Short-term pharyngeal airway changes after mandibular advancement surgery in adult Class II-Patients--a three-dimensional retrospective study

Pharyngeal airway subdivisions in 3-dimensional analysis: Differences between anterior and posterior anatomic boundaries

INTRODUCTION

This study aimed to evaluate if there were differences between anterior and posterior anatomic boundaries used for the 3-dimensional determination of pharyngeal airway.

METHODS

The sample included 150 cone-beam computed tomography scans from healthy patients divided according to (1) age: 6-11, 12-16, and ≥16 years; (2) sex: female and male; (3) anteroposterior skeletal pattern: Class I, II, and III; (4) vertical pattern: brachyfacial, mesofacial, and dolichofacial; and (5) craniocervical inclination (CCI): natural head posture, head flexion, and head extension. Anatomic regions were created to determine the correspondences between structures anteriorly and posteriorly to the pharyngeal airway.

RESULTS

The location of the epiglottis, vallecula, hyoid, C2, and C3 were statistically different according to the CCI, and the location of vallecula, C3, and C4 were different according to sex. However, no statistically significant differences were observed between the frequencies of anterior and posterior anatomic region locations among age and different anteroposterior and vertical skeletal patterns. Posterior landmarks tend to be located below the anterior ones; consequently, the anatomic subregion they define will also be located below.

CONCLUSIONS

Anterior and posterior structures and vertical and anteroposterior skeletal patterns may determine upper airway limits regardless of age. However, the studies must be paired according to sex, and CCI must be standardized.

Changes in the upper airway volume after orthognathic surgery: three-dimensional measurements in a supine body position

The objectives of this study were to analyse the changes in airway cross-sectional areas and volumes due to surgical movements of the jaws and to identify any possible correlation with the direction of the movements. Fifty-seven participants, aged 18-28 years (mean 20.8 years) at surgery, were followed up for 12 months postoperatively. Pre- and postoperative measurements of the facial region obtained from computed tomography in a supine position were analysed according to the surgical movements and changes in the upper airways. Intra-rater reliability was assessed. Comparisons and correlations of jaw movements, changes in airway volume, and body mass index (BMI) were made. The cohort showed a significant change between the pre- and postoperative measurements for areas associated with the anterior nasal spine (P = 0.013), posterior nasal spine (P = 0.049), uvula (P = 0.006), and epiglottis (P = 0.046). Additionally, a correlation was found between the airway volume change and the change in mandible position (correlation coefficient 0.324, P = 0.014). All participants were non-smokers, and no correlation was observed between BMI and the upper airway volume. Changes in the upper airway can be expected following surgical movements of the jaws. A correlation was shown between a sagittal direction of the movements and the changes in the airways. Patients with obstructive sleep apnoea who are indicated for surgical movements of the jaws are expected to benefit from orthognathic surgery.

Retrospective study on the pharyngeal airspace in the lateral cephalogram - A mathematical model to predict changes due to bimaxillary orthognathic surgery

The aim of this study was the development of a statistical model for reliable prediction of Posterior Airway Space (PAS) changes in lateral cephalograms (LCR) of patients after bimaxillary orthognathic surgery. The LCRs of patients who underwent bimaxillary orthognathic surgery were retrospectively analyzed. The anteroposterior dimension of the PAS was measured at three levels in the pre-operative and postoperative LCR: On the nasopharyngeal (SPAS), oropharyngeal (MAS), and hypopharyngeal level (IAS). The data of 139 patients were collected. The following changes of the PAS were measured: in class II patients SPAS: 0.291 mm (SD = 2.570 mm); MAS: 2.444 mm (SD = 2.986 mm); IAS: 0.750 mm (SD = 3.017 mm); in class III patients SPAS: 1.377 mm (SD 3.212 mm); MAS: 0.962 (SD: = 3.135 mm); IAS: 0.370 mm (SD = 3.468 mm). Linear regression analysis showed for class II patients, a significant influence of mandibular movement on MAS (p = 0.049) and a significant effect of maxillary and mandibular movements on SPAS (p = 0.001) and MAS (p = 0.022) in class III patients. The other jaw displacements had no significant impact on the investigated PAS levels. While the presented method does not permit exact prediction of the dimension of the PAS, it is still an easily accessible method of orientation for the surgeon. The surgeon can initiate three-dimensional examinations to provide exact three-dimensional prediction based on this calculation.

Cone beam computed tomography volumetric airway changes after orthognathic surgery: a systematic review

The aim of this systematic review was to provide a structured overview of three-dimensional airway volume changes in relation to various orthognathic surgeries. Clinical human studies performing pre- and postoperative three-dimensional airway volume assessments to investigate volumetric changes of the airway after orthognathic surgery were included. Pre-determined inclusion and exclusion criteria were applied in an extensive search of the PubMed, Embase, and Web of Science electronic databases. The cut-off date was set to January 1, 2022. Forty-one articles reporting retrospective and prospective case-control and case series studies were included. All studies were determined to be of medium quality (moderate risk of bias). The included studies were categorized by type of intervention. Pre- and postoperative volumes were extracted from the available data, and volume changes as a percentage of the preoperative levels were calculated. Isolated mandibular setback surgery generally decreased the airway volume. Isolated maxillary or mandibular advancement, bimaxillary advancement, and surgically assisted maxillary expansion generally increased the airway volume in the total airway and oropharynx, among which the effect of bimaxillary advancement surgery appeared most significant. High heterogeneity exists in the terminology and definitions of the airway and its segments. A more uniform methodology for airway volume measurement is needed to provide an insight into the impact on the airway of specific types of surgical intervention. In conclusion, airway volumes are affected after orthognathic surgery, which may be of clinical significance, especially in patients who are predisposed to obstructive sleep apnoea.

