Does psychological well-being influence oral-health-related quality of life reports in children receiving orthodontic treatment? Shoroog Agou, a David Locker, b Vanessa Muirhead, c Bryan Tompson, d and David L. Streiner e Toronto, Ontario, Canada Introduction: Although the associations between oral biologic variables such as malocclusion and oral-health- related quality of life (OHRQOL) have been explored, little research has been done to address the influence of psychological characteristics on perceived OHRQOL. The aim of this study was to assess OHRQOL outcomes in orthodontics while controlling for individual psychological characteristics. We postulated that children with better psychological well-being (PWB) would experience fewer negative OHRQOL impacts, regardless of their orthodontic treatment status. Methods: One hundred eighteen children (74 treatment and 44 on the waiting list), aged 11 to 14 years, seeking treatment at the orthodontic clinics at the University of Toronto, participated in this study. The child perception questionnaire (CPQ11-14) and the PWB subscale of the child health question- naire were administered at baseline and follow-up. Occlusal changes were assessed by using the dental aesthetic index. A waiting-list comparison group was used to account for age-related effects. Results: Although the treatment subjects had significantly better OHRQOL scores at follow-up, the results were significantly modified by each subject’s PWB status (P \0.01). Furthermore, multivariate analysis showed that PWB contributed significantly to the variance in CPQ11-14 scores (26%). In contrast, the amount of variance explained by the treatment status alone was relatively small (9%). Conclusions: The results of this study support the postulated mediator role of PWB when evaluating OHRQOL outcomes in children undergoing ortho- dontic treatment. Children with better PWB are, in general, more likely to report better OHRQOL regardless of their orthodontic treatment status. On the other hand, children with low PWB, who did not receive orthodontic treatment, experienced worse OHRQOL compared with those who received treatment. This suggests that chil- dren with low PWB can benefit from orthodontic treatment. Nonetheless, further work, with larger samples and longer follow-ups, is needed to confirm this finding and to improve our understanding of how other psychological factors relate to patients’ OHRQOL. (Am J Orthod Dentofacial Orthop 2011;139:369-77) A s orthodontic outcome research continues to move away from the traditional biomedical model 1 toward a biopsychosocial perspective, 2 more attention is being given to the concept of oral- health-related quality of life (OHRQOL). 3 OHRQOL is de- fined as the absence of negative impacts of oral condi- tions on social life and a positive sense of dentofacial self-confidence. 4 Studies with reliable OHRQOL mea- sures have identified differences between treated and un- treated orthodontic patients. 5-9 For example, a Brazilian study of 1675 adolescents indicated that children who had completed orthodontic treatment reported fewer OHRQOL impacts than those who were never treated. 5 These differences were mostly related to socio- emotional aspects of well-being such as smiling, laugh- ing, and showing teeth without embarrassment. 8,9 Such differences between treated and untreated subjects are expected in light of studies emphasizing the importance of dentofacial esthetics in daily social interactions. For instance, an unattractive dentition has been associated with teasing, bullying, 10,11 and negative OHRQOL impacts. 5,11-13 Improving dental esthetics and, subsequently, psychological well-being (PWB) are From the University of Toronto, Toronto, Ontario, Canada. a Assistant professor of orthodontics, Faculty of Dentistry, King Abdulaziz University. b Professor, Faculty of Dentistry. c Graduate Student, Faculty of Dentistry. d Associate professor, Faculty of Dentistry. e Professor, Department of Psychiatry and Baycrest Center. Based on a thesis submitted by the first author to the school of graduate studies, University of Toronto, in partial fulfillment of the requirements for the PhD degree. A preliminary report was presented at the International Association of Dental Research meeting in Toronto in 2008. The authors report no commercial, proprietary, or financial interest in the prod- ucts or companies described in this article. Reprint requests to: Shoroog Agou, Faculty of Dentistry, University of Toronto, 124 Edward St, Toronto, Ontario, Canada M5G 1G6; e-mail, sagou@kau.edu.sa. Submitted, January 2009; revised and accepted, May 2009. 0889-5406/$36.00 Copyright Ó 2011 by the American Association of Orthodontists. doi:10.1016/j.ajodo.2009.05.034 369 ORIGINAL ARTICLE