Root surface conditioning with bone morphogenetic protein‐2 facilitates cementum‐like tissue deposition in beagle dogs

Miyaji H, Sugaya T, Ibe K, Ishizuka R, Tokunaga K, Kawanami M. Root surface conditioning with bone morphogenetic protein‐2 facilitates cementum‐like tissue deposition in beagle dogs. J Periodont Res 2010; 45: 658–663. © 2010 John Wiley & Sons A/S Background and Objective: Modification of the root surface may play an important role in regenerating the periodontal attachment between the root and periodontal connective tissue. We speculated that bone morphogenetic protein (BMP) application to the root surface constructed a novel attachment by cementum‐like hard tissue, although gingival connective tissue proliferated to the root surface. The aim of this study was to examine whether BMP‐2 guided cementum‐like tissue deposition on a BMP‐conditioned root surface. Material and Methods: Root dentin on the buccal side of 24 teeth in four beagle dogs was surgically exposed. The denuded root dentin surfaces were demineralized with EDTA and washed with saline. Subsequently, 15 μL of BMP‐2 solution (loading dose, 0.4 and 1.0 μg/μL) was applied to the root dentin surface. In the control roots, phosphate‐buffered saline was applied to the root surface. Specimens were analyzed histologically 16 wk after surgery. Results: Formation of cementum‐like tissue was frequently observed on the BMP‐2‐conditioned root at the coronal portion. Cellular cementum‐like tissue was separated from the original cementum and encapsulated with gingival connective tissue. Cementum‐like tissue formation with BMP‐2 at 1.0 μg/μL was significantly greater than that in the control roots and those with BMP‐2 at 0.4 μg/μL. Downgrowth of the junctional epithelium in the 1.0 μg/μL BMP‐2 group was significantly less than that in the control roots. Conclusion: Root dentin surface conditioning with BMP‐2 stimulated cementum‐like tissue formation and inhibited epithelial downgrowth.     

Evaluation of a β‐Calcium Metaphosphate Bone Graft Containing Bone Morphogenetic Protein‐7 in Rabbit Maxillary Defects

Background: Calcium phosphate–based materials have been widely used as bone substitutes and more recently are being exploited together with growth factors as bone tissue engineering scaffolds regulating cell behavior. The aim of this study is to evaluate the in vitro and in vivo response to a newly developed calcium metaphosphate (CMP) bone graft, with and without bone‐stimulating growth factor. Methods: Porous scaffolds of CMP were developed and extensively tested in vitro. Subsequently, CMP grafts with osteogenic protein‐1 (OP‐1) (test) and without OP‐1 (control) were implanted into experimental rabbit maxillary bone defects. Animals were sacrificed at 2, 4, and 8 weeks, and samples were examined with microcomputed tomography (micro‐CT) and processed for histomorphometric analysis. Results: At 8 weeks, the scaffolds containing OP‐1 induced greater bone formation (P = 0.018) than CMP alone, based on histomorphometric evaluation (percentage bone area: test: 57.1 ± 5.6; control: 49.4 ± 7.7) and micro‐CT analysis (percentage bone volume density: test: 63.46 ± 5.61; control: 51.20 ± 6.71). Thus, these data indicated that both test and control CMP grafts showed a good degree of bone formation. Furthermore, the CMP materials showed signs of resorption from 4 weeks, and no graft materials were observed at 8 weeks. Conclusions: In vitro, the OP‐1 loaded graft demonstrated a release profile and bioactivity over a 28‐day period. In vivo testing confirmed enhanced bone formation of the OP‐1 loaded graft after 8 weeks of healing.     

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壳聚糖是甲壳素最主要的衍生物,具有良好的生物相容性、可降解性和抗菌性等诸多优点,可以促进成骨细胞的增殖和表达以及修复骨缺损,在生物医药领域被广泛应用。近几年,许多学者都致力于研究壳聚糖在骨组织工程中的开发与应用,力图使壳聚糖的优势得到最大化利用。随着研究的深入,壳聚糖应用越来越广泛。本文就壳聚糖成骨性能方面的研究进行综述。     

骨组织工程3D生物打印的研究进展

近几十年来,骨组织工程在骨缺损修复治疗的应用中获得了飞速的发展,而3D生物打印是近十年来在骨组织工程中一种非常具有前景的技术.传统骨组织工程支架制造方法无法精确控制空间结构,且在支架制作完成后接种细胞也无法控制细胞的均匀分布.尽管3D生物打印作为一类含细胞骨组织工程支架制造技术,以水凝胶类材料作为基础将细胞置入支架中,...     

口腔骨组织工程研究进展

创伤、炎症、肿瘤、先天畸形所引起口腔颌面部骨缺损的修复一直是口腔医学的难题,而组织工程已成为骨缺损修复新的研究热点。下面就骨组织工程及其在口腔医学领域的研究进展作一综述。     

Bone augmentation after soft‐tissue expansion using hydrogel expanders: effects on microcirculation and osseointegration

