Dental impressions are used to create a record of a person's teeth and oral structures. Conventional impressions are made using impression material placed in a tray, whereas digital impressions are obtained using an intraoral scanner.

This randomized clinical trial compared conventional alginate impressions with digital intraoral scanning using the TRIOS 3 and Medit i700 scanners among dental students aged 18 to 24 years. Participants were randomly assigned to one of the three impression techniques. Each participant underwent recording of both the upper and lower dental arches using the assigned technique.

The study primarily compared the chairside time required for each technique and the participants' experience immediately after the procedure. Comfort, nausea, breathing, pain, dry-mouth sensation, perceived procedure speed, overall satisfaction, and preference for conventional or digital impressions were also evaluated.

Inclusion Criteria:

• Undergraduate dental students at the University of Medicine and Pharmacy, Hue University.
• Aged 18 to 24 years.
• Willing to undergo one maxillary and one mandibular dental impression using the assigned technique.
• Willing and able to complete the study questionnaire.
• Provided written informed consent.

Exclusion Criteria:

• Currently undergoing orthodontic treatment.
• Presence of a systemic disease or acute condition that limited the ability to cooperate or increased the risk of discomfort during impression taking or intraoral scanning, including an acute respiratory disorder or frequent vomiting.
• Limited mouth opening or an oral and maxillofacial condition that prevented correct impression-tray seating or scanner-tip placement according to the study protocol.
• A maxillofacial abnormality that markedly affected the procedure or caused significant recording distortion.
• An excessive gag reflex that prevented completion of the assigned procedure.