Creation of materials with comparable mechanical performance and esthetic effects to that of natural human enamel and dentin fascinates dental materials scientists. Under this circumstance, reduction or elimination of...
Creation of materials with comparable mechanical performance and esthetic effects to that of natural human enamel and dentin fascinates dental materials scientists. Under this circumstance, reduction or elimination of metals and increasing demand for use of computer aided design/computer-aided manufacturing(CAD/CAM) technology represents recent trend in esthetic dentistry), which stimulates the use of ceramic and composite materials, and triggers the CAD/CAM market growth. In contrast to conventional materials, polymer/ceramic hybrid composites have the potential to tailor the mechanical performance by offering a combination of properties in two phases. Ceramics and polymers are highly suitable for the construction of composites with an optimized mechanical behavior, due to their different material properties. While ceramic materials show excellent mechanical, biomechanical, tribological, and high temperature properties, polymers are an example of materials with higher ductility and low elastic modulus. Therefore, development of polymer infiltrated ceramic composites tailoring individual components’ performance offers a promising step toward such a goal). Mixing of polymers and ceramics on t he molecular level can be thought of as a route to enhance the brittleness of ceramics or the strength of polymers. The classic approach to combine polymer and ceramic these two materials is to imbed ceramic particles in a polymer matrix). Materials strength, elastic properties, and tribological resistance rise because of the incorporated ceramic particles). Adding the facts that the manufacturing costs are relative low and both materials are biocompatible, it is no surprise that polymer ceramic composites are frequently used in dental restorations). There are several excellent publications extensively reviewed dental composites prepared by this conventional route), therefore it is not a focus for this current review. Rather, this review focuses on a route that allows polymer ch
Aims: The purpose of this study was to evaluate and compare the fracture toughness, Vickers-hardness and compressive strength of fiber reinforced composites(FRCs) loaded with various percentages of short zirconia fibe...
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Aims: The purpose of this study was to evaluate and compare the fracture toughness, Vickers-hardness and compressive strength of fiber reinforced composites(FRCs) loaded with various percentages of short zirconia fibers. Materials and methods: Novel silane system with 1.0-vol%(3-acryloxypropyl) trimethoxysilane + 0.5-vol% bis-1,2-(triethoxysilyl)ethane in 90-vol% ethanol(p H=4.0) was used to silanize zirconia fibers(diameter: 3-8-mm, length 50-250-mm). Various amounts of silanized zirconia fibers(1 wt%, 3 wt%, and 5 wt%) were then mixed with resin matrix(78.4 wt%-bis-GMA/19.6-wt%-MMA/1 wt%-CEMA/1 wt%-CQ). Resin matrix without any fibers served as control. These resin composites were then poured and light-cured(Elipar 2500, 3 M-ESPE) into various moulds for different mechanical testing: notchless triangular prism(NTP) test(n=6) was undertaken;hardness values(n=6) were measured by using a Vickers hardness testing machine and compressive strength(n=6) was tested. Six test specimens from each group were stored in either ambient(room temperature, 1-day) and water(37°C, 7-day). EDX and SEM were taken at the silanized fibers and fracture site, respectively. The data were statistically analyzed with 1-way ANOVA and Bonferroni post hoc tests(α=0.05)Results: The ANOVA test revealed that the experimental FRCs with 1 wt% and 3 wt% zirconia fibres showed statistically significant differences in Vickers hardness at dry condition and NTP fracture toughness after 7-day water storage(p<0.05), respectively. However, compressive strength of the experimental groups demonstrated no significant difference(p>0.05). Conclusion: Silanized zirconia fiber-reinforcement in resin is a novel FRC demonstrates promising biomechanical properties.
Objective:Several types of flaps and techniques have been used in the reconstruction of maxillomandibular and skull defects. Myocutaneous flaps of the fibula, the scapula, the rib, the iliac bone, the radial forearm, ...
