Objective  To investigate oral healthcare related knowledge and bad behaviors in children with orthodontic diseases and to provide evidences for developing targeted interventions.

  Methods  With convenient sampling and a self-designed questionnaire, we conducted an on-site self-administered anonymous survey among 6 – 12 years old children (n = 362) undergoing orthodontic treatment in Department of Stomatology of the Eighth People′s Hospital of Qingdao in Qingdao city of Shandong province from June 2015 to June 2017.

  Results  Among all the participants, the caries rate was 59.24%; the average caries number was 1.83 ± 0.22 and the gingivitis rate was 37.29%; the lowest awareness rate (29.56%) was for the number of deciduous and permanent teeth and the highest (76.80%) was for periodic oral examination. The awareness rate of oral health knowledge was significantly higher in urban participants and in girls than in the rural participants and in the boys (both P < 0.05). The awareness rate of oral health knowledge increased with the increment of age. Bad oral health-related behaviors were reported by a majority of the participants. More than one half (54.14%) of the participants reported acquiring oral health knowledge from their parents but less than one fifth (19.61%) of the participants reported receiving the knowledge from medical personnel.

  Conclusion  The awareness rate of oral health knowledge is relatively low among school-age children undergoing orthodontic treatment, especially in the rural, the male and young children and bad oral health related behaviors are prevalent among the children, suggesting that education on oral health should be promoted in the children.