Do osteoconductive bone substitutes result in similar bone regeneration for maxillary sinus augmentation when compared to osteogenic and osteoinductive bone grafts? A systematic review and frequentist network meta-analysis

The purpose of this network meta-analysis was to identify the most effective biomaterials producing higher new bone formation (NBF) and lower residual graft (RG) and connective tissue (CT) following maxillary sinus augmentation (MSA), and to generate a ranking based on their performance. The MEDLINE, Embase, and CENTRAL databases were searched to identify randomized controlled trials (RCTs) published until March 2018, evaluating histomorphometric outcomes after MSA. Predictor variables were autogenous bone (AB), allografts (AG), xenografts (XG), alloplastic bone (AP), AB + XG, AB + AP, AG + XG, XG + AP, and grafts combined with autologous platelet concentrates/recombinant growth factors, mesenchymal stem cells (MSCs), or recombinant bone morphogenetic proteins (BMPs). Outcome variables were NBF%, RG%, and CT%. Healing time was considered. The weighted mean difference (WMD) with 95% confidence interval (CI) was calculated via frequentist network meta-analysis using Stata software. Fifty-two RCTs (1483 biopsies) were included. At a healing time <6 months, AB was superior to AP (WMD − 10.66%, 95% CI − 16.38% to −4.94%) and XG (WMD − 7.93%, 95% CI − 15.11% to −0.75%) for NBF. Regarding CT, AB was superior to XG + AP, AP, MSCs, and XG. At a healing time ≥6 months, NBF was higher for AB than AP (WMD − 7.06%, 95% CI − 12.59% to −1.52%). RG was lower in AB than AP (WMD 12.03%, 95% CI 3.04% to 21.03%), XG (WMD 14.62%, 95% CI 4.25% to 24.98%), and growth factors (WMD 12.32%, 95% CI 0.04% to 24.60%). The three highest ranked biomaterials for increasing NBF were AG + XG (95%, very low quality evidence), growth factors (69.9%, low quality evidence), and AB alone (69.8%, moderate quality evidence). The three highest ranked biomaterials for decreasing RG were BMPs (88.8%, very low quality evidence), AB alone (81.5%, moderate quality evidence), and AB + AP (58.9%, very low quality evidence). Finally, XG + AP (84.7%, low quality evidence), AP alone (77.7%, moderate quality evidence), and MSCs (76.1%, low quality evidence), were the three highest ranked biomaterials for decreasing the amount of CT. Network meta-analysis provided moderate quality evidence that AB alone is probably the best option to obtain greater NBF after MSA in the first 6 months after surgery. Additionally, the results of this network meta-analysis support the hypothesis that osteoconductive bone substitute materials should be combined with osteogenic or osteoinductive grafts for superior histomorphometric outcomes in MSA.     

Efficacy of reconstruction of alveolar bone using an alloplastic hydroxyapatite tricalcium phosphate graft under biodegradable chambers

Our aim was to test the efficacy of a synthetic alloplastic graft under biodegradable chambers to reconstruct a horizontal bony deficiency as an alternative to autogenous, allogeneic, or xenogenic grafts. We used 11 New Zealand white rabbits. On each rabbit's mandible one test sample (grafted chamber) was placed on the (right or left) body, while its control sample (empty (E) chamber) was placed on the other side. Twelve weeks postoperatively the animals were sacrificed and the samples extracted for gross assessment, micro-computed tomographic imaging, and histological and histomorphometric analyses. There was significantly more new bone with a greater surface area in the test group than in the control group, and the alloplastic graft was osteoconductive when used as an onlay graft under a synthetic biodegradable chamber. Synthetic products can be efficient alternatives to autogenic, allogeneic, or xenogenic grafts.     

