表面粗糙度对水与唾液在纯钛及PMMA上润湿作用的影响

目的:评价全口义齿基托材料及其表面粗糙度对义齿固位的影响。方法:测定水与唾液在表面粗糙度不同的纯钛和聚甲基丙烯酸甲酯(PMMA)上的前进接触角和后退接触角,通过两者的差值θh反映水与唾液对它们的润湿效果。结果:1、随着表面粗糙度增加,唾液在纯钛上的θh逐渐降低,但当Ra≥1.0,Rz≥1.5时,θh突然增大;而PMMA组,当Ra<1.2,Rz<2时,粗糙度对θh无明显影响,当Ra≥1.2,Rz≥2时θh也显著增加,多数情况下,唾液在相同粗糙度的纯钛上的θh大于在PMMA上的θh。2、水在光滑的PMMA和纯钛上的前进接触角比唾液的大。结论:唾液对纯钛的润湿效果,可以通过高度磨光或形成较为粗糙的表面(Ra≥1.0,Rz≥1.5)得到提高,多数情况下这种润湿效果好于PMMA。提示从润湿效果看,对于不能高度研磨和抛光的义齿组织面,全口义齿上颌腭托选择纯钛并形成较为粗糙的表面可能更有利于固位。     

4种义齿基托材料表面润湿性的实验研究

目的评价临床常用的钴铬合金、钴铬钼合金、纯钛和热凝型义齿基托树脂的润湿性,为临床选择合适的全口义齿基托材料提供理论指导。方法分别测定人工唾液在不同处理的钴铬合金、钴铬钼合金、纯钛、热凝型义齿基托树脂上的接触角,通过接触角大小反应4种材料的润湿性。结果按临床实际磨光处理组的接触角均比磨光成镜面状组的小,且差异具有统计学意义。磨光成镜面状组中热凝型义齿基托树脂接触角最大,其次是纯钛,钴铬合金和钴铬钼合金接触角最小,除钴铬合金和钴铬钼合金外其余材料两两间比较差异均具有统计学意义。临床实际磨光处理组中接触角最大的是纯钛,其次为热凝型义齿基托树脂,钴铬合金和钴铬钼合金接触角最小,除钴铬合金和钴铬钼合金外其余材料两两间比较差异均具有统计学意义。结论钴铬合金和钴铬钼合金润湿性优于纯钛和热凝型义齿基托树脂,从润湿性对固位力的影响角度考虑,选择这两种材料制作全口义齿基托对全口义齿的固位更加有利。     

Biomedical Ti–Mo Alloys with Surface Machined and Modified by Laser Beam: Biomechanical,Histological, and Histometric Analysis in Rabbits

Purpose: In vivo bone response was assessed by removal torque, hystological and histometrical analysis on a recently developed biomedical Ti‐15Mo alloy, after surface modification by laser beam irradiation, installed in the tibia of rabbits. Materials and Methods: A total of 32 wide cylindrical Ti‐15Mo dental implants were obtained (10 mm × 3.75 mm). The implants were divided into two groups: 1) control samples (Machined surface – MS) and 2) implants with their surface modified by Laser beam‐irradiation (Test samples – LS). Six implants of each surface were used for removal torque test and 10 of each surface for histological and histometrical analysis. The implants were placed in the tibial metaphyses of rabbits. Results: Average removal torque was 51.5 Ncm to MS and >90 Ncm to LS. Bone‐to‐implant‐contact percentage was significantly higher for LS implants both in the cortical and marrow regions. Conclusions: The present study demonstrated that laser treated Ti‐15Mo alloys are promising materials for biomedical application.     

Modification of poly(ether urethane)elastomers by incorporation of poly(isobutylene)glycol. Relation between polymer properties and thrombogenicity

Non-polar hydrophobic poly(isobutylene)glycol (PIBG) was substituted for poly(tetramethylene ether)glycol (PTMEG) in poly(ether urethanes) based on 4,4'-methylenebis-(phenylisocyanate) (MDI) and 1,4-butanediol (BD) as chain extender. Two series of polyurethanes differing in their soft segment length, polymer composition, and hard segment content were studied by dynamic mechanical analysis (DMA) and static, as well as dynamic, contact angle measurements. The thrombogenicity of these polymers was characterized by studying the adhesion and activation of platelets using ELISA for GMP 140 and fluorescence microscopy. It was found by DMA that in PIBG-containing polyurethanes (PUE) exist soft domains containing hard segments, strictly separated hard segment domains, and hard segments partially mixed with soft segments. Contact angle measurements revealed that 25% PIBG or even less, are sufficient for a remarkable enrichment of these non-polar soft segments on the polymer surface. The platelet adhesion/activation on these materials was demonstrated to increase with the rise in hard segment content, as well as with an enhancement of the PIBG content. However, comparison of PIBG-containing PUE with medical applied polypropylene and pellethane expressed that PUE with PIBG content equal or less 25% have excellent haemocompatibility.     

