STATEMENT OF PROBLEM: Attaining a passive fit in implant restorations is desirable but clinically difficult to achieve, especially in screw-retained prostheses. At a certain magnitude, this misfit will not cause mechanical and biological complications, but the exact level has yet to be determined.
PURPOSE: The purpose of this systematic review was to gather, compare, and appraise studies that attempted to determine the biological and mechanical tolerance of misfits.
MATERIAL AND METHODS: The review protocol was published in the Prospective Register for Systematic Reviews (PROSPERO; registration no. CRD42021268399) and follows the Preferred Reporting for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. An electronic search was conducted through PubMed, Ebscohost, and Web of Science followed by a manual search up to December 2021.
RESULTS: A total of 413 manuscripts were identified by electronic and manual search. After removing duplicates, nonrelevant titles, and abstract screening, 62 manuscripts were eligible for full-text assessment. Finally, a total of 13 articles (1 cross-sectional study, 1 retrospective and prospective, 7 in vitro studies, and 4 animal studies) met the eligibility criteria and were included in this review. A wide range of tolerable misfits were reported. Vertical misfit up to 1 mm and horizontal misfit up to 345 μm were associated with no adverse outcomes.
CONCLUSIONS: The current literature provides inadequate data to determine a clinical threshold of an acceptable misfit. However, this review demonstrated that the mechanical response to misfit is more critical than the biological response.
* Title and MeSH Headings from MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.