Background Plaque quantification indices are frequently used to evaluate personal oral hygiene. Education in self-care and self-diagnosis is effective in prevention and control of both dental and periodontal disease. Mobile technology has become a ubiquitous technology and can be particularly useful in the self-monitoring of health promotion. To evaluate the selfie dental plaque index compared with O´Leary index (DPI) and visible plaque index (VPI). The secondary outcome was to compare full-mouth and anterior teeth plaque index analysis. Material and Methods A sample of 47 adults were evaluated using a four-stage protocol. All teeth (except third molars) were analyzed for VPI and DPI. A selfie Digital Camera captured the image of the patient’s smile (without and with disclosing solution), which was analyzed using Image J software (ImageJ 1.52a, National Institutes of Health). Adobe Photoshop software (Copyright © 2020 Adobe) was used for individual segmentation. The calculation of the selfie index of visible plaque (SVPI) and disclosed (SDPI) was done through the area with plaque of each image in relation to the total teeth area. Results Spearman’s correlation test showed a moderate correlation between VPI and SVPI (rho = 0.6, p <0.001), whereas between DPI and SDPI the correlation was weak (rho = 0.2, p = 0.13). The correlation between the plaque index using all the teeth present, showed a strong correlation with the analysis only of the anterior teeth (rho = 0.8, p <0.001). Conclusions Our results showed the potential of smiling images as a new tool for quantitative measurements and showed moderate correlation when compared with the visible plaque index. Anterior teeth provided reliable plaque indexes when compared with full mouth analysis. Key words: Dental Plaque Index, dental hygiene, mHealth, health Promotion, oral Health.