| Contemporary conceptual models of health emphasize the importance of patient-based outcomes and recognize the complexity involved in their assessment. Various health conditions, personal, social, and environmental factors, are all thought to contribute to individual's quality of life. However, the impact of orthodontic treatment on Oral Health-related Quality of Life (OH-QOL) outcomes in children has not yet been systematically studied. Hence, this research was planned to assess the effect orthodontic treatment has on pediatric OH-QOL outcomes. Further, the important moderational role of children's psychological assets on OH-QOL reports is explored.;This PhD dissertation is presented in the "Publishable Style". The journals which hold the copyrights for the papers published from this thesis have given permission for the reproduction of the text and figures for this dissertation.;The preliminary data confirmed that the CPQ11-14 is sensitive to change when used with children receiving orthodontic treatment. Our cross-sectional findings indicated that the impact of malocclusion on OH-QOL is substantial in children with low SE and identified SE as a salient determinant of OH-QOL in children seeking orthodontic treatment. Longitudinal data, on the other hand, detected significant improvement of OH-QOL outcomes after orthodontic treatment. As postulated, these improvements were most evident for the social and emotional domains of OH-QOL. However, covariate analysis emphasized the important role psychological factors play in moderating OH-QOL reports, as children with better PWB were more likely to report better OH-QOL regardless of their orthodontic treatment status.;These results substantiate the validity of contemporary models of patient-based outcomes linking biological, personal, social, and environmental factors. Researchers and clinicians are encouraged to adopt this forward thinking approach when dealing with children with oro-facial conditions. Further studies with larger samples and longer follow-ups would be of value to expand on these findings.;Following completion of a preliminary study to confirm the psychometric properties of the Child Perception Questionnaire (CPQ11-14), the current two-phase study was undertaken. This consisted of a cross-sectional study examining the relationship among Self-Esteem (SE), malocclusion, and OH-QOL, and a longitudinal study examining the influence of orthodontics and children's Psychological Wellbeing (PWB) on OH-QOL reports. |
