Comparative evaluation of marginal and internal fit of multi‑unit fixed dental prostheses: A systematic review and meta‑analysis of conventional versus digital impressions

Abstract

Background: The incorporation of digital techniques has gained popularity in the fabrication of
fixed dental prostheses (FDPs) over the last decade; however, limited evidence exists regarding the
marginal and internal fit when using conventional versus digital impression techniques. This systematic
review and meta‑analysis aimed to compare the marginal and internal fit of tooth‑supported
multi‑unit FDPs produced from conventional and digital impressions.
Materials and Methods: A comprehensive search was conducted in electronic databases, including
Cochrane Library, PubMed, and Scopus. A meta‑analysis was conducted using the standardized mean
differences (SMDs) to quantify the effect sizes.
Results: Fourteen studies, three randomized controlled trials (RCTs) and 11 in vitro were
included in the review, all complying with the inclusion criteria. The meta‑analysis revealed that
multi‑unit FDPs fabricated using digital impressions generally exhibited improved marginal and
internal fit compared with those produced using conventional impressions. In the RCT subgroup,
digital impressions showed a trend toward improved marginal fit (SMD: −0.25; 95% confidence
interval [CI]: −0.64–0.14) and statistically significant improvement for internal fit (SMD: −0.15; 95%
CI: −0.55 to −0.24). In contrast, in vitro studies demonstrated statistically significant superiority of
digital impressions for both marginal fit (SMD: −0.81; 95% CI: −1.06, −0.56) and internal fit (SMD:
−0.52; 95% CI: −0.79 to −0.24).
Conclusion: Although digitalized impressions demonstrated statistically superior marginal and
internal fit compared with conventional impressions, the observed differences should be interpreted
with caution. Most outcomes remained within clinically acceptable limits. Among the intraoral
scanners, the Trios system showed a trend toward improved marginal fit.
Key Words: Conventional impression, digital impression, fixed dental prostheses, marginal fit

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 Gunjan Srivastava: Pubmed,Google Scholar