CarieCheck: An mHealth App for Caries-Risk Self-Assessment—User-Perceived Usability and Quality in a Pilot Study

<b>Background/Objectives:</b> Mobile health (mHealth) technologies are increasingly used to support preventive oral care and patient self-management. CarieCheck is a Portuguese app intended to improve oral health literacy and support caries-risk self-assessment. This prospective pilot study focused on users' perceived app quality and usability, assessed with uMARS-PT. <b>Methods</b>: Thirty participants from the academic community of Egas Moniz School of Health and Science used the app for 30 days and completed the uMARS-PT questionnaire. Descriptive statistics were used to calculate mean scores for Engagement, Functionality, Aesthetics, Information Quality, Subjective Quality, and Perceived Impact. <b>Results:</b> The overall mean uMARS-PT score was 4.22, indicating excellent perceived quality. The highest domain scores were Functionality (4.51), Aesthetics (4.45), and Information Quality (4.22). Engagement (3.71) and Subjective Quality (3.05) were moderate. Perceived Impact (3.85) reflected self-reported perception of increased awareness and motivation regarding oral health behaviors. <b>Conclusions:</b> CarieCheck was rated highly in usability, aesthetics, and information quality. These findings suggest that CarieCheck may be considered as a digital tool for preventive education and user-supported caries-risk self-assessment. Larger, longer-term studies in diverse populations using objective behavioral and clinical outcomes are warranted.