Objectives: The success of bone augmentation, for example of the alveolar ridge, might be endangered by dehiscence of the soft tissue that covers the augmented bone. Soft‐tissue coverage can be achieved without tension through pre‐augmentation tissue expansion with hydrogel expanders. We used a periosteal chamber to study the influence of tissue expansion on microcirculation and osseointegration in an in vivo animal model. Material and methods: Sixteen isogeneic Lewis rats were randomised into two groups. Additional eight animals served as donors of isogeneic bone grafts (Group 3, n=8). The bone grafts were harvested and implanted into Group 1 animals (n=8) (without tissue expansion) and Group 2 animals (after tissue expansion). In Group 2 (n=8), hydrogel expanders were inserted subperiosteally at the site to be augmented for 21 days. We used intravital microscopy to monitor microcirculation in vivo for 19 days after implantation. Specimens from both groups were evaluated histologically. Results: During the entire study period, functional microvessel density in the region above the augmentation material was significantly higher after previous tissue expansion (P>0.05). Both groups showed physiological microcirculation around the augmentation material. Histology revealed bone osseointegration of the bone graft in the group with tissue expansion and the presence of connective and granulation tissue in the group without tissue expansion. Conclusions: Pre‐augmentation soft‐tissue expansion with hydrogel expanders leads to higher functional microvessel density in the tissue above the augmentation material and thus, to more rapid osseointegration. The use of hydrogel expanders appears to increase the probability of success, especially of pre‐implant bone augmentation. To cite this article:
von See C, Gellrich N‐C, Jachmann U, Laschke MW, Bormann KH, Rücker M. Bone augmentation after soft‐tissue expansion using hydrogel expanders: effects on microcirculation and osseointegration.
Clin. Oral Impl. Res. 21 , 2010; 842–847
doi: 10.1111/j.1600‐0501.2009.01847.x     

Use of hyaluronic acid binding protein for detection of hyaluronan in ligature-induced periodontitis tissue

This study was designed to demonstrate, by use of biotin-labeled hyaluronic acid binding protein (HABP) and an avidin-enzyme system, the localization of hyaluronan (HA) in periodontal tissue of beagle dogs during experimentally induced periodontitis. Experimental periodontitis was induced in the dogs by ligation of the gingival sulcus. Experimental tissue was collected at 0, 3, 7 and 21 days after ligation. HA was revealed by strong staining in the intercellular space around epithelial cells and periodontal ligament, and by light staining in the gingival connective tissue. According to the progression of periodontal tissue breakdown, HA was detected in a small number of leukocytes and monocytes, on the surface of osteoclasts, the surface of alveolar bone, thickened endothelium and in epithelial cells related to rete peg formation. Streptomyces hyaluronidase-treated specimens gave negative staining. This study suggests that HA may be associated with the inflammatory reaction in experimental periodontitis tissue.     

骨组织工程技术瓶颈及其原因分析

组织工程骨的研究发展迅速,但仍存在许多问题.主要的瓶颈是培养的细胞在功能和行为上与体内的细胞有较大差异,组织工程骨的成骨能力存在缺陷,形成的组织工程骨与天然的生理骨仍有较大差距.可能的原因是细胞的培养微环境不够完善,没有实现组织工程骨的同步血管化和神经化,组织工程骨与骨膜复合体的构建目前仍缺乏研究.     

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组织工程化骨是用于颌骨缺损修复治疗的一种新途径,当前其研究焦点是寻求能够作为细胞移植及引导新骨生长的支架,以充当细胞外基质的替代物。这些支架通常由多孔、可降解的生物材料制备,并且可以负载不同的生长因子、药物或干细胞。本文就骨组织工程支架的研究现状、面临的挑战及未来的研究动向做一综述。     

Use of hyaluronic acid binding protein for detection of hyaluronan in ligature-induced periodontitis tissue

This study was designed to demonstrate, by use of biotin-labeled hyaluronic acid binding protein (HABP) and an avidin–enzyme system, the localization of hyaluronan (HA) in periodontal tissue of beagle dogs during experimentally induced periodontitis. Experimental periodontitis was induced in the dogs by ligation of the gingival sulcus. Experimental tissue was collected at 0, 3, 7 and 21 days after ligation. HA was revealed by strong staining in the intercellular space around epithelial cells and periodontal ligament, and by light staining in the gingival connective tissue. According to the progression of periodontal tissue breakdown, HA was detected in a small number of leukocytes and monocytes, on the surface of osteoclasts, the surface of alveolar bone, thickened endothelium and in epithelial cells related to rete peg formation. Streptomyces hyaluronidase-treated specimens gave negative staining. This study suggests that HA may be associated with the inflammatory reaction in experimental periodontitis tissue.     

骨组织工程血管化技术的构建思路

血管化是骨组织工程的关键技术,构建组织工程化血管的细胞有血管内皮细胞、平滑肌细胞、成纤维细胞等;相关的生长因子有血管内皮细胞生长因子、碱性成纤维细胞生长因子等;支架材料有生物活性材料、可吸收材料和复合材料;构建组织工程化血管的途径有内皮细胞培养、体内埋植构建血管瓣、血管移植构建动静脉环等。     

Systematic scoping review of mandibular bone tissue engineering

Tissue engineering is a promising alternative that may facilitate bony regeneration in small defects in compromised host tissue as well as large mandibular defects. This scoping systematic review was therefore designed to assess in vivo research on its use in the reconstruction of mandibular defects in animal models. A total of 4524 articles were initially retrieved using the search algorithm. After screening of the titles and abstracts, 269 full texts were retrieved, and a total of 72 studies included. Just two of the included studies employed osteonecrosis as the model of mandibular injury. All the rest involved the creation of a critical defect. Calcium phosphates, especially tricalcium phosphate and hydroxyapatite, were the scaffolds most widely used. All the studies that used a scaffold reported increased formation of bone when compared with negative controls. When combined with scaffolds, mesenchymal stem cells (MSC) increased the formation of new bone and improved healing. Various growth factors have been studied for their potential use in the regeneration of the maxillofacial complex. Bone morphogenic proteins (BMP) were the most popular, and all subtypes promoted significant formation of bone compared with controls. Whilst the studies published to date suggest a promising future, our review has shown that several shortfalls must be addressed before the findings can be translated into clinical practice. A greater understanding of the underlying cellular and molecular mechanisms is required to identify the optimal combination of components that are needed for predictable and feasible reconstruction or regeneration of mandibular bone. In particular, a greater understanding of the biological aspects of the regenerative triad is needed before we can to work towards widespread translation into clinical practice.