Changes in the arch width and buccal corridor after fixed orthodontic treatment with Damon self-ligating system: premolar extraction vs. non-extraction.

Introduction: Extraction vs. non-extraction is a crucial decision in orthodontic therapy.

Objective: The aim of the present study was to investigate the changes in the dental arch width and buccal corridor after orthodontic treatment using extraction and non-extraction therapy with Damon self-ligating system.

Material and methods: This retrospective study consisted of 35 patients (20 female and 15 male patients with median age of 12.5 years), treated by extracting 4 or 2 premolars, and 37 patients (16 female and 21 male patients with the median age of 12.8 years), treated without premolar extraction. Both groups were treated with Damon self-ligating system. Plaster models before (T0) and after (T1) treatment were measured, and the arch width values were determined at the level of the first molars, second premolars, canines and palatal rugae. Buccal corridor width was measured using the extraoral images at T0 and T1. Paired t-test was used for the analysis of the normally distributed data, and Wilcoxon Mann-Whitney U test was used for the data with non-normal distribution. Values of p<0.05 were set as statistically significant.

Results: The upper intercanine width increased significantly in both groups (p<0.01). In the non-extraction group, the arch width increased significantly in the maxillary second premolar and first molar region (p<0.01) as well as in the region of the canines (p=0.04), second premolars (p=0.01) and first molars (p<0.01) of the mandible. The buccal corridor decreased significantly in the non-extraction group (p<0.01).

Conclusion: Premolar extraction in combination with Damon self-ligating system did not lead to reduction of the dental arch width in the maxilla, nor did it increase the size of the buccal corridors.