Thesis (M.Sc.) - Cairo University - Faculty of Oral and Dental Medicine - Department of Dental Materials

The aim of this study was to evaluate and compare zinc-reinforced GIC (chemFil rock) to commercially available conventional GIC (ketac molar aplicap) and resin modified GIC (photac Fil quick aplicap) with respect to microstructure, flexural strength, diametral tensile strength, fluoride release, solubility and water sorption and wear resistance. A total number of one hundred forty four specimens were prepared and divided into three groups (forty eight each) according to the type of material used, then distributed according to testing methods and further subdivided according to storage period. The specimens shape and dimensions were prepared and evaluated according to (ANSI / ADA) specification numbers 27 and 66. Specimens for microstructure (n = 9) were examined under scanning electron microscope attached with energy dispersive X ray spectroscopy (EDX) unit. Specimens for flexural strength (n = 45) and diametral tensile strength (n = 45) were measured using universal testing machine with crosshead speed of 1.0 and 0.5 mm/min. respectively. Specimens for fluoride release (n = 15) were hanged separately. Fluoride was assessed using fluoride ion selective electrode cell. Specimens for solubility and water sorption (n = 15) were measured using digital analytical balance (0.0001g accuracy). Specimens for wear resistance (n = 15) were measured using TNO TRIBO meter wear testing machine. Data were analyzed statistically using paired t test, ANOVA and duncan post - Hoc multiple comparisons tests at p {u2264} 0.05. Zinc reinforced GIC had less cracks and voids, intermediate flexural strength, highest initial diametral tensile strength and intermediate fluoride release compared to both the conventional and the resin modified GICs. Zinc reinforced GIC had significant the highest wear resistance and the highest solubility and water sorption (p = 0.05) followed by the resin modified GIC and the conventional GIC, respectively. Zinc reinforced GIC is a promising restorative dental filling material

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