The Relationship Between Body Dysmorphic Disorder and Orthodontic Treatment Need: A Systematic Review

Background: Body Dysmorphic Disorder (BDD) is characterized by an intense preoccupation with perceived flaws in physical appearance, which can influence choices related to aesthetically driven healthcare. In orthodontics, this may cause a mismatch between a person's subjective concern about their appearance and the treatment need determined by established indices. Therefore, orthodontic treatment indices are crucial to ensure that interventions are clinically justified rather than primarily motivated by disproportionate appearance-related distress. Objective: To systematically review and appraise the existing evidence on the connection between BDD and orthodontic treatment need as assessed by established indices. Materials and Methods: A systematic search of five electronic databases was conducted for studies published up to March 2026 that examined the association between BDD and orthodontic treatment need. Eligible studies included individuals undergoing orthodontic treatment or seeking orthodontic care, in whom BDD was evaluated using validated instruments and treatment need was assessed using established orthodontic indices. Risk of bias was assessed using the ROBINS-E tool. Results: A total of 2743 records were identified, and four observational studies met the inclusion criteria. Due to heterogeneity in study design, assessment methods and outcomes, findings were synthesized narratively. Orthodontic treatment need was assessed using the Dental Health Component of the Index of Orthodontic Treatment Need (IOTN-DHC), the Aesthetic Component of the Index of Orthodontic Treatment Need (IOTN-AC), and the Index of Complexity, Outcome and Need (ICON). Two studies using IOTN-DHC reported a negative association between BDD and orthodontic treatment need, whereas studies using IOTN-AC and ICON found no significant relationship. Associations with sex, age, education, depression, and anxiety were inconsistent across studies. Conclusions: Current evidence suggests an inconsistent relationship between Body Dysmorphic Disorder and orthodontic treatment need, highlighting the relevance of personalized assessment in orthodontic decision-making. Given the limited number of studies and the high risk of bias, the findings should be considered preliminary, and further standardized studies are needed to clarify this association.