Alveolar bone height changes in the anterior tooth region before and after orthodontic treatment for Angle's Class II division 1 malocclusion and related factors

BACKGROUND: The aim of this study was to observe the alveolar bone height changes in the anterior tooth region after orthodontic treatment for Angle’s Class II division 1 malocclusion.METHODS: Ninety-three patients treated from January 2015 to December 2019 were retrospectively analyzed, of whom 48 received tooth extraction and 45 did not.RESULTS: After orthodontic treatment, the alveolar bone heights in the anterior tooth regions of tooth extraction and non-extraction groups decreased by 67.31% and 66.94%, respectively. Except for the maxillary and mandibular canines in the tooth extraction group as well as the labial side of maxillary anterior teeth and the palatal side of maxillary central incisors of the non-extraction group, the alveolar bone heights of other sites significantly reduced (P<0.05). The reduction in the alveolar bone height of the tooth extraction group significantly exceeded that of the non-extraction group on the palatal side of maxillary incisors and the lingual side of mandibular anterior teeth (P<0.05).CONCLUSIONS: Alveolar bone height in the anterior tooth region decreases after orthodontic treatment for Angle’s Class II division 1 malocclusion, being closely related to tooth position together with movement direction and amplitude.