Evaluation of three-dimensional root surface changes and resorption following rapid maxillary expansion: a cone beam...

To evaluate root surface changes and resorption following toothborne rapid maxillary expansion (RME) using cone beam computed tomography (CBCT).

The Department of Orthodontics at The University of Texas Health Science Center. Twenty-four consecutively treated patients (mean age: 12.8 years) requiring maxillary expansion.

An observational cohort included 48 CBCT images collected prior to (T1) and 4.8 months after (T2) RME from the study sample. Maxillary (study group) and mandibular (control group) first molars (n=48) and first premolars (n=48) were segmented and digitally registered using a 'best-fit' algorithm. Linear surface and volumetric changes between the study and control groups were compared using independent sample t-tests. Additionally, individual root length measurements were compared between the T1 and T2 images in each group using paired t-tests.

All study teeth had significant changes for the evaluation of maximum linear surface area and volumetric changes as compared to control teeth (p<0.05). On average, premolars and molars in the study group experienced a root shortening of 0.36-0.52 mm (p<0.05). Color-coded diagrams demonstrated thinning and resorption occurring primarily at the apex and buccal aspects of the roots. Severity of these changes was individual-specific, as root resorption patterns were non-uniform.

Significant volume loss, linear surface area changes, and thinning/shortening of maxillary first molar and premolar roots were common findings with the use of toothborne RME therapy.