• The korean journal of orthodontics
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• v.50 no.4
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• pp.238-248
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• 2020

Objective: To investigate the effects of the long-term use of a maxillary protraction facemask with miniplate (FM-MP) on pharyngeal airway dimensions in growing patients with cleft lip and palate (CLP). Methods: The study included 24 boys with CLP (mean age, 12.2 years; mean duration of FM-MP therapy, 4.9 years), divided into two groups according to the amount of A point advancement to the vertical reference plane (VRP): Group 1, > 4 mm; Group 2, < 2 mm; n = 12/group. After evaluating the skeletodental and airway variables using lateral cephalograms acquired before and after FM-MP therapy, statistical analyses were performed. Results: Group 1 showed greater forward and downward displacements of the posterior maxilla (posterior nasal spine [PNS]-horizontal reference plane [HRP]; PNS-VRP), greater increase in ANB, more forward tongue position (tongue tip-Pt vertical line to Frankfort horizontal plane), and greater increase in the oropharynx (superior posterior airway space [SPAS]; middle airway space [MAS]) and upper nasopharynx (PNS-adenoid2) than did Group 2. While maxillary advancement (A-VRP and PNS-VRP) correlated with increases in SPAS, MAS, and PNS-adenoid2, downward displacement of the PNS (PNS-HRP) correlated with increases in SPAS, MAS, PNS-adenoid1, and PNS-adenoid2, and with a decrease in vertical airway length (VAL). Mandibular forward displacement and decrease in mandibular plane correlated with increases in MAS. Conclusions: FM-MP therapy had positive effects on the oropharyngeal and nasopharyngeal airway spaces without increases in VAL in Group 1 rather than in Group 2. However, further validation using an untreated control group is necessary.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.38 no.1
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• pp.9-13
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• 2012

Introduction: To evaluate the 3-dimensional changes in the pharyngeal airway of skeletal class III patients after bimaxillary surgery. Materials and Methods: The study sample consisted of 18 Korean patients that had undergone maxillary setback or posterosuperior movement and mandibular bilateral sagittal split osteotomy setback surgery due to skeletal class III malocclusion (8 males, 10 females; mean age of 28.7). Cone beam computed tomography was taken 1 month before and 6 months after orthognathic surgery. Preoperative and postoperative volumes of the nasopharyngeal, oropharyngeal, and laryngopharyngeal airways and minimum axial areas of the oropharyngeal and laryngopharyngeal spaces were measured. Moreover, the pharyngeal airway volume of the patient group that had received genioplasty advancement was compared with the other group that had not. Results: The nasopharyngeal and laryngopharyngeal spaces did not show significant differences before or after surgery. However, the oropharyngeal space volume and total volume of pharyngeal airway decreased significantly (P<0.05). The minimum axial area of the oropharynx also decreased significantly. Conclusion: The results indicate that bimaxillary surgery decreased the volume and the minimum axial area of the oropharyngeal space. Advanced genioplasty did not seem to have a significant effect on the volumes of the oropharyngeal and laryngopharyngeal spaces.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.37
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• pp.38.1-38.6
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• 2015

Background: The posterior movement of mandible was known as the main cause of the changes in the pharyngeal airway space (PAS) and the postoperative obstructive sleep apnea (OSA). The purpose of this study was to know the changes of PAS and position of hyoid bone. Methods: Lateral cephalographies of 13 patients who had undergone sagittal split ramus osteotomy (SSRO) setback surgery were taken preoperatively (T1), postoperatively within 2 months (T2), and follow-up after 6 months or more (T3). On the basis of F-H plane, diameters of nasopharynx, oropharynx, and hypopharynx were measured. The movements of the soft palate, tongue, and hyoid bone were also measured. Results: The amount of mandible setback was $7.5{\pm}3.8mm$. In the measurements of PAS, there was a statistically significant decrease of $2.8{\pm}2.5mm$ in nasopharynx (P < 0.01), and $1.7{\pm}2.4mm$ in oropharynx (P < 0.01) were observed after surgery. The hypopharynx decreased $1.0{\pm}2.1mm$ after surgery and continuously decreased $1.0{\pm}2.8mm$ at follow-up. The changes in hyoid bone position showed the posterior movement only after surgery and posteroinferior movement at follow-up. Conclusions: The PAS such as nasopharynx, oropharynx, and hypopharynx showed relatively high correlation with the amount of mandibular setback. The change of resistance in upper airway may be important for the prevention of OSA after mandibular setback surgery.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.39
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• pp.22.1-22.9
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• 2017

