Fracture strength and behavior of resin-faced CAD/CAM anterior crowns.

The fracture strength and behavior of a novel resin-faced computer-aided design/computer-aided manufacturing (CAD/CAM) crown were investigated to evaluate application to the anterior teeth. Resin-faced CAD/CAM crowns were fabricated by arranging a resin composite on a frame prepared from a CAD/CAM resin block. The fracture strength was evaluated after 24 h of complete polymerization (day 0) and after water immersion for 30 days (day 30). Uniaxial loading was applied to the center point between the incisal edge and cingulum (loading point 1) or at 1.5 mm from the incisal edge (loading point 2). There was no significant difference in the fracture strength of the resin-faced CAD/CAM crowns between day 0 and 30 at loading point 1. At loading point 2, they exhibited decreased fracture strength after water immersion; however, the mean strength was still >1 kN. This novel crown showed good mechanical properties to serve as a prosthesis for the anterior teeth.

Fluorescence and physical properties of thulium and erbium co-doped dental zirconia.

The fluorescence and physical properties of thulium and erbium co-doped dental zirconia were investigated. The high-translucency yttria-stabilized dental zirconia specimens co-doped with Tm2O3 powder 0.8 wt% and Er2O3 powder at proportions from 0.1 to 0.8 wt% were used. The specimens co-doped with Tm2O3 powder 0.8 wt% and Er2O3 from 0.3 to 0.5 wt% exhibited the fluorescence similar to that of natural tooth. All the specimens had a tetragonal peak and no major change in the Vickers hardness, fracture toughness and bending strength on addition of Tm2O3 and Er2O3. These results suggest that the method of co-doping trace amounts of Tm2O3 and Er2O3 into high-translucency dental zirconia powder can effectively improve the esthetics of zirconia monolithic fixed dental prothesis.