基因重组人骨形成蛋白-2和牛骨形成蛋白异位诱导成骨的比较

目的：观察基因重组人骨形成蛋白-2（rhBMP-2)和牛骨形成蛋白（bBMP)分别与珊瑚/聚乳酸形成复合人工骨的异位诱导成骨活性，同时比较两种骨形成蛋白的成骨效率，方法：把rhBMP-2和bBMP分别与珊瑚/聚乳酸形成复合人工骨，进行小鼠肌内种植1、3、6周后，组织学观察和组织形态测量，比较其异位诱导成骨活性。结果：rhBMP-2和bBMP存在骨诱导差异，rhBMP-2诱导成骨量相对较少但血管，骨髓含量丰富，bBMP则相反，结论：两种BMP都具有良好的诱骨活性，但在居骨量和血管，骨髓样组织的形成量上有明显不同。     

复合人工骨双重机制修复骨质缺损的实验研究

目的　研究生物珊瑚 /聚乳酸和rhBMP 2合成人工骨 (复合骨 )修复兔颅骨缺损的骨修复能力。方法　选择 2 4只新西兰兔 ,随机分成 2组 ,每组 1 2只 ,建立兔颅骨缺损标准模型。植入复合骨 ,用珊瑚 /聚乳酸作为对照。术后 4、8、1 2周每组各处死 4只动物。进行X线片、组织学观察。结果　复合骨在植入缺损后 ,不仅在其周边部有骨组织长入 ,而且在整个植入物内均有新骨形成 ,即出现多中心成骨。复合骨在同一时间点的成骨量明显多于对照组 ,随时间推移 ,成骨量递增。结论　生物珊瑚 /聚乳酸和rhBMP 2合成人工骨在体内以传导成骨和诱导成骨双重机制完成骨修复 ,作为植骨材料具有良好的应用前景     

Biotechnology, material sciences and bone repair

Summary It is very likely that the need for bone substitutes will increase in the next decade. The present substitutes are generally bioactive and osteoconductive. Glassy or ceramic materials have been used up to now to act as a guide for bone healing tissue and were shown to admit bone apposition at their surface, probably due to the epitaxial growth of carbonated apatite crystals on it. Different forms of bone substitutes have been developed which do not show exactly the same properties. The reaction of bone tissue against bioactive material debris shows major differences from that of polymers or metals.In vitro models were developed to study the interface between bone cells and extracellular matrix, and the surface of bioactive material. Biotechnology makes available some morphogenetic proteins or growth factors in large quantities for combination with osteoconductive material which then can become osteoinductive. Bioartificial bone tissue constituted by a primary osteogenic cell line immobilised at the surface of osteoconductive materials made it possible to obtain osteogenic materials. The ideal bone biomaterial is still to be engineered. The combination of material sciences and molecular biology will help to optimise the next generation of material surfaces.     

多孔羟基磷灰石生物活性玻璃修复兔颌骨缺损

目的 探讨羟基磷灰石/生物活性玻璃复合多孔材料(HA-BG)修复兔下颌骨缺损的机理.方法 兔下颌骨贯通性骨缺损,分别以HA-BG及羟基磷灰石HA修复,分批处死动物,进行X光密度、组织学及新骨面积百分比观察.结果 4周、8周、12周修复区密度逐渐减小;组织学观察,随时间延长新骨呈渐进性成熟,新骨面积百分比逐渐增长,各期HA-BG组新骨面积百分比均高于HA组.结论 HA-BG具有良好的生物相容性、生物降解性及引导成骨活性.     

碳磷灰石鸡蛋壳粉作为骨修复材料的初步研究

目的：研制一种新型的碳磷灰石骨修复材料,初步观察其成骨作用。方法：以鸡蛋壳为原料,采用微波法制备不同加热条件下的骨修复材料,利用扫描电镜（SEM）、X射线衍射仪（XRD）、傅立叶红外（FT-IR）和能谱分析（EDXA）手段,表征微波处理前后材料的理化性能。进一步选用新西兰兔制备直径5mm的颅骨全层缺损区,以未经微波处理的鸡蛋壳粉及Bio—Oss作为对照,充填经微波处理后的新型骨修复材料,8周后观察新生骨的生成情况。结果：SEM,XRD,FT-IR和EDXA分析证实：随加热时间延长,材料的微观形态由针状向球状转变,碳磷灰石的特征性波峰也不断增强;研制的新材料含有与人体骨相似的碳、磷和钙成分。动物实验的结果表明,经微波处理的碳磷灰石鸡蛋壳粉充填的缺损区,比未处理组和空白对照组的缺损区有更多的矿化新生骨和较少的未矿化新生骨,接近Bio—Oss的效果。结论：微波加热法能有效地将天然碳酸钙转化为碳磷灰石,该材料有望作为一种潜在的新型骨修复材料。