SUMMARY A recent systematic review demonstrated that, overall, orthodontic treatment might result in a small worsening of periodontal status. The aim of this retrospective study was to test the hypothesis that a change of mandibular incisor inclination promotes development of labial gingival recessions.
One hundred and seventy-nine subjects who met the following inclusion criteria were selected: age 11–14 years at start of orthodontic treatment (TS), bonded retainer placed immediately after treatment (T0), dental casts and lateral cephalograms available pre-treatment (TS), post-treatment (T0), 2 years post-treatment (T2), and 5 years post-treatment (T5). Depending on the change of lower incisor inclination during treatment (ΔInc_Incl), the sample was divided into three groups: Retro (N = 34; ΔInc_Incl ≤ –1 degree), Stable (N = 22; ΔInc_Incl > –1 degree and ≤1 degree), and Pro (N = 123; ΔInc_Incl > 1 degree). Clinical crown heights of mandibular incisors and the presence of gingival recessions in this region were assessed on plaster models. Fisher’s exact tests, one-way analysis of variance, and regression models were used for analysis of inter-group differences.
The mean increase of clinical crown heights (T0 to T5) of mandibular incisors ranged from 0.6 to 0.91 mm in the Retro, Stable, and Pro groups, respectively; the difference was not significant (P = 0.534). At T5, gingival recessions were present in 8.8, 4.5, and 16.3 per cent patients from the Retro, Stable, and Pro groups, respectively. The difference was not significant (P = 0.265).
The change of lower incisors inclination during treatment did not affect development of labial gingival recessions in this patient group.