Clinical evaluation of digital versus conventional impression in edentulous patients with flabby ridges: a randomized controlled clinical trial

The optimal impression technique for flabby ridge cases remains ambiguous despite the advancements in impression techniques. This randomized controlled trial (RCT) aimed to compare the Oral Health Related Quality of Life (OHRQoL) and retention of maxillary dentures fabricated from intraoral scanning (IOS) versus window impression technique in completely edentulous patients with maxillary flabby ridges. The study utilized a crossover design, where participants were randomly assigned to receive conventional complete dentures fabricated by using two different techniques for complete denture fabrication: one utilizing conventional impression method (Group I dentures) and the other employing digital impression technique (Group II dentures). OHRQoL and retention of maxillary dentures were evaluated at baseline (T0), 3 months (T3), and after 6 months (T6). A new complete denture was delivered for each participant after 6 months, with those initially receiving Group I dentures transitioning to Group II dentures, and vice versa. Comparison between groups using paired t-test, while comparison between different time points was performed by using Repeated Measures ANOVA test followed by Tukey’s Post Hoc test. The significant level was set to be at P ≤ 0.05. Both groups reported improvement in OHRQoL with no significant difference between groups at six months follow-up period (P < 0.0001). Additionally, both groups reported a decline in denture retention at the follow up periods with no significant difference between groups at six months follow-up period (P < 0.0001). Digital impression is a viable alternative to conventional impression in the fabrication of complete dentures for edentulous arches with flabby ridges with similar outcomes in terms of OHRQoL and denture retention. The study protocol was retrospectively registered and posted on the ClinicalTrials.gov public website (ClinicalTrials.gov identifier: NCT07108322) on August 7, 2025.