| Objective: To contrast, analyze and research three kinds of usually-used composite resin teeth and Nano-composite materials,on structure, element and the mechanic properties.Methods: Observed the structure of longitudinal sections of composite resin teeth's with light microscope; and observed the natural fracture surface of composite resin with Enviroment Scanning Electron Microscope (ESEM); to analysis the samples four kinds of composite resin with ICPS, infrared spectrum and Dynamic Ultra Micro hardness Tester.1. Macroscopic structure observation: Choose Heaeus-kulzer, Endua Posterio and NC Veracia of SHOFU,make longitudinal sections in 02-0.3mm thickiness. All the sections are stained with gentian violet, then observed under light microscope.2. Fracture surface of test piece observation: Choose three kinds of composite resin teeth and neotype nano-material and fractured naturally, then observe their microstructures with ESEM.3. Inorganic element analysis: Take enough test sample-material powder dissolved them in fluoric acid, and evaporated to the solution. Then dissolved surplus solid with hydrochloric acid (0.9M), got 50ml pellucid solution. Analysised with ICPS.4. Main organo- group analysis: Mixed the alcohol and deionized water at 1:1(volume ratio) ,dissolved 10.5g NaOH in 120ml the mixed liquor. Put enough four tested sample-material powder at four reaction kettles, pour 30ml the mixed liquor to each, and put all kettles into drying oven. After 24 hours of drying at 120℃, the settled liquor is obtained. Analysised the liquor with infrared spectrum.5. Microhardness test: Intersected the four test sample-material with carborundum disk and make the two surfaces parallel. The test pieces were about 6mm in thickness. Encased the axial surface of each piece uniformly, with epoxy resin, then buff and polish them. Tested the microhardness with Dynamic Ultra Micro Hardness Tester.Results:1. Macroscopic structure observation: The first kind of composite resin tooth has two layers: the outer is thinner; semitransparent and light-coloured; the inner is anachromasis, cancellous and adiaphanos. The outer and inner coating are tight combined. The demarcution between two layers is clear and consecutive. The second test sample has three layers: the outer is thick, semitransparent and light-coloured; the intermediate is much thicker than outer, anachromasis even, and pykno-texture. The inner is cancellous and adiaphanos. The demarcutions among three layers are clear and consecutive. NC Veracia of SHOFU has three layers: the outer is semitransparent and light-coloured. The inner layer is cancellous and adiaphanos. The combination between outer and intermediate layers is tight. The conspicuous demarcation can be sought between the intermediate and inner layers.2. Fracture surface of specimens observation: There is no conspicuous addition polymer in the first tested-sample material, the fracture surface of it is smooth; About 40%(wt%±) of nano-SiC>2, the particle diameter of which is between 80-100nm, is observed only at the outer of Endua Posterio under ESEM. The addition polymer disperse evenly and the fracture surface is very coarse. About 20%(wt%±) of nano-SiO2 are found at the outer of NC Veracia under ESEM. The particle diameter is between 40-60nm, disperse evenly, the fracture surface is coarse. We didn't found conspicuous addition polymer in other two layers. 10%(wt%±) nano-SiC^was added into PMMA powder; but... |
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