Year : 2019

Volume : Volume 10

Issue : Issue 3

Address for correspondence :
Dr. Naveen S Yadav.
naveensyadav@gmail.com

Abstract

Aim:  The objective of this study was to evaluate the effect of different impression materials on the accuracy of marginal fit of metal castings. Materials and Method: The master molar typhodont tooth was prepared. Sixty duplicates of the tooth were made.  The duplicates were divided into three groups of 20 each. The three groups were: Group 1 (Putty and light body elastomeric impression material), Group 2 (Alginate) and Group 3 (Modelling compound). The impressions were made and marginal gap between metal crown and finish line was measured at buccal and lingual margins using scanning electron microscopy (SEM) at magnification of 60X & 400X. Statistical Analysis: A master chart was prepared for all the data and was analyzed using Statistical Package for the Social Sciences version. Analysis of variance and Post-hoc analysis were used to make comparisons between and within the three groups respectively. Result: Comparison of the mean and standard deviation values of marginal discrepancies (µm) on buccal and lingual margin at 60X and 400X was found to be highest for alginate and lowest for polyvinyl siloxane. Conclusion: - The marginal discrepancies found in this study were within the clinically acceptable standard (120 µm). There were no statistically significant differences between buccal and lingual margin at both 60X and 400X magnification within the impression materials. There was no statistically significant difference between the marginal discrepancies for alginate, impression compound and polyvinyl siloxane impression material.

Keywords: Marginal fit, metal casting, impression, scanning electron microscopy.