Methods: In total, 60 restorations were placed in 39 patients restoring 16 premolars and 44 molars. After tooth preparation, impression taking using polyether and model casting, each preparation was contact less scanned by strip-light-projection. The digital construction of the metal copings was with computer software (Softshape, BEGO Medical, Germany). Metal copings were produced with a laser melting technology by BEGO Medical (Germany). A base metal alloy (Wirobond C+) and a precious alloy (BioPontoStar+, both: BEGO Medical, Germany) were used in this study with 30 restorations each. After veneering ceramic firing (IPS d.Sign, Ivoclar-Vivadent) the metal-ceramic crowns were air-borne particle abraded (Al2O3, 50µm, 2.5 bar) and cemented with glass-ionomer cement (Ketac Cem, 3M Espe). Patients were recalled after 6-12 months, and then every year.
Results: The mean observation time for the 60 single metal-ceramic crowns until the last recall visit was 40±9 months (minimum 19 months, maximum 50 months). One restoration was regarded a drop-out because the patient did not attend the recall program for more than 24 months. One of the crowns failed during the observation period because of extraction after endodontic problems. One crown debonded but was recemented immediately. One abutment tooth had to be endodontically treated and three teeth were treated because of caries at the margin of the restoration. However, these complications did not affect the clinical function of the involved crowns.
Conclusion: The clinical outcome after 40 months of posterior single metal-ceramic crowns fabricated with laser melting technology (Bego Medical, Germany) is promising.
Supported by Bego Medical, Bremen, Germany