Influence of two different cement space settings and three different cement types on the fit of polymer-infiltrated ceramic network material crowns manufactured using a complete digital workflow.

ABSTRACT

OBJECTIVES: The study evaluates the influence of two spacer settings and three resin luting materials on the marginal and internal fit of polymer-infiltrated ceramic network (PICN) material crowns manufactured using a complete digital workflow. METHODS: Optical impressions of fifty identical dies were performed using the 3M scanner (software version 5.0.2). Twenty crowns were designed using Ceramill Mind (version 3.4.10.1163), from which ten with spacer setting of 50 µm (G1) and ten with 80 µm (G2). Thirty crowns (spacer setting of 50 µm) were divided into three groups corresponding to the resin materials used as follows RelyX Unicem (RX), Variolink Esthetic (VLE), and Nexus 3 (NX3). All crowns were milled from Vita Enamic blocks. After micro-CT scanning, absolute marginal discrepancy (AMD), internal gap (IG), total cement space volume (TCV), and marginal porosities (VP) were measured. RESULTS: Significant difference was detected on the VP between the RX and NX3 group (p = 0.033). The mean values of all parameters were the following AMD (µm) G1 182.6, G2 253.7, RX 210.8, VLE 195.5, NX3 186.6; IG (µm) G1 215.6, G2 173.1, RX 171.1, VLE 198.6, NX3 203; TCV (mm3) G1 22.9, G2 20.49, RX 17.57, VLE 17.49, NX3 20.59; VP (mm3) G1 0.26, G2 0.34, RX 0.32, VLE 0.46, NX3 0.54. CONCLUSIONS: Fit of PICN material crowns was not significantly influenced by increasing the spacer settings and cementation with different resin materials. Additionally, RelyX Unicem showed significantly less porosities as compared with Nexus3. CLINICAL RELEVANCE Both 50 µm and 80 µm virtual spacer settings can be suggested for the manufacture of PICN crowns when Ceramill Mind (version 3.4.10.1163) is used. Furthermore, a self-adhesive system can be recommended for the cementation.