Postorthodontic Lower Incisor and Canine Inclination and Labial Gingival Recession in Adult Patients : A prospective Study

Purpose: The goal was to determine whether changes in the inclination of lower incisors and canines upon orthodontic treatment with fixed appliances poses a threat for labial gingival recession in adult patients.

Methods: The sample of this prospective clinical trial consisted of 32 adult patients (mean age 25.08 ±6.50 years) treated with fixed appliances. Plaque and bleeding indices, probing pocket depth, clinical attachment level, gingival recession height (GR) and width (GRW), gingival thickness (GT), and keratinized tissue width were clinically recorded, while cone beam computed tomography (CBCT) was used to evaluate teeth inclination before (T1) and after treatment (T2). Oral hygiene, brushing habits, and smoking were controlled.

Results: During orthodontic treatment on 15 (8.33%) teeth (10 incisors and 5 canines), spontaneous complete improvement of pre-existing GR was observed. On 2 incisors, GR decreased and on 3 teeth GR did not change. Moreover, 1 incisor presented an increased GR, while 2 teeth developed new defects. Mean GR, GRW, and GT decreased significantly only on the incisors. Proclination of incisors and canines during treatment (compared with retroclination of the teeth) implicated a lower reduction in GR at T2: 0.19 mm (p = 0.034) and 0.18 mm (p = 0.037), respectively. Multiple regression analysis confirmed that more tooth proclination was associated with a higher risk for an increase in GR (p < 0.00).

Conclusion: Properly planned changes in lower incisor and canine inclination can be carried out in adult patients without posing a high risk to labial gingival recessions if the individual periodontal biotype is respected. The reported outcomes underscore the orthodontic principle to keep tooth roots inside the alveolar bone.