Effectiveness of Surgical Mandibular Advancement in Improving Airway Dimensions in Nongrowing Skeletal Class II Patients With Obstructive Sleep Apnea—A CBCT Study

Background:

Skeletal nongrowing class II patients with retrognathic mandible are often at risk of developing obstructive sleep apnea (OSA). This skeletal discrepancy, when severe enough, is often addressed by surgical mandibular advancement which not only achieves aesthetics, structural balance, and functional efficiency but also improves the airway function.

Objective:

The aim of the study was to evaluate the effectiveness of surgical mandibular advancement on airway dimensions, in nongrowing skeletal class II patients with mandibular retrognathism associated with OSA.

Materials and Methods:

The sample consisted of 8 patients with skeletal class II due to retrognathic mandible associated with OSA. Screening was done with functional outcomes of sleep questionnaire (FOSQ) score and confirmed with polysomnography. Pretreatment and posttreatment airway dimensions/volume were assessed and calculated on cone beam computed tomography (CBCT). Three months post surgery, oxygen saturation was recorded.

Results:

A statistically significant improvement in mean oxygen saturation level was observed from 87.62 ± 7.70 to 97.75 ± 0.46 and mean increase in airway volume was from 48.60 ± 7.17 to 69.48 ± 26.22. The smallest cross section increased from 137 ± 74.37 to 253.75 ± 76.67. Anteroposterior dimensions increased significantly from 6.17 ± 1.78 to 9.33 ± 2.07 and transversed from 24.56 ± 6.41 to 30.14 ± 3.35. FOSQ score improved from 9.37 ± 2.61 to 15.25 ± 0.88.

Conclusion:

Surgical mandibular advancement is an effective treatment option in improving airway dimensions in nongrowing skeletal class II patients with mandibular retrognathism associated with OSA.

Three-Dimensional Pharyngeal Airway Space Changes Following Isolated Mandibular Advancement Surgery in 120 Patients: A 1-Year Follow-up Study

Lack of evidence exists related to the three-dimensional (3D) pharyngeal airway space (PAS) changes at follow-up after isolated bilateral sagittal split osteotomy (BSSO) advancement surgery. The present study assessed the 3D PAS changes following isolated mandibular advancement at a follow-up period of 1 year. A total of 120 patients (40 males, 80 females, mean age: 26.0 ± 12.2) who underwent BSSO advancement surgery were recruited. Cone-beam computed tomography (CBCT) scans were acquired preoperatively (T0), immediately following surgery (T1), and at 1 year of follow-up (T2). The volume, surface area, and minimal cross-sectional area (mCSA) of the airway were assessed. The total airway showed a 38% increase in volume and 13% increase in surface area from T0 to T1, where the oropharyngeal region showed the maximum immediate change. At T1−T2 follow-up, both volumetric and surface area showed a relapse of less than 7% for all sub-regions. The mCSA showed a significant increase of 71% from T0 to T1 (p < 0.0001), whereas a non-significant relapse was observed at T1−T2 (p = 0.1252). The PAS remained stable at a follow-up period of 1 year. In conclusion, BSSO advancement surgery could be regarded as a stable procedure for widening of the PAS with maintenance of positive space at follow-up.

Comparison of anthropometric and conic beam computed tomography measurements of patients with and without difficult intubation risk according to modified mallampati score: New markers for difficult intubation

Background

The aim of this study was to compare the anthropometric and cone beam computed tomography (CBCT) measurements taken from risk-free and risky groups by using the modified Mallampati score (MMS).

Patients and Methods

A total of 176 volunteers between the ages of 18 and 65 in four different MMS classes were included in the study. The patients in classes MMS I and MMS II were accepted as risk-free and the patients in classes MMS III and MMS IV were accepted as risky for intubation. The Mann-Whitney U test was performed on the data to compare the anthropometric and radiological measurements taken from the risk-free and risky groups. A receiver operating characteristic (ROC) analysis was applied to the parameters that had a statistically significant difference.

Results

According to the analysis results, statistically significant differences were found in the neck circumference (NC), maximum interincisal distance (MID), thyromental distance (TMD) and sternomental distance (SMD) of the anthropometric measurements of men and women between the risk-free and risky groups (P < 0.05). In terms of CBCT measurements, the thickness of the tongue (TT), distance between the uvula and posterior wall of pharynx (U-Ph), distance between posterior nasal spine and nasopharynx (Snp-Nph) and length of the epiglottis (LE) were found to have statistically significant differences between the risk-free and risky groups of men and women (P < 0.05).

Conclusion

The NC, MID, TMD and SMD anthropometric measurements and TT, U-Ph, Snp-Nph and LE radiologic measurements were found to support MMS, which is one of the most widely used bedside intubation prediction tests. In addition to the inclusion of CBCT for intubation prediction, U-Ph and Snp-Nph radiologic measurements were added as difficult intubation markers.

