Responsiveness refers to the sensitivity of an instrument to detect clinical changes. The aim of the present study was to assess the responsiveness of the Child Perception Questionnaire (CPQ11−14) to an oral health care treatment program for non-privileged 10–15 years old adolescents in the region of Itapoã, Federal district of Brazil. Adolescents who answered the CPQ11−14, were clinically and radiographically examined at baseline (n = 618) and after 1 year (n = 560). The program was based on intensive patient oral health care education and training in addition to professional toothcleaning (prophylaxis with or without scaling) according to individual requirements. [...