A Study About The Application Of Digital Techniques In Genioplasty Of Patients With Asymmetric Prognathism

Objective: To study the patients with asymmetric prognathism who underwent genioplasty,and to refer to the values of the normal chin morphological indicators.Through retrospective research,compare the computer-aided design guided surgery only and the 3D printed surgical guides to know the accuracy of digital assisted surgery.Methods: According to the inclusion criteria and exclusion criteria,14 patients with asymmetric prognathism admitted to the Maxillofacial Surgery Department of the Affiliated Stomatological Hospital of China Medical University between January 2017 and September 2018 were included in the study.Among them,patients with numbers 1-7 were patients undergoing computer-aided design only(Group A),and patients with numbers 8-14 were patients with computer-aided design and 3D printed surgical guides(Group B).The image data of the cephalometric measurement items related to the operation of preoperative,postoperative,and postoperative simulation of each patient were measured.At the same time,the preoperative simulation and the actual amount of movement of the chin during the operation were measured.Comparing the measurement data of the Group A to simulate the difference between postoperative and actual postoperative;comparing the data of the Group B to simulate the difference between postoperative and actual postoperative;comparing the difference between the actual postoperative measured value and the standard value differences between the two groups.The differences between the preoperative and postoperative differences in the chin movement values of the Group A were compared;the differences in the Group B's chin movement values between preoperative and actual postoperative were compared.For the comparison of the two sets of measurement data,if the normality is observed,the independent sample t test is used for comparison between groups,and the paired sample t test is used for comparison within the group.If the normal distribution is not followed,the nonparametric test of two independent samples is used.Results: There were significant differences between the two groups in the position and relationship of chin and lip,and adjustment of the teeth midline.In terms of the soft tissue position of the chin,there is a significant difference between the two groups.After using 3D printed palate to guide the operation,it can achieve the effects obtained by the traditional methods,and has certain application value.The prediction results of the computer-aided design group are better predicted in the sagittal direction,and the coronal aspect predictions are more different.The prediction results of the 3D printed palate guide group are accurate both in the sagittal direction and the coronal direction.Conclusion: The application of digital technology in the surgical simulation of patients with asymmetric prognathism and the design of the related 3D printed surgical guides can better transfer the preoperative design to the actual surgery compared with the previous model of computer-aided design as a reference only before surgery.Further improve the accuracy of the operation and reduce the dependence of the surgical effect on the surgeon's experience,which has certain guiding significance for the future application of digital technology in the field of orthognathic surgery.