Evaluation of Nasal Function and Upper Airway Morphology After Bi-Maxillary Surgery Using Rhinomanometry and Computed Tomography

PURPOSE

This study was performed to evaluate changes in nasal airflow, nasal airway resistance, nasal cross-sectional area, pharyngeal horizontal area, nasopharyngeal and oropharyngeal volume following Le Fort I osteotomy (L1) impaction with sagittal split ramus osteotomy (SSRO) in classes II and III.

MATERIALS AND METHODS

The subjects consisted of 35 patients (6 males and 29 females, 70 sides) 17 of which were diagnosed as class II and 18 as class III who underwent L1 and SSRO. Nasal airflow and resistance were measured using the rhinomanometry system (GM NR-6 EXECUTIVE) before and at 1 and 6 months after surgery. Nasal, cross-sectional area, and volume were measured using a 3-dimensional computed tomography respectively, before and 1-year after surgery.

RESULTS

Although a significant decrease was found in nasal volume after surgery (P = 0.0042), there was no difference between before and after surgery in the nasal airway resistance in class II.A significant decrease in nasal volume was found after surgery (P = 0.0005) and there were no postoperative changes in both nasal airflow and resistance in class III.

CONCLUSION

The study suggested that L1 impaction with SSRO did not worsen nasal function such as nasal airflow and nasal airway resistance, although nasal volume significantly decreased in both groups.

Upper Airway Changes Following Different Orthognathic Surgeries, Evaluated by Cone Beam Computed Tomography: A Systematic Review and Meta-analysis

PURPOSE

This study sought to assess the upper airway changes following different orthognathic surgeries using cone-beam computed tomography.

METHODS

An electronic search of the literature was conducted in major electronic databases including Medline (PubMed), Web of Science, Scopus, and Open Grey for articles published up to January 20, 2018. Human studies that evaluated the changes in the volume and minimum cross-sectional area of the upper airway or its subdivisions in patients who had undergone orthognathic surgery by use of cone-beam computed tomography were included. Manual search of the bibliographies of the included articles was also conducted. The included studies underwent risk of bias assessment.

RESULTS

A total of 1330 articles were retrieved. After excluding the duplicates and irrelevant articles, 41 studies fulfilled the eligibility criteria for this systematic review; out of which, 30 entered the meta-analysis. The majority of studies had a medium risk of bias. Mandibular setback, and maxillary advancement + mandibular setback decreased the volume of the upper airway (-6042.87 mm3 and -1498.78 mm3, respectively) and all its subdivisions in long-term (>3 months), except for the nasopharynx, the volume of which increased following maxillary advancement + mandibular setback. Mandibular advancement and maxillomandibular advancement both increased the upper airway volume in long-term (7559.38 mm3 and 7967.06 mm3, respectively); however, only the changes after the former procedure were significant. The minimum cross-sectional area increased after maxillomandibular advancement (161.43 mm2), and decreased following maxillary advancement + mandibular setback (-23.79 mm2) in long-term.

CONCLUSION

There is moderate evidence to suggest that mandibular advancement is the only orthognathic movement that provides a statistically significant change in long-term upper airway volume.

Effects of surgical mandibular advancement on the upper airways of adult class II patients: A systematic review with meta-analysis

AIM

To systematically review the effects of surgical mandibular advancement (SMA) regarding changes of the upper airways in adult patients with skeletal Class II malocclusion.

MATERIALS AND METHODS

Five electronic databases were searched up to April 2020. Human studies focusing on the morphology and dimension of the upper airways after SMA were included. 'Quality assessment for Before-After (Pre-Post) Studies' was used to assess the risk of bias of the individual studies. Standard mean differences (SMD) with 95% confidence intervals (CI) were calculated for random effect model meta-analysis. The certainty of evidence was assessed using the GRADE tool.

RESULTS

Twenty cohort studies of only treated patients without control group were eligible for qualitative synthesis, of which 17 were used for quantitative synthesis. Very low certainty of evidence indicated that SMA resulted in significant increase of the volume and of the smallest cross-sectional area (SMC) of the nasopharynx (volume SMD: 1.43, CI: 0.62, 2.24, P = .001, I²  = 87.8%; SMC SMD: 1.53, CI: 0.59, 2.47, P = .001, I²  = 90.5%) and oropharynx (volume SMD: 1.36, CI: 0.37,2.35, P = .007, I²  = 92.1%; SMC SMD: 1.21, CI: 0.11,2.32, P = .032, I²  = 93.1%). Significant augmentation of the distances between the posterior pharynx wall and the uvala (SMD: 0.73, CI: 0.46,0.98, P < .001, I²  = 72.7%), the posterior border of the tongue (SMD: 0.52, CI: 0.21,0.84, P = .001; I² : 60.5%), the gonion (SMD: 1.24, CI: 0.56,1.91, P < .001; I²  = 88.8%) and the epiglottis (SMD: 0.40, CI: 0.06,0.74, P = .033; I²  = 84.8%) were observed.

CONCLUSIONS

Weak evidence suggests enlargement of the upper airways of adult Class II subjects following SMA, with major increases in the oropharynx.

