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CBCT Assessment of Dental and Skeletal Changes Using the Damon versus Conventional (MBT) System

Marjan Askari,Robert Williams,Elaine Romberg,Maureen Stone,Stanley A Alexander*

Introduction: The primary aim of this pilot study was to compare cases treated with the Damon System and a Conventional Mechanics system utilizing Cone Beam Computed Tomography (CBCT) in the evaluation of changes in dental and skeletal arch width and length. The secondary purpose was to evaluate differences between the three CBCT views (3-D coordinate, sectional, and volume views).

Methods: Eleven patients (≥ 18 years of age; measured total of 40 maxillary antimeres and 44 mandibular antimeres) with moderate to severe crowding who had both pre and post-treatment CBCTs and were treated nonextraction, either with conventional edgewise or self-ligating Damon appliances were retrospectively selected from two orthodontic practices. The arch length, inter-occlusal, inter-apical, inter-buccal and inter-lingual alveolar crest arch widths and the bucco-lingual angulation for canine, premolars and first molars were measured. Different CBCT views were evaluated by first measuring the inter-occlusal distances of the respective teeth in the coronal section and the volume views. These measurements were compared with those gathered previously using the 3-D coordinate system. A paired t-test, an independent t-test, and an ANOVA were used for statistical analysis.

Results: Both non-extraction treatment modalities resulted in inter-occlusal arch width expansion in both the maxilla and mandible. The overall expansion of arches in the Damon treated cases was statistically greater than in the Conventional cases. Maxillary and mandibular arch lengths were increased, but not significantly in both groups. There were no statistically significant differences between the three CBCT views.

Conclusions: Both the Damon and the Conventional systems resulted in increased arch width and length, but the Damon system caused significantly more overall arch expansion. There was less tipping of the teeth during arch expansion in the Conventional system. The ratio of crown to root movement in the Conventional system versus the Damon system in the maxilla was approximately 1:1 versus 3:1, and in the mandible 3.6:1 versus 6:1, respectively.