Department of Prosthetic Dentistry, BIOMAT Research Cluster, University of Leuven, Leuven, Belgium.
PLoS One. 2012;7(7):e40488. doi: 10.1371/journal.pone.0040488. Epub 2012 Jul 10.
Mechanical loading is known to play an important role in bone remodelling. This study aimed to evaluate the effect of high- and low-frequency axial loading, applied directly to the implant, on peri-implant bone healing and implant osseointegration.
Titanium implants were bilaterally installed in rat tibiae. For every animal, one implant was loaded (test) while the other one was not (control). The test implants were randomly divided into 8 groups according to 4 loading regimes and 2 experimental periods (1 and 4 weeks). The loaded implants were subject to an axial displacement. Within the high- (HF, 40 Hz) or low-frequency (LF, 8 Hz) loading category, the displacements varied 2-fold and were ranked as low- or high-magnitude (LM, HM), respectively. The strain rate amplitudes were kept constant between the two frequency groups. This resulted in the following 4 loading regimes: 1) HF-LM, 40 Hz-8 µm; 2) HF-HM, 40 Hz-16 µm; 3) LF-LM, 8 Hz-41 µm; 4) LF-HM, 8 Hz-82 µm. The tissue samples were processed for resin embedding and subjected to histological and histomorphometrical analyses. Data were analyzed statistically with the significance set at p<0.05.
After loading for 4 weeks, HF-LM loading (40 Hz-8 µm) induced more bone-to-implant contact (BIC) at the level of the cortex compared to its unloaded control. No significant effect of the four loading regimes on the peri-implant bone fraction (BF) was found in the 2 experimental periods.
The stimulatory effect of immediate implant loading on bone-to-implant contact was only observed in case of high-frequency (40 Hz) low-magnitude (8 µm) loading. The applied load regimes failed to influence the peri-implant bone mass.
机械加载被认为在骨重塑中起着重要作用。本研究旨在评估直接施加于植入物的高、低频轴向加载对种植体周围骨愈合和种植体骨整合的影响。
钛植入物被双侧植入大鼠胫骨。对于每只动物，一个植入物（实验组）被加载，而另一个植入物（对照组）未加载。根据 4 种加载方案和 2 个实验周期（1 周和 4 周），将实验组植入物随机分为 8 组。加载的植入物受到轴向位移的影响。在高（HF，40 Hz）或低（LF，8 Hz）频加载范围内，位移相差 2 倍，并分别归类为低或高幅度（LM，HM）。两种频率组之间的应变率幅度保持恒定。这导致了以下 4 种加载方案：1）HF-LM，40 Hz-8 µm；2）HF-HM，40 Hz-16 µm；3）LF-LM，8 Hz-41 µm；4）LF-HM，8 Hz-82 µm。对组织样本进行树脂包埋处理，并进行组织学和组织形态计量学分析。数据采用统计学方法进行分析，显著性水平设为 p<0.05。
加载 4 周后，与未加载的对照组相比，HF-LM 加载（40 Hz-8 µm）在皮质水平上诱导了更多的骨与种植体接触（BIC）。在两个实验周期内，四种加载方案对种植体周围骨量（BF）均无显著影响。
只有在高频（40 Hz）低幅度（8 µm）加载的情况下，即刻加载对骨与种植体接触的刺激作用才会观察到。所应用的加载方案未能影响种植体周围的骨量。