Accuracy of Three-Dimensional Upper Airway Prediction in Orthognathic Patients Using Dolphin Three-Dimensional Software

BACKGROUND

Orthodontists and surgeons have been looking for more accurate methods to predict surgical outcomes in patients with skeletal discrepancies.

METHODS

The sample consisted of 20 patients from the surgical clinic of a graduate orthodontic program who had been treated with Le Fort I maxillary movement, bilateral sagittal split osteotomy, with or without genioplasty. All patients had to have preoperative (T0) and at least 6 months postoperative (T1) cone-beam computed tomographies that were imported to Dolphin 3-dimensional (3D) software. The 3D voxel-based superimposition on the cranial base was performed for T0 and T1 to accurately measure the skeletal surgical movements. A virtual orthognathic surgery was performed on T0 to mimic the actual skeletal osteotomies using the treatment simulation tool in Dolphin 3D. A prediction 3D soft-tissue image (Tp) was generated based on the Dolphin virtual skeletal planning. The upper airway was segmented and exported as stereolithography surface files in both T1 and Tp. The measurements of the 3D volume of the airway were calculated and compared among T1 and Tp by using surface superimposition technique. Mean and standard deviations of upper airway volume were compared and correlated using paired t-test.

RESULTS

There was no statistically significant difference between the upper airway volume of T1 and Tp.

CONCLUSION

Dolphin 3D delivers accurate airway prediction which is an important step in 3D virtual planning.

Relations between mandible-only advancement surgery, the extent of the posterior airway space, and the position of the hyoid bone in Class II patients: a three-dimensional analysis

The objective of the present study was to evaluate the relation between mandibular advancement, the three-dimensional extent of the posterior airway space (PAS), and the position of the hyoid bone, using cone-beam computed tomography (CT). Twenty-eight Class II patients (21 women (mean (SD) age 29 (9) years) and seven men (mean (SD) age 23 (6) years)), who had had mandibular-only advancement surgery (Obwegeser-Dal Pont) were included in the study. In each case, cone-beam CT scans were taken one week before and six months after operation, and a retrospective analysis made of the alterations of several airway variables (volume, mean cross-sectional area, and diameter) and the three-dimensional extent of mandibular and hyoid movement, by using IPlan® cranial software. A linear regression was also done to correlate mandibular advancement, the movement of the hyoid bone, and airway variables. There were significant postoperative increases in all volumetric PAS variables, and in most diametric and spherical variables (p<0.05). There was also a significant linear relation between forward displacement of the mandible and the movement of the hyoid bone (p<0.05). These results show that mandible-only advancement surgery causes an increase in most dimensions of the PAS. This intervention can be assumed to reduce airway resistance and therefore might be a suitable treatment option for patients with obstructive sleep apnoea syndrome.

Pharyngeal dimensional changes in class II malocclusion treatment when using Forsus® or intermaxillary elastics - An exploratory study

OBJECTIVE

Pharyngeal airway obstruction can facilitate some forms of sleep disorder breathing (SDB) in susceptible children, especially in those having class II malocclusion. Changes in the anatomic areas surrounding the pharyngeal region during orthodontic treatment could hypothetically impact the pharyngeal airway dimensions. Management of a class II malocclusion on a growing individual with either intermaxillary elastics or different removable or fixed class II appliance designs have been proposed over the last century. The objective of this retrospective exploratory cohort study is to investigate to what extent the class II malocclusion treatment with either intermaxillary elastics (IME) or Forsus® fatigue resistance device (FFRD) leads to changes in oropharyngeal airway dimensions.

MATERIALS AND METHODS

Twenty-nine patients diagnosed as class II with an average age of 12.7years were included in this study, (11 males, 18 females). The sample was divided into group 1: IME and group 2: FFRD. CBCT's scans before (T1) and after treatment (T2) were obtained and analysed using Dolphin software. Reliability was obtained using Intraclass Correlation Coefficient (ICC). Descriptive statistics, ANOVA and paired t-test were used for analysis.

RESULTS

Intra-rater reliability test was excellent in all measurements for both groups. There were no statistically significant differences in pharyngeal airway dimensions between both groups (P=0.919). A statistically significant correlation was found for sex, where male patients had the highest increase in oro-space area (ORS), and in oropharyngeal volume. Children under 14-year-old in IME group showed statistically negative correlation for sub-mandibular (SM) and for ORS, meaning the younger the greatest increase. Additionally, individuals younger than 14years had a statistically significant increase in the vertical dimension.

CONCLUSIONS

Both orthodontic treatment approaches appear to be associated with a similar increase in oropharyngeal airway dimensions. Male patients under 14-year-old had a greater significant increase compared to female patients and older children. Normal pharyngeal dimensions changes were not accounted for.

Impact of Le-Fort I osteotomy on anatomical and functional aspects of the nasal airway and on quality of life

OBJECTIVES

Orthognathic surgery is a well-established procedure for skeletal deformities. Beneficial influences to the posterior airway space (PAS) have been described, but little is known about the subjective aesthetical and functional nasal aspects after orthognathic surgery. The aim of this study was to evaluate nasal airflow by anterior rhinomanometry and volumetric changes in the nasal airway space after mono- or bimaxillary surgery using cone-beam computed tomography (CBCT) and a new segmentation software. Furthermore, changes of patient's quality of life (QoL) should be assessed.

