Fracture resistance of CAD/CAM provisional crowns with two different designs: an in vitro study

Abstract

Aim: To evaluate the fracture resistance of printed crowns with two different designs. Methods: Forty restorations (n = 20/group) were fabricated using resin matrix ceramic (VarseoSmileTM) with different designs as follows: group 1: overlay restoration with chamfer margin; group 2: overlay restoration with chamfer margin located 3 mm above the gingiva. Restorations were bonded to resin dies using 3M RelyX Luting Cement. Compression forces were applied with a 4 mm diameter steel bar at the midline fissure of each crown using the universal testing machine. Restorations were loaded until fracture, and fracture resistance at maximum load was recorded. Statistical analysis: A t-test was used for statistical comparison between groups. Results: No difference in the fracture resistance was detected for both groups. Conclusions: Different designs of composite resin crowns fabricated using CAD/CAM techniques can be used, however further research is needed to assess the clinical outcomes.

Keywords

• crown
• overlay
• indirect restorations
• fracture