Fogorvosi szemle, 2021 (114. évfolyam, 1-4. szám)
2021-12-01 / 4. szám
FOGORVOSI SZEMLE 114. évf. 4. sz. 2021. n 176 nasolabial soft tissue changes after orthognathic surgery [22 ], while Modabber and colleagues concluded that the Artec Eva scanner leads to more accurate 3D models as compared to scanning with FaceScan3D, and it is comparable to the other commercially available scanners [33 ]. To minimize the effects of different types of malocclusion and surgeon-related factors, the subjects’ selection was limited to those with skeletal class III defects, and all operations were performed by one surgeon (J. P.). Unfortunately, considering gender-related effects within the small sample size in our study further analyses were not feasible. Notwithstanding that, Chen and colleagues found no sex-related differences in soft tissue changes in patients with mandibular prognathism after orthognathic surgery [12 ]. Further studies with larger sample size to inspect the sex-related effects of bimaxillary surgery on the soft tissue are essential. The timing of the soft tissue analysis is very critical. A period up to 6 months after bimaxillary surgery was chosen as the T1 stage due to the fact that a suffi cient facial soft tissue stabilization is required to avoid any subsequent modifications, such as post-operative swelling, soft tissue remodelling, due to which the relocation should be minor enough to be insignificant [23 ]. Proffit and colleagues explained that postoperative changes do not show a normal distribution and that only a few patients exhibit considerable changes [38 ]. Similarly, Oh et al. found that 6 months post-surgery will be the ideal time for a proper assessment [36 ]. Soft tissue changes We found a statistically significant increase in the nasal width and widening of the alar bases after bimaxillary osteotomies (2.31 mm and 2.02 mm p < 0.05 respectively). We can explain these increases by the remodelling and relocating of the surrounding muscles in the alar region [36 ]. Our results confirmed the results of Baik and colleagues who found a 2.0 mm nasal width increase after maxillary advancement and mandibular setback [7 ]. Similarly, an increase was also reported in the alar width after bimaxillary surgery in class III patients using a 3D laser scanner and 3D facial morphometry [18 ]. Liebregts and colleagues found an increase of 0.24 mm in the alar width for every 1 mm of maxillary advancement [28 ]. Altman and Oeltjen noted that all Le Fort I osteotomies caused widening of the alar bases due to retraction of perioral muscles around the maxilla, which results in their detachment from insertions during maxillary surgery [5 ]. In the study by Worasakwutiphong and colleagues, which evaluated the nasal changes in class III patients who underwent two-jaw surgery, it was found that, after the surgery, the alar width was increased by 0.74 mm and the nasolabial angle had increased significantly, while the width of the alar base and the nasal height and length remained similar [44 ]. No significant changes neither in the intercanthal width, nor in the mouth width, were found in our study. This corresponds to results in previous studies following bimaxillary surgeries, and it was reported that changes in the lips were produced by the stretching of soft tissues [7 , 41 ]. With regards to the vertical plane, we found substantial increases in both the upper lip height and the upper lip vermilion height (1.47 and 2.31 mm, p < 0.05 respectively); thus, the total upper lip height was significantly increased by (3.8 mm). We can explain these increases by the relocation of the orbicularis oris muscle and a soft tissue tension in the upper lip region. Marsan et al. found elongation in the upper lip (1.2 ± 1.6 mm) after bimaxillary surgery in Turkish female Class III patients [31 , which supports our findings. In our study, we found a statistically significant decrease in the lower lip height (Li-Sl; 1.9 mm, p < 0.05). In these changes, the upward and backward movement of the mandible may have played a role. A 4 mm decrease was reported by Marsan et al . in their study [ 31 ], whilst the findings of Kim et al. suggest that the lower lip decrease could be rather due to influence of the muscle rather than the bone [24 ]. Regarding the angular measurements, we found a statistically significant increase in the Nasal tip angle (7.36 o, p < 0.05), which could be affected by the lateral movements of the alar landmarks, and the increase in the nasal and nasal base width due to the relocation of the nasalis muscle after the surgery. Usually, in addition to the nasal tip projection, the nasolabial angle is used to record the maxillary protrusion in the upper lip. We found an insignificant increase in this angle (11.57 o), which could be produced by stretching the soft tissues in this area. We also noticed a decrease in the Inter-labial angle (–8.81°, p < 0.05), which could be explained by the relocation of the orbicularis oris muscle and the upper and lower lips after the bimaxillary osteotomies. Following a bimaxillary surgery, a significant increase found in the lower lip angle (10.46 o) which could refer to the backward movement of the (Li) landmark, a decrease (–5.32 o) was also found in the Labiomental angle, but without reaching a significant level. In their study on skeletal class III patients after a bimaxillary surgery Al-Gunaid et al., evaluating the hard and soft tissue changes, found an increase in the nasol abial angle, a decrease in the labio-mental angle, and an improvement of dentofacial aesthetics. They also reported that the soft tissue facial profiles and the posture of the lips were improved [2 ]. A gradual advancement at the nasal tip, a significant increase in the nasolabial angle, and a decrease in the labio-mental angle were reported in the study by Marsan et al [ 31 ]. In our post-operative study, to improve
