Weight changes during the initial phase of orthodontic treatment with clear aligners versus fixed appliances: a pilot prospective cohort study

The aim was to assess adult patients’ weight changes during the initial phase of orthodontic treatment (OT) with clear aligner therapy (CAT) versus fixed bracket systems (FBS).

This pilot prospective cohort study included systemically-healthy adults who were treated with CAT or FBS. Participants with eating disorders and/or undergoing dietary programs were excluded. Weight was assessed using a calibrated digital scale at the start of OT (T1), 6–8 weeks (T2), and 12–16 weeks (T3) after starting OT. A questionnaire was used to record demographic variables, diet and exercise habits, self-reported compliance and discomfort during OT, and use of analgesics. Repeated measures analysis of variance was used to assess the association between treatment type (FBS versus CT) and time-period (T1, T2, T3) on participants’ weight while adjusting for baseline covariates such as age, gender, height, and weight.

Forty-two participants (CAT group: 22 and FBS group: 20) were analysed. In the CAT group, there was a slight initial mean weight gain of 0.2 Kg (~ 0.4 pounds) (T2-T1), and 0.8 Kg (~ 1.7 pounds) overall mean weight loss between T1 and T3. For the FBS group, there was a slight initial weight loss of 0.3 Kg (~ 0.7 pounds) (T2-T1) and no overall change between T1 and T3. Treatment type (CAT versus FBS) was not significantly associated with weight changes during the initial phase of OT.

There were no significant differences in the weight changes during the initial phase of OT with CAT compared with FBS.

Clear aligner therapy should not be advertised as a weight loss strategy.