Reply: Presurgical Nasoalveolar Molding for Cleft Lip and Palate: The Application of Digitally Designed Molds.

Reply: Presurgical nasoalveolar Molding for Cleft Lip and Palate: The Application of Digitally Designed Molds Sir: Loeffelbein et al. present excellent points that warrant discussion regarding our article presenting three-dimensional technology–assisted nasoalveolar molding: finding the proper trajectory for maxillary growth in cleft patients and achieving optimal results in greater segment molding.1 They bring up the importance of implementing a three-dimensional factor for growth when simulating alveolar segment movement in nasoalveolar molding. In our model, we compensated for transverse maxillary growth using a growth factor based on a small amount of historical data from our cleft patients. However, as the distance between T and T′ did not change significantly before and after nasoalveolar molding, it is possible that we did not compensate enough for transverse maxillary growth, maxillary casts were designed virtually. Based on these printed casts, the molding devices were manufactured in the conventional method. The software-based design attempted to imitate maxillary segment alignment by a guided reorientation.1 The molding treatment was performed following the principles of Grayson et al.2 and was described as having been performed with the intention of achieving alveolar symmetry.3 Not only was this attempted by elongating the smaller alveolar segment, but also the greater segment was extended and the anterior part was also rotated. The illustrated computer-aided design casts, however, predominantly seem to bend the segment from a 50-degree angle to one of approximately 70 degrees, thereby resulting in a nonharmonic arch with a kink. Therefore, we would like to question this approach, because the intended symmetry may not be achieved. Moreover, the lack of the implementation of a threedimensional factor for growth might result in an undesired restriction of growth. Without considering transversal maxillary growth, posterior expansion might be blocked; this could be the answer to the static and decreasing dimensions of points T and T′, when the anteroposterior (sagittal) direction slightly increases (T to C2 and T′ to C2′), although without statistical significance. In our own studies, we have empirically implemented a factor for growth, which is currently being refined and is about to be determined automatically by analyzing three-dimensional patient models of the maxilla. This so-called RapidNAM Project will allow us to detect the divided alveolar segments of cleft lip and palate patients to determine an anatomically appropriately shaped alveolar ridge. The ridge is described by curves that are fitted to the alveolar segments and that will provide three-dimensional information over time from a control group without cleft lip and palate.4 Because the molding devices have been customized in the conventional way, the superiority of this new approach with regard to the expenditure of time is not conclusive. Based on our own research, we should mention that this can also be achieved by preconstructing the nasoalveolar molding plates by means of computeraided design/computer-aided manufacturing.5 DOI: 10.1097/PRS.0000000000002057