# Analysis of changes in ABT, ABH and ABA after orthodontic treatment of adult bimaxillary protrusion

## TL;DR

This study examines how orthodontic treatment affects alveolar bone thickness and area in adults with bimaxillary protrusion.

## Contribution

The study provides new insights into alveolar bone changes on labial and palatal sides after orthodontic treatment in adults.

## Key findings

- Labial alveolar bone thickness increased significantly after treatment.
- Palatal alveolar bone thickness and area decreased significantly after treatment.
- Orthodontic treatment caused significant resorption on the palatal side of incisors.

## Abstract

To investigate the changes in alveolar bone thickness (ABT), the height of the enamel bone border-alveolar ridge apex (ABH), and alveolar bone area (ABA) of the labial and palatal sides of the maxillary incisor region after orthodontic treatment of adult bimaxillary protrusion.

Ninety-eight adult patients with bimaxillary protrusion who underwent orthodontic treatment in our hospital between November 2023 and November 2024 were clinically selected for retrospective study, and patient data were obtained from the medical record system, comparing the widths of the intercuspal space between the cuspids, the width of the space between the first premolar teeth, the width of the space between the second premolar teeth, the convexity of the anterior teeth (UI-SN, UI-NA), and the lip and palate of maxillary incisor region before and after treatment. ABT, ABH, and ABA changes.

Comparison of intercuspal width and MP-SN levels before and after treatment in all patients showed no statistically significant differences (P > 0.05). The intercuspal width of the first premolar, intercuspal width of the second premolar, UI-SN and MP-SN were higher than those before treatment, and the difference was statistically significant (P < 0.05). The labial cervical, labial mid-root, and labial apical ABT levels of maxillary mesial incisors and lateral incisors were higher than those before treatment, and the palatal cervical, palatal mid-root, and palatal apical ABT levels were lower than those before treatment, and the difference was statistically significant (P < 0.05). There was no statistically significant difference in the comparison of labial ABH levels of mesial incisors and lateral incisors before and after treatment (P > 0.05); the levels of palatal ABH of mesial incisors and palatal ABH of lateral incisors were higher than those before treatment, and the levels of palatal ABA of mesial incisors and palatal ABH of lateral incisors were lower than those before treatment, and the difference was statistically significant (P < 0.05).

Orthodontic treatment is effective in adult patients with bimaxillary protrusion, but significant resorption of the alveolar bone on the palatal side of the incisal region occurs after treatment, reducing the amount of alveolar bone in the entire incisal region. Therefore, the long-term effects on periodontal tissues need to be paid attention to.