First, we want to thank Dr Daniel A. Kuncio for his interest in our article.
Regarding all the other forces and moments, Dr Kuncio wondered where they did come from. We have to state that it is a really interesting question, dealing with 1 key characteristic of an aligner. An aligner has a complex 3-dimensional geometry that is loaded by placing the aligner onto the dental arch. We planned the aligner therapy so that isolated tooth movements should have been accomplished: ie, only the tooth in question should have deformed the aligner material around itself, delivering exactly the force system necessary for the desired tooth movement. Due to the complex aligner geometry, it is of course impossible to predict the exact aligner deformation for such an isolated tooth movement. Thus, the aligner steps usually are designed so that the tooth’s crown shall be moved in small, incremental steps, ignoring biomechanically exact force systems. The complex deformation of the aligner will always generate additional force and moment components. Moreover, displacement of the tooth with respect to its center of resistance must be taken into account.
Considering the molar distalization, Table II only lists the forces; however, moments are displayed in Figure 7 as well. We hope this will help to understand our findings, especially as the clinical results showed bodily molar movements with our aligners.
About the accusation of “cherry-picked” data to make certain statements: even if you do not agree with all the conclusions we have drawn from our findings, we would like to state that neither the data nor the patient population was “cherry-picked,” and that we presented all available data that touched the topic of our article. The results of the studies presented here and in reference 1 are based on some kind of a prospective study. Patients were selected according to certain criteria, including the necessity to perform these 3 tooth movements: incisor torque, premolar derotation, and molar distalization. Aligner series were produced to perform these isolated movements, and the force systems of the aligners were measured. Consequently, we do not see any “cherry-picking” to generate certain results. This procedure can be performed for any tooth movement. All patient data available from the study presented in reference 1 were used; no data were excluded for whatever reason.