# Easy, Fast, and Accurate Method of 3-Dimensional Mirror Plane Creation for Actual Clinical Users
## 4 Discussion  
Unilateral defects or asymmetrical figures on facial area may result from congenital abnormality, trauma, or neoplastic lesions. It is essential to set a proper mid-plane to begin evaluation and analysis for the patients with such facial conditions. Three reference points are usually used to establish the facial mid-plane; however, the plotting error of the points cannot be neglected in order to carry out precise evaluation and accurate analysis. There has been an enormous advance in technology  
Figure 3: Final mirror plane (in red) was created by bisecting the two planes; initial and moved mirror planes. Complete reconstruction of the defected areas of each model was achieved after the registration.  
in the medical field from data collection using computer assisted devices to software enabling 3D image processes [10; 11; 12]. Engineering algorithms, such as ICP could also enhance the application of currently progressing medical resources by improving precision and rate of overlap. Although the algorithms are very effective, it could be very challenging to apply them in actual clinical use. Accordingly, this study attempted to combine the commercially available medical software and concept of ICP to bring them into practical use at the genuine clinical settings. Taking advantage of these highly developed current technologies, the mid-plane generated by using mirror images can be a beneficial solution for the interest in decreasing errors of primary setup. This mirroring technique not only helps decrease such errors during the initial steps of evaluation and analysis, but also provides an ideal image of the structure to be reconstructed or reshaped. As a consequence, surgeons can come up with meticulous treatment plans which are more patient specific and suitable. Traditional free flap techniques may exhibit limitations of positioning the flaps and bones properly because large defects and congenital asymmetry can cause dramatic deviations on the normal structures [13]. On the other hand, reconstruction or asymmetry correction by using computer aided mirror images can allow the surgeons to overcome such problems and achieve better outcomes. The benefits of using mirror images are expected to be exceedingly productive when they are combined with bio-printing and even tissue engineering. In addition, this kind of application of current technologies would lead surgeons to the next level of oral and maxillofacial surgery, such as the fabrication of bio-reactive scaffolds that can be an alternative for the traditional free flap surgeries [6; 14]. Donor site morbidity would thereby no longer be an issue, eventually pursuing a decreased duration of surgery and recovery time. Therefore, this method could help actual users as an appropriate start point to plan comprehensive treatment for reconstruction or asymmetry correction surgeries in an easier, fast, and accurate way.  
Conceptualization, J.-W.L. and M.-S.K.; methodology, B.-Y.H. and H.L., software, B.-Y.H., J.-W.L. and M.-S.K.; writing--original draft preparation, J.-W.L. and M.-S.K.; writing--review and editing, J.-W.L.; project administration, J.-W.L.; funding acquisition, J.-W.L. All authors have read and agreed to the published version of the manuscript. This work was supported by the National Research Foundation of Korea Grant funded by the Korean Government (NRF-2017R1D1A1B04030398)  
The authors declare no conflict of interest. The funders had no role in the design of the study; in the collection, analyses, or interpretation of data; and in the writing of the manuscript, or in the decision to publish the results.