Microperoxidase primer promotes adhesion of butylborane-polymerized resin to dentin

The purpose of this study was to investigate the effect of dentin primers containing microperoxidase (MP-11) with 2-hydroxyethyl methacrylate (HEMA) on the bond strength between a tri-n-butylborane-initiated self-polymerizing resin and dentin. Bovine dentin surfaces were etched with 10 wt % phosphoric acid, primed, and then bonded with stainless steel rods. Tensile bond strength after 24 h of storage in water was significantly influenced by both MP-11 and HEMA. Groups with no MP-11 showed the lowest values. Without HEMA, the bond strengths of groups using 0.01, 0.1, and 1.0 micromol/g MP-11 were statistically identical, and also greater than that of the no MP-11 control. In the presence of HEMA, the bond strength was significantly enhanced with an increasing concentration of MP-11. The highest bond strength of 29.0 MPa was obtained with aqueous HEMA primer, containing 1.0 micromol/g MP-11. Microscopic observation showed the formation of a hybrid layer at the bonded interface. Polymerization of the resin was significantly accelerated with the MP-11 primer. In conclusion, MP-11 has a potential for adhesive bonding promoter between the resin and the demineralized dentin surface.     

Biocompatibility of 17-4 PH stainless steel foam for implant applications

In this study, biocompatibility of 17-4 PH stainless steel foam for biomedical implant applications was investigated. 17-4 PH stainless steel foams having porosities in the range of 40-82% with an average pore size of around 600 μm were produced by space holder-sintering technique. Sintered foams were precipitation hardened for times of 1-6 h at temperatures between 450-570 °C. Compressive yield strength and Young's modulus of aged stainless steel foams were observed to vary between 80-130 MPa and 0.73-1.54 GPa, respectively. Pore morphology, pore size and the mechanical properties of the 17-4 PH stainless steel foams were close to cancellous bone. In vitro evaluations of cytotoxicity of the foams were investigated by XTT and MTT assays and showed sufficient biocompatibility. Surface roughness parameters of the stainless steel foams were also determined to characterize the foams.     

Bone-implant interface mechanics of in vivo bio-inert ceramics

We have previously demonstrated that there was no significant difference between the affinity of bone to bio-inert ceramics and stainless steel in a histological study. In this study, the bone-implant interface shear strength of alumina ceramics (AI₂O₃), zirconia ceramics (ZrO₂), stainless steel (SUS316L) and sintered hydroxyapatite (HA) were compared in 19 dogs using a transcortical push-out model of the femur 4 and 12 wk after implantation. The interface shear strength of HA was significantly greater than that of alumina ceramics, zirconia ceramics and stainless steel (P < 0.001). There was no significant difference between bio-inert ceramics and stainless steel.     

Effect of metal surface characteristics on the adhesion performance of the integrated low-level energies method of adhesion

We have previously proposed a new method of adhesion using the integrated low-level energy sources heat, vibration, and pressure. This adhesion method can be used to attach biological tissue to a metal object. Effects of surface roughness and energy of the metal subject on adhesion performance were studied by using commercially pure titanium (cpTi) and stainless steel (SUS304). Surface roughness and energy were changed by sandblast treatment and heat treatment, respectively. A porcine aorta was adhered to sandblast-treated SUS304 by use of an adhesion temperature of 80?°C, a vibration amplitude of 15???m, a pressure of 2.5?MPa, an adhesion time of 120?s, and a surface roughness of an Ra 0.25???m. The shear tensile strength of the adhesion was 0.45?MPa. The adhesion performance was improved by roughening the surface of the metal specimen. Surface energy has an insignificant effect on adhesive strength. The adhesion performance varied depending on metal material for the same surface roughness, Ra, and energy. Results from analysis of the surface roughness profile suggested that the size of surface asperity has an effect on adhesion performance.     

Bioglass composites: a potential material for dental application

Bioglass, a promising material for dental applications, can be reinforced with ductile stainless steel fibres. Three aspects of the fibre-reinforced bioglass composites are discussed. They are the interface between the glass and the metal fibres, the mechanical properties of the composites and their in vivo bonding behaviour. The importance of a good interfacial bond between the glass and the metal fibres is outlined. The improvement in strength and toughness, due to the fibres, is explained. The in vivo bonding behaviour of the bioglass composite is checked under statically loaded conditions.     

