ABSTRACT
BACKGROUND: Good evidence is available that socioeconomic status (SES) positively correlates with access to orthodontic treatment. There is much less literature, however, on whether socioeconomic inequities affect patients once they are in treatment. SES predicts of treatment outcomes across many health disciplines. OBJECTIVES: To determine whether a similar relationship exists with orthodontic treatment and identify, evaluate and summarise the available evidence. METHODS: Systematic review with searches of multiple databases to identify studies of children and adolescents who underwent orthodontic treatment, in which parental SES was the variable of interest, and treatment duration, treatment outcome or adherence of patients to the treatment plan were the measured outcomes of interest. Quality appraisal used CASP checklists. Data were synthesised narratively and in tables and graphs. RESULTS: Seventeen studies were included in the final review. The high level of heterogeneity between studies made it hard to draw conclusions from the data as a whole. Many studies also had several quality issues. Some evidence suggested an association between low SES and discontinuation of orthodontic treatment, and between the receipt of state subsidised care and poor appointment attendance. CONCLUSION: No strong associations can be concluded. There is a need for more high-quality studies, perhaps incorporating access and uptake variables, to capture how different socioeconomic groups interact with orthodontic care.