Objectives:The aim of the present systematic review was to analyze the survival and com plication rates of zirconiabased and metalceramic implantsupported single crowns (SCs). Materials and Methods: An electronic MEDLINE search complemented by manual searching was conducted to identify randomized controlled clinical trials, prospective cohort and retrospective case series on implantsupported SCs with a mean followup time of at least 3 years. Patients had to have been clinically examined at the followup visit. Assessment of the identified studies and data extraction was performed independently by two reviewers. Failure and complication rates were analyzed using robust Poisson's regression models to obtain summary estimates of 5year proportions. Results: The search provided 5,263 titles and 455 abstracts, fulltext analysis was performed for 240 articles, resulting in 35 included studies on implantsupported crowns. Metaanalysis revealed an estimated 5year survival rate of 98.3% (95% CI: 96.8-99.1) for metalceramic implant supported SCs (n = 4,363) compared to 97.6% (95% CI: 94.3-99.0) for zirconia implant supported SCs (n = 912). About 86.7% (95% CI: 80.7-91.0) of the metalceramic SCs (n = 1,300) experienced no biological/ technical complications over the entire observation period. The corresponding rate for zirconia SCs (n = 76) was 83.8% (95% CI: 61.6-93.8). The biologic outcomes of the two types of crowns were similar; yet, zirconia SCs exhibited less aesthetic complications than metalceramics. The 5year incidence of chipping of the veneering ceramic was similar between the material groups (2.9% metalceramic, 2.8% zirconia ceramic). Significantly (p = 0.001), more zirconiaceramic implant SCs failed due to material fractures (2.1% vs. 0.2% metalceramic implant SCs). No studies on newer types of monolithic zirconia SCs fulfilled the simple inclusion criteria of 3 years followup time and clinical examination of the present systematic review. Conclusion: Zirconiaceramic implantsupported SCs are a valid treatment alternative to metalceramic SCs, with similar incidence of biological complications and less aesthetic problems. The amount of ceramic chipping was similar between the materialgroups; yet, significantly more zirconia crowns failed due to material fractures. K E Y W O R D Sbiological, complications, fixed dental prostheses, implant crown, metaanalysis, metal ceramics, success, survival, systematic review, technical, zirconia frameworkThis is an open access article under the terms of the Creative Commons AttributionNonCommercial License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited and is not used for commercial purposes.

Objectives:The aim of the present review was to compare the outcomes, that is, survival and complication rates of zirconia-ceramic and/or monolithic zirconia implant-supported fixed dental prostheses (FDPs) with metal-ceramic FDPs. Materials and Methods: An electronic MEDLINE search complemented by manual searching was conducted to identify randomized controlled clinical trials, prospective cohort studies and retrospective case series on implant-supported FDPs with a mean follow-up of at least 3 years. Patients had to have been examined clinically at the follow-up visit. Assessment of the identified studies and data extraction was performed independently by two reviewers. Failure and complication rates were analyzed using robust Poisson regression models to obtain summary estimates of 5-year proportions. Results: The search provided 5,263 titles and 455 abstracts. Full-text analysis was performed for 240 articles resulting in 19 studies on implant FDPs that met the inclusion criteria. The studies reported on 932 metal-ceramic and 175 zirconia-ceramic FDPs. Meta-analysis revealed an estimated 5-year survival rate of 98.7% (95% CI: 96.8%-99.5%) for metal-ceramic implant-supported FDPs, and of 93.0% (95% CI: 90.6%-94.8%) for zirconia-ceramic implant-supported FDPs (p < 0.001). Thirteen studies including 781 metal-ceramic implant-supported FDPs estimated a 5-year rate of ceramic fractures and chippings to be 11.6% compared with a significantly higher (p < 0.001) complication rate for zirconia implant-supported FDPs of 50%, reported in a small study with 13 zirconia implant-supported FDPs. Significantly (p = 0.001) more, that is, 4.1%, of the zirconia-ceramic implant-supported FDPs were lost due to ceramic fractures compared to only 0.2% of the metal-ceramic implant-supported FDPs. Detailed analysis of factors like number of units of the FDPs or location in the jaws was not possible due to heterogeneity of reporting. No studies on monolithic zirconia implant-supported FDPs fulfilled the inclusion criteria of the present review. Furthermore, no conclusive results were found for the aesthetic outcomes of both FDP-types. Conclusion: For implant-supported FDPs, conventionally veneered zirconia should not be considered as material selection of first priority, as pronounced risk forThis is an open access article under the terms of the Creative Commons Attribution-NonCommercial License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited and is not used for commercial purposes.

Objectives:The objective of this systematic review was to assess the influence of implant-abutment connection and abutment material on the outcome of implantsupported single crowns (SCs) and fixed dental prostheses (FDPs). Methods: An electronic Medline search complemented by manual searching was conducted to identify randomized controlled clinical trials, prospective and retrospective studies with a mean follow-up time of at least 3 years. Patients had to have been examined clinically at the follow-up visit. Failure and complication rates were analyzed using robust Poisson regression, and comparisons were made with multivariable Poisson regression models. Results: The search provided 1511 titles and 177 abstracts. Full-text analysis was performed for 147 articles resulting in 60 studies meeting the inclusion criteria. Meta-analysis of these studies indicated an estimated 5-year survival rate of 97.6%for SCs and 97.0% for FDPs supported by implants with internal implant-abutment connection and 95.7% for SCs and 95.8% for FDPs supported by implants with external connection. The 5-year abutment failure rate ranged from 0.7% to 2.8% for different connections with no differences between the types of connections. The total number of complications was similar between the two connections, yet, at external connections, abutment or occlusal screw loosening was more predominant. Ceramic abutments, both internally and externally connected, demonstrated a significantly higher incidence of abutment fractures compared with metal abutments. Conclusion:For implant-supported SCs, both metal and ceramic abutments with internal and external connections exhibited high survival rates. Moreover, implantsupported FDPs with metal abutments with internal and external connections for also showed high survival rates. K E Y W O R D Sbiological, ceramic, complications, implant abutments, implant crowns, implant fixed dental prostheses, meta-analysis, metal, survival, systematic review, technical, titanium, zirconia | 161 PJETURSSON ET al.

This is an open access article under the terms of the Creat ive Commo ns Attri butio n-NonCo mmerc ial-NoDerivs License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non-commercial and no modifications or adaptations are made.

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