The Influence of Aging Conditions on the Properties of Polymer Dental Composites

Abstract

Long-term exposure of polymer dental composites to selected liquids of different chemical composition and characteristics (pH level, sugar content, etc.), like: coffee, red wine, soy sauce, alkaline mineral water, coke drinks and mouthwash liquid, was studied. The degree of chemical and physical changes to the surface layer of the materials were evaluated based on the results determined by infrared spectroscopy, colorimetry, microhardness, microroughness and wettability. The experiments confirmed suspicions about the liquids studied adversely affect polymer dental composites. It was expected that the material is generally not resistant to the aging agents present in beverages. However, quite unexpectedly, similar behavior was also exhibited by the liquid for oral hygiene. Diet coke, alkaline water and mouthwash liquid had the biggest impact on wear of the composites, contrary to soy sauce. Colorimetry proved the greatest color changes for the samples treated with red wine and coffee, whereas their incubation in alkaline mineral water and mouthwash liquid, made them clearly brighter. Chemical modification of the their surface layer, influenced their microhardness and, together with changes to the surface geometry, wettability. Intriguing differences were observed between regular coke and diet one. Coke with sugar penetrated the composite samples to a smaller depth in comparison to its sugar free version. The observations are important in the context of the selection of polymer composite materials for a specific dental case and the awareness of patients regarding discoloration of teeth and composite fillings, under the influence of liquids present in the daily diet and hygiene.