# Dimensional changes of alveolar bone after orthodontic expansion with Invisalign® aligners: study by Cone Beam Computed Tomography

## TL;DR

This study used 3D imaging to assess how Invisalign aligners affect alveolar bone in different facial types during orthodontic treatment.

## Contribution

The study provides new insights into alveolar bone changes during orthodontic expansion using clear aligners across different facial types.

## Key findings

- Minor alveolar bone changes in height and thickness were observed in maxillary premolars after orthodontic expansion.
- Significant differences in bone thickness were found in specific teeth across different facial types.
- No significant differences in bone changes were found among facial types overall.

## Abstract

This study aimed to evaluate changes, using Cone-Beam Computed Tomography (CBCT), in the buccal and palatal alveolar bone of maxillary premolars in young adult individuals who underwent dentoalveolar expansion with Invisalign® aligners, and to compare these changes across different facial types.

Forty-five patients (32 women and 13 men; mean age: 34.2 years) underwent orthodontic expansion with clear aligners. CBCT scans were obtained before (T0) and after expansion of the maxillary arch (T1), with a mean treatment period of 21.4 months. Changes in alveolar bone height and thickness were assessed at the cervical, middle, and apical regions of the maxillary premolars across different facial types (mesofacial, brachyfacial, and dolichofacial). The level of significance was set at 5%.

Regarding bone thickness, significant differences between T0 and T1 were observed for tooth 15 and 24 in the mesofacial group; tooth 25 in the dolichofacial group; and teeth 14, 15, 24, and 25 in the brachyfacial group. Regarding bone height, a significant difference was found for tooth 15 in the brachyfacial group. No differences were observed in bone height or thickness when comparing the different facial types.

Minor alveolar bone changes in height and/or thickness of maxillary premolars were observed across all facial types between the evaluated time points. No significant differences in alveolar bone alterations were found among the facial types; however, when analyzed separately, greater changes in alveolar thickness and height were observed in the horizontal growth group.