A systematic review and meta analysis of the longevity of anterior and posterior all-ceramic crowns

Background: Clinical experience suggests that there is a difference in survival between anterior and posterior all ceramic restorations. Objectives: This systematic review compared the difference in survival for full coverage all-ceramic materials used in adults to restore anterior or posterior vital teeth, not involved with fixed dental prostheses, but opposed by teeth. Data and sources: Searches using Medline, Embase, and the Cochrane Library, including hand searches, with the inclusion criteria containing all-ceramic full coverage crowns in human adults over 17 years of age, prospective and retrospective studies, opposed by teeth, periodontal pocketing <= 5 mm, but not involving implant supported crowns or non-vital teeth. All papers were published between 1980 and March 2014 and available in English. From the selected studies a meta analysis was undertaken. The chi square test, I-2, Begg's and Egger's test were analysed and the publication bias was assessed using a Funnel plot. The, Kappa scores were 0.63, 0.88, and 0.81 at each selection stage. Study selections: Pooled data produced 1112 anterior crowns with 73 failures (6.5%) and 1821 posterior crowns with 166 failures (9.1%) with a follow up time from 36 to 223 months. Relative risk meta-analysis of the 14 selected papers demonstrated that anterior all-ceramic crowns were 50% less likely to fail than posterior all-ceramic crowns (p = 0.001). Conclusion: These results indicate that there were differences in failure between anterior and posterior all ceramic crowns but the difference was only 3%. Although this has clinical relevance and some caution is needed when prescribing all ceramic posterior crowns the difference was relatively small. Clinical significance: The clinically relevant results of this review, based on currently available data, demonstrate a need for some caution when considering posterior all-ceramic crowns. Lithium disilicate restorations were observed to have higher failures on anterior restorations and more research is needed to investigate why. (C) 2016 Elsevier Ltd. All rights reserved.