Insertional torque and axial pull-out strength of mini-implants in mandibles of dogs
Insertional torque and axial pull-out strength of mini-implants in mandibles of dogs
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DOI：
10.1016/j.ajodo.2007.12.020
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发表时间：
2008-06-01
影响因子：
3
通讯作者：
Maruob, Hiroshi
中科院分区：
文献类型：
--
作者：
Salmoria, Karine Kimak;Tanaka, Orlando Motohiro;Maruob, Hiroshi
简介：本研究的目的是评估微型种植体（MI）用于正畸支抗的插入扭矩，比较它们在放置后0（T0），15（T15）和60（T60）天的轴向拔出强度，确定初始和种植体周围的皮质骨厚度，并分析这些变量之间的相关性。方法：将60个MI植入10只犬的下颌骨内。记录峰值插入扭矩值，并在动物处死后制备标本。将MI与试验机对齐，以记录轴向拔出强度。取出MI后测量皮质骨厚度。采用ANOVA和Tukey HSD检验进行统计学分析。结果：不同时间的抗拔强度和种植体周围皮质骨厚度差异有统计学意义（P < 0.01）。T0值显示最高的拔出强度，T60时种植体周围皮质骨厚度最小。T0时拔出强度与种植体周围皮质骨厚度呈规律相关（r = 0.44，P = 0.05）。旋入扭矩与拔出强度、旋入扭矩与初始皮质骨厚度之间无相关性。结论：MI置入后即刻的拔出强度更大，皮质骨厚度因骨吸收而降低，插入扭矩不是预测MI保留的有效方法。
Introduction: The objectives of this study were to evaluate insertional torque of mini-implants ( MI) for orthodontic anchorage, to compare their axial pull-out strength at 0 ( T0), 15 ( T15), and 60 ( T60) days after placement, to determine initial and peri-implant cortical bone thickness, and to analyze the correlations among these variables. Methods: Sixty MI were placed in the mandibles of 10 dogs. Peak insertional torque values were recorded, and, after the animals were killed, specimens were prepared. The MI were aligned with a testing machine to register axial pull-out strength. Cortical bone thickness was measured after removal of the MI. Statistical analyses were conducted with ANOVA and Tukey HSD tests. Results: Pull-out strength and peri-implant cortical bone thickness had differences ( P < 0.01) at the various times. The T0 value showed the highest pull-out strength, and the smallest peri-implant cortical bone thickness was at T60. There was a regular correlation between pull-out strength and peri-implant cortical bone thickness at T0 ( r = 0.44, P = 0.05). There was no correlation between insertional torque and pull-out strength, and insertional torque and initial cortical bone thickness. Conclusions: Pull-out strength is greater immediately after placement of MI, cortical bone thickness decreases because of bone resorption, and insertional torque is not an efficient method for predicting the retention of MI.