Literature Search Methods

This report is based on a literature search conducted for a previous CADTH report. A limited literature search was conducted on key resources including PubMed, The Cochrane Library, University of York Centre for Reviews and Dissemination (CRD), ECRI databases, Canadian and major international health technology agencies, as well as a focused Internet search. Methodological filters were applied to a broad search of any type of dental crown to limit retrieval to health technology assessments, systematic reviews, meta-analyses, randomized controlled trials, non-randomized studies and economic studies. No filters were applied to a narrower search of articles comparing all-ceramic to metal-ceramic dental crowns. Where possible, retrieval was limited to the human population. The search was also limited to English language documents published between January 1, 2000 and April 17, 2015.

Rapid Response reports are organized so that the evidence for each research question is presented separately.

Selection Criteria and Methods

One reviewer screened citations and selected studies. In the first level of screening, titles and abstracts were reviewed and potentially relevant articles were retrieved and assessed for inclusion. The final selection of full-text articles was based on the inclusion criteria presented in Table 1.

Table 1

Selection Criteria.

Exclusion Criteria

Articles were excluded if they did not meet the selection criteria outlined in Table 1, they were duplicate publications or already included in one of the included systematic reviews. Studies were also excluded if they were case series, commentary, reviews, laboratory studies, and surveys. Studies evaluating crowns supported by implants or multiple-unit crowns were excluded. Implant-supported crowns were excluded because their abutments are not prepared by dentists in the dental clinics; instead, they are usually provided by implant’s manufacturers or fabricated in dental laboratories. Therefore, including implant-supported crowns in this review would have masked a major confounding factor related to the effect of dentist skills and experience on all-ceramic crown survival. Studies that evaluated esthetics without reporting crown survival or longevity were also excluded.

Critical Appraisal of Individual Studies

The included systematic reviews were critically appraised using AMSTAR tool.⁴ Downs and Black checklist was used to evaluate randomized and non-randomized,⁵ economic studies were assessed using the Drummond checklist.¹ Summary scores were not calculated for the included studies; rather, a review of the strengths and limitations of each included study were described.