Increased BMI in children-an indicator for less compliance during orthodontic treatment with removable appliances

To assess whether or not childhood overweight is associated with lower levels of compliance during orthodontic therapy with removable appliances.

Starting in 2011, all upper expansion plates and Sander II appliances were equipped with a Theramon® microsensor chip to assess appliance wear time objectively. According to their pre-treatment, BMI normal weight patients were matched to consecutively treated overweight or obese patients by gender, age, and appliance type. Cooperation was assessed with microelectronic wear time documentation over a period of at least 6 months.

A total of 50 patients (25 overweight, 25 normal weight) with upper expansion plates and 64 patients (32 overweight, 32 normal weight) with Sander II appliances were analysed. Spearman Rho coefficients showed an indirect association between BMI and appliance wear time, indicating that the higher the BMI, the less the patients wore their appliances (P < 0.05). Furthermore, both normal- and overweight children wore upper expansion plates significantly more than Sander II appliances (P < 0.05). Although no gender-specific difference was found (P = 0.723), an age-related correlation could be verified, indicating a decrease in wear time with increasing age (P < 0.05).

An increased BMI appears to be a risk factor for less appliance wear during orthodontic treatment with removable appliances. Additional factors which influenced cooperation during treatment with removable appliances were patient age and appliance type.