Background: Two-jaw surgery including mandibular and maxillary backward movement procedures are commonly performed to correct class III malocclusion. Bimaxillary surgery can reposition the maxillofacial bone together with soft tissue, such as the soft palate and the tongue base. We analyzed changes of pharyngeal airway narrowing to ascertain clinical correlations with the prevalence of snoring after two-jaw surgery. Methods: A prospective clinical study was designed including a survey on snoring and three-dimensional (3D) computed tomography (CT) in class III malocclusion subjects before and after bimaxillary surgery. We conducted an analysis on changes of the posterior pharyngeal space find out clinical correlations with the prevalence of snoring. Results: Among 67 subjects, 12 subjects complained about snoring 5 weeks after the surgical correction, and examining the 12 subjects after 6 months, 6 patients complained about the snoring. The current findings demonstrated the attenuation of the largest transverse width (LTW), anteroposterior length (APL), and cross-sectional area (CSA) following bimaxillary surgery given to class III malocclusion patients, particularly at the retropalatal level. The average distance of maxillary posterior movements were measured to be relatively higher (horizontal distance 3.9 mm, vertical distance 2.6 mm) in case of new snorers. Conclusions: This study found that bimaxillary surgery could lead to the narrowing of upper airway at the retropalatal or retroglossal level as well as triggering snoring in subjects with class III malocclusion. Based on the current clinical findings, we also found that upper airway narrowing at retropalatal level may contribute to increasing the probability of snoring and that polysonography may need to be performed before orthognathic surgery in subjects with class III malocclusion.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.35 no.4
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• pp.211-220
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• 2013

Purpose: The purpose of this study was to compare the changes in the pharyngeal airway space, tongue and hyoid bone positions according to the orthognathic surgical methods of mandibular prognathism. Methods: The subjects included 30 patients (16 males, 14 females) with the skeletal class III malocclusion. Group 1 (10 patients) underwent bilateral sagittal split ramus osteotomy (BSSRO) only; group 2 (10 patients) underwent BSSRO with genioplasty; and group 3 (10 patients) underwent BSSRO, Le Fort I osteotomy. We measured the lines between the selected upper air way, hyoid bone and tongue landmarks on the lateral cephalometric x-ray films of skeletal class III. The measurements were made preoperation, within 1 week after the operation, 3~6 months after the operation and 1 year after the operation. We compared and analyzed the measurements with matched paired t-test and independent samples t-test. Results: There were no postoperative changes in the nasopharyngeal airway space in group 3. The measurements of group 3 also increased during the follow-up period as compared to the preoperative measurements. In group 1, 2 and 3, the immediate postoperative oropharyngeal and hypopharyngeal airway spaces were decreased. In the following period, the hypopharyngeal airway space returned to the preoperative positions, but the oropharyngeal airway space was not significantly changed. The upper and lower tongue was posteriorly repositioned immediately after the surgery. During the follow-up period, the lower tongue position returned to the preoperative position, and the upper tongue position was not significantly changed. Immediately after the surgery, the B point was moved to the posterior position, and a slight anterior advancement was found in the follow-up period. Conclusion: Patients who received the mandibular setback surgery showed a decrease in the posterior airway space, and those who underwent maxillary advancement showed a significant increase of the nasopharyngeal airway space, which remained stable during the evaluation period. The change of the airway space, position of the hyoid bone and tongue did not differ according to the presence or absence of genioplasty.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.33 no.1
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• pp.36-43
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• 2011

Purpose: This study evaluated the pharyngeal airway space changes in CT images in patients receiving bilateral sagittal split osteotomy (BSSRO) for the surgical correction of mandibular prognathism. Methods: A total of 22 patients with mandibular prognathism were treated using BSSRO. Computed tomography was performed 1 month (T0) before surgery and, 1 month after surgery (T1). The anteroposterior length (AP), lateral width (LAT) and cross-sectional area (AREA) at the level of soft palate (C2) and base of the tongue (C3) were measured using CT images. Results: The mean amount of mandibular setback was 7.41 mm (${\pm}$3.46 mm). All the AP, LAT and AREA at the C2 and C3 level were decreased significantly 1 month after surgery (P<0.001). As the amount of mandibular setback was increased, the AP, LAT and AREA levels at the level of C2 and C3 had decreased. In addition, the reduction of the AREA at the C3 level was associated with the amount of mandibular setback (P<0.05). Conclusion: A significant decrease in pharyngeal airway space was observed 1 month after the operation. The cross-sectional area at the level of base of tongue was decreased with increasing amount of mandibular setback.

• The korean journal of orthodontics
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• v.40 no.3
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• pp.145-155
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• 2010

Objective: Lateral cephalometric radiographs have been the main form of resource for assessing two dimensional anteroposterior airway changes. The purpose of this study was to evaluate the three dimensional volumetric change in the upper airway space in Class III malocclusion patients who underwent mandibular setback surgery. Methods: Three dimensional cone-beam computed tomographs (CBCT) and their three dimensional reconstruction images were analyzed. The samples consisted of 20 adult patients (12 males and 8 females) who were diagnosed as skeletal Class III and underwent mandibular setback surgery. CBCTs were taken at 3 stages - Baseline (1.8 weeks before surgery), T1 (2.3 months after surgery), and T2 (1 year after surgery). Pharyngeal airway was separated according to the reference planes and reconstructed into the nasopharynx, the oropharynx and the hypopharynx. Measurements at Baseline, T1, and T2 were compared between groups. Results: The result showed the volume of the pharyngeal airway decreased significantly 2.3 months after surgery (p < 0.001) and the diminished airway did not recover after 1 year post-surgery. The oropharynx was the most decreased area. Conclusions: These findings suggest that mandibular setback surgery causes both short-term and long-term decrease in the upper airway space.

