To: Editor, The Angle Orthodontist Response to: Effects of skeletally anchored Class II elastics: A pilot study and new approach for treating Class II malocclusion. Selin Ozbilek, Ahmet Yalcin Gungor and Salih Celik. Angle Orthod 2017;87:505-512.

We would like to congratulate the authors for their work. We have some questions regarding the study and would appreciate it if the authors could clarify some points raised in the paper:

1. How did you ensure symmetrical placement of the mini-plates bilaterally so that force vectors would be directed similarly? At which part of the ramus were the mini-plates placed?

2. Was the maxillary dental arch already wide enough to accommodate advancement of the mandible or were some modifications (such as expansion) required? As shown in Figure 2 of the article, the maxillary arch is often too narrow to accommodate the anterior movement of the lower teeth.

3. Why did you decide to apply 500g force for each elastic when previous studies gradually increased forces from 75g to a maximum of 250g?

4. Can you please explain how the measurements reported (for example, in Table 3) mathematically explain the decrease in overjet observed? In the elastic group, the overjet decreased by 4.80 ± 1.18mm, but the L1-VRL change was -0.71 ± 0.47 and the U1-VRL increased by 2.05 ± 1.68. By these numbers relative to VRL, the overjet would have increased.

5. What do you think would be an appropriate retention protocol after the corrections achieved in the two groups of patients that were treated?

Thank you very much for publishing this very interesting study.