Effect of cynoacrylate as surface hardener on gypsum die material

Objectives: to determine the effect of cynoacrylate on surface hardness of type iv dental objectives: stone. material and methods: this comparative observational study was conducted at prostho-dontics department; lahore medical and dental college,lahore,during august 2009 to february 2010. a total of 60 specimens were included in this study to compare the effects of surface hardener (cynoacrylate coated group) with control group. the dimension of the specimen: 5 acrylic sheet (perspex) dies were made having dimensions 5×5×1.25-cm3. the die comprises of three compartments upper,middle and lower compartments,which were secured with the help of screw and bolts. type iv die stone was mixed with tap water and was left in the dies for 45minutes. the specimens were weighed first on a digital balance and then abrasion test was carried out on abrasion testing machine. the wear produced was again analyzed by weighing the specimen on the digital balance and the wear loss was calculated. the increase in abrasion resistance was measured by calculating weight reduction of specimen with relation to pre-abrasion weight. results: pre and post abrasion of mean weight reduction was 4.47(0.94) grams in group a,average weight of specimen was 54.03 ± 1.47 grams while in group b 54.07 ± 1.66 grams before abrasion test significant difference was not observed between groups. after abrasion of test average weight of the specimen was 49.46 ± 1.52 grams in group a and 54.02 ± 1.66 grams in group b. significant difference was observed between the groups after abrasion of test (p=0.0005). conclusion: surface hardness of type iv dental stone can be increased by surface coating its surface with cyanoacrylate resin.