Background According to the World Health Organization (WHO), dental caries is considered one of the greatest pediatric health problems in the world, due to its high prevalence and incidence. Therefore, the early diagnosis of caries lesions is a fundamental procedure for planning treatment aimed at prevention, minimal intervention and promotion of oral health. The present study aims to evaluate, through a randomized and controlled clinical study, which is the best strategy for diagnosing primary caries lesions located in the interproximal region. Materials and methods Eighty patients, aged between 4 and 10 years will be randomized and allocated into 2 groups for analysis and comparison of methods for diagnosing caries lesions. The following diagnostic methods will be analyzed and compared: visual clinical examination using ICDAS (International Caries Detection and Assessment System), the iTero Element 5D System (intraoral scanner with near infrared imaging (NIRI) technology) and bitewing radiography (BWX). All evaluations will be carried out by 02 examiners. Examiners will be trained and calibrated to use the visual and radiographic criteria and also to use the iTero 5D intraoral scanner, following the manufacturer’s instructions. Trial registration NCT04900246 in ClinicalTrial.gov. First released in 05/11/2021 and last updated in 10/06/2021.