To: Editor, The Angle Orthodontist

Re: Response to: Comparison of orthodontic root resorption of root-filled and vital teeth using micro-computed tomography. Kadir Kolcuoğlu and Aslihan Zeynep Oz. Angle Orthod. 2020; 90: 56-62.

Thank you for your great interest and for the valuable contribution that you made about our study. The reader asks if we think having baseline data would improve the impact of the study. We used a split-mouth design to rule out the etiologic factors related to patient variables. The only way to evaluate the root resorption before treatment is to get two-dimensional (2D) radiographs or computed tomography (CT) images. However, 2D radiographs, such as panoramic and periapical radiographs, can only detect shortening of the root length. On the other hand, because of the extra radiation dose, CT images are not preferred for evaluating root resorption before treatment. We took routine radiographs, such as panoramic and periapical radiographs, before treatment and did not see any shortening of the root length for the premolar teeth that were extracted. Maybe it would have been better if we had stated this information in the study.

It is correct that the original contour and outline of the root before treatment was unknown. The program estimated a new line that connected the two points at the edge of the resorption crater, thus reconstructing the convexity of the root surface. Many studies have used this method to calculate the amount of the root resorption.13 

We are aware that the results reported did not reflect the comprehensive orthodontic treatment period. But the aim of the study was to compare the root resorption status of the root-filled teeth with vital teeth after the same orthodontic force and movement. Future studies are required to evaluate root resorption under different movement conditions and force magnitudes.

Thank you.

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