METHODS

Ten patients (9 skeletal class malformation III, 1 skeletal class malformation I) were included. CBCT images, rhinological inspections and anterior rhinomanometries were performed before (T0) and after surgery (T1). All patients completed the FROI-17, the ROE and the SF-36 questionnaires.

RESULTS

A significant postoperative gain for nasal airway volume compared with the baseline was shown (p < 0.014). No statistically significant differences between pre- and postoperative flow rates were found (p = 0.114). Pre- and postoperative cohorts did not differ in responses of disease-specific (ROE and FROI-17) and generic QoL questionnaires (SF-36).

CONCLUSION

Maxillary relocation surgery leads to a significant increase in nasal airway space. Subjectively, orthognathic patients did not experience any functional but psychosocial aspects after bimaxillary surgery.

Reliability of upper pharyngeal airway assessment using dental CBCT: a systematic review

Background

Upper airway analysis is an often-cited use of cone beam computed tomography (CBCT) imaging in orthodontics. However, the reliability of this process in a clinical setting is largely unknown.

Objective

Our objective was to systematically review the literature to evaluate the reliability of upper pharyngeal airway assessment using dental CBCT.

Search methods

MEDLINE, EMBASE, Web of Science, and Google Scholar were searched through June 2015.

Selection criteria

Human studies that measured reliability of upper airway assessment in patients using CBCT as part of the study protocol were considered.

Data collection and analysis

The Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) was followed. Data were collected on overall study characteristics and measurements, CBCT unit and machine settings used, and examination characteristics of the included studies. Methodological quality of the included studies was evaluated.

Results

Forty-two studies were evaluated, representing the CBCT scans of 956 patients. Studies included a wide variety of patients and CBCT machines with various scan settings. Only five studies were deemed high quality. The available evidence indicates that under specific restricted conditions there is moderate to excellent intra- and inter-examiner reliability. Airway volume demonstrated greater intra- and inter-examiner reliability than did minimum cross-sectional area. However, significant methodological limitations of the current literature, most importantly a lack of manual orientation of the images and selection of threshold sensitivity in study protocols, suggest that reliability has not been adequately established.

Conclusions

The current literature reports moderate to excellent reliability, with airway volume having higher reliability than minimum cross-sectional area. However, only limited aspects of the process of airway analysis have been evaluated, indicating that further research is required to adequately establish the reliability of upper pharyngeal airway assessment of patients using dental CBCT.

Registration

None.

Volumetric changes of the upper airway following maxillary and mandibular advancement using cone beam computed tomography

The objective of this project was to retrospectively evaluate changes in volume of different compartments of the upper airway in response to maxillary, mandibular, and bimaxillary advancement surgeries and to predict the extent of volumetric changes associated with these surgical movements. Pre- and post-surgical cone beam computed tomography scans of 36 patients were evaluated for changes in nasal cavity, nasopharyngeal, oropharyngeal, and hypopharyngeal compartments. The amount of movement for each surgery was measured from skeletal landmarks to reference planes and was correlated with volumetric changes. Maxillary advancement of 4.0±2.2mm increased the oropharyngeal volume significantly (41.40%), and mandibular advancement of 3.8±1.6mm also significantly increased the oropharyngeal volume (21.17%). Bimaxillary advancement of 5.1±1.3mm for the maxilla and 6.4±3.1mm for the mandible significantly increased nasopharyngeal (27.45%), oropharyngeal (66.39%), and hypopharyngeal (52.48%) volumes. Furthermore, for every millimeter anterior movement, oropharyngeal volume increased by 2319.2±771.8mm³. Bimaxillary advancement showed a greater increase than isolated maxillary and mandibular advancement in all pharyngeal compartments. Every millimeter of advancement in the bimaxillary group led to a significant increase in oropharyngeal volume, while every millimeter downward movement showed a significant increase in nasopharyngeal volume.

Three-dimensional pharyngeal airway changes in dento-skeletal class II patients after two-jaw orthognathic surgery with segmentation - a pilot study

PURPOSE

To investigate short- and long-term post-surgical three-dimensional changes of pharyngeal airway morphology and hyoid bone position in dento-skeletal class II deformity patients after two-jaw surgery with segmentation.

METHODS

Relations between skeletal movement, hyoid bone position and three-dimensional pharyngeal airway changes were retrospectively analyzed on pre- and post-surgical CBCTs in dento-skeletal class II patients who underwent orthognathic two-jaw surgery with segmentation.

RESULTS

While long-term significant reductions in length (P= 0.003), surface area (P= 0.042) and volume (P= 0.004) were found in the nasopharynx, the highly significant increases in oropharyngeal airway length, surface area, volume and the minimal cross-sectional area (P < 0.05) prevailed only in the short-term. Although a significant antero-superior movement of the hyoid bone was detected both in short- and long-term follow-up CBCTs (P < 0.05), only its superior, but not the anterior movement was found to be associated with an increased lateral width of the oropharyngeal minimal cross-sectional area.

CONCLUSION

Two-jaw orthognathic surgery with segmentations in dento-skeletal class II patients improved oropharyngeal airway parameters significantly in the short-, but not long-term.

