• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文学位 >Characterization of hydrophilic-rich phase mimic in dentin adhesive and computer-aided molecular design of water compatible visible light initiators.
【24h】

Characterization of hydrophilic-rich phase mimic in dentin adhesive and computer-aided molecular design of water compatible visible light initiators.

机译：牙本质粘合剂中富亲水相模拟物的表征以及与水相容的可见光引发剂的计算机辅助分子设计。

获取原文
获取原文并翻译 | 示例
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

The clinical lifetime of moderate-to-large dental composite restorations is lower than dental amalgam restorations. With the imminent and significant reduction in the use and availability of dental amalgam, the application of composite for the restoration of teeth will increase. Since composite has a higher failure rate, the increased use of composite will translate to an increase in the frequency of dental restoration replacement, overall cost for dental health and discomfort for patients. The composite is too viscous to bond directly to the tooth and thus, a low viscosity adhesive is used to form the bond between the composite and tooth. The bond at the adhesive/tooth is intended to form an impervious seal that protects the restored tooth from acids, oral fluids and bacteria that will undermine the composite restoration. The integrity of the adhesive/tooth bond (the exposed tooth structure is largely composed of enamel and dentin) plays an important role in preventing secondary caries which undermine the composite restoration. This study focuses on the durability of etch-and-rinse dental adhesives.;As the adhesive infiltrates the demineralized dentin matrix, it undergoes phase separation into hydrophobic- and hydrophilic-rich phases. The hydrophilic-rich phase contains the conventional hydrophobic photo-initiator system (camphorquinone/ethyl 4-(dimethylamino)benzoate) and cross-linker both in inadequate concentrations. This may compromise the polymerization reaction and the cross-linking density of this phase, making it vulnerable to failure. The goal of this study is to characterize the hydrophilic-rich phase of the dental adhesive by monitoring its polymerization kinetics and glass transition temperature under the presence of an iodonium salt (reaction accelerator), and varying water concentration, photo-initiator concentration and light intensity. The final goal is to develop a computational framework for designing water compatible visible light photosensitizers specifically for the hydrophilic-rich phase of dental adhesives.;It was observed that the degree of conversion of the hydrophilic-rich mimics is dominated by the photo-initiator concentration and not the cross-linker. A secondary rate maxima was observed in the case of hydrophilic-rich phase mimics which was associated with the formation of microgels during polymerization. A polymerization mechanism involving polymerization- and solvent-induced phase separation was proposed for the hydrophilic-rich mimics. The hydrophilic dental resins were sensitive to light intensity, i.e. at low light intensities the degree of conversion of the hydrophilic resin was reduced substantially in the presence of camphorquinone/ethyl 4-(dimethylamino)benzoate as photo-initiators, whereas a substantial degree of conversion was observed for the hydrophobic resin even at these lower light intensities. The addition of iodonium salt in the hydrophilic