Calvo-Guirado José L, Boquete-Castro Ana, Negri Bruno, Delgado Ruiz Rafael, Gómez-Moreno Gerardo, Iezzi Giovanna
Department of General and Implant Dentistry, Faculty of Medicine and Dentistry, University of Murcia, Murcia, Spain.
Department of Pharmacological Interactions in Dentistry, Dental School, University of Granada, Granada, Spain.
Clin Oral Implants Res. 2014 Mar;25(3):344-351. doi: 10.1111/clr.12110. Epub 2013 Jan 25.
The aim of the present study was to evaluate bone-to-implant contact (BIC) and bone remodeling dynamics after immediate implant placement at different levels in relation to the crestal bone.
The mandibular second, third, and fourth premolars of six Foxhound dogs were extracted bilaterally. Randomly, three implants were immediately placed in the hemi-arches of each dog, crestally or 2 mm subcrestally. Three dogs were allowed an 8-week submerged healing period, and the other three at 12-week submerged healing period. The animals were sacrificed at 12 weeks and samples were obtained. Biopsies were processed for ground sectioning. Histomorphometric analysis was carried out to compare BIC, bone neoformation, and bone remodeling.
All implants osseointegrated clinically and histologically. Healing patterns examined microscopically at eight and twelve weeks for both groups (crestal and subcrestal) yielded similar qualitative bone findings. The Total BIC mean value for the crestal group 44.52% at 8 weeks and 39.50% at 12 weeks, and for the subcrestal group was 47.33% at 8 weeks and 53.85% at 12 weeks%. There was less bone resorption in the subcrestal group (test) than in crestal group (control).
Within the limitations of this study, our findings suggest that apical positioning of the top of the implant does not jeopardize bone crest and peri-implant tissue remodeling. However, less resorption of the lingual crest may be expected when implants are placed 2 mm subcrestally. Moreover, higher BIC values were found in implants placed subcrestally.
本研究的目的是评估在与嵴顶骨不同水平处即刻种植后骨与种植体的接触（BIC）以及骨重塑动力学。
双侧拔除6只猎狐犬的下颌第二、第三和第四前磨牙。随机在每只犬的半侧牙弓中即刻植入3枚种植体，分别位于嵴顶或嵴顶下2mm处。3只犬给予8周的潜没愈合期，另外3只给予12周的潜没愈合期。在12周时处死动物并获取样本。对活检样本进行磨片处理。进行组织形态计量分析以比较BIC、骨新生和骨重塑情况。
所有种植体在临床和组织学上均实现骨结合。两组（嵴顶组和嵴顶下组）在8周和12周时显微镜下观察的愈合模式产生了相似的定性骨学结果。嵴顶组的总BIC平均值在8周时为44.52%，在12周时为39.50%；嵴顶下组在8周时为47.33%，在12周时为53.85%。嵴顶下组（试验组）的骨吸收比嵴顶组（对照组）少。
在本研究的局限性范围内，我们的研究结果表明种植体顶部的根尖定位不会损害牙槽嵴和种植体周围组织的重塑。然而，当种植体放置在嵴顶下2mm处时，舌侧牙槽嵴的吸收可能会更少。此外，在嵴顶下植入的种植体中发现了更高的BIC值。
