Prosthodontic Insights Newsletter

October 1999 Volume 12, Number 2

Continues..

Precision of Fit of the Procera® AllCeram Crown
May et al

Strength, color stability and precision of fit are requirements of all-ceramic restorations if they are to contribute to the successful rehabilitation of teeth. The Procera® AllCeram crown system, composed of a densely sintered high-purity alumina core combined with a low fusing surface porcelain appears to satisfy most requirements. However, measurement data for marginal fit has not been reported. This investigation was initiated to measure the marginal opening (MO) and internal adaptation of Procera® All Ceram crowns fabricated for premolar and molar dies using the Procera CAD/CAM technology. The method selected to measure the precision of fit between the AllCeram crowns and the dies was Laser Videography. The mean gap dimension at the MO for the molar was 62 um (SD 49) with lower and upper 95% CIs of 55 um and 70 um, respectively. The premolar mean MO was 55 um. (SD 51) with lower and upper 95% CIs of 48 um and 63 um, respectively. The MOs for both crown groups were well below the clinically accepted 100 um used to determine an acceptable crown. Based on the findings of this investigation, the clinician can prescribe a Procera® AllCeram crown with confidence knowing that the MO will consistently be less than 70 um.

J Prosthet Dent. 1997(5)p.497-502.