Gingival labial recessions and the post-treatment proclination of mandibular incisors

Introduction: A prerequisite for development of gingival recession is the presence of alveolar bone dehiscence. Proclination of mandibular incisors can result in thinning of the alveolus and dehiscence formation. Objective: To assess an association between proclination of mandibular incisor and development of gingival recession. Methods: One hundred and seventeen subjects who met the following inclusion criteria were selected: 1. age 11-14 years at start of orthodontic treatment (T-5), 2. bonded retainer placed immediately after treatment (T-0), 3. dental casts and lateral cephalograms available pre-treatment (T S), post-treatment (T-0), and 5 years post-treatment (T-5), and 4. post-treatment (T-0) lower incisor inclination (Inc_ Incl) < 95 degrees or > 100.5 degrees. Two groups were formed: non-proclined (N = 57; mean Inc_Incl = 90.8 degrees) and proclined (N = 60; mean Inc_ Incl = 105.2 degrees). Clinical crown heights of mandibular incisors and the presence of gingival recession sites in this region were assessed on plaster models. Fisher's exact tests, t-tests, and regression models were computed for analysis of inter-group differences. Results: The mean increase of clinical crown heights (from T-0 to T-5) of mandibular incisors ranged from 0.75 to 0.83 mm in the non-proclined and proclined groups, respectively (P = 0.273). At T-5, gingival recession sites were present in 12.3% and 11.7% patients from the non-proclined and proclined groups, respectively. The difference was also not significant (P = 0.851). Conclusions: The proclination of mandibular incisors did not increase a risk of development of gingival recession during five-year observation in comparison non-proclined teeth.