The aim of this study is to evaluate the accuracy of newer computerized software (Onyx Ceph 3™) in comparison with the manual method for predicting hard tissue and soft tissue profiles following mandibular advancement. Materials and Methods: This is a retrospective cephalometric study of fifteen Class II skeletal subjects who had undergone mandibular advancement by bilateral sagittal split osteotomy. The cephalograms were converted into digital format using flatbed scanner (Epson V700 Perfection). The prediction for mandibular advancement was done using Onyx Ceph 3™ and compared with manual tracings made on acetate paper. A total of fourteen variables were compared, of which seven were hard tissue, and seven were soft tissue. Both angular and linear measurements were considered. Results: Onyx Ceph 3™ software overestimated mandibular advancement showing significant differences in OP-SN_M, Sella-Nasion-point B_D, N-Pog_D. The comparisons between the manual and digital error showed statistically significant differences in N-Pog (P = 0.013), L i -L1 (P = 0.043) Sn-Gn'-C (P = 0.052), and G-Sn-Pog' (P < 0.001). The margin of error was more in soft-tissue prediction performed digitally than manually. Conclusions: The prediction error was more in soft-tissue prediction performed digitally than manually. Onyx Ceph 3™ algorithms set for soft tissue have not matched the actual postsurgical treatment. Further, this software overestimated the mandibular advancement and has not accounted for the rotational movement associated with mandibular surgery.

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