Accuracy in the Marginal Adaptation and/or Internal Adaptation of Full-coverage Fixed Prostheses Made with Digital Impressions and Conventional Impressions: A Systematic Review

María Cajas-Guamán1, María Cabrera-Toro1, *, Jaime Astudillo-Ortiz1, Yulissa Abad-Salinas1, Daniela Astudillo-Rubio1, Bolívar Delgado-Gaete2
1 Postgraduate Oral Rehabilitation and Implant-Assisted Prosthesis, Faculty of Dentistry, University of Cuenca, Cuenca 010107, Ecuador
2 School of Dentistry, Department of Prosthodontics, Catholic University of Cuenca, Cuenca, Ecuador

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© 2023 Cajas-Guamán et al.

open-access license: This is an open access article distributed under the terms of the Creative Commons Attribution 4.0 International Public License (CC-BY 4.0), a copy of which is available at: This license permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

* Address correspondence to this author at the Faculty of Dentistry, University of Cuenca, Cuenca 010107, Ecuador; Tel.: +593 0982827326; E-mail:



The study aimed to verify compliance of the systematic reviews with the requirements established by the scientific community and demonstrate the validity and reliability of the systematic reviews conducted on the accuracy (marginal adaptation and/or internal adaptation) of the full-coverage fixed prostheses made with digital impressions versus conventional impressions.


A search was performed for systematic reviews in three electronic databases, PubMed, Scopus, and Web of Science, as well as in the gray literature. In the search strategy, medical subject heading (MeSH) words were used in PubMed, and free terms were used for the titles and abstracts of each article. Each keyword was separated by the Boolean operator OR and later combined with the Boolean operator AND. Six systematic reviews were included for qualitative synthesis. To assess the methodological quality of the included systematic reviews, the AMSTAR 2 tool was used.


The search yielded 131 studies, of which 78 remained after removing duplicates. The title and abstract of each chosen study were assessed, and 22 articles were included for full-text reading. Finally, six studies were included, of which three studies were considered to have low confidence, while the other three were considered to have critically low confidence. In addition, the six SRs evaluated the adaptation or marginal fit, while only three studies measured internal adaptation.


The use of digital impressions in single fixed prostheses maintains a marginal level within the limit of clinical acceptability; however, the methodological quality of systematic reviews is poor, according to the AMSTAR 2 tool.

Keywords: Marginal fit, Internal fit, Conventional impressions, Digital impressions, Fixed prostheses, Systematic review.