Letters From Our Readers

To: Editor, The Angle Orthodontist

Re: Response to: Evaluation of root resorption in the lower incisors after orthodontic treatment of skeletal Class III malocclusion by three-dimensional volumetric measurement with cone-beam computed tomography. Junjie Chen, Ruoyu Ning. The Angle Orthodontist. 2023; 93: 320–327.

Thank you for giving us the opportunity to respond to the letter. The reader raised three interesting questions.

1. Since previous studies showed that patient- and treatment-related root resorption risk factors included blunt and short roots, Class III patients who had preexisting short root anomaly were excluded when collecting samples for the study. We just used T-loop for extraction space closing as a rigid requirement, but not every patient used Class III intermaxillary elastics. The anchorage need determined whether or not to use Class III intermaxillary elastics.

2. All patients were able to retrude their mandibles but some could reach to an incisior-to-incisior (edge-to-edge), and others could not. However, this information was not documented in detail in each case.

3. Table 1 did not show the pretreatment mandibular plane angle (MMPA), as there were patients with high, average, and low angle skeletal pattern. However, a mean value of MMPA cannot reflect whether the bone was thick or thin. We can group the samples into high-, average-, and low-angle skeletal patterns in a future study to investigate the association between MMPA and incisor resorption.

Thank you very much for the opportunity to respond and clarify.