Evaluation of fit and accuracy of single crowns fabricated from self-glazed zirconia compared with milled zirconia

Abstract

Statement of problemSelf-glazed zirconia is a novel dental material fabricated with a combination of subtractive and additive manufacturing techniques. However, how the marginal and internal fit of these restorations compare with conventionally fabricated zirconia is unclear. PurposeThe purpose of this in vitro study was to evaluate the marginal and internal fit and internal accuracy of single crowns made from self-glazed zirconia compared with those made from milled zirconia. Material and methodsA metal die was scanned, and a crown was designed using a computer-aided-design program. The computer-aided-manufacturing milling method (conventional technique) was used to produce 10 zirconia crowns, and additive manufacturing was used to produce 10 self-glazed zirconia crowns. Internal and marginal fit measurements were made by using the silicone replica method; marginal fit was also measured by using the direct-view technique. An independent t test was performed to compare both types of crowns and test the null hypothesis (α=.05). ResultsFor the occlusal, internal, and total mean distances, significant differences were found between self-glazed and milled zirconia crowns (P<.001). With the direct-view technique, a significant difference (P=.004) between the 2 techniques was found in the marginal area. The accuracy for the axial and occlusal areas combined for self-glazed and milled zirconia was 27 μm and 49 μm, respectively. ConclusionsBoth techniques produced crowns with clinically acceptable marginal and internal fit. The self-glazed zirconia crowns had higher accuracy of internal fit than milled zirconia crowns.