Different calcium phosphate bioglass ceramics implanted in rabbit cortical bone. An interface study

In order to study the interface of calcium phosphate bioglass ceramics, cylinders of standard size were implanted in the tibiae of rabbits. The materials were evaluated by radiography, light microscopy and microradiography. Bioceramics with hydroxyapatite surface give rise to a closer contact with new bone than calcium phosphate glass ceramics.     

Bioglass enhanced wound healing ability of urine‐derived stem cells through promoting paracrine effects between stem cells and recipient cells

In cell therapy, tissue regeneration ability of stem cells relies on the paracrine effects between stem cells and recipient cells. Our recent studies demonstrated that, in tissue engineering, bioactive silicates could stimulate paracrine effects between stem cells and recipient cells, which enhanced tissue generation. Therefore, we proposed that, in cell therapy, it may be an effective method to improve tissue regeneration ability of stem cells through activating the paracrine effects between stem cells and recipient cells with bioactive silicates. As urine‐derived stem cells (USCs) have been injected for wound healing and bioglass (BG) have shown bioactivity for various types of stem cells, in this study, we activated USCs with effective BG ionic products. Then the conditioned medium of BG‐activated USCs were used to culture endothelial cells and fibroblasts as well as co‐cultures of endothelial cells and fibroblasts. Results showed that growth factor expression in BG‐activated USCs was upregulated. In addition, paracrine effects between USCs and recipient cells in wound healing were stimulated, which resulted in enhanced capillary‐like network formation of endothelial cells and matrix protein production as well as myofibroblast differentiation of fibroblasts. Finally, the BG‐activated USCs were applied on full‐thickness excisional wounds. Results confirmed that BG‐activated USCs had better wound healing ability through improving angiogenesis and collagen deposition in wound sites as compared with USCs without any treatment. Taken together, BG can be used to promote wound healing ability of USCs by enhancing paracrine effects between USCs and recipient cells.     

Histological evaluation of healing after transalveolar maxillary sinus augmentation with bioglass and autogenous bone

Objectives: The aim was to evaluate histologically the outcome of a bioglass and autogenous bone (at 1 : 1 ratio) composite implantation for transalveolar sinus augmentation. Methods: In 31 patients, during implant installation ca. 4 months after sinus augmentation, biopsies were harvested through the transalveolar osteotomy by means of a trephine bur and non‐decalcified sections through the long axis of the cylinder were produced. After a strict selection process, taking into account the presurgical residual bone height and biopsy length, 8 and 15 biopsies representing the new tissues formed inside the sinus and the transalveolar osteotomy, respectively, qualified for analysis. The tissue fractions occupied by newly formed bone (mineralized tissue+bone marrow), soft connective tissue, residual biomaterial+empty spaces, and debris inside the sinus cavity or the transalveolar osteotomy were estimated. Results: Bone and connective tissue fraction in the newly formed tissues inside the sinus cavity averaged 23.4 ± 13.2% and 54.1 ± 23.5%, respectively. Residual biomaterial, empty spaces, and debris averaged 1.9 ± 3.5%, 10.5 ± 6.3%, and 8.4 ± 14.5%, respectively. In the transalveolar osteotomy, bone and connective tissue fraction averaged 41.6 ± 14.3% and 46.1 ± 13%, respectively, while the amount of residual biomaterial, empty spaces, and debris was 2.8 ± 5%, 4.7 ± 1.9%, and 3.2 ± 2.6%, respectively. Statistically significant differences between the sinus cavity and the transalveolar osteotomy were found only for bone and empty spaces' values (P=0.02 and 0.04, respectively). Conclusion: Sinus augmentation with a bioglass and autogenous bone composite is compatible with bone formation that, in a short distance from the floor of the sinus, shows similar density as that reported previously for other commonly used bone substitutes. New bone fraction inside the transalveolar osteotomy was almost twice as much as in the sinus cavity, while the amount of residual biomaterial was much less than that inside the sinus. To cite this article :
Stavropoulos A, Sima C, Sima A, Nyengaard J, Karring T, Sculean A. Histological evaluation of healing after transalveolar maxillary sinus augmentation with bioglass and autogenous bone.
Clin. Oral Impl. Res. 23 , 2012; 125–131.
doi: 10.1111/j.1600‐0501.2011.02161.x     

