We thank Drs Katti and Talapaneni for the comments and observations on our article (Lee H, Nguyen A, Hong C, Hoang P, Pham J, Ting K, Biomechanical effects of maxillary expansion on a patient with cleft palate: a finite element analysis. Am J Orthod Dentofacial Orthop 2016;150:313-23). We have considered each comment and prepared a point-by-point reply below. We believe that in addition to a small confusion in suggestion 2, the overall quality of the article has not been changed.
Thank you for your first suggestion regarding a possible contradiction. However, we stand by the finding that equal expansion was observed for URE-ULD, between the cleft and normal sides. URC (cleft-side deciduous canine) was used as a reference landmark for which expansion can be tracked. Here, the authors stated that, “Maximum displacement occurred on the cleft side at the incisal edge of the URC when transverse forces were applied anteriorly on the cleft side and posteriorly on the normal side, and there was a gradual decrease from the anterior to the posterior teeth, with minimum expansion at the UR6,” when forces were applied between URE-ULD. For URE-ULD expansion, equal expansion between the cleft and normal sides was still possible without this combination eliciting the “maximum displacement on the cleft side.” The observation that a gradual decrease from anterior to posterior teeth with minimal expansion at the UR6 when forces were applied between URE-ULD holds true and does not contradict the aforementioned observation in which the cleft side and noncleft side expand equally, despite being minimal.
We agree with the suggestions that a statement in the summary could be improved. The following sentence more clearly explains our intent: Expansion on the normal side was greater than on the cleft side when forces were applied to cleft-side molars and noncleft-side deciduous molars, UR6-ULD and UR6-ULE.
Regarding the statement in the methodology section, we cannot locate the exact wording of the quotation: “trying to simulate transverse forces from various expansion devices to achieve an optimal desired expansion in UCLP patients….” We believe Drs Katti and Talapaneni were referring to this statement in the Material and methods section: “The transverse forces attempted to stimulate the resultant forces from either a jack-screw type of RPE expansion device placed directly between the teeth across the palate or a 4-banded quad-helix….” We understood this study as trying to use our limited available knowledge to explore the complicated UCLP orthodontic biomechanics. This study is just the beginning of our series projects; therefore, it is appropriate to use the statement in the methodology section.