PURPOSE: Oral health-related quality of life (OHRQoL) is a construct for 
assessing the self-perceived oral health of patients. The aim of this study was 
to investigate the correlation between OHRQoL and orthodontic treatment need in 
consideration of demographic and psychological factors.
PATIENTS AND METHODS: This multicentre study included 250 patients with an 
indication for orthodontic diagnostics. In cooperation with the Institute of 
Clinical Psychology at the University of Würzburg, validated and internationally 
acknowledged questionnaires were selected to assess OHRQoL (COHIP-G19) and 
health-related quality of life (HRQOL). Self-esteem and behavioural problems 
were taken into consideration as possible psychological factors. Orthodontic 
treatment need was assessed using the Index of Orthodontic Treatment Need-Dental 
Health Component (IOTN-DHC), the Index of Orthodontic Treatment Need-Aesthetic 
Component (IOTN-AC) and the Dental Aesthetic Index (DAI). Possible significant 
correlations between the collected parameters and OHRQoL were evaluated by means 
of linear regression analysis.
RESULTS: Objective orthodontic treatment need (IOTN-DHC and DAI) was 
significantly correlated with OHRQoL. Further factors significantly influencing 
OHRQoL in children and adolescents were age, HRQOL, self-esteem and behavioural 
problems.
CONCLUSIONS: Objective orthodontic treatment need significantly influences 
OHRQoL in children and adolescents. Further studies are required to investigate 
if OHRQoL may be improved by correcting misaligned teeth and jaws.