Du Zhibin, Xiao Yin, Hashimi Saeed, Hamlet Stephen M, Ivanovski Saso
Institute of Health and Biomedical Innovation, Queensland University of Technology, Kelvin Grove, Brisbane, Queensland, Australia.
School of Dentistry and Oral Health, Griffith University, Gold Coast Campus, Queensland, Australia.
Acta Biomater. 2016 Sep 15;42:351-363. doi: 10.1016/j.actbio.2016.06.035. Epub 2016 Jun 29.
Compromised bone quality and/or healing in osteoporosis are recognised risk factors for impaired dental implant osseointegration. This study examined the effects of (1) experimentally induced osteoporosis on titanium implant osseointegration and (2) the effect of modified implant surface topography on osseointegration under osteoporosis-like conditions. Machined and micro-roughened surface implants were placed into the maxillary first molar root socket of 64 ovariectomised and sham-operated Sprague-Dawley rats. Subsequent histological and SEM observations showed tissue maturation on the micro-rough surfaced implants in ovariectomised animals as early as 3days post-implantation. The degree of osseointegration was also significantly higher around the micro-rough implants in ovariectomised animals after 14days of healing although by day 28, similar levels of osseointegration were found for all test groups. The micro-rough implants significantly increased the early (day 3) gene expression of alkaline phosphatase, osteocalcin, receptor activator of nuclear factor kappa-B ligand and dentin matrix protein 1 in implant adherent cells. By day 7, the expression of inflammatory genes decreased while the expression of the osteogenic markers increased further although there were few statistically significant differences between the micro-rough and machined surfaces. Osteocyte morphology was also affected by estrogen deficiency with the size of the cells being reduced in trabecular bone. In conclusion, estrogen deficiency induced osteoporotic conditions negatively influenced the early osseointegration of machined implants while micro-rough implants compensated for these deleterious effects by enhancing osteogenic cell differentiation on the implant surface.
Lower bone density, poor bone quality and osseous microstructural changes are all features characteristic of osteoporosis that may impair the osseointegration of dental implants. Using a clinically relevant trabecular bone model in the rat maxilla, we demonstrated histologically that the negative effects of surgically-induced osteoporosis on osseointegration could be ameliorated by the biomaterial's surface topography. Furthermore, gene expression analysis suggests this may be a result of enhanced osteogenic cell differentiation on the implant surface.
骨质质量受损和/或骨质疏松症愈合不良是公认的牙种植体骨整合受损的风险因素。本研究考察了(1)实验性诱导骨质疏松对钛种植体骨整合的影响，以及(2)在类似骨质疏松症的条件下，改良种植体表面形貌对骨整合的影响。将机械加工表面和微粗糙表面的种植体植入64只去卵巢和假手术的Sprague-Dawley大鼠的上颌第一磨牙牙槽窝。随后的组织学和扫描电镜观察显示，去卵巢动物微粗糙表面种植体在植入后3天就出现了组织成熟。愈合14天后，去卵巢动物微粗糙种植体周围的骨整合程度也显著更高，不过到第28天，所有测试组的骨整合水平相似。微粗糙种植体显著增加了种植体黏附细胞中碱性磷酸酶、骨钙素、核因子κB受体活化因子配体和牙本质基质蛋白1在早期(第3天)的基因表达。到第7天，炎症基因的表达下降，而成骨标志物的表达进一步增加，尽管微粗糙表面和机械加工表面之间几乎没有统计学上的显著差异。骨细胞形态也受到雌激素缺乏的影响，小梁骨中细胞大小减小。总之，雌激素缺乏诱导的骨质疏松症状态对机械加工种植体的早期骨整合产生负面影响，而微粗糙种植体通过增强种植体表面的成骨细胞分化来补偿这些有害影响。
骨密度降低、骨质质量差和骨微结构改变都是骨质疏松症的特征，可能会损害牙种植体的骨整合。利用大鼠上颌骨临床上相关的小梁骨模型，我们通过组织学证明，手术诱导的骨质疏松症对骨整合的负面影响可以通过生物材料的表面形貌得到改善。此外，基因表达分析表明，这可能是种植体表面成骨细胞分化增强的结果。