Miniscrew-assisted multidisciplinary orthodontic treatment with surgical mandibular advancement and genioplasty in a brachyfacial Class II patient with mandibular asymmetry

This article describes the complex dental treatment of a 43-year-old man with skeletal Class II, mandibular asymmetry, severe brachyfacial pattern, Class II Division 2, canting of the occlusal plane, and an increased curve of Spee. To achieve optimal results, we adopted a multidisciplinary approach to treatment, involving periodontics, oral surgery, orthodontics, maxillofacial surgery, and prosthetics specialists. After periodontal treatment, miniscrews were placed to correct the occlusal plane canting and the excessive curve of Spee with orthodontic treatment. The surgical treatment plan consisted of a bilateral asymmetric sagittal split osteotomy for mandibular advancement and genioplasty. The patient had an infection after the surgery at the site of the right fixation plate, so the plate was removed, and active orthodontic treatment was continued and finished. Mandibular first molar implants and maxillary ceramic crowns using the Digital Smile Design method (Digital Smile Design, Doral, FL) were placed at the end of orthodontic treatment. The patient was satisfied with the treatment results and with his facial and dental appearance, as well as his oral function. The 2-year follow-up pictures show a stable result both esthetically and functionally.

How does mandibular advancement with or without maxillary procedures affect pharyngeal airways? An overview of systematic reviews

BACKGROUND

Mandibular advancement surgery may positively affect pharyngeal airways and therefore potentially beneficial to obstructive sleep apnea (OSA).

OBJECTIVE

To collect evidence from published systematic reviews that have evaluated pharyngeal airway changes related to mandibular advancement with or without maxillary procedures.

METHODOLOGY

PubMed, EMBASE, Web of Science, and Cochrane Library were searched without limiting language or timeline. Eligible systematic reviews evaluating changes in pharyngeal airway dimensions and respiratory parameters after mandibular advancement with or without maxillary surgery were identified and included.

RESULTS

This overview has included eleven systematic reviews. Maxillomandibular advancement (MMA) increases linear, cross-sectional plane and volumetric measurements of pharyngeal airways significantly (p<0.0001), while reducing the apnea-hypopnea index (AHI) and the respiratory disturbance index (RDI) significantly (p<0.0001). Two systematic reviews included primary studies that have evaluated single-jaw mandibular advancement, but did not discuss their effect onto pharyngeal airways. Based on the included primary studies of those systematic reviews, single-jaw mandibular advancement was reported to significantly increase pharyngeal airway dimensions (p<0.05); however, conclusive long-term results were lacking.

CONCLUSION

MMA increases pharyngeal airway dimensions and is beneficial to patients suffering from OSA. However, more evidence is still needed to draw definite conclusion related to the effect of single-jaw mandibular advancement osteotomies on pharyngeal airways.

Long-term influence of mandibular advancement on the volume of the posterior airway in skeletal Class II-patients: a retrospective analysis

In the past, maxillomandibular advancement has resulted in considerable improvement in the volume of the posterior airway space. The objective of the present study was to find out how mandibular advancement without maxillary involvement would affect the posterior airway space in patients with mandibular retrognathism. Cone-beam computed tomographic (CT) scans were done for 20 patients before, and six months after, mandibular advancement. Cephalometric analysis at both time points included 2-dimensional and 3-dimensional assessment of the upper airway. Eight men and 12 women presented a preoperative mean (SD) Wits value of 7.4 (1.54) mm, with an airway area of 7.11 (1.88) cm² and a volume of 14.92 (4.46) cm³. Six months postoperatively they showed a Wits value of 2.7 (0.41) mm, an airway area of 11.33 (3.49) cm², and a volume of 25.7 (6.10) cm³. There was a mean (range) enlargement of 59 (22-82) % of the area and 73 (29-108) % of the volume. A preoperative Wits value of 8mm or more correlated significantly with a larger increase of the posterior airway space (p=0.002). At the same time, an improvement in the Wits value of 4.5mm or more correlated significantly with an increase in volume (p=0.016). The effect of mandibular advancement on the posterior airway space was significant, and the volumetric effect seems to be even more relevant than the two-dimensional changes.

Evaluation of the oropharynx in class I and II skeletal patterns by CBCT

PURPOSE

This study aimed to evaluate the dimensions of the oropharynx and its shape in the minimum cross-sectional area, in individuals with Class I and Class II skeletal patterns, using three-dimensional CBCT images.

METHODS

Forty-two cone-beam computed tomography images of grown individuals were evaluated. The images were divided according to the patient's skeletal patterns. The dimensions of the oropharyngeal airway space were determined using the Dolphin Imaging software.

RESULTS

The volume and the minimum cross-sectional area were greater in patients with a Class I skeletal pattern, with a median difference of 5379 mm³ and 86.8 mm², respectively. The anteroposterior and lateral diameters in the minimum cross-sectional area were also higher in Class I individuals (2.3 and 6.0 mm, respectively), but the ratio between them was not different.

CONCLUSIONS

The volume and the minimum cross-sectional area of the oropharynx, as well as the anteroposterior and lateral diameters, are lower in individuals with a class II skeletal pattern than in individuals with a class I skeletal pattern. There was no difference in the shape of the oropharynx in healthy individuals with different skeletal patterns.

