Kerberger Robert, Brunello Giulia, Drescher Dieter, van Rietbergen Bert, Becker Kathrin
Department of Orthodontics, University Hospital Düsseldorf, Moorenstraße 5, 40225 Düsseldorf, Germany; Department of Orthodontics and Dentofacial Orthopedics, Charité, Charité Centrum CC03, Institute for Dental and Craniofacial Sciences, Aßmannshauser Straße 4-6, 14197 Berlin, Germany.
Department of Oral Surgery, University Hospital Düsseldorf, Moorenstraße 5, 40225 Düsseldorf, Germany; Department of Neurosciences, School of Dentistry, University of Padova, Via Giustiniani 2, 35128 Padova, Italy.
Bone. 2023 Dec;177:116912. doi: 10.1016/j.bone.2023.116912. Epub 2023 Sep 20.
Implant migration has been described as a minor displacement of orthodontic mini-implants (OMIs) when subjected to constant forces. Aim of this study was to evaluate the impact of local stresses on implant migration and bone remodelling around constantly loaded OMIs. Two mini-implants were placed in one caudal vertebra of 61 rats, connected by a nickel‑titanium contraction spring, and loaded with different forces (0.0, 0.5, 1.0, 1.5 N). In vivo micro-CT scans were taken immediately and 1, 2 (n = 61), 4, 6 and 8 (n = 31) weeks post-op. Nine volumes of interest (VOIs) around each implant were defined. To analyse stress values, micro-finite element models were created. Bone remodelling was analysed by calculating the bone volume change between scans performed at consecutive time points. Statistical analysis was performed using a linear mixed model and likelihood-ratio-tests, followed by Tuckey post hoc tests when indicated. The highest stresses were observed in the proximal top VOI. In all VOIs, stress values tended to reach their maximum after two weeks and decreased thereafter. Bone remodelling analysis revealed initial bone loss within the first two weeks and bone gain up to week eight, which was noted especially in the highest loading group. The magnitude of local stresses influenced bone remodelling and it can be speculated that the stress related bone resorption favoured implant migration. After a first healing phase with a high degree of bone resorption, net bone gain representing consolidation was observed.
种植体迁移被描述为正畸微型种植体（OMIs）在受到持续力作用时的微小位移。本研究的目的是评估局部应力对持续加载的OMIs周围种植体迁移和骨重塑的影响。在61只大鼠的一个尾椎中植入两个微型种植体，通过镍钛收缩弹簧连接，并施加不同的力（0.0、0.5、1.0、1.5 N）。术后立即以及术后1、2（n = 61）、4、6和8（n = 31）周进行体内微型计算机断层扫描（micro-CT）。在每个种植体周围定义九个感兴趣区域（VOIs）。为了分析应力值，创建了微观有限元模型。通过计算连续时间点扫描之间的骨体积变化来分析骨重塑。使用线性混合模型和似然比检验进行统计分析，必要时进行Tuckey事后检验。在近端顶部VOI中观察到最高应力。在所有VOIs中，应力值在两周后趋于达到最大值，此后下降。骨重塑分析显示，在前两周内有初始骨丢失，到第八周有骨增加，这在最高负荷组中尤为明显。局部应力的大小影响骨重塑，可以推测与应力相关的骨吸收有利于种植体迁移。在经历了一个高度骨吸收的初始愈合阶段后，观察到代表巩固的净骨增加。
