Long-term three dimensional stability of orthognathic surgery
AlMugairin, Sarah Abdullah
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PURPOSE: The aim of this study was to evaluate the stability of different orthognathic surgical procedures. METHODS: CBCT scans of 61 patients who had orthognathic surgery were reviewed. These included pre-operative (T0), postoperative (T1), and at least one year postoperative (T2) (12-47 months) scans. All subjects had undergone maxillomandibular advancement surgery, with 23 subjects having clockwise rotation, and 38 having counterclockwise rotation of the mandibular occlusal plane. Mimics Innovation Suite™ Research Edition software (version 21) (Leuven, Belgium) was used for analysis. Thirty-seven parameters were chosen that represented the maxillary and mandibular segments. Measurements between points and/or planes were used to detect the sagittal, vertical, and transverse movements in each time interval. Linear mixed models analysis was used to detect significant differences between time points. Linear regression analysis was used to evaluate the correlations between the amount of surgical movement and the postoperative changes. RESULTS: Overall, 17 measurements showed significant differences between T1 and T2 (postoperative). 11 measurements presented statistically significant time point differences according to either direction of rotation. Only one measurement showed statistically significant difference between T1-T2 (Left ramus plane- Mid sagittal plane) in clockwise group while 8 other measurements were found significantly different between T1-T2 in the counterclockwise group. CONCLUSION: Except for mandibular advancement measured at right and left mental foramen to right and left lingulae, and interlingula distance, bimaxillary advancement surgeries with clockwise or counterclockwise rotation of the mandibular occlusal plane were stable at least for one year. The main difference between clockwise and counter clockwise surgeries was found in the vertical changes of the posterior maxilla and the distance between the right and left mental foramen to the coronal plane.