Comparative Evaluation of Effect Of Different Food-Simulated Dietary Solvents On The Microhardness Of Activa Bioactive, Nanohybrid Composite, Nanoceramic And Compomer Restorative Materials Using A Vicker Hardness Tester.

Aim: The aim of this study was to evaluate the effect of food simulating dietary solvents on the  Microhardness of different restorative materials by Vickers hardness tester. Method: 192 disc-shaped specimens of different restorative materials were prepared using a self-cure resin mold and cured by light-emitting diode curing units and these discs were stored in distilled water at 37oC in an incubator for 15 days. The discs were randomly assigned to four experimental groups and were subjected to Vickers micro hardness testing (HV B1200) to record baseline value of  Microhardness before the experimental procedure. Each of the four restorative groups were again subdivided according to the dietary solvents (Artificial saliva, 10% Citric acid, 7% Lactic acid and 50% Ethanol-water solution) 12 specimens each and immersed for 15 days. Then  microhardness were tested again using the same parameters. The results obtained were subjected to Statistical analysis by  one way ANOVA and Post Hoc Tukey Test. Results: The result revealed that all food simulating dietary solvents tested decrease the microhardness of the tested restorative materials. Among all the solvents 50% ethanol water solution induced the maximum impact on the vicker’s microhardness across all materials (p<0.01), and Compomer was  affected most. Whereas 10% citric acid solution significantly reduced microhardness (p<0.01), particularly affecting Compomer.  7% Lactic acid had a milder effect for all the restorative materials, while artificial saliva showed the least impact (p<0.01). Conclusion: On the basis of result obtained, it could be concluded that all the food simulating dietary solvents affected the micro-hardness of restorative materials, but the effect was both food simulating dietary solvents and material dependent.