ObjectivesThe aim of the present study was to evaluate the effects of orthodontic treatment on patients' oral health-related quality of life (OHRQoL) in a population aged 17 to 21 years. The influence of gender and malocclusion severity was also investigated.Materials and MethodsIn the present study, 108 patients were enrolled. Each patient completed a questionnaire about oral health impact profile (OHIP)-14 before treatment and after 12 months of treatment. The severity of the initial malocclusion was evaluated through the index for orthodontic treatment need (IOTN).Statistical AnalysisStatistical analysis was performed to assess the presence of difference in OHRQoL score before and after the treatment, and the influence of gender and IOTN score on the observed outcomes.ResultsWe found no significant differences related to gender regarding their perception of how malocclusion affects the quality of life before orthodontic treatment. Moreover, no significant differences were found between males and females regarding their perception of how orthodontic treatment affects the quality of life 12 months after orthodontic treatment. Also, the analysis showed no statistically significant difference between males and females in the correlation IOTN-OHIP for Grades 2 and 3. A statistically significant difference between males and females was found only in Grade 4, both before (p= 0.046) and after treatment (p= 0.051).ConclusionFinally, OHIP-14 can be a valuable instrument to assess the perceptions and the expectations of patients toward orthodontic treatment.