Spectrophotometric assessment of different surface coating materials on conventional glass ionomer cement

The purpose of this in vitro study was to analyse the absorbance of dye material in conventional glass ionomer cement (gic) by applying various commercially available surface protecting layers on gic. 90 disc-shaped specimens were made using brass mold measuring 7mm in diameter and 2mm in thickness. 30 specimens were selected for each week testing having 6 groups (n=5). the groups were: g1 (control group),g2 (nail polish coated gic),g3 (master bond coated gic),g4 (copal varnish coated gic),g5 (varnal coated gic),g6 (cold mold seal coated gic). the specimens of each group were immersed in a separate test tube filled with methylene blue dye,and placed in an incubator (37°c±2°c) for 1 week,2 weeks and 3 weeks' time. after required time period,the specimens were rinsed under distal water for 1 minute and air dried for 1 hour. next,the specimens of each group were put into new test tubes containing 1ml absolute alcohol and again stored at (37°c±2°c) for 24 hours. absorbance were recorded in ultravoilet spectrophotometer. results were analysed by student t-test and pearson's correlation. the results suggest that varnal and copal varnish are effective protecting materials with significant difference (p<0.01) after 3 weeks time. our results conclude that the application of suitable protecting material may lead to longevity of gic restorative biomaterial in a complexed oral environment.