Comparison between digital and conventional impression techniques in children on preference, time and comfort: A crossover randomized controlled trial.

Objective: To compare the conventional alginate impression and the digital impression taken with an intraoral scanner of both dental arches in children, using a randomized crossover design.

Trial Design: This is a monocentric, controlled, superiority, randomized, crossover, open study.

Methods: Twenty-four orthodontic patients between 6 and 11 years of age underwent intraoral scanning (TRIOS 3; 3Shape) and alginate impression of both dental arches with an interval of 1 week between the two procedures. Participants were recruited from September 2021 to March 2022 and the study was completed in April 2022. Impression time for the two procedures was compared. Patients were asked which one of the two impression procedures they preferred. A questionnaire including Visual Analogue Scale (VAS) for comfort, pain, gag reflex and difficulty in breathing, was administered to the patients.

Results: Eighteen out of 24 patients preferred digital impression (75%, 95% confidence interval [CI]: 55% to 88%; P = .014). Scanning time was significantly shorter than alginate impression time (difference -118 seconds; 95% CI: -138 to -99; P < .001). Comfort was significantly higher for digital impression (difference 1.7; 95% CI: 0.5 to 2.8; P = .007). There was no difference in pain (difference -0.2; 95% CI: -1.5 to 1.0; P = .686) while gag reflex and breathing difficulties were smaller for digital impression (gag reflex difference -2.5; 95% CI: -4.0 to -0.9; P = .004 and breathing difficulties difference -1.5; 95% CI: -2.5 to -0.5; P = -.004).

Conclusions: Digital impression is preferred by children aged 6-11 years and it is significantly faster in acquisition time than conventional alginate impression.

Registration: The study was registered on ClinicalTrials.gov with registration number NCT04220957 on January 7th, 2020 (https://clinicaltrials.gov/ct2/show/NCT04220957).