A systematic review of the survival and complication rates of all-ceramic and metal-ceramic reconstructions after an observation period of at least 3 years. Part I: Single crowns

Objectives: The objective of this systematic review was to assess the 5-year survival rates of all-ceramic single crowns and to compare it with the survival rates of metal-ceramic crowns and to describe the incidence of biological and technical complications. Methods: An electronic Medline and Dental Global Publication Research System search complemented by manual searching was conducted to identify prospective and retrospective cohort studies on all-ceramic and metal-ceramic crowns with a mean follow-up time of at least 3 years. Patients had to have been examined clinically at the follow-up visit. Assessment of the identified studies and data abstraction was performed independently by two reviewers. Annual failure rates were analyzed using standard and random-effects Poisson regression models to obtain summary estimates of survival proportions. Results: The search provided 3473 titles and 177 abstracts. Full-text analysis was performed for 86 articles, resulting in 34 studies that met the inclusion criteria. In meta-analysis, the 5-year survival of all-ceramic crowns was estimated at 93.3% (95% confidence interval (CI): 91.1%-95%) and 95.6% (95% CI: 92.4%-97.5%) for metal-ceramic crowns. All-ceramic crowns were also analyzed according to the material utilized. Densely sintered alumina (Procera®technique) crowns showed the highest 5-year survival rate of 96.4%, followed by reinforced glass-ceramic crowns (Empress®technique) and InCeram-crowns with survival rates of 95.4% and 94.5%, respectively. A significantly lower survival rate of 87.5% was calculated for glass-ceramic crowns after 5 years. All-ceramic crowns were also grouped and analyzed regarding the position in the mouth. All four types of all-ceramic crowns showed lower survival rates when seated on posterior teeth. Moreover, for glass-ceramic crowns (84.4%) and InCeram-crowns (90.4%), this difference reached statistical significance (P=0.009, P=0.028). Conclusion: Based on the present systematic review, all-ceramic crowns, when used for anterior teeth, showed survival rates at 5 years comparable to those seen for metal-ceramic crowns. When used for posterior teeth, the survival rates at 5 years of densely sintered alumina crowns (94.9%) and reinforced glass-ceramic crowns (93.7%) were similar to those obtained for metal-ceramic crowns. Furthermore, lower survival rates of 90.4% and 84.4% can be expected for InCeram crowns and glass-ceramic crowns when utilized for premolars and molars.