Long-term clinical results of galvano-ceramic and glass-ceramic individual crowns

Statement of problem. Alternatives to metal-ceramic restorations should possess clinical durability before being recommended to the dentist. Longitudinal clinical studies are required for evaluation so innovative types of restorations can meet the expectations of dentists and patients. Purpose. This study compared the performance of galvano-ceramic restorations (Auvo Galvano Crown [ACG]) and glass-ceramic individual crown (Dicor) based on longitudinal clinical trials. Material and methods. A total of 769 galvano-ceramic single crowns (AGC) in 322 patients and 173 glass-ceramic individual crowns (Dicor) in 88 patients were reviewed for 8 years and a maximum of 11 years, respectively, after cementation. Risk of fracture was determined with use of a survival analysis (Kaplan and Meier). Results. Partial ceramic cracking was observed at time time of the last recording of data in 11 galvano-ceramic crowns, 8 of the units remained in place. Two crowns became dislodged and 1 tooth exhibited a fractured root, despite an intact crown. One restoration was removed because of hypersensitivity and 1 with partial ceramic fracture. Forty-two of the glass-ceramic crowns were completely fractured. After a comparable 7 years under risk, 96.5% (+/-3.4; 95% confidence interval) of the galvano-ceramic premolar and molar crowns and 92% (+/- 8.5) of crowns placed on incisors and canines crowns were intact. The corresponding data for the glass-ceramic restorations were only 70% (+/- 10.6) in posterior and 82.7% (+/- 8.1) in anterior quadrants. Conclusion. Long-term results of electroformed individual crown restorations were superior to glass ceramic restorations.