Clinical Evaluation of Marginal and Internal Gaps of Zirconia-based 3-unit CAD/CAM Fixed Partial Dentures

Abstract

Purpose: We conducted an in vivo evaluation of the marginal and internal gaps of 3-unit all-ceramic fixed partial dentures (FPDs) with zirconia frameworks by using black and white silicone materials. These FPDs were fabricated using a computer-aided design/computer aided machining (CAD/CAM) system (Cercon Smart Ceramic).
Methods: Forty-two abutments of 21 Cercon FPDs were examined before the final cementation. Silicone materials obtained from each FPD were sectioned buccolingually and mesiodistally, and the thickness of the silicone layer was measured under a microscope.
Results: The mean marginal gaps of the mesial and distal abutments were 83.3 and 90.6 μm, respectively. No difference was observed between the corresponding measurement points on the mesial and distal abutments with regard to the gap size.
Conclusion: The mean marginal gap between the abutments and the retainers of the 3-unit zirconia FPDs fabricated using the Cercon system was 86.9 μm, which is a clinically acceptable value.