Evaluation of marginal and internal adaptation of zirconia crowns constructed from traditional and digital impressions

Abstract

Background and objective: Recent advancement in restorative dentistry from impression to fabrication is toward digital workflow. There are very few studies, evaluating the internal and marginal fitness of full anatomic zirconia crowns fabricated with different impression techniques. The aim of this study was to determine whether improved technology of digital workflow results in better fitting crowns. Methodology: The mandibular right first molar of a dentoform model was prepared for a full ceramic crown with deep shoulder finish line. Two impression techniques were used,for group one, ten traditional impressions with addition silicone were obtained, while in group two, ten digital intraoral impressions were captured.Twenty full anatomic zirconia crowns were designed and milled using dental CAD/CAM system . The internal and marginal gaps were measured for each crown on the master die with the aid of a stereomicroscope. Results: The average (±SD) for the internal and marginal adaptation was: 145 μm (±39) and 85 μm (±17) for the digital impression group, 188 μm (±141) and 178 μm (±41) for the traditional impression group, respectively. The Kruskal -Wallis test showed no statistically significant difference between the two groups regarding marginal and internal adaptation. Conclusion: Full anatomic zirconia crowns fabricated from intraoral digital impressions demonstrated comparable or even better marginal and internal fit than crowns fabricated with traditional silicone impressions.