UL Smile: A Mobile Health Application to Promote Oral Health in Portuguese Adolescents

This study is part of a doctoral research project in Oral Health Sciences and Technologies, with a specialization in Dental Hygiene, at the Faculty of Dental Medicine, University of Lisbon. With the advancement of technology, smartphones and mobile applications (apps) have become an integral part of daily life, especially among adolescents and young adults, who are the main users of these devices. In 2023, global app downloads reached an estimated 257 billion, including a growing number of health-related apps, known as Mobile Health or mHealth, and, more specifically, apps targeting oral health. Oral diseases, such as dental caries and periodontal disease, remain a major public health issue due to their high prevalence and impact on quality of life. Although these conditions are preventable, the adoption and maintenance of healthy behaviors continues to be challenging. Mobile apps may serve as an effective complement to oral health consultations, promoting motivation, adherence to recommendations, and communication with healthcare professionals. Despite the increasing availability of oral health apps, evidence regarding their effectiveness is still limited. Many of these tools lack scientific rigor and fail to adequately meet users' needs. In this context, an original Portuguese-language mobile application for promoting oral health was developed, based on current scientific evidence and preliminary exploratory studies involving adolescents and oral health professionals. These studies aimed to identify the most relevant features for this type of tool. The app was designed using the Behaviour Change Wheel (BCW) model, widely recognized for structuring effective behavior change interventions in health. This mobile app was developed by a multidisciplinary team from the University of Lisbon, involving experts from various faculties, including Psychology, Sciences, Dental Medicine, and Fine Arts. As an original tool, it is not yet available on app stores. The main aim of this study is to test the effectiveness of this app as a complement to oral health consultations in a population of adolescents living in Portugal, contributing to the advancement of knowledge in this field and to the promotion of more innovative and user-centered clinical practices. These are the specific objectives of the study: 1. To assess the effectiveness of the app when used as a complement to dental hygiene consultations in relation to several oral health indicators, namely risk of dental caries, gingival inflammation, dental plaque presence, and oral self-care behaviors. 2. To analyze the level of satisfaction and usability of the app's features. The main hypotheses are: 1. The app will significantly improve oral health indicators, including plaque levels, gingival inflammation, and caries risk, compared to a control group. 2. The app will increase adherence to recommended oral hygiene behaviors (e.g., brushing frequency, interdental cleaning). 3. Adolescents using the app will report higher motivation and self-efficacy for oral self-care. 4. The app will demonstrate high usability and user satisfaction, supporting its potential for broader implementation.