Background The COVID-19 pandemic was associated with several changes in maintenance of children's dental health. The aim of the present study was to evaluate the extent of these changes. Methods Parents were asked to anonymously respond to a questionnaire regarding alterations in their children's oral-habits, such as frequency of eating and drinking, tooth brushing, signs of stress and receiving dental care during the lockdown period. The participants were reached either during their visit to the clinics or by social media groups of the authors. Results 308 parents to children aged 1-18 years responded to the questionnaires. Associations were shown between increased frequency of eating and drinking, decreased frequency of tooth brushing, and postponing dental care. Of the children, 11% suffered from more frequent oral signs of stress, such as temporomandibular disorder and aphthous-stomatitis, during the lockdown. Although children from all age-groups ate and drank more frequently between meals, younger children were diagnosed with more carious lesions during the lockdown (P=0.015). Conclusions During the lockdown many children changed their eating, drinking and tooth-brushing habits, and thus increased their own risk for development of caries.