Mobile App-Based Intervention to Improve Toothbrushing in Children and Teens With Autism (BU)

Testing a Mobile App-Based Intervention to Improve Toothbrushing Skills and Habits in Children and Teens With Autism

The goal of this clinical trial is to test whether the autism-friendly app improves toothbrushing outcomes compared to a control app with only a digital mirror and countdown timer among children and teens (ages 8-17 years) with autism.

The main questions it aims to answer are:

1. Will toothbrushing distribution, duration, and frequency be greater in the experimental arm than in the control arm?
2. Will toothbrushing habit formation be higher in the experimental arm than in the control arm?
3. Is caregiver and child self-efficacy a mediator of toothbrushing habit formation?
4. Do children who exhibit habit formation report better oral health-related quality of life?

Participants will:

1. Use either the autism-friendly app or the control app during their daily toothbrushing routine for 3 months.
2. Complete surveys and assessments about toothbrushing behaviors and oral health over the course of the study.

Study Overview

• Status: Enrolling by invitation
• Conditions: Autism Spectrum Disorder
• Intervention / Treatment: Behavioral: Brush Up App; Behavioral: Brush Down App

Detailed Description

The UH3 RCT will be conducted over four years. We will obtain a list of eligible participants from the main study recruitment site (Seattle Children's Hospital). We will obtain a list of individuals who express interest in participating in the study from other recruitment sites. UW staff will contact potential participants, describe the study, verify interest and screen for eligibility, and obtain informed consent and assent. The caregiver and their child/teen, aged 8-17 years, will be enrolled (N=270) as dyads and randomly assigned (1:1) to an experimental or control arm, accounting for sex and autism severity. The study participation will span one year. The participants in both arms will follow the same procedures.

After enrollment, caregivers from both control and experimental groups will complete all surveys according to the determined schedules. Caregivers will complete a demographics survey and a toothpaste survey via phone. Caregivers will also complete an online survey, Social Responsiveness Scale-2 (SRS-2), via WPS Publishing, to provide data on the user's autism severity. Before the app use, caregivers will be asked to complete a 9-item Oral Health Behavior Survey (OHBS), 30-item Behavioral Survey (BS) and 38-item Short Sensory Profile (SSP) via REDCap at baseline.

Caregivers will then be given a unique link to install a modified Brush Up/Brush Down app, depending on their assignment in the experimental or control arm respectively. The Brush Up app (experimental) features a cartoon character that helps guide the child through toothbrushing with a catchy song. It also includes a digital mirror where the child can watch themselves brush and a matching game where they earn stars by matching their toothbrushing movements with the character. The Brush Down app (control) includes only a digital screen mirror and a timer. We will ask the user to use the app twice a day for 3 months. The app will record the user's toothbrushing sessions. Users will be made aware of this during consent/assent process. The 9-item OHBS will be re-administered at 1 month, 2 months and 3 months of app use via REDCap. The 30-item BS will be re-administered at 2 weeks, 1 month, 2 months, and 3 months of app use via REDCap. Study staff will recruit 60 dyads (N=30 from each arm) for a post-trial debriefing interview lasting about 60 minutes using a semi-structured interview script to elicit responses about the experiences of using the app, the effects of the app on their child's long-term toothbrushing habit formation as well as ways the intervention could be further strengthened in the future to meet the needs of individuals with autism. The interviews will be audio recorded, transcribed, and verified for accuracy, and coded deductively using standard methods.

After 3 months of app use, the caregivers will be asked to complete a 6-item BS, an abridged version of a 30-item BS, to assess long-term habit formation and oral health quality of life from months 4 to 12 of participation via REDCap.

Study staff will reach out to the dyads who participated in post-trial interviews to obtain feedback on their experiences of using the app. The interviews will be audio recorded, transcribed, and verified for accuracy, and coded deductively using standard methods.

