【作者】 张翔；

【导师】 陈吉华； 王迎捷；

【作者基本信息】 第四军医大学 ， 口腔临床医学， 2013， 博士

【摘要】 口腔粘接修复技术能够在不磨切或少磨切牙体组织的前提下实现牙体缺损、牙色及形态异常、咬合关系异常的微创修复与治疗。全瓷修复体则能够最大程度地还原牙齿的形态、色泽与层次感，且具有优异的生物相容性。因此，全瓷粘接修复已成为近年来口腔医学研究的焦点领域之一。瓷与树脂之间良好、持久的结合是粘接修复成功的关键，影响着修复体的固位与功能、长期成功率以及修复体与牙体组织间的微渗漏及继发龋等并发症。目前，粘接强度与耐久性不足仍是导致粘接修复体临床失败的主要问题，其原因主要是界面上存在着不良润湿、收缩应力和弱界面层等，导致粘接剂与被粘体之间的界面结合强度无法满足或无法长期满足口腔特殊环境与功能要求。修复体表面处理是目前提高界面粘接强度的有效途径，主要包括机械粗化处理和无机物表面化学改性。在化学改性中，偶联剂表面处理是目前应用最简便也最广泛的方法。硅烷偶联剂能够在无机和有机材料界面之间起到“分子桥”作用，将两相有机地连接在一起，从而有效改善界面层的粘接强度；同时还能够避免表面机械处理造成的修复体表面结构改变、适合性降低等问题。因此，硅烷偶联剂处理是具有良好研究前景的一类修复体表面处理方式。近年来，口腔粘接修复领域所使用的硅烷偶联剂大多以γ-MPS（γ-甲基丙烯酰氧基丙基三甲氧基硅烷）为主要功能成分，分子结构相对简单，难以与修复体表面产生理想的化学结合；在口腔环境中受湿度、酸碱度、温度变化及咬合应力等影响，作用效果不够持久；因而，其作用尚不能完全满足实际要求。化工材料领域的研究显示，长链硅烷分子在有机-无机两相间具有界面增强增韧的作用。因此，本研究借鉴高分子化学与材料学的最新研究进展和相对成熟的技术，依据口腔粘接修复的特点与要求，设计、合成新型长链硅烷分子并筛选高效的合成路径与条件。在此基础上，对新型硅烷分子的相关性能进行初步评估，并对其在口腔粘接修复中瓷-树脂粘接界面的作用机理进行初步分析，为长链硅烷偶联剂在口腔粘接修复领域中的进一步研究及应用提供一定的实验依据。本研究第一部分借鉴有机化学与材料学相关基础，尝试使用不同前体经不同合成路径合成目标分子：实验一在室温下依次将合成前体混合搅拌，经硅氢加成、醇解、酯化三步反应合成含甲基丙烯酸基团的长链硅烷分子；产物经红外光谱及核磁共振表征，特征官能团的变化符合设计的反应路线，证实获得了目标产物。实验二变更了合成前体，通过硅氢加成与酯化两步反应合成了长链硅烷分子；产物经红外光谱与核磁共振表征，证实获得了目标分子，合成路径可行；二步法合成反应条件温和易控制，操作方便，污染危害小。实验三比较了不同反应条件对产物结构及产率的影响。在25℃室温条件下，本实验硅氢加成反应的时间和加料方式对产物的结构、组成无明显影响；温度对甲基丙烯酰氯与烯醇酯化反应的产物浓度与产率均有一定影响。推荐采取合成前体缓慢滴加的方式，在20-25℃室温条件下进行硅氢加成反应30分钟、85℃加热回流条件下进行酯化反应2小时，反应完全且产率较高。本研究第二部分在规范剪切粘接强度测试方法的基础上，评价了新型硅烷表面处理对瓷-树脂粘接强度的影响，并对其作用机理进行了初步分析与探讨：实验一发现样本材质对剪切粘接强度值有明显影响，弹性模量高的粘接体能够获得较高的剪切强度测试值；剪切粘接强度值受到样本粘接面积的影响，粘接面积越小，粘接强度值越高；粘接强度测试前，应根据研究对象与目的选择适宜的样本材质与粘接面积，以能够更加准确真实地反映材料的性能。实验二证实新型长链硅烷分子对瓷-树脂粘接强度有增强作用，即刻粘接强度与市售商品硅烷偶联剂相当；样本经体外老化处理后，较高浓度新型硅烷处理组的粘接强度值高于商品偶联剂及短链偶联剂；随硅烷浓度增加，偶联效果逐渐增强；但当浓度达到4%质量浓度时，粘接强度增加不明显且在部分实验组出现下降。实验三用分析化学手段分析新型硅烷的作用机理以及与粘接强度的关系。ATR-FTIR结果显示硅烷分子与瓷表面形成了硅氧烷化学结合，硅烷浓度达到2%以上时各特征官能团能够获得明确表征；XPS分析结果表明硅烷与瓷表面形成了Si-O-Si硅氧烷结合，且表面各元素比例的变化趋势与硅烷浓度的增减相一致；综合ATR-FTIR与XPS分析结果，可知新型硅烷分子能够与瓷表面形成化学结合，在一定浓度范围内，随浓度增加，硅烷的化学结合亦增加。实验四测试了新型长链硅烷处理后全瓷表面润湿性的变化，证实其能够显著降低甘油与含硅全瓷表面的接触角，改善无机物表面的润湿性；扫描电镜观察结果则显示当硅烷浓度过高时，可能在无机物表面形成硅氧烷膜而导致粘接强度降低。新型长链硅烷宜配制成2~4%的乙醇溶液用作齿科含硅全瓷材料的表面处理。综上所述，本课题借鉴高分子材料与化工研究经验与基础，设计合成了理论上具有较好作用效果的新型长链硅烷分子，并利用成熟的化学分析方法对产物进行了表征；研究比较分析了不同合成路径、不同反应条件对产物的影响，初步筛选出了高效低害的合成方法；在此基础上，对新型长链硅烷分子作用后对瓷-树脂粘接强度的影响进行了测试，并对作用效果做出了初步评价；通过分析化学和表面形态学研究对新型硅烷分子影响粘接强度的作用机理进行了初步探讨，证实其与牙科含硅全瓷材料表面形成了化学结合并改善了瓷表面的润湿性。更多还原

【Abstract】 Dental bonding technology now is widely used in many branches of dentistry. Withless cut of tooth tissue, it can repair the tooth defects, color and occlusion abnormalities bytooth-colored restorations. All-ceramic restoration can greatly restore the tooth shape,color and layering, and has excellent biocompatibility. Therefore, the all-ceramic adhesiverestoration has become one of the focuses in dental research in recent years. Permanentbonding between ceramic and resin is the key point of adhesive restoration’s long-termsuccess.At present, the deficiency of bond strength and durability is still the main problem ofthe clinical failure in restoration. It is mainly due to the inefficient wetting, shrinkagestress and weak layer on the