Effect of orthodontic treatment with fixed appliances on the development of gingival recession. A prospective controlled study.

Objective To assess in a prospective controlled study whether orthodontic treatment with fixed appliances results in development of gingival recession (GR), compared with an untreated group of participants. Materials & Methods The sample consisted of 40 consecutive adult orthodontic patients (Intervention group) and 40 untreated adult volunteers, that satisfied the inclusion and exclusion criteria and were selected from the same background population, as the control group. GR was measured as part of a full periodontal assessment: before treatment (T0) and 12 months after removal of the fixed appliances (T1) in the intervention group, i.e. at about 30 months from T0, and at baseline (T0) and 30 months after (T1) in the control group. A count data model was fit using the sum of recessions at T1 and as predictors: treatment, periodontal phenotype (thin/thick), side (buccal/lingual), sex, age, and number of recessions at baseline, with robust standard errors to account for the multiple within patient observations. Results Nineteen females and 21 males in each group [mean age in years (range): intervention group 23.1 (16.8 - 43.3); control: 21.85 (18.2 - 43.9)] were analyzed. During the whole study period, the control group exhibited a modest increase in the number of recessions over time. Several patients in the intervention group exhibited a larger increase in the number of recessions than the controls. However, this was partly counteracted by a considerable amount of reduction in the number of recessions in several patients receiving treatment. The adjusted incidence for recession was 67% higher for the intervention group versus the control group (IRR = 1.67, 95% CIs: 1.05, 2.67, P = 0.03). Most recessions, though, were up to 1mm. The most affected teeth were the canines and the first premolars. Conclusions Compared to untreated individuals, patients undergoing orthodontic treatment with fixed appliances showed a higher incidence rate of gingival recession at 1-year posttreatment, adjusted for age, periodontal phenotype, side, gender and number of recessions at baseline. However, the severity of gingival recessions was of limited extent.