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Objective:Several types of flaps and techniques have been used in the reconstruction of maxillomandibular and skull defects. Myocutaneous flaps of the fibula, the scapula, the rib, the iliac bone, the radial forearm, the rectus abdominis, the anterolateral thigh, the latissimus dorsi, and the pectoralis major have been used either alone or in combination for this purpose. However, many doctors have taken the rib flaps, they do not handle with rib defects. Large defects of the ribs can lead to the damage of thoracic integrity and stability, resulting in paradoxical respiration and other respiratory dysfunctions. Therefore, it's important for the reconstruction of large rib defects to attain a fine functional and cosmetic result. In this study, we have made the study of bone formation by periosteum and mineralized collagen(MC) to restore the rabbit ribs defection. The purpose of this experiment was to investigate the application of periosteum and mineralized collagen for reconstruction of large rib defects, so as to assess its feasibility in clinical maxillomandibular and skull reconstruction. Methods: Large rib defects of 5～8 cm were created in 10 rabbits and then divided into 2 groups. In the first group, the defects were repaired by the 5 cm MC(left) and 8 cm MC(right). The second: left was 6 cm and right was 7 cm. Biochemical blood parameters such as serum levels of alkaline phosphatase(ALP), calcium and phosphorus were measured before surgery(time 0) and l, 2, 4, 6, 8, 10, 12 weeks after operation. Radiography and gross and his tological and massion examinations were performed in 4, 8, 12 weeks after operation to dynamically observe the progress of bone healing. Results: No intraoperative and postoperative deaths were observed in three groups, flail chest, paradoxical breathing and infections were not found in all the miniature pigs. The serum ALP concentrations followed the same pattern in both groups, decreased from 1 weeks to 6 weeks, lowest at 6 weeks and the
引言:种植体的表面特性影响其骨整合。开发新型的表面处理技术获得具有稳定性、再现性好的不同尺寸范围微观形貌结构既能促进种植体表面处理工艺的进一步更新换代,又能为成骨细胞-钛材表面相互作用基础研究提供合适的实验模型。材料与方法:本文采用一种新型的钛种植体表面处理技术:新型阳极氧化处理整合碱热处理在钛表面制备微米-亚微米/纳米多尺度类骨吸收陷窝形貌新型涂层。工业纯钛TA1加工成直径15mm的小圆片在1#混合电解液（0.7M甲酸钠+0.3M2乙酸钠）中采用阶梯式升流模式（5 to 50 m A/cm with a step of 5 m A/cm,2min/step）的阳极氧化方法处理来制备微米级凹坑结构,在2#电解液（1M乙酸钠）恒压180V处理1min得到亚微米微孔,经10M氢氧化钠60℃处理得到纳米多孔表面。通过扫描电子显微镜检测表面形貌特征,X晶体衍射仪检测表面金相组成,粗糙度仪检测表面粗糙度,静态接触角仪检测亲水性。利用Micro-BCA蛋白试剂盒检测蛋白吸附能力,利用电化学方法在人工模拟体液中检测涂层耐腐蚀性能。体外与人骨肉瘤细胞MG63共培养,选取第6h,1d,3d不同时间点,采用免疫荧光染色和扫描电镜检测成骨细胞的黏附铺展情况;采用DAPi染色检测成骨细胞的早期粘附率;采用CCK-8法检测成骨细胞的增殖特性;通过碱性磷酸酶试剂盒检测成骨细胞分化早期标志物-碱性磷酸酶（ALP）在的活性变化,通过天狼星红和茜素红染色分别检测胶原7分1泌和细胞外基质的矿化。1结果与讨论:获得微米凹坑长径5-70μm,宽径10-36μm,亚微米孔直径0.2-0.8μm,纳米尺寸20-220 nm,形貌的定性及统计分析结果表明新型阳极氧化处理技术整合碱热处理在钛表面制得了在形状与尺寸上与骨吸收陷窝结果十分相近的仿生多孔形貌涂层。该仿生多孔涂层含金红石相和锐钛矿型TiO。粗糙度和接触角结果显示仿生多孔表面呈现中等粗糙度和超亲水性,其粗糙度和接触角分别为1.06μm和7.3°。蛋白吸附实验表面其具有良好的蛋白吸附能力,电化学方法显示耐腐蚀性能较纯钛有了提高。体外成骨细胞实验结果表明,仿生多孔涂层表面细胞随时间呈现明显的黏附和增殖特性,表现出很强的ALP活性,天狼星红和茜素红染色显示出明显的胶原分泌和细胞外基质矿化能力。结论:具有仿生多尺度复合多孔表面形貌的钛表面有利于成骨细胞的分化,该表面处理技术有潜力用于钛种植体产品的表面改性,提高骨整合力。
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