interface between adhesive and adherends. Restorationsurface treatment is an effective way to improve the bond strength of the interface,including mechanical roughening treatment and chemical surface modification. Surface treatment by coupling agent is the simplest and also the most widely used method ofchemical modification. Silane coupling agent can play the role of ‘molecular bridge’between the inorganic and organic interface, which can connect two different materialstogether and improve the bond strength effectively, as well as avoid surface structurechange and compatibility decrease in restoration. Therefore, silane coupling agenttreatment is a prosthesis surface treatment with good prospects.In recent years, most of the dental silane coupling agents have used γ-MPS as themain functional component. Because of relatively simple molecular structure, it is difficultto obtain sufficient chemical bonding with ceramic surface. Influenced by factors asmoisture, pH, temperature and occlusal stress in oral environment, the bonding effect isnot permanent. Studies of chemical materials have suggested that long-chain silanemolecules can strengthen the interface between organic-inorganic phases.Therefore, this study is based on the latest research progress in polymer chemistryand materials science. Accoding to the characteristics and requirements of dental bonding,this study aims to synthesize a novel long-chain silane molecule, and screen efficientsynthetic route and conditions. Then, we have analyzed the effect of the new silane onceramic-resin bonding strength. And an analysis of the mechanism of interaction betweensilane with ceramic interface has also been performed, so as to provide experiment datafor the further application of long-chain silane in restoration.Part I of this study focuses on synthesis of target long-chain silane molecules throughdifferent routes and different reaction conditions.Experiment1: At room temperature, long-chain silane molecules containing amethacrylate group were synthesized following three-step reaction (hydrosilylation,alcoholysis, esterification). Molecules were characterized by FTIR and NMR.Experiment2: At room temperature, long-chain silane molecules containing amethacrylate group were synthesized following two-step reaction (hydrosilylation,esterification) with different raw materials. Molecules were characterized by FTIR andNMR. Two-step synthesis route is easy to operate and has less pollution.Experiment3: Effect of different reaction conditions on the structure of the productwas analyzed. At a room temperature of25℃, time and feeding methods ofhydrosilylation reaction had no significant effect on the structure of the product. To someextent, temperature influenced the esterification reaction product concentration and the production rate. Slow dropping of reactants is recommended in hydrosilylation reaction ata room temperature of25℃for30minutes and esterification for two hours under85℃heating