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

NCT07276191 | Recruiting

• 1 other identifier: CE-FMDUL202530
• Study Type: interventional
• Target: 150
• Locations: 1 country
• Sites: 1

Brief 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. 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. 2.To analyze the level of satisfaction and usability of the app's features.
3. 3.The app will significantly improve oral health indicators, including plaque levels, gingival inflammation, and caries risk, compared to a control group.
4. 4.The app will increase adherence to recommended oral hygiene behaviors (e.g., brushing frequency, interdental cleaning).
5. 5.Adolescents using the app will report higher motivation and self-efficacy for oral self-care.
6. 6.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

Keywords

Adolescent; Mobile Applications; Oral Health; Health Promotion; MHealth; Health Behavior; Behavior change techniques

Outcome Measures

Primary Outcomes (4)

• Dental caries risk assessed by Cariogram

  Evaluation of each participant's individual risk of developing dental caries using the Cariogram tool, a validated computer-based model that considers clinical, behavioural, microbiological, and salivary factors to generate a visual and numerical (percentage) estimation of caries risk. This tool incorporates ten parameters, although it is not mandatory to use all of them, the simplified version can be applied with seven parameters, while still maintaining its clinical usefulness. Each parameter is scored on a scale from 0 to 3, where 0 represents the most favourable condition and 3 the least favourable, contributing differently to the final risk estimation. In the present study, due to resource constraints, Cariogram will be applied without the collection of salivary and microbiological data, acknowledging that this decision may reduce the accuracy of the caries risk assessment.

  Baseline and 3-month follow-up

• Gingival inflammation

  Measurement of gingival inflammation using the percentage of bleeding sites upon gentle probing, following the Bleeding on Probing Index (BOP), which reflects the presence and severity of gingival inflammation.

  Baseline, 1-month, and 3-month follow-up

• Dental Plaque accumulation

  The Simplified Oral Hygiene Index (OHI-S) will be used to evaluate soft debris and calculus based on two components: the Debris Index-Simplified (DI-S) and the Calculus Index-Simplified (CI-S). Each component measures the amount of debris or calculus on specific tooth surfaces, allowing the effectiveness of oral hygiene practices to be monitored over time. Teeth will be dried and six specific tooth surfaces examined with a mouth mirror and periodontal probe, each surface scored from 0 to 3 for debris and 0 to 3 for calculus, according to the extent of crown coverage. Component scores will be calculated by averaging the surface scores, and the final OHI-S will be the sum of DI-S and CI-S (range 0-6), categorized as excellent (0), good (0.1-1.2), fair (1.3-3.0), or poor (3.1-6.0) to describe oral hygiene status in the trial.

  Baseline, 1-month, and 3-month follow-up

• Oral self-care behaviours

  Evaluation of participants' oral hygiene behaviours using a structured self-reported questionnaire administered at two time points (baseline and 3-month follow-up). The questionnaire includes 6 items assessing perceived oral health status, frequency and duration of toothbrushing, use of fluoride toothpaste, use and type of interdental cleaning aids (e.g., dental floss, interdental brushes), and frequency of their use. Questions are closed-ended, using yes/no responses, multiple-choice options, or frequency scales, with a few items allowing open responses for further specification.

  Baseline and 3-month follow-up

Secondary Outcomes (4)

• Oral health knowledge

  Baseline and 3-month follow-up

• App usage frequency (UL Smile)

  3-month follow-up

• Perceived usefulness of the app

  3-month follow-up

• Satisfaction with the mobile application UL Smile

  3-month follow-up

Other Outcomes (2)

• Suggestions for app improvement

  3-month follow-up

• Qualitative feedback on app usability

  3-month follow-up

Study Arms (2)

ULSMILE group

EXPERIMENTAL

The intervention arm will receive an oral hygiene consultation supported by the "UL Smile" mobile application, which includes features such as educational videos, brushing guidance, reminders, and motivational messages.Both groups will receive a hygiene kit and be assessed at baseline, 1 month, and 3 months.

Behavioral: Oral Health Behavioral change; Other: MHealth; Other: Oral Health education

CONTROL group

ACTIVE COMPARATOR

The control arm will receive the same oral hygiene consultation without access to the app, using traditional educational materials such as oral cavity models. Both groups will receive a hygiene kit and be assessed at baseline, 1 month, and 3 months.

