Marginal and Internal Crown Fit Evaluation of CAD/CAM versus Press-Laboratory All-Ceramic Crown

The aim of this article is to evaluate marginal and internal fit between the all-ceramic crowns manufactured by the conventional press-dental laboratory and CAD/CAM systems. Methods: Tooth #14 was prepared per standard specification to receive an all-ceramic crown restoration. Forty-five prep tooth #14 were duplicated and randomly divided into three groups (n=15). All-ceramic CAD/CAM system (Group 1) was fabricated with the E4D CAD/CAM system according to the manufacturer's instructions. For press-dental laboratory made crowns, impressions were taken on the region area with two-step impression techniques with light and putty consistency VPS. Impressions were sent to two independent dental laboratories (Groups 2 and 3) for fabricating the monolithic press lithium disilicate crown. All crowns were cemented using Multilink® Automix (Ivoclar Vivadent) under constant pressure of 100N. Samples were embedded in acrylic and sectioned buccolingually. Sections were evaluated under digital stereo microscope and measured on three locations per buccal and lingual side of section: marginal-edge, mid-axial wall, and cusp-tip. One measurement was made on the occlusal table. Statistical analysis was accomplished with Kruskal-Wallis one-way ANOVA and significance was predetermined at p<.05. Results: No significant difference was found at the buccal and lingual margins in all groups. However, there was significance difference found for cement thickness in midaxial, cusp, and occlusal locations within the group. Conclusions: Based on the statistical results there was no statistical difference in marginal fit of all-ceramic crowns made by CAD/CAM system or dental laboratory press ceramic.