Division of Prosthodontics, Department of Restorative Sciences, School of Dentistry, University of Minnesota, Minneapolis, MN, USA.
Clin Implant Dent Relat Res. 2013 Jun;15(3):460-9. doi: 10.1111/j.1708-8208.2011.00357.x. Epub 2011 Dec 15.
This study aimed to investigate whether push-in and pull-out tests measure mechanical properties of the bone-implant interface differently, and which test is more sensitive to changes over the healing period.
Two identical self-threading dental implants (3.3×8.5mm) were placed in medial surface of the proximal condyles of left and right tibias of 20 rabbits (40 implants total). Five rabbits each were sacrificed after 1, 4, 8, and 12 weeks of healing. Push-in test was performed on one side's tibia implant and pull-out on the other side's implant, at a rate of 6mm/min. Primary and secondary implant stabilities and tibia weight were measured on all implants.
The push-in test generated significantly higher failure load (p=.0001; 530N vs 279N), lower displacement at failure (p=.0003; 0.436mm vs 0.680mm), and higher interface stiffness (p<.0001; 1,641N/mm vs 619N/mm) than pull-out test. Failure load, stiffness, and secondary implant stability were significantly higher for longer compared with shorter healing periods, while displacement, tibia weight, and primary stability were not. Failure load and stiffness differed significantly for four healing times for the push-in but not for the pull-out test. Failure load was significantly correlated with secondary implant stability for both push-in (r=0.66) and pull-out (r=0.48) tests, but stiffness was significantly correlated with secondary stability only for the push-in test (r=0.72; pull-out test r=0.40).
The push-in test appeared more sensitive than pull-out to changes in mechanical properties at bone-implant interfaces during healing in rabbit tibia model.
本研究旨在探讨推入和拔出试验是否在测量骨-种植体界面的机械性能方面存在差异，以及哪种试验对愈合期间的变化更为敏感。
将 20 只兔子（共 40 个种植体）双侧胫骨近端内侧面各植入 2 个相同的自攻螺纹种植体（3.3×8.5mm）。每组各有 5 只兔子分别在植入后 1、4、8 和 12 周处死。一侧胫骨种植体行推入试验，另一侧行拔出试验，速度为 6mm/min。对所有种植体测量初始和次级种植体稳定性及胫骨重量。
推入试验产生的失败负荷显著高于拔出试验（p=.0001；530N 比 279N），失败时的位移显著低于拔出试验（p=.0003；0.436mm 比 0.680mm），界面刚度显著高于拔出试验（p<.0001；1,641N/mm 比 619N/mm）。与较短愈合期相比，较长愈合期的失败负荷、刚度和次级种植体稳定性显著更高，而位移、胫骨重量和初始稳定性则不然。对于推入试验，四个愈合时间的失败负荷和刚度差异显著，但拔出试验则不然。对于两种试验，失败负荷均与次级种植体稳定性显著相关（推入试验 r=0.66，拔出试验 r=0.48），但只有推入试验的刚度与次级稳定性显著相关（r=0.72；拔出试验 r=0.40）。
在兔胫骨模型中，与拔出试验相比，推入试验对愈合过程中骨-种植体界面机械性能的变化更为敏感。
