutively inserted into and removed from the polyurethane foam blocks three times under constant axial displacement and rotational speed. Axial force and torque were recorded synchronously. Insertion energy was calculated from the area under the torque-displacement curve. In this study, we found the main insertion mechanics were thread forming for the first insertion. For the second and third insertions, the main mechanics shifted to thread tightening. Maximum insertion torque (MIT) responded differently to the four insertion factors in comparison to IE. Bone surrogate density, drill protocol and surface finish had the largest main effects for first MIT. For the first IE, drill protocol, surface finish and cutting flute were significant contributors. These results suggest that MIT and IE are influenced by different mechanics: the first MIT and the first IE were sensitive to thread tighten and forming, respectively. Together MIT and IE provide a complete assessment of dental implant anchorage.
种植体的固位力通过机械嵌合来量化，例如最大插入扭矩（MIT）和插入能量（IE）。种植体的良好固位力与积极的临床结果高度相关。然而，骨密度、钻头方案、表面处理和切割槽如何影响固位力仍不清楚。在这项研究中，使用全因子实验在两个水平上研究了插入因素对 MIT 和 IE 的影响：骨替代物密度（0.32 g/cm 与 0.48 g/cm）、钻头方案（Ø2.4/2.8 与 Ø2.8/3.2 mm）、种植体表面处理（机械加工与阳极氧化表面）和切割槽（有与无）。在尺寸为 40×40×8mm 的刚性聚氨酯泡沫块上制备了牙槽。具有可变锥形体的螺钉状种植体在恒定轴向位移和转速下连续三次插入和从聚氨酯泡沫块中取出。轴向力和扭矩被同步记录。从扭矩-位移曲线下的面积计算插入能量。在这项研究中，我们发现第一次插入的主要插入机制是螺纹形成。对于第二和第三次插入，主要机制转变为螺纹拧紧。与 IE 相比，最大插入扭矩（MIT）对四个插入因素的响应不同。骨替代物密度、钻头方案和表面处理对第一次 MIT 有最大的主要影响。对于第一次 IE，钻头方案、表面处理和切割槽是显著的贡献者。这些结果表明，MIT 和 IE 受到不同力学的影响：第一次 MIT 和第一次 IE 分别对螺纹拧紧和形成敏感。MIT 和 IE 共同提供了对种植体固位力的完整评估。
