Mandibular Incisor Position Changes do not Explain Increase in Keratinized Gingiva Height after Periodontally Accelerated Osteogenic Orthodontics

Abstract

Purpose This study aimed to reexamine the relationship between mandibular incisor inclination, prominence and vertical changes in position, and keratinized gingival tissue (KT) height changes labial to the mandibular incisors after orthodontic treatment with and without augmented corticotomy (Cort). Materials and Methods Two orthodontically treated groups of 35 individuals each, with (Cort) and without (conventional [Conv]) alveolar decortication and augmentation bone grafting (periodontally accelerated osteogenic orthodontics [PAOO]), were matched for sample size, gender, mandibular premolar extractions, pretreatment age, posttreatment observation period, and pretreatment KT height in this case–controlled retrospective study. Pre- and post-treatment lateral cephalometric radiographs were evaluated for mandibular incisor vertical, inclination, and prominence changes. Results As reported previously (Wilcko 2015), KT height had significantly increased by 0.78 mm (P = 0.001) in the Cort group and decreased by 0.38 mm (P = 0.002) in Conv on an average of 1.5 years after completion of active orthodontic therapy. In this study, Cort mandibular incisors proclined and protruded significantly during therapy while Conv incisors did not. Changes in mandibular incisor inclination and prominence explained neither the decrease in keratinized gingiva height in Conv nor the KT height gain in Cort. Conclusions In spite of mandibular incisor proclination and protrusion, orthodontic therapy combined with alveolar decortication and augmentation bone grafting resulted in a clinically significant increase in keratinized gingiva height 1.5 years’ posttreatment.