I appreciate these valuable remarks.

In paragraph 6 in the Discussion, we stated that the distance between root apices and the sinus floor in the hyperdivergent skeletal group was shorter compared with that in the normodivergent group (page 817). I think this agrees with the opinion or results, which say that hyperdivergent skeletal patients have an up-canted palatal plane (PP) and an open mandibular plane angle. The results of this study showed that the distance between root apices and the sinus floor is the shortest in hyperdivergent and next is hypodovergent and normodivergent subjects. This means that hypodivergent skeletal patients also have root apices close to the sinus floor.

Regarding the proximity of root apices to the sinus floor according to the cant of the PP, the results were different from our expectation. The distance in an up-canted PP was shorter than that in a normal PP and a down-canted PP. I have checked raw data again and confirmed it. Also, there was no positive relationship between the FMA and the PP cant. One possible explanation is that the sample consisted of Class I, Class II, and Class III subjects, and this may have affected the cant of the PP angle. For instance, hyperdivergent Class III patients may not have an up-canted PP in most instances.

If patients have an up-canted PP, it may have more open-bite tendency. Kim emphasized the importance of the palatal cant on the development of anterior open bite. He showed that if the PP is canted down or normal, there is no open bite, even though the patient has a hyperdivergent skeletal pattern. As I have discussed already, there was no positive relationship between skeletal hyperdivergency and PP cant in this sample.

With this limited sample, root apices in the up-canted PP had longer distances to the sinus floor than other cants. I think the relationships of root apices to the sinus floor with the cant of the PP need to be evaluated with a larger sample and a more uniform skeletal pattern.