Department of Mechanical and Aerospace Engineering, University of California-San Diego, USA.
Am J Orthod Dentofacial Orthop. 2010 Jan;137(1):80-90. doi: 10.1016/j.ajodo.2007.12.035.
Mini-implants are often immediately loaded for orthodontic treatment; however, changes in interfacial tissues caused by early loading and its effects might compromise the mini-implant's function. The purpose of this study was to compare the healing of interfacial tissues 1, 4, and 12 weeks after the placement of titanium-alloy mini-implants in New Zealand rabbits; some of the implants were loaded immediately and others were left unloaded.
Eighteen animals were used in the experiment. Each received 4 titanium grade 5 mini-implants (2.0 x 6.0 mm), 2 of which were immediately loaded with 1 N of force. Tissue healing was verified at 1, 4, and 12 weeks after placement. Four different fluorescent molecules were injected into the rabbits to label calcium deposition. After the rabbits were killed, mineralized bone samples with the mini-implants were removed, fixed, cut, stained, and observed with bright-field, polarized, and fluorescence microscopy.
After 12 weeks of healing, higher bone contact and bone area were observed than after 1 or 4 weeks, regardless of loading. Differences between the loaded and unloaded groups were not observed (P <0.05) at 1 and 4 weeks. The bone deposition rate was higher in the loaded group.
The 1-N immediate force application did not compromise bone formation around mini-implants.
微型种植体常用于正畸即刻负载；然而，早期负载引起的界面组织变化及其影响可能会影响微型种植体的功能。本研究的目的是比较新西兰兔种植钛合金微型种植体后 1、4 和 12 周界面组织的愈合情况；部分种植体立即负载，部分未负载。
本实验共使用 18 只动物。每只动物接受 4 个钛合金 5 级微型种植体（2.0 x 6.0 mm），其中 2 个立即加载 1 N 的力。在植入后 1、4 和 12 周时验证组织愈合情况。将 4 种不同的荧光分子注入兔子体内以标记钙沉积。在兔子死后，取出带有微型种植体的矿化骨样本，进行固定、切割、染色，并通过明场、偏光和荧光显微镜进行观察。
无论是否负载，在愈合 12 周后，观察到的骨接触和骨面积均高于 1 周或 4 周时。在 1 周和 4 周时，加载组和未加载组之间未观察到差异（P<0.05）。加载组的骨沉积率较高。
1N 的即刻力应用并未影响微型种植体周围的骨形成。
