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

Summary

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.

Conditions

• Oral Health Care
• Oral Health Behavior Change
• Oral Health Self-efficacy

Interventions

BEHAVIORAL

Oral Health Behavioral change

The app includes goal setting (e.g., brushing twice daily, using floss or interdental brushes), self-monitoring tools (e.g., daily brushing checklists), and individualized feedback provided by oral health professionals through a private section of the app. It also incorporates modeling via instructional videos, direct suggestions for healthy habits, reinforcement through badges and motivational messages upon task completion, and prompts to reinforce key messages and behaviours. These components are based on the Behaviour Change Wheel (BCW) framework and are specifically adapted to adolescent users. Although the control group does not receive a digital behavioural intervention, the oral health education and motivational strategies provided during the hygiene consultation are also informed by the BCW framework, ensuring a consistent theoretical basis across both study arms.

OTHER

MHealth

Use of a mobile application (UL Smile) to deliver structured oral health content and behavioural strategies directly to adolescents via their smartphones. The app provides personalized and interactive tools, including guided brushing animations, educational videos, and digital reminders. It is designed to be used independently by participants throughout the 3-month study period, integrating oral health promotion into their daily routines in a familiar and accessible format. Participants in the control group do not have access to the mobile application and will receive only the standard oral hygiene consultation.

OTHER

Oral Health education

Delivery of evidence-based information on oral hygiene practices, prevention of dental caries and gum disease, use of oral hygiene products, and the impact of diet on oral health. The educational content in the experimental group is delivered through short, age-appropriate videos and visual resources developed in collaboration with oral health and communication experts. Messages are designed to promote awareness, self-efficacy, and long-term habit formation. In the control group, oral health education is provided through a standard hygiene consultation using traditional methods, such as verbal explanations and demonstration with oral cavity models, without the use of the mobile application.

Sponsors & Collaborators

• University of Lisbon

  lead OTHER

Principal Investigators

• Sónia Mendes, PhD · Faculty of Dental Medicine, University of Lisbon

• Luísa Barros, PhD · Center for Research in Psychological Science (CICPSI), University of Lisbon

• Carlos Duarte, PhD · Faculty of Sciences, University of Lisbon

Study Design

Allocation

RANDOMIZED

Purpose

PREVENTION

Masking

SINGLE

Model

PARALLEL

Eligibility

Min Age

15 Years

Max Age

19 Years

Sex

ALL

Healthy Volunteers

Yes

Timeline & Regulatory

Start

2026-02-02

Primary Completion

2026-06-30

Completion

2026-12-31

Countries

• Portugal

Study Locations