# 3D Soft-Tissue Prediction Methodologies for Orthognathic Surgery--A Literature Review
## 3 Results
### Prediction Methodologies
#### 3.2.1 Works Based on Traditional (2D) Methodologies
Nevertheless, authors concluded that statistically the differences in the considered measurements do not invalidate the surgical prediction generated with the software, because the predicted result was close to the surgical outcome. Moreover, they noticed that concerning the mandible, dentoskeletal measurements in horizontal and vertical directions showed a greater correlation to the profile than the maxillary measurements [13]. [PERSON] et al. worked on a subjective comparison of the soft-tissue surgical simulation of two software: Dentofacial Planner Plus (Dentofacial Software, Toronto, Ontario, Canada) and Dolphin Imaging (version 9.0). Surgeries considered in the study involved retro-positioning of the mandible and advancement of the maxilla, in which linear movements were at least 4 mm for one bone segment or in the sum of both mandibular and maxillary movements, without, or least possible, postsurgical orthodontic movements. Profile predictions were made six months after the surgery; real movements, obtained from the superimposition of the cephalometries of pre- and post-operative of each subject, were used as values of the prediction. Soft-tissue images of pre-operative, real predictive images of Dentofacial Planner Plus (DFP) and Dolphin Imaging (DI) and post-operative images were compared (Figure 2). With Photoshop program (version 6.0, Adobe, San Jose, Calif), pre- and post-operative profile images were digitized and standardized; then, images were imported in DFP and DI. Movements of maxilla and mandible were made using the real values extracted from the comparison between pre- and post-operative lateral cephalograms of the surgical displacements along the vertical and horizontal directions for molars and incisors of the maxilla and for incisors of the mandible. The tip of the nose, the nasolabial angle, upper and lower lips, menton region, the base of the mandible and the complete profile were used to compare simulated and real images. A group of orthodontists, maxillofacial surgeons and general dentists evaluated the similarity among the programs simulated images and the real post-operative images with a scale ranging from \"very similar\" to \"different\". For the comparison of soft-tissue cephalometric points, to compare the two programs and to judge the criteria of similarity, chi-square test was used. From their analysis, the authors reported that for nasal tip, chin area and mandibular base DI gave better results, while for nasolabial angle, upper lip and lower lip DFP produced a more accurate prediction; authors also reported that there was no difference in the evaluation of the complete profile. Moreover, in terms of time, working with DI was longer than working with DFP. In conclusion, it was stated that in treating subjects affected by dentofacial deformities, it would be better if orthodontists and oral maxillofacial surgeons were to base on their clinical experience and to use software just as a co adjuvant. Considering the methodology of the study, there were not many differences in obtaining a two-dimensional prediction of patient's profile [14]. Other software are available for the prediction of soft tissue changes. OrthFoForecast is a data-based prediction software; its database contains information of 400 patients (100 pts with asymmetry, 100 pts with skeletal class II jaw relationship and 200 pts with skeletal class III jaw relationship). All patients underwent SSRO or IVRO, with or without LFI osteotomy (respectively, 352 and 48 cases). It was evaluated by [PERSON] et al. ; the study included 15 patients with facial asymmetry, 15 with skeletal class II jaw relationship and 15 with skeletal class III jaw relationship. Patients underwent LFI osteotomy,  
Figure 2: Profile images of a patient with Class III malocclusion, treated with orthognathic surgery: (**A**) pre-treatment; (**B**) simulation from Dentofacial Planner Plus (DFP); (**C**) simulation from Dolphin Imaging (DI); (**D**) actual post-operative photograph [14]. SSRO and IVRO. Twenty-four landmarks were chosen and digitized.