Effect of Air Abrasion on the Marginal Configuration of Titanium Crowns after Casting

Abstract

The present study was carried out to evaluate and compare the effect of air abrasion on marginal accuracy of titanium crowns after casting. A total of 90 samples were prepared which were divided in three groups of 30 specimens each of shoulder, chamfer and shoulder with bevel marginal configurations respectively. Thirty samples were air abraded using 120 μm particle size of aluminum oxide particle and remaining 30 specimens by 250 μm particle sizes respectively. The length from the reference line and tip of the cast specimens before and after sand blasting was measured with the help of traveling microscope. Same specimens were subjected to trimming for removal of alpha case layer for a standardized time, speed and pressure. The basic data of marginal discrepancy due to sand blasting and alpha case removal for each marginal configuration were evaluated and compared with data for the control group using student 't' test and ANOVA. The smaller the margin angle, the greater was the loss of alloy after air abrasion (shoulder with bevel > chamfer > shoulder). Particle size of the abrasive also influenced the vertical marginal loss, as the particle size increased from 120 to 250 μm, marginal loss also increased. Finishing of casting margins after sandblasting also induced vertical marginal loss.