• Study Type: Interventional
• Enrollment (Estimated): 270
• Phase: Not Applicable

Contacts and Locations

Study Locations

• United States
  • Washington
    • Seattle, Washington, United States, 98195
      • University of Washington School of Dentistry

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Child
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

1. Child participants will have Autism Spectrum Disorder that will be confirmed by: (1) chart review by clinical staff at the recruitment sites to determine if the child meets the DSM-5 criteria for autism spectrum disorder; OR (2) affirmative caregiver self-reporting: (YES) to the question, "Has a healthcare provider ever diagnosed your child with autism?" which has been used in previous studies as a valid method of identifying ASD in children.23,24
2. Willingness to take the SRS-2 [Social Responsiveness Scale-2], which will be completed through an online link sent by University of Washington study staff.
3. Child brushes independently. The child needs to be able to hold a toothbrush and move it around their teeth, mostly unassisted.
4. Child uses touch screen devices (e.g., iPhone, iPad, Android).
5. Ages 8 to 17 years at enrollment.
6. Caregiver and child able to communicate in English.
7. Caregiver age ≥18 years and able to provide informed consent to participate; and willing to provide assent on behalf of a child who is not capable of comprehending the assent process and materials.
8. Children ages 8 and older willing to provide assent, if they can comprehend the assent process and materials and communicate a voluntary willingness to participate.
9. Caregiver and child live in the same home.
10. Caregiver must have a valid and active email address to receive study related materials and study related communications.
11. Child has ready access to a mobile device with a front-facing camera onto which apps can be installed (iPad or iPhone with iOS 17.0+; Android tablet or phone with Android 14.0+).
12. Family has a Wi-Fi or cellular data plan to allow app data to be transmitted with confirmation of via tools like the Ookla Speed Test to help problem solve and ensure that app data can be transmitted.

Exclusion Criteria:

An individual who meets any of the following criteria will be excluded from participation in the study:

• Children with autism younger than age 8 years at enrollment.
• Children with autism who cannot brush their teeth without assistance (e.g., if caregiver needs to hold the toothbrush).
• Children with autism who have a sibling enrolled in the trial. o For families with more than 1 eligible child with autism, we will enroll the youngest eligible child. Any other children from the same family who are not enrolled in the study will be given access to the app their sibling is using (experimental or control) after 3 months, if they are interested.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Single

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Experimental; Dyads in the experimental arm will use the modified, experimental version of the app (Brush Up) twice a day for 3 months.	Behavioral: Brush Up App; The Brush Up app is an autism-friendly mobile app modified to improve toothbrushing skills and habits in children with autism spectrum disorder and includes a health education module, a cartoon role model, toothbrushing instructional song, digital screen mirror, and customizable app features.
Placebo Comparator: Control; Dyads assigned to the control arm will use the control version of the app (Brush Down) twice-per-day for 3-months.	Behavioral: Brush Down App; The Brush Down app provides health education module, a digital screen mirror and a countdown timer. This app does not include autism-friendly features.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Toothbrushing distribution	The primary outcome being measured is toothbrushing distribution. Toothbrushing distribution refers to the mean proportion of different tooth surfaces in the mouth that should be brushed during each toothbrushing episode (i.e., lingual, buccal occlusal). For each subject, one toothbrushing episode per day will be randomly sampled during week 12 to measure distribution.	The primary outcome will be measured based on data from week 12 of the 3-month trial.

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Toothbrushing duration	Toothbrushing duration refers to the mean number of seconds brushed per toothbrushing episode. For each subject, one toothbrushing episode per day will be randomly sampled during week12 to measure this outcome. For each sampled episode, the duration will be measured in seconds from the time toothbrushing commences until toothbrushing concludes. Idle time, which is defined as time not spent actively brushing during an episode will also be measured in seconds.	The secondary outcome will be measured based on data from week 12 of the 3-month trial.
Toothbrushing Frequency	Toothbrushing frequency refers to the number of days the app was used at least twice per day. Timestamps will be recorded for each instance of toothbrushing with the app, which will be used to determine the number of days for measuring frequency.	The secondary outcome will be measured based on data from week 12 of the 3-month trial.

