OBJECTIVES: To determine the effect of cynoacrylate on surface hardness of type IV dental
stone.
MATERIAL AND METHODS: This comparative observational study was conducted at Prosthodontics
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 preabrasion
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.
Key words: Gypsum Die Material, Type IV die stone, Cynoacrylate Surface hardeners
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