自体松质骨加骨玻璃植入治疗缺血性股骨头坏死--犬股骨头骨缺损模型初步实验研究

目的:探讨使用人工合成骨移植替代材料--骨玻璃部分或完全代替自体骨移植,用于保存自身股骨头手术中充填股骨头骨缺损灶.方法:实验犬12只随机分为3组,每组4只,单侧髋制作成股骨头骨缺损模型,对侧髋作为对照.Ⅰ组植入自体松质骨;Ⅱ组植入自体松质骨加骨玻璃;Ⅲ组植入骨玻璃.对实验侧和对照侧犬股骨头行大体观察、X线检查、力学性质测定和组织学观察.结果:共10只犬术后存活4个月.大体观察:只有Ⅰ组1髋未发生塌陷,三组间平均塌陷高度无显著差异.X线检查:Ⅲ组塌陷高度显著高于Ⅰ、Ⅱ组.组织学观察:回植愈合的软骨帽软骨均出现软骨增厚纤维化,Ⅰ组和Ⅱ组的植入物区均出现骨小梁粗大、骨细胞量增加新生骨形成、骨髓腔小;Ⅲ组的植入物区呈现类粗大骨小梁样改变但骨细胞样结构量少,无新生骨形成.股骨头压应力强度测定:Ⅰ组对照侧与实验侧间无显著差异;Ⅱ组和Ⅲ组对照侧与实验侧间差异显著.结论:对股骨头缺血坏死实验犬植入自体骨和植入自体骨加骨玻璃后,组织学和影像学均显示愈合良好.采用"活门板"式手术充填股骨头骨缺损灶时骨玻璃可部分替代自体骨.     

新型硼酸盐生物玻璃对成骨细胞行为影响的体外研究

目的硼酸盐生物玻璃具有较高的化学反应活性,可以诱导骨再生。通过调整配方构建新型硼酸盐生物玻璃,探讨其对体外培养成骨细胞行为的影响,为其下一步的体内研究及临床应用奠定实验基础。方法采用熔融法制备Na2O-K2O-MgO-CaO-P2O5-B2O3-SrO新型硼酸盐生物玻璃。并根据ISO10993-12:2007的要求制备材料初次浸提液及二次浸提液。取体外培养第5～15代MC3T3-E1细胞,分别与初次浸提液、二次浸提液共培养,以α-MEM培养基为对照。观察新型硼酸盐生物玻璃对成骨细胞增殖率、蛋白合成、ALP活性、细胞凋亡以及细胞横向、纵向迁移的影响。结果初次浸提液组、二次浸提液组与对照组成骨细胞增殖吸光度A值分别为0.356 0±0.018 7、0.331 0±0.025 4、0.204 0±0.013 8,各组间比较差异均有统计学意义(P<0.05)。初次浸提液组、二次浸提液组与对照组总蛋白含量分别为(382.847±9.521)、(226.071±5.847)、(220.248±8.213)U,初次浸提液组与对照组、二次浸提液组比较,差异均有统计学意义(P<0.05),但二次浸提液组与对照组比较,差异无统计学意义(P>0.05)。初次浸提液组、二次浸提液组及对照组ALP活性分别为(0.013 01±0.000 39)、(0.012 93±0.000 44)、(0.012 92±0.000 35)U/mg;细胞凋亡率分别为7.03%±1.95%、6.46%±2.88%、6.18%±2.21%;细胞横向迁移距离分别为(137.50±11.43)、(134.98±10.50)、(135.21±8.66)μm;Transwell中穿膜细胞数分别为(10.92±4.99)、(10.07±2.50)、(9.81±2.64)个/视野;以上指标3组间两两比较差异均无统计学意义(P>0.05)。结论新型硼酸盐生物玻璃具有良好的成骨细胞相容性,对细胞增殖、分泌、迁移等行为均有一定调节作用。     