refluxing, since the reaction will be complete and the productivity will be higher.Part II of this study aims to evaluate the effect of new silane treatment on ceramicbond strength, and to analyze its mechanism of interaction.Experiment1: The study showed that sample material had significant effect on theshear bond strength value. Adherend with higher elastic modulus was able to obtain highershear strength test value. Shear bond strength values were also influenced by the bondingarea. The smaller the bonding area, the higher the bond strength value is. We should useappropriate sample material and bonding area, according to the research object andpurpose, to reflect the performance of the material more accurately and realistically.Experiment2: The enhancement of new long-chain silane to ceramic-resin bondingwas confirmed. Its instant bond strength was as effective as commercial silane couplingagent. After aging treatment, the samples useing novel silane showed higher bond strengthvalues. The silane coupling effect was gradually enhanced when the concentration wasincreased. But when the concentration reached4%, the bond strength was not significantlyincreased, and even decreased in some experimental groups.Experiment3: The mechanism of the novel silane and its relation with bond strengthwere analyzed by analytical chemistry methods. ATR-FTIR results showed that the silanemolecule and the ceramic surface formed a siloxane chemical bonding. When silaneconcentration was2%or higher, each characteristic functional group got clearcharacterization. XPS analysis showed that the silane formed the Si-O-Si siloxane on theceramic surface. The proportion of each element is consistent with the silaneconcentration.Experiment4: Wettability of ceramic surface treated by the new silane was tested. Itwas confirmed that new silane treatment could significantly reduce the contact angle ofglycerol to silicon-containing ceramic surface. The long-chain silane could improve thewettability of the surface of inorganic material. SEM showed that when the silaneconcentration was too high, silicone membrane formed on the surface of inorganicmaterial. This might result in bond strength reduction. Accordingly, the new long-chainsilane should be formulated as2-4%ethanol solution to be used as the dental ceramiccoupling agent. In summary, based on polymer materials and chemical research, this study designedand synthesized a novel long-chain silane molecule with better theoretical effect. Theproducts were characterized by series chemical analysis methods. Synthetic route withhigh efficiency and low harm was screened out. On this basis, the effect of long-chainsilane molecules on bond strength between ceramic and resin were tested. By the chemicaland surface morphology studies, we analyzed the mechanism of new silane molecules onthe bonding strength. It was confirmed that the chemical bonding formed betweensilicon-containing all-ceramic surface and long-chain silane molecules.更多还原