Novel Multifunctional Methacrylate Monomers and Their Visible-light Cured Polymer/SiO2 Hybrids as Dental Restorative Materials
Date Issued
2006
Date
2006
Author(s)
Chen, Chia-Yin
DOI
zh-TW
Abstract
The novel multifunctional methacrylates were prepared by the reaction between the hydroxyl groups of the epoxy-acrylate resin (EA) and the isocyanate groups of the diisocyanate, such as toluene-2, 4-diisocyanate (TDI), 1,6-Diisocyanatohexane (HDI) or isophorone diisocyanate (IPDI) , which were pre-reacted with 2-hydroxyethyl- methacrylate (HEMA) with 2:1 equivalent ratio, and utilized as the dental monomers. By varying the molar ratios between the hydroxyl groups of EA and the isocyanate groups of diisocyanate, the methacrylaes with three types of different functionalities were obtained. As the reaction proceeded, the reaction underwent the nucleophilic addition and the stronger hydrogen bonding raised, resulted in the increase of molecular weights and viscosity. By adding the different amounts of tripropylene glycol diacrylate (TPGDA), the viscosity of the resin matrix could be reduced and adjusted.
The mono-dispersed silica spheres were synthesized by the sol-gel process. By varying the reaction temperature, the concentration of ammonium hydroxide, the molar ratio of water to TEOS (R value), and the concentration of tetraethoxysilane (TEOS), the size of mono-dispersed silica spheres could be controlled. In this study, the size of silica spheres ranged from 0.082 to 1.16μm. The silica spheres were successfully modified by 3-(trimethoxy silyl) propyl methacrylate (MSMA), and the acrylate functional groups were chemically bonded to the surface of silica spheres, in order to enhance the compatibility of organic and inorganic interface. FT-IR, DLS and SEM were employed to characterize the modification of the silica spheres.
The pastes were composed of the novel multifunctional methacrylate resin, TPGDA, DL-camphoroquinone (CQ), the compound of tertiary amine, and the modified silica spheres or fumed silica (digussa®202). After visible light curing (400-520nm) in 30sec, the hybrids or composites were formed. The shrinkage, hardness, swelling ratio and the acetone solubility of the hybrids or composites obtained from the multimethacrylate resins were analyzed. Those data obtained from the analysis of multimethacrylate-containing materials were compared with the control 2,2-bis[4-(2’-hydroxy-3’-methacryloyloxypropoxy)phenyl] propane (bis-GMA) based materials and the commercialized products in order to evaluate the application of the multimethacrylates as the dental resins and the modified mono-dispersed silica spheres as dental fillers. In this study, the maximum loading of fumed silica was 50wt%, but the modified mono-dispersed silica could reach 70wt%. Hence, the materials composed of modified mono-dispersed silica others than fumed silica could obtain the higher hardness. The maximum hardness of the hybrids composed of the modified mono-dispersed silica spheres and the multifunctional methacrylates was 61.1Hv which was higher than the Estilite (53.6Hv). And its shrinkage was much lower in comparison with the bis-GMA hybrids (lowered by about 4 times) and the commercialized products (lowered by about 10 times). Therefore, it is the potential dental restorative material.
Subjects
多官能基
壓克力
光聚合
均一粒徑二氧化矽
混成
牙科修復
聚合收縮
multifunctional
acrylate
photocurable
mono-dispersed silica
hybrid
restorative
dental
shrinkage.
Type
thesis
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