Full-ceramic CAD/CIM anterior crowns and copings

The purpose of the investigation was to examine the marginal and internal fit of Cerec anterior crowns and crown copings. The marginal and internal fit of Cerec anterior crowns (n = 18) and copings was examined on each of six anterior model tooth preparations, with different types of butt-margin crown preparation design on different teeth: 1.) straight flat (tooth 22), 2.) following the CEJ with mid-approximally steep curvature angles of 90 degrees mesial and 40 degrees distal (tooth 21) and 3.) same as 2, but with obtuse angles of 130 degrees and 150 degrees (tooth 41). The anterior crowns were machined on Cerec 2 units using Mark II ceramic (Vita), and the Cerec copings using In-Ceram Spinell (Vita). Laboratory slip-cast In-Ceram spinell anterior crown copings served as controls (n = 18). All reconstructions were seated (with adhesive) on the preparations, and the width of the marginal interface was measured circumferentially using SEM at 150x magnification. After cross-sectioning all samples in the bucco-oral direction, the internal fit was measured using this same technique. The marginal width of computer machined Cerec CAD/CIM anterior crowns (59.9 +/- 5.6 microns) was significantly (p < 0.01) lower than that of machined (73.4 +/- 12 microns) and slip-cast In-Ceram spinell copings (75.5 +/- 17 microns). The internal fit values of the slip-cast copings (94.1 +/- 20 microns) were significantly (p < 0.001) lower than those of the Cerec Mark II anterior crowns (141.3 +/- 21 microns) and copings (146.8 +/- 17 microns). Cerec CAD/CIM machined anterior full-ceramic crowns and copings showed excellent fit in comparison with slip-cast In-Ceram spinell copings. In terms of the marginal and internal fit, there were no significant differences (p > 0.05) between the different butt-margin preparation designs. Selected clinical cases demonstrate the high esthetics of anterior Cerec crowns.