Multislice computed tomography evaluation of the expansion achieved by the nonextraction treatment of orthodontic cases using Damon system

Abstract

Objectives The purpose of this study is to evaluate the dental, alveolar changes and behavior of teeth movement during expansion achieved by the nonextraction treatment approach of crowding cases using the Damon system. Materials and methods High-resolution multislice computed tomography (MSCT) imaging was performed pretreatment (T1) and posttreatment (T2) on a sample composed of twenty patients aged 17.8 ± 3.7 years in average selected based on a pretreatment class I skeletal and molar relationships, and moderate crowding range between 4.0 and 9.0 mm for the maxilla and 2.0 and 6.0 mm for the mandible. On the Digital Imaging and Communications (files obtained from MSCT scans, dental and alveolar measurements were recorded including interocclusal, interapical widths, angulations of the maxillary and mandibular teeth and four bilateral bone thickness distances at the furcation level. Results The evaluation of the study was performed by detecting the dental and alveolar changes between pretreatment and posttreatment MSCT scans. Paired t test was used for statistical analysis. The interocclusal to interapical ratio indicated that, the roots moved by the same distance as the crowns except the canines roots moved 15 times as the crowns. While in the mandible, the roots of the premolars and molars moved less than the crowns but in the canines the opposite was happened. There was a significant increase of the axis angles of the maxillary canines and a significant decrease of the axis angles of the mandibular second premolars and first molars. This expansion resulted in a significant decrease of the buccal bone thickness and alveolar width and a significant increase of the palatal and lingual bone thickness. Conclusion The results of this study revealed that the expansion produced a small amount of uprighting in the maxillary teeth and a more significant degree in the mandibular teeth except the mandibular first premolars, were tipped buccally.