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Chemical Degradation of Restorative Materials

The chemical environment is an important aspect of the oral environment that could have an appreciable influence on restorative materials. The effects of chemical media on surface roughness, Vickers hardness and weight loss of a ceramic material, a hybrid ceramic resin, an ormocer and a posterior composite were investigated. The specimens were made for each material and were stored in artificial saliva at 37oC for 24 h. The weight of the specimens were recorded and then randomly divided into two groups and stored in the following chemicals for 2 weeks at 37oC: 0.02 N citric acid and 0.02 N lactic acid. After conditioning, the specimens were weighed again and subjected to Vickers hardness and surface roughness tests. The specimens were also examined in the scanning electron microscopy (SEM). All results were analyzed statistically. After a 2 week storage period, there was a significant weight loss in P60 TM stored in citric acid and Admira TM stored in lactic acid. Vickers hardness values of all materials except Finesse were increased significantly (p<0.05).