14 December 2023

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Digital vs conventional impressions in edentulous patients: a systematic review

Lorenzo Breschi

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As people’s age increases, the rehabilitation of completely edentulous patients using conventional complete dentures has become widespread. A crucial phase in the prosthetic treatment is the impression-taking process, where the impression technique and materials employed play a key role in ensuring proper retention and function of the final denture.

In this context, the traditional two-step impression technique remains the gold standard for conventional complete dentures. However, with the advent of the digital era, intraoral scanners are gaining prominence in the field of dentistry. Despite the potential advantages of digital impressions (DI) such as reduced processing times and enhanced patient comfort, some challenges have been reported for the precision and accuracy of the scans relating to the presence of large edentulous areas.

In this regard, Casucci et al. conducted a systematic review to evaluate the accuracy, working time and patient satisfaction of DI compared to conventional impressions (CI) taken for removable prostheses on completely edentulous arches.

Materials and methods

A systematic search of the literature was conducted in electronic databases, including PubMed, Cochrane Library, Scopus, and Science Direct. Published articles were selected with no limitation on publication date, focusing on in vivo studies comparing DI and CI techniques for the fabrication of complete removable prostheses. The primary outcomes assessed were accuracy (in terms of trueness and precision), working time (scanning time), and patient satisfaction. The risk of bias in each included study was thoroughly assessed.

Results

After the screening process, 6 articles were deemed eligible for inclusion and selected for qualitative analysis. All these studies involved full-arch scans performed intra-orally with a focus on investigating the trueness of DI; however, no publication evaluated the accuracy in terms of precision. Specifically, discrepancy between DI and CI were primarily identified in the peripheral areas. Notable, working time for scanning procedures and patient satisfaction were assessed in only one study. Moreover, there was a lack of standardization in CI procedures and sample size collection across all studies. The highest risk of bias was predominantly associated with participant selection due to potential variability in anatomical and tissue conditions that occur in clinical practice.

Conclusion

The authors concluded that the current available scientific evidence on DI for complete edentulous arches is limited, particularly regarding scanning time and patient satisfaction. While digital scanning in edentulous patients appears to be a predictable procedure within the limits of the attached mucosa, the lack of complete information emphasize the need for further research and standardization.

For more information: Casucci A, Mazzitelli C, Tsiplakis V, D'Arienzo LF, Breschi L, Ferrari M. Digital Impressions in Edentulous Patients: A Systematic Review for Clinical Evidence. Int J Prosthodont. 2023 Sep 12;36(4):486-497