All-ceramic partial coverage restorations--midterm results of a 5-year prospective clinical splitmouth study

Midterm-evaluation of a 5-year prospective clinical splitmouth-investigation on survival rate and long-term behavior of all-ceramic partial coverage restorations (PCRs) on molars. Pressed ceramic and CAD/CAM fabricated PCRs were compared.

80 vital molars of 25 patients were restored with all-ceramic PCRs (40 IPS e.max Press*[IP] and 40 ProCAD*[PC]). IP-PCRs were heat pressed following the lost-wax method. PC-PCRs were fabricated with Cerec 3** and Cerec InLab** CAD/CAM system (**Sirona Dental Systems, Bensheim, Germany). All PCRs were adhesively luted with a light-polymerizing composite (Syntac*/Tetric*) (*Ivoclar Vivadent, Schaan, Liechtenstein). Clinical reevaluations were performed at baseline and 13, 25, and 36 months after insertion of the PCRs according to the modified United States Public Health Services (USPHS) criteria. Absolute failures were demonstrated by Kaplan-Meier survival rate.

After an observation time up to 3 years, survival rate of IP-PCRs was 100% and 97% for PC-PCRs due to one severe fracture. The PC-PCR had to be replaced after 9 months. Secondary caries and endodontic complications did not occur. Increased clinical service time resulted in significant decrease of marginal adaptation (p=0.031) and enhanced marginal discoloration (p<0.0001). Both PCR ceramic materials demonstrated significant deteriorations in color match (p<0.0001) and surface roughness (p<0.0001), IP-PCRs were significantly more affected (p< or =0.005). Regarding anatomic form IP-PCRs performed significantly better (p=0.0012).

Pressed ceramic and CAD/CAM fabricated partial coverage restorations exhibited a reliable treatment option to restore larger defects in posterior teeth. Marginal degradation of the resin cement and deterioration of the all-ceramic materials during clinical function determine the clinical long-term performance of partial coverage restorations.