Document Type: Original Article


1 Assistant Professor of Operative Dentistry Department, School of Dentistry, Shiraz University of Medical Sciences

2 Dentist


Background: The clinical use of composite and polyacid modified composite restorative materials has greatly increased over the last few years. The chemical environment is one aspect of the oral environment which could have influenced the degradation of composite resins. The aim of this study is to evaluate the effect of acid food-simulating liquids on surface characteristics (Roughness and Hardness) of two composites and one polyacid modified composite.Materials and Methods: Twenty disks of each material (Composites Z250 and Heliomolar) and Compomer (Compoglass) were prepared (a total of 60 experimental specimens). Half of them were used for microhardness testing and the remaining half for studying surface roughness by using Roughness tester. Each group of 30 disks was divided into two subgroups of 9 and one subgroup of 12 disks, the samples were then conditioned for one week as follows: sub groups 1 (control), 12 disk: distilled water at 37oc, sub groups 2, 9 disks: citric acid 0.02n at 37oc, sub groups 3, 9 disks: lactic acid 0.02n at 37oc. The data were analyzed using two- way ANOVA, Tukey- HSD and Tamhan test.Results: No Significant changes in the surface hardness were noted with conditioning at Z250, Heliomolar and Compoglass in distilled- water and citric acid, but in lactic acid, the surface hardness of Z250 was more than that of Compoglass while the surface hardness of Heliomolar was similar to Compoglass.Conclusion: Roughness Average (RA) and surface-hardness of all the evaluated restoratives was not significantly affected by acid food- simulating liquids.Key words:  Food, Simulating acid liquids, Surface characteristics, Composite, Compomer