Objective: This study aimed to 1) investigate the relationships between hair cortisol concentration (HCC), insomnia symptoms, Health-Related Quality of Life (HRQoL) and Oral Health-Related Quality of Life (OHRQoL) in preschool children with severe early childhood caries, 2) compare HCC, insomnia symptoms, HRQoL and OHRQoL in preschool children with severe early childhood caries with these factors in children without clinical signs of dental caries, and 3) explore correlations between caries scores and HCC, insomnia symptoms, HRQoL and OHRQoL.

Material and Methods: A case-control pilot study, including 12 children with severe early childhood caries and 28 controls, aged 3-5 years. Dental examination was performed and hair samples for cortisol were taken. Parents filled out questionnaires about their child’s insomnia symptoms, HRQoL and OHRQoL. Interpreters were used in families with language difficulties.

Results: The key findings in this pilot study were tendencies that children with severe early childhood caries had more insomnia symptoms, and poorer OHRQoL than the controls. Caries scores was correlated with insomnia symptoms and OHRQoL.

Conclusions: Dentists should include questions about the child’s sleep when they see the child, as insomnia related to dental caries may lead to several physical, mental, and social problems.