title: Evaluation of the marginal fit of single-unit, complete-coverage ceramic restorations fabricated after digital and conventional impressions: A systematic review and meta-analysis.
abstract: BACKGROUND
  In existing published reports, some studies indicate the superiority of digital impression systems in terms of the marginal accuracy of ceramic restorations, whereas others show that the conventional method provides restorations with better marginal fit than fully digital fabrication. Which impression method provides the lowest mean values for marginal adaptation is inconclusive. The findings from those studies cannot be easily generalized, and in vivo studies that could provide valid and meaningful information are limited in the existing publications.
  
  
  OBJECTIVE
  The purpose of this study was to systematically review existing reports and evaluate the marginal fit of ceramic single-tooth restorations after either digital or conventional impression methods by combining the available evidence in a meta-analysis.
  
  
  METHODS
  The search strategy for this systematic review of the publications was based on a Population, Intervention, Comparison, and Outcome (PICO) framework. For the statistical analysis, the mean marginal fit values of each study were extracted and categorized according to the impression method to calculate the mean value, together with the 95% confidence intervals (CI) of each category, and to evaluate the impact of each impression method on the marginal adaptation by comparing digital and conventional techniques separately for in vitro and in vivo studies.
  
  
  RESULTS
  Twelve studies were included in the meta-analysis from the 63 identified records after database searching. For the in vitro studies, where ceramic restorations were fabricated after conventional impressions, the mean value of the marginal fit was 58.9 μm (95% CI: 41.1-76.7 μm), whereas after digital impressions, it was 63.3 μm (95% CI: 50.5-76.0 μm). In the in vivo studies, the mean marginal discrepancy of the restorations after digital impressions was 56.1 μm (95% CI: 46.3-65.8 μm), whereas after conventional impressions, it was 79.2 μm (95% CI: 59.6-98.9 μm)
  
  
  CONCLUSIONS
  No significant difference was observed regarding the marginal discrepancy of single-unit ceramic restorations fabricated after digital or conventional impressions.
authors.affiliation: Postgraduate student, Department of Prosthetic Dentistry, Center for Dental and Oral Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany. Electronic address: tsirogiannis.contact@gmail.com.
authors.forename: Panagiotis
authors.initials: P
authors.lastname: Tsirogiannis
authors.affiliation: Associate Professor, Department of Prosthetic Dentistry, Center for Dental and Oral Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.
authors.forename: Daniel R
authors.initials: DR
authors.lastname: Reissmann
authors.affiliation: Professor, Department of Prosthetic Dentistry, Center for Dental and Oral Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.
authors.forename: Guido
authors.initials: G
authors.lastname: Heydecke
mesh_terms: D002516:Ceramics / Q000627:therapeutic use*; D017076:Computer-Aided Design; D003761:Dental Impression Technique; D018772:Dental Marginal Adaptation / Q000592:standards; D017267:Dental Prosthesis Design / Q000379:methods* / Q000592:standards; D003793:Dental Restoration, Permanent / Q000379:methods* / Q000592:standards; D006801:Humans