Other Outcome Measures

Outcome Measure	Measure Description	Time Frame
Exploratory Outcomes	For each subject, one toothbrushing episode per day will be randomly sampled during weeks 1, 2, 4, 8 and 12 to measure this outcome. Toothbrushing distribution will be defined by the mean proportion of tooth segments brushed during each episode. The distribution for each week will be used to assess trends in toothbrushing distribution between the two apps during the 3-month trial through linear regression models.	App use during Weeks 1, 2, 4, 8, and 12 during the 3-month trial.
Exploratory Outcome	For each subject, one toothbrushing episode per day will be randomly sampled during weeks 1, 2, 4, 8 and 12 to measure this outcome. Toothbrushing duration will be defined by the mean number of seconds brushed per episode. The duration for each week will be used to assess trends in toothbrushing duration between the two apps during the 3-month trial through linear regression models.	App use during weeks 1, 2, 4, 8, and 12 during the 3-month trial.
Exploratory Outcome	Toothbrushing frequency refers to the number of days the app was used at least twice per day. Timestamps will be recorded for each instance of toothbrushing with the app, which will be used to determine the number of days for measuring frequency. Linear regression models will be used to assess trends for frequency during the 3-month trial.	App use from baseline to end of month 3.
Exploratory Outcome	Habit formation will be measured using responses to a Behavioral Automaticity Index collected during post-trial follow-up from enrolled caregivers of children who used the app during the 3-month trial. The responses will be used to assess if there are linear or non-linear trends for each arm to determine if the experimental app leads to better habit formation compared to the control app.	Month 4 to Month 12
Exploratory Outcome	Oral health quality of life will be measured using responses to a short-form version of the Child Oral Health Impact Profile assessment, collected during post-trial follow-up from enrolled caregivers of children who used the app during the 3-month trial. The responses will be used to assess if there are linear or non-linear trends for each arm to determine if the experimental app leads to better oral health quality of life compared to the control app.	Month 4 to Month 12
Exploratory Outcome	Caregiver and child self-efficacy will be measured using responses to an Oral Health-related Self-Efficacy scale assessment and Toothbrushing Self-Efficacy scale assessment completed by caregivers during the 3-month trial. The average changes in caregiver and child self-efficacy will be used to identify potential mediators. A mediation analysis will be conducted to assess if changes in caregiver and child self-efficacy related to app use during the 3-month trial directly or indirectly mediate toothbrushing habit formation observed during the 9-month follow-up.	Baseline to Month 3 (self-efficacy), and Month 4 to Month 12 (habit formation).
Exploratory Outcome	A subset of caregivers and children enrolled in the trial will be recruited through purposeful sampling to complete semi-structured qualitative interviews as dyads after completing the 3-month trial. Dyads who completed interviews after the 3-month trial will be asked again after the 9-month follow-up to complete a second interview before completing the study. The interviews will generate qualitative data about the potential effects of the experimental of control app on the child's toothbrushing habit formation, and ways to further improve the intervention. Qualitative data will be analyzed using deductive methods.	After the 3-month trial period and after the 9-month follow-up.

Collaborators and Investigators

• Sponsor: University of Washington
• Collaborators: National Institute of Dental and Craniofacial Research (NIDCR)
• Investigators: Principal Investigator: Donald L Chi, DDS, PhD, University of Washington

Study record dates

Study Major Dates

• Study Start (Actual): May 7, 2026
• Primary Completion (Estimated): August 31, 2028
• Study Completion (Estimated): August 31, 2029

Study Registration Dates

• First Submitted: January 21, 2026
• First Submitted That Met QC Criteria: February 25, 2026
• First Posted (Actual): March 3, 2026

Study Record Updates

• Last Update Posted (Actual): June 2, 2026
• Last Update Submitted That Met QC Criteria: May 29, 2026
• Last Verified: May 1, 2026

More Information

Terms related to this study

• Keywords: Autism Spectrum Disorder; Toothbrushing habits; Mobile App based intervention
• Additional Relevant MeSH Terms: Mental Disorders; Neurodevelopmental Disorders; Child Development Disorders, Pervasive; Autism Spectrum Disorder
• Other Study ID Numbers: STUDY00022501; UH3DE033184 (U.S. NIH Grant/Contract)

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: No