Dentist-time expenditure for two different adhesive all-ceramic systems

The purpose of this clinical investigation was to compare a chair-side adhesive all-ceramic system to a laboratory processed adhesive all-ceramic system with respect to quality and time expenditure for the dentist. The same dentist treated 10 patients, who were each to receive two large posterior single tooth restorations of similar location and extent. One restoration was made in the laboratory by using the IPS Empress™ system [LAB], the other one was done chair-side by utilizing the Cerec™ system [CHAIR]. The time expenditure was measured for [LAB] and [CHAIR] and compared by the Wilcoxon signed rank test. The restorations were also evaluated according to the USPHS criteria. The mean time expenditure for the dentist with low-level assistance was 111:03 min [S.D. ± 24:09 min] for [LAB] and 115:31 min [S.D. ± 15:54 min] for [CHAIR]. Time expenditure with medium level assistance for the operator was 100:53 min [S.D. ± 23:59] for [LAB] and 105:50 [S.D. ± 15:28] for [CHAIR]. Assuming a high level of assistance, the mean time values were 53:11 min [S.D. ± 14:29] for [LAB] and 54:29 min [S.D. ± 09:21] for [CHAIR]. The baseline investigation according to the modified USPHS criteria did not reveal any differences between [CHAIR] and [LAB]. There were no statistical significant differences with respect to time expenditure or quality between [LAB] and [CHAIR] in this study.