Sugiura Tsutomu, Yamamoto Kazuhiko, Horita Satoshi, Murakami Kazuhiro, Tsutsumi Sadami, Kirita Tadaaki
Department of Oral and Maxillofacial Surgery, Nara Medical University, Nara, Japan.
Applied Electronics Laboratory, Kanazawa Institute of Technology, Tokyo, Japan.
J Periodontal Implant Sci. 2017 Aug;47(4):251-262. doi: 10.5051/jpis.2017.47.4.251. Epub 2017 Aug 28.
The purpose of this study was to investigate the effects of implant tilting and the loading direction on the displacement and micromotion (relative displacement between the implant and bone) of immediately loaded implants by experiments and finite element analysis (FEA).
Six artificial bone blocks were prepared. Six screw-type implants with a length of 10 mm and diameter of 4.3 mm were placed, with 3 positioned axially and 3 tilted. The tilted implants were 30° distally inclined to the axial implants. Vertical and mesiodistal oblique (45° angle) loads of 200 N were applied to the top of the abutment, and the abutment displacement was recorded. Nonlinear finite element models simulating the experiment were constructed, and the abutment displacement and micromotion were calculated. The data on the abutment displacement from experiments and FEA were compared, and the validity of the finite element model was evaluated.
The abutment displacement was greater under oblique loading than under axial loading and greater for the tilted implants than for the axial implants. The and FEA results showed satisfactory consistency. The maximum micromotion was 2.8- to 4.1-fold higher under oblique loading than under vertical loading. The maximum micromotion values in the axial and tilted implants were very close under vertical loading. However, in the tilted implant model, the maximum micromotion was 38.7% less than in the axial implant model under oblique loading. The relationship between abutment displacement and micromotion varied according to the loading direction (vertical or oblique) as well as the implant insertion angle (axial or tilted).
Tilted implants may have a lower maximum extent of micromotion than axial implants under mesiodistal oblique loading. The maximum micromotion values were strongly influenced by the loading direction. The maximum micromotion values did not reflect the abutment displacement values.
本研究旨在通过实验和有限元分析（FEA），研究种植体倾斜和加载方向对即刻加载种植体位移和微动（种植体与骨之间的相对位移）的影响。
制备六个人工骨块。植入六个长度为10mm、直径为4.3mm的螺旋型种植体，其中3个轴向放置，3个倾斜放置。倾斜种植体相对于轴向种植体向远中倾斜30°。在基台顶部施加200N的垂直和近远中斜向（45°角）载荷，并记录基台位移。构建模拟实验的非线性有限元模型，计算基台位移和微动。比较实验和FEA得到的基台位移数据，评估有限元模型的有效性。
斜向加载时基台位移大于轴向加载，倾斜种植体的基台位移大于轴向种植体。实验和FEA结果显示出令人满意的一致性。斜向加载时的最大微动比垂直加载时高2.8至4.1倍。垂直加载时，轴向和倾斜种植体的最大微动值非常接近。然而，在倾斜种植体模型中，斜向加载时的最大微动比轴向种植体模型小38.7%。基台位移与微动之间的关系因加载方向（垂直或斜向）以及种植体植入角度（轴向或倾斜）而异。
在近远中斜向加载下，倾斜种植体的最大微动程度可能低于轴向种植体。最大微动值受加载方向的强烈影响。最大微动值不能反映基台位移值。