Behavioral: Oral Health Behavioral change; Other: Oral Health education

Interventions

Oral Health Behavioral change BEHAVIORAL

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.

CONTROL group; ULSMILE group

MHealth OTHER

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.

ULSMILE group

Oral Health education OTHER

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.

CONTROL group; ULSMILE group

Eligibility Criteria

• Age: 15 Years - 19 Years
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Child (0-17), Adult (18-64)

You may qualify if:

• Be aged between 15 and 18 years at baseline.
• Be fluent in Portuguese.
• Have access to a mobile phone or computer/tablet with internet.
• Be willing to participate in the study by providing signed assent/consent. For participants under 18 years old, consent must be signed by a legal guardian.
• Use of the app at least twice during the first month of the study.

You may not qualify if:

• Current or previous use of any oral health-related mobile application.
• Not being responsible for their own oral hygiene.

Sponsors & Collaborators

• University of Lisbon: lead

Study Sites (1)

Faculty of Dental Medicine, University of Lisbon

Lisbon, Lisbon District, 1600-277, Portugal

RECRUITING

Related Publications (2)

• Costa JF, Mendes S. Exploring mobile applications for oral health promotion: a randomized clinical trial. Can J Dent Hyg. Forthcoming. Available from: https://files.cdha.ca/profession/journal/earlyview/CJDH_Early_View--FONSECA--Mobile_apps_for_oral_health.pdf

  BACKGROUND

• Costa J, Mendes S. Young Portuguese adults' perception of mobile apps for motivation tooral health care. Rev Port Estomatol Med Dent Cir Maxilofac 2024;65(2):59-65. doi:10.24873/j.rpemd.2024.06.1220

  BACKGROUND

MeSH Terms

Conditions

Health Behavior

Interventions

Telemedicine; Health Education, Dental

Condition Hierarchy (Ancestors)

Behavior

Intervention Hierarchy (Ancestors)

Delivery of Health Care; Patient Care Management; Health Services Administration; Health Education; Preventive Health Services; Health Services; Health Care Facilities Workforce and Services; Public Health Dentistry; Environment and Public Health

Study Officials

• Sónia Mendes, PhD

  Faculty of Dental Medicine, University of Lisbon

  STUDY DIRECTOR

• Luísa Barros, PhD

  Center for Research in Psychological Science (CICPSI), University of Lisbon

  STUDY CHAIR

• Carlos Duarte, PhD

  Faculty of Sciences, University of Lisbon

  STUDY CHAIR

Central Study Contacts

Joana F Costa, MSc, PhD student

CONTACT

+351 21 792 2600; joanac@edu.ulisba.pt

Sónia Mendes, PhD

CONTACT

+351 21 792 2600; soniaborralho@edu.ulisboa.pt

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: SINGLE
• Who Masked: OUTCOMES ASSESSOR
• Masking Details: The outcomes assessor is blinded to group allocation to minimize detection bias. This assessor will perform clinical evaluations (e.g., simplified oral hygiene index, bleeding on probing, DMFT and caries risk assessment) at intermediate and final follow-up points without knowledge of whether participants belong to the intervention or control group. Masking is maintained by using separate investigators for intervention delivery and outcome assessment. Participants, care providers, and the principal investigator are not masked due to the nature of the intervention, which requires active engagement with the mobile app or the standard consultation approach.
• Purpose: PREVENTION
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: PhD Student Joana Fonseca Costa

Model Details: This is a two-arm, parallel-group, cluster-randomized controlled trial. Entire school classes (clusters) are randomly assigned to either the intervention group, which will use the UL Smile mobile application in conjunction with oral hygiene consultation, or the control group, which will receive standard consultation without access to the app. The allocation ratio is 1:1. Cluster randomization at the class level helps prevent cross-contamination between groups. The intervention period lasts approximately three months, with data collected at baseline, 1-month, and 3-month follow-up.

Study Record Dates

• First Submitted: November 28, 2025
• First Posted: December 10, 2025
• Study Start: February 2, 2026
• Primary Completion (Estimated): June 30, 2026
• Study Completion (Estimated): December 31, 2026
• Last Updated: February 3, 2026

Record last verified: 2026-01

Data Sharing

• IPD Sharing: Will not share

Locations

PT (1)