The effect of endodontic access on all-ceramic crowns: A systematic review of in vitro studies.

OBJECTIVES: The aim of this systematic review was to identify from in vitro studies the effect of endodontic access on the fracture resistance and damage around the access cavity of all-ceramic crowns.

DATA: The articles identified were screened by two reviewers according to inclusion and exclusion criteria. The reference lists of articles advanced to second round screening were hand searched to identify additional potential articles. The risk of bias for the articles was independently performed by two reviewers.

SOURCES: An electronic search was conducted on PubMed/Medline, Web of Science, Scopus and Embase databases with no limitations.

STUDY SELECTION: 383 articles were identified, of which, eight met the inclusion criteria and formed the basis of this systematic review. Factors investigated in the selected articles included the, presence of microcracks at the access cavity, repair protocol, ceramic type, crown fabrication method, luting agent and grit size of the diamond bur. The risk of bias was deemed to be high for three, medium for two and low for three of the reviewed studies. The high level of heterogeneity across the studies precluded meta-analyses.

CONCLUSION: Based on the currently available scientific evidence, a 'best practice' protocol with regard to improving the fracture resistance of endodontically accessed and repaired all-ceramic crowns cannot be conclusively identified. However, some key factors which potentially impact on the fracture resistance of endodontically accessed and repaired all-ceramic crowns have been isolated. Cautious clinical interpretation of these factors is concluded for the maintenance of the crown as a permanent restoration.

CLINICAL SIGNIFICANCE: Key factors which impact on the fracture resistance of endodontically accessed and repaired all-ceramic crowns have been isolated from in vitro studies. Cautious clinical interpretation of these factors is advised for the maintenance of the crown as a permanent restoration.