Evaluation of three-dimensional root surface changes and resorption following rapid maxillary expansion: A cone beam computed tomography investigation

Abstract

Objectives: To evaluate root surface changes and resorption following toothborne rapid maxillary expansion (RME) using cone beam computed tomography (CBCT). Setting and Sample Population: 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. Material and Methods: 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. Results: 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. Conclusion: 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.