A radiographic analysis of computer prediction in conjunction with orthognathic surgery.

This retrospective study analysed the accuracy and reliability of predictions generated in patients treated with orthognathic surgery by comparing Quick Ceph Image software (Quick Ceph Image Pro version 3.0) predictions with post-surgical lateral cephalographs. Pre- and post-surgical lateral cephalographs of 28 adult patients (12 males and 16 females) were scanned into the computer and 28 landmarks were identified and digitized. Digitization error was assessed from repeated digitization. Fourteen measurements of the predicted and actual postsurgical hard tissue landmarks were compared using Student's t-test. Results showed a good correlation between repeated digitization for all measurements. Student's t-test indicated that 10 of the 14 measurements showed no statistically significant differences. Only the ANB (P=0.008), FMA (P=0.001), SN-Mxl (P=0.03) and Wit's (P=0.0001) showed statistically significant differences between the predicted and actual measurements. However only the Wit's showed clinical significant differences between the two measurements. Caution still must remain as the surgeon may not achieve his planned position in an individual patient. In some cultures there may also be medico-legal implications of these predictions.