Year : 2017

Volume : Volume 7

Issue : Issue 1

Address for correspondence :
Dr. Nitin Rastogi
nrastogi302@gmail.com

Abstract

Background:  A serious problem with the use of PVS material is their low surface energy which renders them difficult to wet with gypsum slurries. Laboratory applied surfactants as well as so called hydrophilic elastomers, are effective in reducing the hydrophobic nature of elastomers and increase the probability of obtaining a void free gypsum cast. With the above background the present study was aimed to investigate the changes in the surface hardness of a dental stone and an investment material poured in polyvinylsiloxane moulds following the application of 3 brands of commercially available topical surfactants.   Material and methods: A cylindrical master model was made from an acrylic resin rod 20mm in diameter and 35mm in length. It was placed on a plastic sheet and seated centrally at the base of a casting ring former to create moulds. PVS duplicating material, Ecosil (Dentaurum) was mixed according to the manufacturer’s instructions and poured into the casting ring former to create eight moulds. Fifteen specimens were poured into each of the moulds for each model material/ surface treatment combination, yielding a total of 120 specimens for testing. Brinell hardness test was performed using a universal testing machine and the results were compared using one way ANOVA and Post-hoc Tukey’s test. Results: Within the group 1, the surfactant Aurofilm (Bego) greatly increased the surface hardness of dental stone ( BHN-69.2 )when compared to the control group. The surfactants Debubblizer (Prime dental) and Waxit (Dentsply) increased the surface hardness of dental stone to a certain extent when compared to the control group. In group 2 Aurofilm greatly increased the surface hardness of investment material (BHN-90) when compared to the control group while the surfactants Debubblizer and Waxit decreased the surface hardness of investment material when compared to the control group. Conclusion: The surfactant Aurofilm was found compatible with both PVS duplicating material (Dentaurum)- dental stone (Kalrock) and PVS duplicating material (Dentaurum)- investment material (Bellavest-T) combinations. The surfactants Debubblizer and Waxit were found incompatible with investment material while in dental stone group both the surfactants were found compatible without significantly increasing the surface hardness. 

Keywords: Polyvinyl siloxane (PVS) duplicating material, surfactants, dental stone, investment material.