Study on preparation and properties ofbiofunctionally gradient coatingsw ith m agnetron cosputtering

ＩＮＴＲＯＤＵＣＴＩＯＮ　　Ｔｈｅｄｉｆｆｅｒｅｎｃｅｓｏｆｓｔｒｕｃｔｕｒｅａｎｄｐｈｙｓｉｃａｌｐｒｏｐｅｒｔｉｅｓｂｅｔｗｅｅｎｔｈｅｃｏａｔｉｎｇａｎｄｔｈｅｓｕｂｓｔｒａｔｅｍａｋｅｔｈｅｂｏｕｎｄａｒｙｚｏｎｅｂｅｃｏｍｅｔｈｅｗｅａｋｅｓｔｚｏｎｅｏｆｔｈｅｗｈｏｌｅｃｏｍｐｏｓｉｔｅｓｙｓｔｅｍ，ｓｔｕｄｙｏｎｉｍｐｒｏｖｉｎｇｔｈｅａｄｈｅｓｉｏｎｏｆｃｏａｔｉｎｇｔｏｓｕｂｓｔｒａｔｅｉｓａｌｗａｙｓａｎａｔｔｒａｃｔｉｖｅａｎｄａｃｔｉｖｅｆｉｅｌｄ〔１～４〕．Ａｎｄｔｈ…     

等离子体预处理对316L不锈钢-EVAL界面结合强度的影响

研究丁Ar、N2及Ar＋N2等离子体预处理对316L不锈钢与其表面EVAL涂层之间结合强度的影响。采用全反射丌IR、AFM测试研究了等离子体预处理前后316L不锈钢表面物化状态的变化；利用X-光电子能谱研究了316L不锈钢与EVAL涂层之间的界面反应。研究结果表明：Ar、N2及Ar＋N2等离子体预处理后，316L不锈钢与EVAL涂层之间的结合强度分别高达0．92MPa、1．2MPa、1．5MPa（未经处理的试样为0．15MPa）。全反射FTIR和AFM分析结果表明Ar、N2等离子体均对基体表面有较好的清洗作用，Ar等离子体对基体表面具有较强的轰击、刻蚀作用。XPS测试表明EVAL在经Ar等离子体处理的基体表面仅以物理吸附状态存在，推测与N2等离子体处理的基体之间形成了metal-N-O形式的氢键结合。     

钛合金内固定材料修复脊柱结核：生物相容性及力学性能

BACKGROUND: Currently, surgical implant fixation is mainly applied for spinal tuberculosis. How to choose implant materials, however, is still under discussion. OBJECTIVE: To compare the biocompatibility and mechanical properties of titanium alloy and stainless steel for rabbit spinal tuberculosis. METHODS: Thirty rabbits were chosen to prepare spinal tuberculosis models. Then, the rabbits were equivalently randomized into two groups, which underwent implant fixation with stainless steel or titanium alloy, respectively. At 30 days after implantation, biocompatibility and biomechanical properties of the two materials in the repaired region of spine were observed and detected, respectively. RESULTS AND CONCLUSION: In view of the biocompatibility, infection and immunological rejection could not been found in the titanium alloy group; in contrast, infection appeared in three rabbits of the stainless steel group. Flexion, extension and lateral bending displacements under the spinal loading in the titanium alloy group were significantly less than those in the stainless steel group (P < 0.05); axial pull-out strength in the titanium alloy group was significantly higher than that in the stainless steel group (P < 0.05); flexion, extension, lateral bending and axial compression in the titanium alloy group were significantly greater than those in the stainless steel group (P < 0.05). In conclusion, titanium alloy material has good biocompatibility that can be used to restore and maintain the spinal stability.     

三种固定方法在颅骨骨瓣回复固定模型中生物力学评价的实验研究

目的对三种骨瓣固定方法在颅骨骨瓣回复固定模型中的生物力学性能进行比较、评价。方法6个颅骨标本共制备24个骨瓣,分为三组,分别采用丝线、不锈钢丝和颅骨固定钉三种方法固定,就操作时间、初始移位、垂直受力试验及最大承受力等方面进行比较。结果颅骨固定钉组的操作时间最短(94±13)s,初始移位最小(0.20±0.12)mm,最大承受力最大(385.4±63.1)N均明显优于不锈钢丝组和丝线组。结论颅骨固定钉操作简便快速,具有良好的复位效果及较大的强度,是较理想的颅骨固定装置。     

