Root Surface Changes in Endodontically Treated Teeth following Orthodontic Movement

Orthodontically induced external root resorption has been labeled an unavoidable consequence of orthodontic tooth movement (OTM). The objective of this study was to investigate the change in surface area (mm2) and volume (mm3) of endodontically treated teeth (ETT) compared with contralateral teeth with a vital pulp (VPT) after OTM.Seventy-six teeth were included in this retrospective analysis: ETT (n = 38) and VPT (n = 38). All teeth were evaluated using cone-beam computed tomographic imaging at 2 time periods: before OTM (T1) and after OTM (T2). Study teeth were segmented to include all areas contained within the lamina dura and then were converted into a mesh model for data calculation. The surface area (mm2) and volume (mm3) of each tooth were calculated at T1 and T2 based on the number of cubic voxels present within the mesh model. Statistical analysis was performed using a linear mixed-effects model.The average change in surface area after OTM in ETT was 13.01 mm2 and 19.95 mm2 in VPT (P < .05). The average percent change in surface area after OTM in ETT was 2.09% and 3.38% in VPT (P < .05). The average change in volume after OTM in ETT was 22.48 mm3 and 32.44 mm3 in VPT (P < .05). The average percent change in volume after OTM in ETT was 2.62% and 4.10% in VPT (P < .05).The results from this study suggest that ETT are less susceptible to root resorption after OTM than their vital counterparts.