Clinical Evaluation of CAD/CAM Zirconium Crowns and Fixed Partial Dentures

Objective: This longitudinal clinical trial studied the clinical performance of an improved zirconium ceramic material for CAD/CAM-generated restorations. Each ceramic restoration consisted of a CAD/CAM-generated, high strength zirconium framework (eMax ZirCAD; Ivoclar Vivadent) veneered with a press-fit veneering porcelain (eMax ZirPress; Ivoclar Vivadent).

Methods: One clinician placed 31 crowns and 10 fixed partial dentures in 33 patients. All preparations were recorded with a PVS impression and sent to the manufacturer for fabrication (Ivoclar Vivadent). Zirconium substructures were machined on a laboratory CAD/CAM system (InLab; Sirona Dental) and were veneered with a press-fit veneering porcelain. All restorations were cemented with a self-etching bonding agent and resin cement (MultiLink Automix; Ivoclar Vivadent).

Results: Tooth sensitivity was evaluated by report to cold stimulus (number of teeth): 1 week: Crowns (5), FPD (0), 6 months: Crowns (4), FPD (0), with no sensitivity reported in either group at 1 year. All restorations were also evaluated by two examiners using a modified USPHS rating. There was no difference in the gingival index and plaque index between the test restorations and the control teeth. The percentage alpha scores (baseline, 6 months, 1 year) were: color match - Crowns (94, 90, 94). FPD (100, 90, 100). The percentage of alpha scores for margin discoloration, margin adaptation, and caries were 100% for both types of restorations at all recall intervals. One crown failed due to porcelain fracture at 1 year. Two year recall data will also be presented.

Conclusions: The zirconium ceramic crowns and fixed partial dentures have performed well at 1 year. This study was supported by a grant from Ivoclar Vivadent.