A peptide-stainless steel reaction that yields a new bioorganic-metal state of matter

A synthetic peptide derived from the native protein sequence of a metal binding bacterial pilus was observed to spontaneously react with stainless steel via a previously unreported type of chemical interaction to generate an altered form of stainless steel which we term bioorganic stainless steel. Bioorganic stainless steel has a significantly increased electron work function (4.9 ± 0.05 eV compared to 4.79 ± 0.07 eV), decreased material adhesive force (19.4 ± 8.8 nN compared to 56.7 ± 10.5 nN), and is significantly harder than regular 304 stainless steel (~40% harder). A formal or semi-formal organo-metallic covalent bond is generated between a pilin receptor binding domain and stainless steel based on XPS analysis which indicates that the electronic state of the surface is altered. Further, we establish that the peptide-steel reaction demonstrates a degree of stereospecificity as the reaction of native L-peptide, D-peptide and a retro-inverso-D-peptide yields bioorganic steel products that can be differentiated via the resulting EWF (4.867 ± 0.008 eV, 4.651 ± 0.008 eV, and 4.919 ± 0.007 eV, respectively). We conclude that electron sharing between the peptide and steel surface results in the stabilization of surface electrons to generate bioorganic steel that displays altered properties relative to the initial starting material. The bioorganic steel generated from the retro-inverso-D-peptide yields a protease stable product that is harder (41% harder at a 400 μN load), and has a 50% lower corrosion rate compared with regular stainless steel (0.11 ± 0.03 mpy and 0.22 ± 0.04 mpy, respectively). Bioorganic steel is readily fabricated.     

钢制人工髋关节力学性能分析

本文对骨科临床中采用的钢制人工髋关节的力学特性，如强度，刚度，振动以及与股骨的相容特性等，用三维等参有限元方法进行了分析．结果表明，采用钢制人工髋关节能与人体相容，具有较好的力学特性。     

A study on cytochrome c oxidoreductase for bonding a tri-n-butylborane-initiated luting agent to dentin.

The purpose of this study was to investigate the effectiveness of cytochrome c, an oxidoreductase, in terms of initiation of polymerization in dentin bonding. The efficacy of experimental dentin primers was evaluated via the bonding of a luting agent to dentin. The eight primers evaluated were cytochrome c aqueous solutions, four with 35 wt% 2-hydroxyethyl methacrylate (HEMA) and four without. The concentrations of cytochrome c in the primers were 0, 0.01, 0.1, and 1[corrected] micromol/g. The luting agent (Super-Bond C&B) consisted of methyl methacrylate (MMA), 4-methacryloyloxyethyl trimellitate anhydride (4-META), and tri-n-butylborane (TBB) initiator. Bovine dentin surfaces were flattened, etched with an aqueous solution of 10 wt% phosphoric acid, primed, and then bonded with stainless steel rods. After 1-day immersion in water, tensile testing revealed that the bond strength was influenced by the application of cytochrome c and HEMA. The maximum bond strength of 24.6 MPa was recorded with aqueous HEMA primer containing 10 micromol/g cytochrome c. This bonding technique, combining oxidoreductase with Super-Bond C&B, may potentially be applied for seating resin-bonded restorations.     

A comparison of in vitro and in vivo degradation of two CPC strain gauge coatings

Calcium phosphate ceramic (CPC) coated strain gauges have been used to measure bone strain in animal models for up to 16 weeks and are being developed to collect measurements in patients for periods of 1 year or more. A published surface roughening and heat treating procedure produced improved dry strength and in vivo stability of CPC-gauge interfaces after 16 weeks. The long term bond strength of two CPC-gauge interfaces prepared using the roughening and heat treating process were evaluated after up to 1 year in vitro and in vivo using a lap shear test. The feasibility of using an in vitro test to predict long term in vivo interface changes was established. A blended tricalcium phosphate + hydroxyapatite had a CPC-gauge interface strength which decreased from 6.07 +/- 2.64 MPa at 16 weeks to 4.71 +/- 1.840 MPa after 1 year in Hanks Balanced Salts (HBS). The same coating had a strength that decreased from 8.51 +/- 2.63 MPa at 16 weeks to 5.35 +/- 1 MPa after 1 year in vivo. A soluble calcium enhanced hydroxyapatite had an interface strength of 4.83 +/- 1.106 MPa after 16 weeks and 4.51+/- 1.100 MPa after 1 year in HBS. The same coating had an interface strength of 8.34 +/- 2.40 MPa after 16 weeks and 5.20 +/- 2.00 MPa after 1 year in vivo. Although interface strengths decreased slightly with time in vivo, after 1 year they were in the same strength range as published CPC-bone interface strengths of 4.8 +/- 2.4 MPa. Comparison of in vitro with in vivo results indicated that in vitro results were a good predictor of strength change in the blended CPC coating, but a poorer predictor of strength changes in the soluble calcium-enhanced coating.     