resin significantly improved the degree of conversion of the hydrophilic resin at low light intensities. These studies also showed that the iodonium salt could lead to enhanced cyclization and shorter polymer chain lengths within the hydrophilic-rich phase. For the physically separated hydrophilic-rich phase specimens, it was observed that in the presence of the conventional photo-initiator system (camphorquinone/ethyl 4-(dimethylamino)benzoate), there was no polymerization, mostly due to the insufficient partition concentrations of the photo-initiator components within this phase. The addition of iodoinum salt in this case significantly improved the degree of conversion but it was still significantly lower. These studies indicated that the overall polymerization efficiency of the hydrophilic-rich phase was lower than the hydrophobic-rich phase. The lower polymerization efficiency of the hydrophilic-rich phase led to a phase that lacks integrity; the hydrophilic-rich phase could be infiltrated by oral fluids and cariogenic bacteria. The infiltration of these noxious agents at the interface between the material and tooth could pave the way for enhanced degradation of the tooth structure (collagen and mineral) as well as the adhesive polymer. Novel photosensitizer molecules were proposed to improve the polymerization efficiency of this phase.;Computer-aided molecular design (CAMD) was employed to obtain the new photosensitizers. These photosensitizers were capable of improving the degree of conversion of the hydrophilic-rich phase. An enhanced degree of conversion of the hydrophilic-rich phase would lead to a better seal at the adhesive/dentin interface and higher bond strength. Computer-aided molecular design (CAMD) is a fast and inexpensive technique compared to the conventional trial-and-error method to rationally design products. (Abstract shortened by ProQuest.).
机译：中型到大型牙科复合修复体的临床寿命低于牙科用汞合金修复体。随着牙科用汞齐的使用和可利用性的迫近和显着减少，复合材料在牙齿修复中的应用将增加。由于复合材料的故障率更高，因此复合材料使用量的增加将导致牙齿修复体更换的频率，牙齿健康的总体成本以及患者不适感的增加。复合材料太粘而无法直接粘结到牙齿上，因此，使用低粘度粘合剂在复合材料和牙齿之间形成粘结。粘合剂/牙齿上的粘结旨在形成不渗透的密封，保护修复后的牙齿免受酸，口腔液和细菌的破坏，这些物质会破坏复合修复体。胶粘剂/牙齿粘结的完整性（露出的牙齿结构主要由牙釉质和牙本质组成）在防止继发性龋齿破坏复合修复中起着重要作用。这项研究的重点是蚀刻和冲洗型牙科粘合剂的耐久性。当粘合剂渗入脱矿质牙本质基质时，它会发生相分离，形成富疏水和富亲水相。富含亲水性的相包含常规疏水性光引发剂体系（樟脑醌/ 4-（二甲基氨基）苯甲酸乙酯）和交联剂，浓度均不足。这可能会损害该相的聚合反应和交联密度，使其易于失效。这项研究的目的是通过监测在碘鎓盐（反应促进剂）存在下的聚合动力学和玻璃化转变温度，以及改变水的浓度，光引发剂的浓度和光强度，来表征牙科粘合剂的富亲水相。 。最终目标是开发一个计算框架，以设计水相容性可见光光敏剂，专门用于牙科粘合剂的富亲水相。;已观察到，富亲水模拟物的转化程度主要取决于光引发剂的浓度而不是交联剂。在富含亲水相的模拟物的情况下，观察到次级速率的最大值，这与聚合过程中微凝胶的形成有关。对于富含亲水性的模拟物，提出了一种涉及聚合和溶剂诱导的相分离的聚合机理。亲水性牙科树脂对光强度敏感，即，在存在樟脑醌/ 4-（二甲基氨基）苯甲酸乙酯作为光引发剂的情况下，在低光强度下，亲水性树脂的转化率大大降低，而转化率却大大提高即使在这些较低的光强度下也观察到疏水性树脂。在亲水性树脂中添加碘鎓盐可显着改善低光强度下亲水性树脂的转化度。这些研究还表明，在富亲水相中，碘鎓盐可导致增强的环化作用和较短的聚合物链长。对于物理上分离的富亲水相样品，观察到在常规光引发剂体系（樟脑醌/ 4-（二甲基氨基）苯甲酸乙酯）存在下，没有聚合反应，这主要是由于未充分分配的此阶段中的光引发剂成分。在这种情况下，加入碘盐可以显着提高转化率，但仍要低得多。这些研究表明，富亲水相的总聚合效率低于富疏水相。富亲水相的较低的聚合效率导致缺乏完整性的相。亲水性丰富的相可通过口腔液和致龋菌渗透。这些有害物质在材料和牙齿之间的界面处的渗透可为增强牙齿结构（胶原蛋白和矿物质）以及粘性聚合物的降解铺平道路。提出了新型光敏剂分子以提高该相的聚合效率。;采用计算机辅助分子设计（CAMD）获得了新型光敏剂。这些光敏剂能够改善富亲水相的转化度。富含亲水性相的转化度的提高将导致在粘合剂/牙本质界面处的更好的密封和更高的结合强度。与传统的反复试验方法相比，计算机辅助分子设计（CAMD）是一种快速且廉价的技术，可以合理地设计产品。 （摘要由ProQuest缩短。）。

著录项

  • 作者

    Abedin, Farhana.;

  • 作者单位

    University of Kansas.;

  • 授予单位 University of Kansas.;
  • 学科 Biomedical engineering.;Materials science.;Polymer chemistry.;Dentistry.
  • 学位 Ph.D.
  • 年度 2016
  • 页码 165 p.
  • 总页数 165
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号