Comparison of marginal fit of lithium disilicate crowns fabricated with CAD-CAM technology using conventional impressions and two intra-oral digital scanners.

Abstract

The use of digital impression techniques in dental crown fabrication is increasing. It is important these techniques yield prosthesis of equal or better accuracy compared to conventional techniques. This study compared marginal gap size in crowns fabricated by conventional and digital impression methods. One typodont maxillary right central incisor was prepared for an all-ceramic crown. Ten impressions were made with each method: conventional using polyvinyl siloxane impression material, digital impressions using the Lava C.O.S. (3M ESPE), and iTero (Cadent) intraoral scanning devices. Lithium disilicate crowns were fabricated and marginal gap measured for each using an optical microscope. There was no significant difference between average gap size in all groups. However, though not statistically significant, the conventional group average gap size was about 23µm larger compared to the digital groups. Within the limitations of this study, the digital and conventional impressions were found to produce crown crowns with similar marginal accuracy