局部运用阿仑磷酸钠对兔人工假体无菌性松动抑制作用的研究

目的 探讨局部运用阿仑磷酸钠对抑制破骨细胞性骨吸收的影响,为临床上人工关节的松动提供预防和治疗的方法。方法 用20只大耳白兔建立骨质疏松模型后,在模型兔右侧股骨中上段截骨,用仿锤形不锈钢假体连接断端,一组用阿仑磷酸钠加骨水泥(PMMA)固定假体,对照组为单用PMMA固定。8周后处死全部实验兔,取出实验股骨,作生物力学实验和病理形态学检查,进行图像分析和统计学处理。结果 在拔出实验和扭转实验,阿仑磷酸钠组均显著优于对照组(P<0.01)。病理组织形态学检查阿仑磷酸钠组骨小梁体积比、厚度和数目高于对照组(P<0.01或P<0.05)。结论局部运用阿仑磷酸钠对人工假体无菌性松动有明显抑制作用,增加了人工假体的稳定性。     

Torsional properties of implant grade titanium

The purpose of this research was to evaluate the torsional strength and ductility of CP titanium in the as received condition, heat treated below the alpha----beta transition temperature, and glass bead blasted. Results were compared to as-received samples of implant quality 316L stainless steel. Little or no effect of any of the treatments was noted. The torsional strength of all titanium samples was comparable to 316L stainless and the torsional ductility of the titanium was significantly greater than 316L stainless (p less than .01). These results are significantly different than those obtained when torsion testing bone screws of the same material. A hypothesis is proposed for the differences in these results.     

新型医用不锈钢研究

现有医用植入不锈钢由于其优良的综合性能广泛应用于医疗领域，但其中含有的镍元素由于腐蚀溶出，除对人体产生过敏反应外，还存在致畸、致癌的危害性。本文研究了新型医用无镍不锈钢（BIOSSN4）的力学性能、耐蚀性能和血液相容性等。与传统使用的医用316L不锈钢相比，BIOSSN4具有更好的强韧性配合，优良的耐蚀性和血液相容性，这种优势将会为其提供广阔的应用前景。     

Adhesion enhancement of steel fibers to acrylic bone cement through a silane coupling agent

The use of a silane coupling agent (methacryloxypropyl-trichlorosilane) to improve the mechanical properties of steel fiber-reinforced acrylic bone cements was assessed. Changes to the tensile and fracture properties of bone cements reinforced with silane-coated or uncoated 316L stainless steel fibers of different aspect ratios were studied. Contact-angle measurements indicated that the coupling agent coats the metal surface through room temperature treatments in a short time (within 2 h). Push-out tests indicated that the interfacial shear strength of silane-coated 316L stainless steel rods is 141% higher than the uncoated rods. The elastic moduli, ultimate stresses, and fracture toughness of the silane-coated, steel fiber-reinforced bone cements are significantly higher than the bone cements reinforced with uncoated steel fibers. There were no differences in the tensile mechanical properties of the silane-coated or uncoated, steel fiber-reinforced cements after aging in a physiological saline solution, indicating that the bonding effectiveness is decreased by the intrusion of water at the metal-polymer interface. Because of possible biocompatibility issues with leaching of the silane coupling agent and no long-term mechanical benefit in simulated aging experiments, the use of these agents is not recommended for in vivo use.     

