Background: Taking alginate impressions for preschoolers is challenging and might be disturbing for them. Therefore, intraoral scanners are suggested as a better alternative to the conventional alginate impression.

Objectives: The present study aims to evaluate and compare the level of patients' discomfort, dental anxiety, gag reflex, behavior and time required for taking alginate impressions with that of intraoral scanning.

Materials and methods: The study will be a randomized, controlled clinical trial, parallel design. A total of 666 pediatric dental patients aged from 4-6 years will be selected from the outpatient clinic of the of Pediatric Dentistry and Dental Public Health Department, Faculty of Dentistry, Alexandria University. Participants will be allocated into 2 groups. Children in the first group will receive digital impressions by an intraoral scanner, while those of the second group will receive conventional alginate impressions. Patients' discomfort will be evaluated by a modified VAS index supported with emojis. Dental anxiety will be evaluated using Facial Image Scale (FIS). Gag reflex will be assessed by Gag Severity Index (GSI). Child's behavior towards the impression technique in the 2 groups will be evaluated using Venham's Behavior rating scale. Time taken to complete the procedures will be recorded using a digital stopwatch.

Inclusion Criteria:

• Children with scores of 3 or 4 during preoperative assessments according to the Frankl Behavioral Rating Scale.
• No previous dental experience.
• Patient's parents signed an informed consent before participating in the trial.

Exclusion Criteria:

• Any physical or mental disability, or psychological problems.
• Children with temporomandibular joint or periodontal discomfort