RecruitingBehavioural interventionTesting a Mobile App to Improve Toothbrushing Skills and Habits in Teens With AutismThe goal of this proposed trial will modify an existing toothbrushing app for teens with autism and compare toothbrushing outcomes with a control app. We have 2 specific aims: * During the 2-year UG3 phase, we will use the Discover, Design+Build, and Test Framework to modify our existing app and pilot the intervention. * During the 4-year UH3 phase, we will recruit 270 pre-adolescents and teens with autism ages 10 to 17 years, randomize participants to one of two arms, and compare outcomes. Participants will asked to use the app, complete surveys on REDCap, participate in feedback interviews and focus groups. Behavior change in the experimental group will be compared with that in the control group.