制作颊侧多曲簧的牙用不锈钢丝的性能分析

目的 通过测试并比较480℃加热退火处理的四种不同品牌,直径为φ0.8 mm牙用不锈钢丝的电镜断口形貌和拉伸断裂机制,为临床选用适宜的牙用不锈钢丝制备颊侧多曲簧提供一定的参考。方法 选用弯制颊侧多曲簧的直径为φ0.8 mm的上齿牌、上海康桥牌、锋棱牌、上海荣祥牌的牙用不锈钢丝,应用万能拉伸仪测量比较四种材料480℃加热退火后的拉伸试验、金相组织微观测试及EDX能谱分析。结果 四种不同品牌的牙用不锈钢丝在480℃加热退火处理下,直径为φ0.8 mm锋棱牌牙用不锈钢丝拉伸能力最好,电镜观察见韧窝大小不一,深浅有别,Ni含量最高,更适合临床弯制颊侧多曲簧。结论 直径为φ0.8 mm锋棱牌牙用不锈钢丝较其他品牌牙用不锈钢丝,更适合弯制颊侧多曲簧,可考虑临床应用。     

316L-Cu抗菌不锈钢种植体中Cu离子的抗菌活性

背景：316L-Cu抗菌不锈钢是通过在不锈钢中添加一定量的铜元素,并采取特殊的热处理使不锈钢基体中均匀弥散分布富铜析出相,从而赋予抗菌不锈钢优异的抗菌性能。 目的：评价新型316L-Cu抗菌不锈钢种植体对牙龈卟啉单胞菌的抗菌性能,并检测316L-Cu抗菌不锈钢的Cu离子溶出行为,为其进一步临床应用提供生物医学证据。 方法：以医用316L不锈钢为成分基础,添加3.5%-4.0%的Cu元素制成316L-Cu抗菌不锈钢。将其按       0.1 cm2/L表面积对容量比置于模拟体液中,在37 ℃震荡水浴中浸泡1-10 d。采用石墨炉原子吸光光度计每天测定浸提液中的铜离子含量。通过覆膜法抗菌实验及扫描电镜形态学观察评价316L-Cu抗菌不锈钢的杀菌性能。 结果与结论：316L-Cu抗菌不锈钢在模拟体液中浸泡1-10 d后的Cu离子溶出量远高于普通医用316 L不锈钢。随着作用时间的延长,316L-Cu抗菌不锈钢的杀菌率逐步提高,10 h时杀菌率已达100%。316L-Cu抗菌不锈钢作用3 h后牙龈卟啉单胞菌的菌体形态即出现明显的变化,6 h后菌体出现明显的裂解,9 h后材料表面绝大多数细菌即崩解为碎片。说明316L-Cu抗菌不锈钢能够有效地杀灭种植体周围炎的主要致病菌,同时能够缓慢释放Cu离子,改变种植体周围微环境,说明其为一种极具潜力的生物材料,具有良好的临床应用价值。 中国组织工程研究杂志出版内容重点：生物材料;骨生物材料; 口腔生物材料; 纳米材料; 缓释材料; 材料相容性;组织工程     

The effect of different power densities and method of exposure on the marginal adaptation of four light-cured dental restorative materials

PURPOSE: To determine whether marginal adhesion is sensitive to different irradiation parameters, we investigated the in vitro adhesion values of four dental resins on metal surfaces. METHODS: Four groups of eight specimens each of Z250, Filtek flow, Dyract AP and Dyract flow were placed in pre-treated stainless steel cavities and irradiated using different methods of exposure. The curing lights used were a Spectrum 800 halogen curing light at settings of 800 and 450 mW/cm(2) and an Optilux 501 ramping light. The maximum amount of push-out force required to displace the resin from the metal cavity was equated with adhesive value (shear bond strength). Comparisons (ANOVA, p<0.0001) were made within the same material and between the different materials when using different curing protocols. RESULTS: Significant lower bond strengths were recorded when curing was done by gradually increasing the intensity (ramping method) compared to curing with the fixed intensities (p>0.0001) Comparing the fixed intensities, significant lower bond strength values were obtained at 800 mW/cm(2) compared to 450 mW/cm(2) (p<0.0001). For all exposures, the two flowable materials demonstrated weaker values when compared to the higher filled materials. CLINICAL SIGNIFICANCE: The advantage of initial slow polymerization (more elasticity and less tension) obtained by the so-called "soft start" method, was offset by a rise in total polymerization shrinkage, when final curing was completed at 1130 mW/cm(2). These tests demonstrated that using halogen units, exposure for 40s with an intensity of 450 mW/cm(2) appeared to be the most promising for light-curing dental resin composites.