A Simple 2-step Silane Treatment for Improved Bonding Durability of Resin Cement to Quartz Fiber Post

IntroductionThis study examined a clinically feasible protocol for improving hydrolytic stability using a 2-step silanization including a nonorganofunctional silane.MethodsThe surfaces of 24 D.T. Light-Posts (Bisco Inc, Schaumburg, IL) were polished and assigned to the following 4 groups: M: 1-step silanization with Monobond-S (MS) (Ivoclar Vivadent, Schaan, Liechtenstein); BM: 2-step silanization with 5% 1,2-bis(triethoxysilyl)ethane and then MS; and HM and HBM: 1-step and 2-step silanization, respectively, after 24% H₂O₂ etching. Four resin composite cylinders (RelyX Unicem; 3M ESPE, St Paul, MN) were bonded on each surface according to a microshear testing protocol. All bonded samples were stored in water at 37°C for 24 hours, and half of them were then thermocycled 5000 times before microshear testing (n = 12). The failure modes were evaluated under an optical and scanning electron microscope. Water contact angles were measured on the post surfaces before and after silanization to estimate surface hydrophobicity. The results were statistically analyzed using 2-way analysis of variance and the Tukey test.ResultsThe bond strengths for the BM and HBM groups were significantly higher than the M and HM groups at 5000 thermocycles (P < .05), whereas no significant differences were found between the 4 groups before thermocycling (P > .05). All debonded samples showed some fractured fibers. No significant difference in the hydrophobicity was found between the 1-step and 2-step silanized post surfaces (P > .05).ConclusionsThe 2-step 1,2-bis(triethoxysilyl)ethane/MS treatment has potential as a silanization procedure for enhancing the hydrolytic stability of the fiber post/resin composite interface.     

Surface Properties of Mesophase‐Forming Fluorinated Bicycloacrylate/Polysiloxane Methacrylate Copolymers

Novel random copolymers were synthesized by free‐radical polymerization of a bicycloacrylate monomer carrying a fluorocarbon chain side group (BAF10) with a methacrylate monomer having a polysiloxane side graft (SiMA). The copolymers with higher contents of BAF10 gave rise to a well‐ordered smectic bilayer mesophase. The surface structure of the derived polymer films was investigated by measurements of the contact angle with several interrogating liquids and X‐ray photoelectron spectroscopy (XPS) at different photoemission angles. The values of the contact angles were used to evaluate the film surface tension, following different additive‐component and equation‐of‐state methods. The low surface energies found were attributed to the pronounced hydrophobicity and oleophobicity of the outermost surface caused by the preferential segregation of the fluorocarbon chains to the polymer–air interface.

     

微粉硅胶用于白芷提取物粉体改性及其促进元胡止痛分散片崩解的原理研究

目的 研究微粉硅胶用于白芷提取物粉体改性及其促进元胡止痛分散片崩解的原理.方法 采用混合与液相分散两种方法,微粉硅胶3％、5％、7％3种改性剂量对白芷提取物进行粉体改性,研究粉体改性前后在红外光谱、比表面积与孔隙度、接触角、差示扫描量热、扫描电镜的差异及其对元胡止痛分散片崩解时间的影响.结果 红外光谱显示液相分散法与混合法的改性方式相同,均属物理改性;改性后,粉体的比表面积与孔隙体积显著增加,接触角显著降低,热效应显著变化;当微粉硅胶用量达到5％时,两种方法均能改善元胡止痛分散片的崩解性能.结论 增强白芷提取物比表面积,增强吸水性、润湿性,分散提取物,降低黏性可能是微粉硅胶改性及促进分散片崩解的主要机制.     

Ti2448与纯钛金瓷结合强度的对比评价

目的：对比相同条件下Ti2448与纯钛的金瓷结合强度,评价Ti2448的烤瓷性能。方法：采用纯钛常规喷砂方法对纯钛和Ti2448分别进行表面处理,测试处理后的金属表面粗糙度、表面能,采用三点弯曲实验对两种金属与Duceratin Kiss瓷粉的结合强度进行评价,采用扫描电镜和能谱分析对金瓷结合界面的显微结构和成分组成进行分析。结果：经相同的喷砂处理后的粗糙度、表面能和三点弯曲结合强度,纯钛组为0.588μm、78.70 mJ/m2和23.89 MPa,Ti2448组为0.621μm、94.17 mJ/m2和31.51 MPa,Ti2448组的各项指标均高于纯钛组,经t检验均具有显著性差异（P〈0.05）。扫描电镜和能谱分析结果显示Ti2448组的瓷剥脱面有更多的残留瓷,且有Sn元素贯穿金瓷界面渗入瓷层。结论：利用纯钛的常规表面处理方法对Ti2448进行表面处理能够获得优于纯钛的表面润湿性和瓷结合强度,并达到了临床要求。     

浸泡消毒对六种弹性体印模材料表面润湿性影响的研究

目的：研究6种弹性体印模材料在2%中性戊二醛消毒液浸泡不同时间后表面润湿性的变化。方法：6种弹性体印模材料Express硅橡胶（3M公司）、Silagum硅橡胶（DMG公司）、Aquasil硅橡胶（Densply公司）、EXAFINE硅橡胶（FUJI公司）、Zetaplus硅橡胶（Zhermack公司）及Impregum-Penta聚乙醚橡胶（3M公司）在2%中性戊二醛消毒液中浸泡不同时间后,运用配对t检验对6种弹性体印模材料不同时间浸泡消毒处理后和未浸泡组之间的接触角进行统计学分析。结果：聚醚橡胶材料和4种添加了亲水基团的硅橡胶材料在消毒液中,其接触角有随浸泡时间的增长而增大的趋势,相应其润湿性有随其浸泡时间的增长而降低的趋势,其中除了Silagum硅橡胶（DMG公司）外均有统计学意义。而传统的疏水性硅橡胶材料在消毒液中,接触角并没有随浸泡时间的增长而增大的趋势。结论：在这6种弹性体印模材料中,亲水性弹性体印模材料在浸泡不同时间后表面润湿性有所降低。