Introduction: Oral hygiene is a crucial element during orthodontic treatment, particularly when patients use removable orthodontic appliances. In the 9–13 year age group, when oral cavity development is still dynamic, proper hygiene can affect the effectiveness of orthodontic therapy and prevent complications, such as tooth decay or gingivitis. Additionally, parental involvement can significantly impact the oral hygiene routine of children in this age group. Aim: The objective of this study was to assess the oral hygiene status in 9–13-year-olds using removable orthodontic appliances under care covered by the National Health Fund. Additionally, the study aimed to investigate the influence of parental involvement on the oral hygiene of these patients. Methods: Patients aged 9–13 years undergoing treatment with removable orthodontic appliances under the National Health Fund were included in the study. The oral hygiene status of patients was assessed using standard tools, such as the Oral Hygiene Index (OHI-S) and decay indices. Parents or guardians of patients were asked to complete a survey on the oral hygiene routine of their children and their involvement in maintaining their children’s oral hygiene during orthodontic treatment. Data were subjected to statistical analysis to assess the relationship between oral hygiene status and parental/guardian influence. Conclusions: The anticipated conclusions from the study may help identify factors influencing effective oral hygiene in children using removable orthodontic appliances. Knowledge about the role of parents or guardians in oral hygiene care could lead to the development of educational strategies aimed at improving oral hygiene status in this patient group.