Browsing Theses and Dissertations by Subjects
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The effect of ethylene glycol analogs on mechanical properties of moist, demineralized dentin matrixThis study evaluated the effect of ethylene glycol analogs on the modulus of elasticity (E) and ultimate tensile strength (UTS) of moist, demineralized dentin matrix. · Six "I" beam and fifty-two hourglass shaped specimens cut from dentin discs (0.5mm thick) were demineralized in 0.5M EDT~ yielding dentin matrix specimens used to measure E and UTS, respectively A universal microtensile testing machine measured the E and UTS of specimens immersed in distilled water, ethylene glycol, 2-methoxyethanol, and ·I,2-dimethoxyethane. The E and UTS values were compared with. the Hoy's solubility parameters for hydrogen bonding (oh), polar (op), an~ dispersive forces (od) of these solvents. Analysis indicated significant (p~<0. 00 I) relationships among the solvents for both E and UTS; and that oh is the most significant (p<0.05) solubility parameter. Water (highest oh) produced the lowest E and UTS. 1,2-Dimethoxyethane (lowest oh) produced the highest E and UTS. The results support our hypothesis that E and UTS of moist, demineralized dentin is inversely proportional to oh of applied solvents.
The effect of water concentration on the rate and expansion of demineralized dentin matrixThe purpose of this study was to test the rate and expansion of air-dried, collapsed, demineralized dentin matrix using three different water-HEMA solutions. Solutions of 10, 25 and 50% water (by weight) were formulated with corresponding amounts of HEMA. Eighteen dentin specimens (0.2 mm thick) were demineralized in 17% EDTA for 5 days, yielding type I collagen disks approximately 200 J.llTI thick. A linear variable differential transformer (L VDT) was used to measure vertical dimensional changes in the demineralized dentin specimens. The specimens were airdried with compressed air, then one of the three test solutions was applied, and the rate and amount of expansion was measured. Repeated measures AN OVA with least squares means comparison test revealed a significant (p < 0.0001) relationship between water concentration and both the rate and amount of re-expansion of dried, demineralized dentin. Hansen's solubility parameter for hydrogen bonding forces was used to express the ability of the different solutions to interact with the demineralized dentin matrix.