Tribological and Mechanical Characteristics of Dental Fillings Nanocomposites

Abstract

Dental fillings nanotechnology considers a significant and increasingly in need to obtain the best and stable dental fillings with excellent performance and long life. Tribological and mechanical characteristics of poly methyl methacrylate (PMMA) nanocomposites reinforced by nanoparticles of Titania (40% TiO2) and Calcium aluminate (60% CaAl2O4) in terms of different volume fractions ( 1 Vol.% - 5 Vol.%) have been studied. Ultrasonic dispersion technique used to prepare the nanocomposites specimens followed by cold – casting technique using flash Teflon molds according to standard conditions. Pin-on-disc technique is used to measure wear coefficient and coefficient of friction. Tribological tests of specimens were conducted at temperature 37°C and in the environment of artificial saliva. Hardness, compressive strength, Young modulus, and toughness have been measured according to ASTM standards. Results of tribological tests were led to improve the coefficient of friction and to decrease the wear coefficient with increasing of volume fraction and increase with slide lifetime, especially for 5 Vol. % specimens. Results of mechanical properties show that the values were increased progressively by succession of volume fraction of fillers. Simulation programs of tribological and mechanical tests for (TiO2 + CaAl2O4) / PMMA nanocomposites were carried out using finite difference method. The program was written in FORTRAN90 language using a computer type HP Pavilion g. The program assumes a load is directed towards a specimen of the composites. Density and optical microscope images were employed to aid interpretation of results. The results of study were reached that the optimum volume fraction was 5 Vol. %.