Assessment of marginal adaptation of lithium disilicate and nanoceramic resin crowns using CAD/CAM system

The aim of this study is to assess the marginal adaptation of different ceramic materials produced by the CEREC system (Sirona, Germany). An analog of the solid abutment Straumann (Straumann, Basel, Switzerland) measuring 5.5mm of height, with platform of 4.8mm, tilt from the axial wall of 6 degrees and chamfer finish line was used as a master model and scanned with an intraoral scanner (CEREC Omnicam). 20 machined crowns were obtained - 10 manufactured from lithium disilicate blocks (IpsE.maxCad, IvoclarVivadent, Liechtenstein, Germany), 10 manufactured from nanoceramic resin blocks (3M ESPE Lava Utimate, USA). The assessment was made using the Replica Technique (RT) and the cementation coating was measured using an optical microscope Mitutoyo (TM 500). Results show a mean marginal disadaptation of lithium disilicate crowns of 78.63µm, which is significantly larger than the one found for nanoceramic resin crowns - 63.15µm. It is possible to conclude that nanoceramic resin crowns have a better marginal adaptation than lithium disilicate ones. Notwithstanding, results found for both groups are within the clinically acceptable values for indirect restorations.