• Imaging Science in Dentistry
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• v.47 no.1
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• pp.1-9
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• 2017

Purpose: This retrospective study aimed to evaluate the nasopharyngeal and oropharyngeal dimensions of individuals with skeletal class II, division 1 and division 2 patterns during the pre-peak, peak, and post-peak growth periods for comparison with a skeletal class I control group. Materials and Methods: Totally 124 lateral cephalograms (47 for skeletal class I; 45 for skeletal class II, division 1; and 32 for skeletal class II, division 2) in pre-peak, peak, and post-peak growth periods were selected from the department archives. Thirteen landmarks, 4 angular and 4 linear measurements, and 4 proportional calculations were obtained. The ANOVA and Duncan test were applied to compare the differences among the study groups during the growth periods. Results: Statistically significant differences were found between the skeletal class II, division 2 group and other groups for the gonion-gnathion/sella-nasion angle. The sella-nasion-B-point angle was different among the groups, while the A-point-nasion-B-point angle was significantly different for all 3 groups. The nasopharyngeal airway space showed a statistically significant difference among the groups throughout the growth periods. The interaction among the growth periods and study groups was statistically significant regarding the upper oropharyngeal airway space measurement. The lower oropharyngeal airway space measurement showed a statistically significant difference among the groups, with the smallest dimension observed in the skeletal class II, division 2 group. Conclusion: The naso-oropharyngeal airway dimensions showed a statistically significant difference among the class II, division 1; class II, division 2; and class I groups during different growth periods.

• The korean journal of orthodontics
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• v.27 no.5 s.64
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• pp.733-741
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• 1997

As a result of surgical orthodontic treatment of mandibular prognathism, changes take place in the skeletal and soft orofacial components. Although some investigators had stated that permanent reduction of airway space was observed after mandibular setback surgery, it was not clear that this permanent reduction was sustained during long-term follow-up. The purpose of this study was to assess the changes in oropharyngeal airway space and soft tissue orofacial component following the mandibular setback surgery and during the follow-up period. The correlation between the changes of the oropharyngeal airway space and the changes of other soft tissue orofacial component was also assessed. The findings of this study were as follows ; 1. The oropharyngeal airway space area decreased following mandibular setback surgery for mandibular prognathism and continued to decrease during the follow-up period(p<0.05). 2. The pharyngeal depth at Xi point level and the 2nd cervical vertebra point level decreased after the surgery and remained during the follow-up period(p<0.05). The decrease of these pharyngeal depth was correlated with the decrease of oropharyngeal airway space area(p<0.01). 3. The decrease of pharyngeal depth at the 3rd and 4th cervical vertebra point level was not significant after the surgery and during the follow up period. 4. The hyoid bone moved downward after the surgery(p<0.05), but returned to its original position during the follow-up period. 5. The length & height of tongue and the Position of epiglottis base did not change significantly(p>0.05). 6. The soft palate was displaced posteriorly after the surgery and remained to its changed position during the follow-up period(p<0.05) due to posterior displacement of tongue. The changes of soft palate were significantly correlated with the decrease of oropharyngeal airway space area(p<0.01). 7. The narrowing of oropharyngeal airway space was due to the posterior displacement of tongue above the level of epiglottis tip. The posterior displacement of tongue following mandibular setback osteotomy remained during the follow-up period.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.41
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• pp.51.1-51.8
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• 2019

Purpose: It has been reported before that the amount of pharyngeal airway space (PAS) significantly decreases following mandibular setback (MS) surgery in patients with mandibular prognathism (MP). Further, MP patients with an anterior open-bite (AOB) presentation may show a larger decrease in PAS compared with those without AOB. However, studies on postoperative PAS changes in MP patients with AOB remain rare. This study sought to evaluate changes in PAS and hyoid bone positioning following MS surgery in MP patients with and without AOB. Patients and methods: Twenty patients who underwent two jaw surgery involving MS movement were included. Patients were divided into a non-AOB group (n = 10; overbite > 2 mm) and an AOB group (n = 10; overbite < - 4 mm). Three-dimensional changes in PAS and hyoid bone positioning were compared and statistically evaluated pre- and postoperatively using computed tomography (CT). Results: The mean magnitude of MS was 6.0 ± 2.8 mm and 5.6 ± 3.2 mm in the non-AOB group and AOB group, respectively. The oropharyngeal volume and upper hypopharyngeal volume were significantly reduced after surgery in both the groups (p = 0.006 and p = 0.003), while the retroglossal cross-sectional area was significantly reduced only in the AOB group (p = 0.028). Although the AOB group showed a larger decrease in PAS, the difference was not statistically significant between the groups. The position of the hyoid bone showed significant posterior and inferior displacement only in the AOB group, while the vertical displacement of the hyoid bone showed a statistically significant difference between the two groups. Conclusion: PAS was significantly decreased after MS in both the groups, while only the AOB group presented a statistically significant reduction in the retroglossal cross-sectional area. Vertical displacement of the hyoid bone showed a statistically significant difference between the groups, while the PAS change was not. Surgeons should be aware of potential postoperative airway problems that may arise when performing MS surgeries.