CaO-MgO-P_2O_5-SiO_2-CaF_2系统自硬性玻璃的研究

为研究钙离子、镁离子在体内环境中对自硬性玻璃结晶行为的影响,为自硬性生物活性玻璃的临床应用提供依据,本文设计了CaO-P2O5-SiO2-CaF2(Ca-glass)和CaO-MgO-P2O5-SiO2-CaF2(CaMg-glass)系统玻璃并使用模拟体液(simulated body flu id,SBF)进行了研究。首先采用磷酸氢二氨[(NH4)2HPO4]/[NH4H2PO4]硬化液与Ca-glass、CaMg-glass制成硬化体,然后使用X射线衍射(XRD)、扫描电镜(SEM)、失重、力学分析等方法,研究硬化体在SBF中的结晶性、降解性和力学性能。实验结果表明,玻璃粉末与磷酸铵缓冲溶液反应形成了磷酸铵钙[(NH4)2.Ca(HPO4)2.H2O]硬化体。硬化体经过SBF浸泡,Ca-glass系统硬化体中部分磷酸铵钙转化成羟基磷灰石,而CaMg-glass系统硬化体仍然为磷酸铵钙。Ca-glass与CaMg-glass硬化体在SBF中浸泡28天分别降解19.4%和31.3%,抗压强度分别为93.14MPa和64.52MPa。镁离子的歧化作用是导致Ca-glass、CaMg-glass硬化体结晶性能、降解性能以及力学性能差别的主要原因。     

Development of β Type Ti23Mo-45S5 Bioglass Nanocomposites for Dental Applications

Titanium β-type alloys attract attention as biomaterials for dental applications. The aim of this work was the synthesis of nanostructured β type Ti23Mo-x wt % 45S5 Bioglass (x = 0, 3 and 10) composites by mechanical alloying and powder metallurgy methods and their characterization. The crystallization of the amorphous material upon annealing led to the formation of a nanostructured β type Ti23Mo alloy with a grain size of approximately 40 nm. With the increase of the 45S5 Bioglass contents in Ti23Mo, nanocomposite increase of the α-phase is noticeable. The electrochemical treatment in phosphoric acid electrolyte resulted in a porous surface, followed by bioactive ceramic Ca-P deposition. Corrosion resistance potentiodynamic testing in Ringer solution at 37 °C showed a positive effect of porosity and Ca-P deposition on nanostructured Ti23Mo 3 wt % 45S5 Bioglass nanocomposite. The contact angles of glycerol on the nanostructured Ti23Mo alloy were determined and show visible decrease for bulk Ti23Mo 3 wt % 45S5 Bioglass and etched Ti23Mo 3 wt % 45S5 Bioglass nanocomposites. In vitro tests culture of normal human osteoblast cells showed very good cell proliferation, colonization, and multilayering. The present study demonstrated that porous Ti23Mo 3 wt % 45S5 Bioglass nanocomposite is a promising biomaterial for bone tissue engineering.     

Enhanced Stability of Calcium Sulfate Scaffolds with 45S5 Bioglass for Bone Repair

Calcium sulfate (CaSO₄), as a promising tissue repair material, has been applied widely due to its outstanding bioabsorbability and osteoconduction. However, fast disintegration, insufficient mechanical strength and poor bioactivity have limited its further application. In the study, CaSO₄ scaffolds fabricated by using selective laser sintering were improved by adding 45S5 bioglass. The 45S5 bioglass enhanced stability significantly due to the bond effect of glassy phase between the CaSO₄ grains. After immersing for four days in simulated body fluid (SBF), the specimens with 45S5 bioglass could still retain its original shape compared as opposed to specimens without 45S5 bioglass who experienced disintegration. Meanwhile, its compressive strength and fracture toughness increased by 80% and 37%, respectively. Furthermore, the apatite layer was formed on the CaSO₄ scaffolds with 45S5 bioglass in SBF, indicating good bioactivity of the scaffolds. In addition, the scaffolds showed good ability to support the osteoblast-like cell adhesion and proliferation.     

Evaluation of hydroxyapatite–bioglass and hydroxyapatite–ethyl vinyl acetate composite extracts on antioxidant defense mechanism and genotoxicity: An in vitro study

Hydroxyapatite–bioglass (HA BG) and hydroxyapatite–ethyl vinyl acetate (HA EVA) are two composite materials that have been developed for bone substitution. Their activity on antioxidant defense mechanism and genotoxicity has not been investigated before. To further confirm its biocompatibility, the present study was undertaken to investigate the effect of HA BG and HA EVA on mice liver antioxidant mechanism along with chromosomal aberrations in human lymphocytes. Physiological saline extract of HA BG and HA EVA showed no adverse effect on liver antioxidant mechanism compared to the cyclophosphamide (CP)-induced toxicity on mice liver homogenate. The results were judged from the in vitro studies made on reduced glutathione, glutathione reductase and lipid peroxidation. These results were well supported by CP- and mytomycin C (MC)-induced genotoxicity studies on human lymphocytes in the presence and absence of a metabolic activator (S9). Hence, it was suggested that these tests could be considered for preliminary toxicological screening of materials intended for clinical applications ahead of in vivo animal model evaluation.