Purpose <p>A few studies address tooth loss in foster care adolescents, whose social vulnerability requires specific health attention. This study aimed to assess tooth loss in foster care adolescents, and compare the findings with adolescents who lived with their families.</p> Methods <p>This is a comparative, cross-sectional, observational study, whose sample was divided into two groups: foster care adolescents (CG) and adolescents who lived with their families (FG). Data were collected in foster care institutions and public schools in Recife, Brazil, in 2022, with adolescents aged 15–18&#xa0;years. They underwent clinical dental examinations, which recorded tooth loss with the DMFT index (decayed, missing, and filled teeth) and secondary data. The sample had 31 participants in CG and 93 in FG.</p> Results <p>Of the foster care adolescents, 22.6% had at least one missing tooth, in contrast with 7.5% tooth loss prevalence in those who lived with their families, representing a significant difference (p = 0.023).</p> Conclusion <p>Hence, foster care adolescents had a higher prevalence of tooth loss, about three times greater than those who lived with their families.</p>