Figure 1 The treatment protocol based on the floating bone concept

Figure 2 Process of postoperative osseous healing

In the 3-dimensional assessment on CT images taken immediately postoperatively and at the 3 months and 6 months postoperative examinations, the gap between the proximal and distal segments of the mandible gradually becomes narrower and is completely closed at the 6 months postoperative examination.

Figure 3 Change of the amount of jaw opening

The average jaw opening is 47.1 mm preoperatively and 1.8 mm on the second postoperative day (2D) when jaw exercises just started. The amount of jaw opening increases gradually and is 45.2 mm at 6 months postoperatively (6M), showing recovery almost to the preoperative level. The amount of jaw opening has finally recovered to 48.5 mm at 12 months postoperatively (12M.). (*: p <0.05; **: p <0.01)

Figure 4 Ramus angle (angle between the FH plane and the ramus plane)

In the analysis of all cases, the ramus angle increases significantly by 4.06° (p < 0.05) for T0-T1, and decreases significantly by 4.32°, 4.73°, and 4.77° (p < 0.05) for T1-T3, T1-T4, and T1-T5, respectively. There are no significant differences between T0 and T2-5. (T0: preoperative, T1: 2 days postoperative, T2: 1 month postoperative, T3: 3 months postoperative, T4: 6 months postoperative, T5: 12 months postoperative)

Figure 5 Gonial angle (angle between mandibular plane and ramus plane)

In the analysis of all cases, the gonial angle increases significantly by 6.06°, 6.65°, and 6.71° (p < 0.05) for T1-T3, T1-T4, and T1-T5, respectively. There are no significant differences between T0 and T1-5. (T0: preoperative, T1: 2 days postoperative, T2: 1 month postoperative, T3: 3 months postoperative, T4: 6 months postoperative, T5: 12 months postoperative)

Figure 6 RAMUS (the angle between the tangential lines of the lateral ramus and Lo-Lo’)

In the symmetry group, the RAMUS increased significantly by 3.700(p < 0.05) for T0-T1, and decreased significantly by 2.730 (p < 0.05) for T1-T2. There was no significant difference between T0 and T2, and for T2-T5. In the asymmetry group, the RAMUS increased significantly by 5.330 (p < 0.05) for T0-T1 and decreased significantly by 3.830 (p < 0.05) for T1-T2 at the deviated side. There was no significant difference between T0 and T2, and for T2-T5. On the other hand, on the non-deviated side, there was no significant difference for T0-T5 (T0: preoperative, T1: 2 days postoperative, T2: 1 month postoperative, T3: 3 months postoperative, T4: 6 months postoperative, T5: 12 months postoperative)