A retrospective cephalometric study on pharyngeal airway space changes after rapid palatal expansion and Herbst appliance with or without skeletal anchorage

Background

The aim of this study is to investigate the pharyngeal airway space changes in patients treated with rapid palatal expansion (RPE) and Herbst appliance with or without skeletal anchorage.

Methods

A 40-patient study group treated with the Herbst RME combination was included; moreover, a comparison between two subgroups based on whether miniscrews were used was evaluated. A subgroup 1 included 20 patients who were treated with RPE and an acrylic splint Herbst with miniscrews, and subgroup 2 included 20 patients who were treated with RPE and an acrylic splint Herbst. A cephalometric analysis was performed before (T1) and after (T2) treatment. The skeletal parameters of the sagittal occlusion analysis of Pancherz were utilized together with some extra measurements to evaluate the airways.

Results

An increased nasopharyngeal airway space was observed in group 1 (p < 0.05) from T1 to T2. Furthermore, the increase in nasopharyngeal airway space was significantly higher in subgroup 1 (p < 0.05) in comparison to the subgroup 2. Oropharyngeal (OA) and laryngopharyngeal (LA) dimensions were significantly increased in the subgroup 1 at the end of the treatment. In the subgroup 1, a significant decrease in SNA, a significant increase in SNB, and a significant decrease in ANB were observed from T1 to T2. In the subgroup 2, the treatment resulted in a significant decrease in ANB. In both groups, Pogonion increased significantly from T1 to T2.

Conclusions

The results suggest that the RPE and the Herbst appliance allow a slight improvement of the sagittal dimensions of the airways. The oropharyngeal dimension increased significantly more in the skeletal anchorage group.

Sleep-disordered breathing in orthodontic practice: Prevalence of snoring in children and morphological findings

OBJECTIVES

The purpose of this work was to evaluate the prevalence of snoring and its correlation with cranial and upper airway morphology in young individuals with orthodontic treatment need.

PATIENTS AND METHODS

Parents of 379 children were consecutively interviewed, using eight questions from a more comprehensive questionnaire about sleep behavior. A total of 100 patients (54 girls, 46 boys, average age 11.3 years) met the inclusion criteria. Based on the parents' interviews, the sample was divided into snorers (n = 53) and nonsnorers (n = 47). Using cephalograms obtained for initial orthodontic diagnostics, airway morphology was measured based on hyoid position and on the posterior airway space (PAS) dimensions at the maxillary, occlusal, and mandibular plane levels (PAS_NL, PAS_OCCL, PAS_ML). Mann-Whitney U testing, ANOVA, and Spearman's rank correlation coefficient were used for statistical analysis.

RESULTS

Snoring was reported by 53 % of parents for 63 % (n = 29) of the boys and 44 % (n = 24) of the girls. Significant morphological differences were noted between snorers and nonsnorers. PAS dimensions were significantly reduced in the snorers compared to the nonsnorers at all three anatomical levels tested, which remained statistically significant when adjusted for age and gender. No differences between the two groups emerged for hyoid position or any of the vertical cranial parameters. A significant correlation between sagittal maxillary position (SNA) and PAS_NL was noted, indicating that larger SNA values were mildly associated with larger sagittal PAS dimensions at the maxillary level.

CONCLUSION

This random sample of young patients with orthodontic treatment need was found to involve a high prevalence of parent-reported snoring. Characteristic features in cranial and upper airway morphology and thus differences between the snorers and nonsnorers were found.

Correlation between hyoid bone position and airway dimensions in Chinese adolescents by cone beam computed tomography analysis

This study aimed to investigate the correlation between upper airway dimensions and hyoid bone position in Chinese adolescents based on cone beam computed tomography (CBCT) images. CBCT images from a total of 254 study subjects were included. The upper airway and hyoid bone parameters were measured by Materialism's interactive medical image control system (MIMICS) v.16.01 (Materialise, Leuven, Belgium). The airway dimensions were evaluated in terms of volume, cross-sectional area (CSA), mean CSA, length, anteroposterior dimension of the cross-section (AP), lateral dimension of the cross-section (LAT), and LAT/AP ratio. The hyoid bone position was evaluated using eight linear parameters and two angular parameters. Facial characteristics were evaluated using three linear parameters and three angular parameters. Most hyoid bone position parameters (especially the distance between the hyoid bone and hard palate) were significantly associated with most airway dimension parameters. Significant correlations were also observed between the different facial characteristic parameters and hyoid bone position parameters. Most airway dimension parameters showed significant correlations with linear facial parameters, but they displayed significant correlations with only a few angular facial parameters. These findings provide an understanding of the static relationship between the hyoid bone position and airway dimensions, which may serve as a reference for surgeons before orthodontic or orthognathic surgery.

Evaluation of Pharyngeal Space in Different Combinations of Class II Skeletal Malocclusion

Objectives:

The study was aimed to evaluate the pharyngeal airway linear measurements of untreated skeletal class II subjects with normal facial vertical pattern in prognathic maxilla with orthognathic mandible and orthognathic maxilla with retrognathic mandible.

Materials and method:

the sample comprised of lateral Cephalograms of two groups (30 each) of class II malocclusion variants. Group 1 comprised of class II malocclusion with prognathic maxilla and orthognathic mandible, whereas group 2 comprised of class II malocclusion with orthognathic maxilla and retrognathic mandible. Each group was traced for the linear measurements of the pharyngeal airway like the oropharynx, nasopharynx and soft palate. The obtained data was subjected to independent t test and the Mann Whitney test to check the difference between the two groups and within the groups respectively.

