Marginal gap of monolithic zirconia endocrowns fabricated by using digital scanning and conventional impressions

Abstract

Statement of problemThe digital scanning technique has been introduced as an alternative to the conventional impression technique for the fabrication of fixed restorations. However, adequate information is not available on the efficacy of digital scanning for the fabrication of endocrowns regarding their marginal accuracy. PurposeThe purpose of this in vitro study was to compare the marginal gap of endocrowns fabricated by computer-aided design and computer-aided manufacturing (CAD-CAM) technology and digital scanning and conventional impression techniques. Material and methodsAn endodontically treated mandibular molar tooth was prepared to receive an endocrown. The impressions were made by using the conventional impression technique with polyvinyl siloxane material (n=11) and digital scanning by using an intraoral scanner (n=11). Endocrowns were fabricated from monolithic zirconia blocks by using a milling machine. Each restoration was seated on the prepared tooth, and the marginal gap was measured by using a video measuring machine at 8 points under magnification. The mean marginal gap for each restoration and the overall mean marginal gap for each group were calculated. Data were analyzed by using a statistical software program. Marginal gaps were compared with the Mann-Whitney U test (α=.05). ResultsThe mean marginal gap was 74 μm for the conventional impression group. A similar mean marginal gap (70 μm) was found for the digital scanning group. No statistically significant difference was found between the groups (P=.375). ConclusionsThe digital scanning technique and the conventional impression technique yielded crowns with comparable marginal adaptation.