Prevalência de más oclus？es em crian？as de 9 a 12 anos de idade da cidade de Nova Friburgo (Rio de Janeiro)

introduction: knowledge of a population's epidemiological situation is important in the planning and provision of dental services. objectives: assess the prevalence of malocclusion in children aged 9 to 12 years old from public schools in the city of nova friburgo, rio de janeiro state, brazil. methods: a randomly selected sample consisting of 407 children (53.1% female) who were evaluated by a trained professional, after parental consent. results: the most prevalent malocclusions were crowding (45.5%), excessive overjet (29.7%), posterior crossbite (19.2%), anterior diastema (16.2%), partially erupted teeth (12.0%) and excessive overbite (10.8%). class i molar relationship prevailed (76.7%). the presence of diastemas was higher in females and excessive overbite was more prevalent in males, both in mixed dentition. negative overjet and the presence of partially erupted teeth had a higher prevalence in permanent dentition. conclusion: it was observed that the mere evaluation of malocclusion prevalence does not reveal case severity or treatment need, both of which are important factors in public health planning.