الفهرس 
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Abstract
This study was conducted to evaluate the effect of the most commonly consumed beverages that have been identified by a group of Egyptian children on the microhardness and color of nanofilled esthetic restorative materials (Filtek Z350 XT nanocomposite and Ketac N100 nanoglass ionomer).
A questionnaire was carried out on 300 patients receiving treatment in the outpatient clinic of Pediatric Dentistry Department in Ain Shams University, to find out the 3 most commonly consumed beverages by them. The patients selected were ranging from 6 to 15 years old and were not medically compromised.
Based on the results of the questionnaire, the three most commonly consumed beverages by the selected sample were found to be Cola drinks (Pepsi and Coca Cola), Mango juice and Tea with Milk. The beverages chosen to carry out the study were Pepsi, Juhayna mango nectar and tea with milk (Lipton Yellow Label tea, Juhayna full cream milk and white sugar).
30 specimens (diameter 7mm and thickness 3mm) were prepared from each of the above mentioned restorative materials using split Teflon mold. The specimens were stored in deionized water as a transporting medium till being measured. Then the specimens were blotted dry with tissue paper and measured for color and microhardness before being immersed in the beverages.
The 30 specimens of each material were further divided into 3 groups. Each group (10 specimens) was immersed in one of the 3 selected beverages (250 ml each) at room temperature and stored for 24 hours in glass beakers sealed tightly using cling wrap.
After the 24 hours storage, the specimens were then rinsed with running deionized water for 5 minutes each. They were stored in deionized water as a transporting medium till being re-measured. The specimens were then blotted dry with tissue paper, and re-measured for color and microhardness.
UV – Shimadzu 3101 PC –Spectrophotometer was used for color measurements. The measurements were performed at the National Institute for Standards (NIS), division of photometry and radiometry of metrology (photometry and colorimetry Lab.).
MHV -2 Shimadzu Microhardness tester was used for microhardness measurements, using vicker’s hardness test. The measurements were performed at the National Institute for Standards (NIS), division of Mass and force Metrology (lab of force and material metrology).
Color results showed that Ketac N100 glass ionomer had statistically significantly higher mean ΔE than the Filtek Z350 XT resin composite after immersion in Pepsi, mango juice and tea with milk. Results also revealed that Pepsi showed the statistically significantly highest mean ΔE for both restorative materials, this was followed by tea with milk, while mango juice showed the statistically significantly lowest ΔE for both materials.
Regarding different interactions between the 2 restorative materials and the 3 beverages used in the current study, Ketac N100 glass ionomer immersed in Pepsi showed the statistically significantly highest mean ΔE.
This was followed by Ketac N100 glass ionomer immersed in tea with milk, then Filtek Z350 XT composite immersed in Pepsi. There was no statistically significant difference between Filtek Z350 XT composite immersed in tea with milk and Ketac N100 glass ionomer immersed in mango juice. Filtek Z350 XT composite immersed in mango juice showed the statistically significantly lowest mean ΔE.
Regarding the microhardness measurements, Filtek Z350 XT resin composite showed statistically significant decrease in mean microhardness after immersion in Pepsi and mango juice. On the contrary, there was no statistically significant difference between the mean microhardness values before and after immersion in tea with milk.
As for Ketac N100 glass ionomer, there was no statistically significant difference between mean microhardness values before and after immersion for all beverages.
Concerning the comparison between the materials, Filtek Z350 XT composite showed statistically significant higher mean % decrease in the microhardness than Ketac N100 glass ionomer after immersion in Pepsi. On the other hand, there was no statistically significant difference between the two materials after immersion in mango juice and tea with milk.
Regarding Filtek Z350 XT composite, Pepsi showed the statistically significantly highest mean % decrease in micro-hardness. This was followed by mango juice. Tea with milk showed the lowest mean % decrease in micro-hardness.
As for Ketac N100 glass ionomer, there was no statistically significant difference between the three beverages. However, mango juice showed the highest mean % decrease in microhardness. This was followed by Pepsi. While Tea with milk showed the lowest mean % change in microhardness (where it caused an increase in microhardness).
Regarding different interactions between the two restorative materials and the three beverages, Filtek Z350 XT composite immersed in Pepsi showed the statistically significantly highest mean % decrease in micro-hardness. This was followed by Filtek Z350 XT composite immersed in mango juice.
There was no statistically significant difference between (Filtek Z350 XT composite immersed in tea with milk), (Ketac N100 glass ionomer immersed in Pepsi), (Ketac N100 glass ionomer immersed in mango juice) and (Ketac N100 glass ionomer immersed in tea with milk); all showed the lowest mean % change in micro-hardness [where all of them showed a decrease in the microhardness, except for the Ketac N100 glass ionomer immersed in tea with milk that, showed an increase in the microhardness].