How does orthodontic treatment affect young adults' oral health-related quality of life? Nath alia B. Palomares, a Roger Keller Celeste, b Branca Heloisa de Oliveira, c and Jos e Augusto M. Miguel d Rio de Janeiro and Porto Alegre, Brazil Introduction: Studies in the dental literature do not yet provide conclusive evidence for the functional and psychosocial benefits of orthodontic treatment. In this cross-sectional study, we aimed to assess the oral health-related quality of life of young Brazilian adults, aged 18 to 30 years, who had completed orthodontic treatment compared with untreated subjects waiting for treatment. Methods: The subjects were recruited at a state-funded university clinic. The sample comprised 100 patients in the retention phase of orthodontic treatment for more than 6 months (treated group) and 100 persons who were seeking orthodontic treatment and were still on a waiting list (nontreated group). Data were collected by using the oral health impact profile, the index of orthodontic treatment need (malocclusion severity and esthetic impairment), the Brazilian economic classification criteria (socioeconomic status), and the index of decayed, missing, and filled teeth (oral health status). Statistical analyses were performed by using chi-square and Fisher exact tests and negative binomial regression. Results: The mean oral health impact profile scores were 3.1 (SD 6 2.99) and 15.1 (SD 6 8.02) in the treated and nontreated groups, respectively. The most frequent impacts in the treated and nontreated groups were “painful aching” and “been self-conscious,” respectively. Comparisons between the groups were controlled for malocclusion severity, clinician-assessed esthetic impairment, age, sex, socioeconomic status, and oral health status. Nontreated young adults had mean oral health impact profile scores 5.3 times higher than did the treated subjects. Conclusions: Young Brazilian adults who received ortho- dontic treatment had significantly better oral health-related quality of life scores in the retention phase, after treatment completion, than did nontreated subjects. (Am J Orthod Dentofacial Orthop 2012;141:751-8) W hy do patients search for orthodontic treat- ment? In the early 1980s, it was thought that orthodontic treatment was important because regular dental arches might facilitate oral hygiene, thus reducing the incidences of dental caries and periodontal disease. 1 Also, it was believed that better occlusal contacts could help prevent temporomandibu- lar joint disorders; however, studies have failed to provide solid evidence to support these claims. 2-4 Because the smile is the second most observed facial characteristic relating to physical attractiveness, 5 psychosocial research suggests that malocclusion might negatively interfere with self-satisfaction concerning appearance and, accordingly, impair social functioning. 2,6-15 Not surprisingly, it seems that the main reason to have orthodontic treatment is to obtain improvement in esthetics and subsequent enhancement of psychosocial well-being that might contribute to a better quality of life. 16-18 Previous research findings have shown that maloc- clusion perceptions differ between professionals and patients, and that self-perceived oral health-related quality of life is not always a reflection of malocclusion severity (ie, some people with severe malocclusions do not report a negative impact on quality of life, whereas others with minor irregularities report high negative impacts on quality of life). 2-4,10,15 Therefore, oral health-related quality of life assessments in orthodon- tics are imperative to the study of treatment needs, therapy effectiveness, and understanding of patients' expectations. These patient-centered measures might help with determining the outcomes of orthodontic care. a Specialist, Department of Orthodontics, State University of Rio de Janeiro, Rio de Janeiro, Brazil. b Associate professor, Department of Preventive and Social Dentistry, Federal University of Rio Grande do Sul, Porto Alegre, Brazil. c Associate professor, Department of Preventive and Community Dentistry, State University of Rio de Janeiro, Rio de Janeiro, Brazil. d Associate professor, Department of Orthodontics, State University of Rio de Janeiro, Rio de Janeiro, Brazil. The authors report no commercial, proprietary, or financial interest in the products or companies described in this article. Supported by the Carlos Chagas Filho Foundation (Fundac ¸ ~ ao Carlos Chagas Filho de Amparo  a Pesquisa do Estado do Rio de Janeiro), Rio de Janeiro, Brazil. Reprint requests to: Nath alia Palomares, Avenida L ucio Meira, 670/514, V arzea, Teres opolis, Rio de Janeiro, Brazil, CEP 25953-003; e-mail, palomares. nathalia@gmail.com. Submitted, July 2011; revised and accepted, January 2012. 0889-5406/$36.00 Copyright Ó 2012 by the American Association of Orthodontists. doi:10.1016/j.ajodo.2012.01.015 751 ORIGINAL ARTICLE