Results:

there was significant difference between all the linear measurements at the soft palate region and the distance between the tip of soft palate to its counter point on the pharyngeal wall in oropharynx region (p-ppm).

Conclusion:

the pharyngeal airway for class II malocclusion with various combination in an average growth pattern adult showed significant difference. The present results suggested, that the pharyngeal airway space might be the etiological factor for different sagittal growth pattern of the jaws and probable usage of different growth modification appliance can influence the pharyngeal airway.

Gender-related difference in the upper airway dimensions and hyoid bone position in Chinese Han children and adolescents aged 6-18 years using cone beam computed tomography

OBJECTIVE

To investigate the gender-related differences in upper airway dimensions and hyoid bone position in Chinese Han children and adolescents (6-18 years) using cone-beam computed tomography (CBCT).

MATERIALS AND METHODS

CBCT-scans of 119 boys and 135 girls were selected and divided into four groups (group 1: 6-9 years; group 2: 10-12 years; group 3: 13-15 years; group 4: 16-18 years). The airway dimensions including the cross-sectional area (CSA), anteroposterior (AP) and lateral (LAT) width, length (L), mean CSA and volume (VOL) of upper airway segmentations and hyoid bone position including 11 linear and three angular measurements were investigated using Materialism's interactive medical image control system (MIMICS) 16.01 software. Gender-related differences were analyzed by two independent sample t-tests.

RESULTS

No gender-related difference was found in values of the facial morphology, airway dimensions and hyoid bone position for group 1 (p > 0.05). The children and adolescents in groups 2, 3 and 4 showed significant gender-related differences in the measurement results of facial morphology, airway dimensions and hyoid bone positions (p < 0.05). What's more, the measurement values of boys were obviously larger than those of girls except some measurements in group 2.

CONCLUSIONS

The measurements of airway dimensions and hyoid bone positions have gender-related differences in children and adolescents aged 10-18 years. These results could be taken into consideration during orthodontic diagnosis and treatment.

Effects of varying mandibular protrusion and degrees of vertical opening on upper airway dimensions in apneic dentate subjects

INTRODUCTION

Despite numerous studies investigating the dimensional and therapeutic effects of mandibular advancement splints (MASs), data regarding the effects of differently designed individual and non-adjustable MASs on the upper airway in fully dentate apneic subjects in the sagittal plane including comparison of these effects with a placebo device are sparse. The present study aimed to determine the dimensional changes in the sagittal plane created by differently designed MASs in the upper airway in fully dentate apneic subjects and to compare these changes with the effects of a placebo device.

MATERIALS AND METHODS

Magnetic resonance (MR) images of 9 dentate apneic subjects with 5 differently designed MASs and without a MAS were obtained. We measured the area of the entire pharynx (velopharynx, oropharynx, hypopharynx) on these MR images and compared the dimensional changes.

RESULTS

The dimensional changes triggered by two specific MASs (75% of the maximum mandibular protrusion with 5 mm vertical opening, and 75% of the maximum mandibular protrusion with 10 mm of vertical opening) in the entire pharynx in the sagittal plane were statistically significant compared to the other MASs (p < 0.05). The MAS effecting 75% of the maximum mandibular protrusion and 10 mm of vertical opening created a significant dimensional increase only in the velopharyngeal area among the three pharyngeal sites (p ≤ 0.003).

CONCLUSION

While the degree of mandibular protrusion created by the MAS affects the dimensions of the upper airway, the degree of the vertical opening exerts no significant dimensional effect in the sagittal plane in fully dentate apneic patients. The mandibular protrusion effect is comparatively larger in the velopharyngeal region.

Skeletal, soft tissue, and airway changes following the alternate maxillary expansions and constrictions protocol

OBJECTIVE

To evaluate the skeletal, soft tissue, and airway effects of the alternate maxillary expansions and constrictions (Alt-RAMEC) protocol in prepubertal patients.

MATERIALS AND METHODS

The appliance containing a double-hinged expansion screw was applied to 20 patients with Class III skeletal malocclusion characterized by maxillary retrognathia. The mean age of the study group was 9 years and 8 months. The patients' parents were instructed to open the screw by 1 mm per day during the first week and to close it by 1 mm per day the week after. This alternate opening and closing was repeated for 9 consecutive weeks. Cone beam computed tomography records and three-dimensional photographs were taken before treatment and after 9 week of the Alt-RAMEC protocol.

RESULTS

Point A moved slightly forward (0.89 mm) and downward (0.92 mm) (P < .05). The average amount of expansion achieved at the level of point A was 5.54 mm (P < .05). Besides the maxilla, the expansive forces also affected the nasal bone, the zygomaticomaxillary and zygomaticotemporal sutures (P < .05). The soft tissue nasal width increased significantly. The airway volume of the anterior nasal compartment and the nasal cavity also increased (P < .05).

CONCLUSIONS

Slight forward movement of point A occurred with the Alt-RAMEC protocol. The expansion affected not only the maxilla but also other structures of the face. Significant cutaneous changes occurred in the paranasal area. Some significant increase in the upper airway volume was obtained.