Effects of Herbst and Pendex appliances treatment on the upper airway: A cone-beam computed tomography analysis.

BACKGROUND Skeletal malocclusions occur because of the defect in the underlying skeletal structure. Mandibular skeletal retrusion is the most common characteristic of class II malocclusion. The purpose of this study was to evaluate pharyngeal airway dimension in Class II patients treated with Herbst appliance and fixed mechanotherapy using cone beam computed tomography (CBCT). METHODS This comparative study was conducted among 30 Class II patients (9 to 15 years of age) selected from the outpatient department of orthopaedics. They were divided into 2 Groups; Group I (15 patients) was treated by Herbst appliance; Group II (15 patients) was treated by fixed mechanotherapy. Pharyngeal airway volume, length and width evaluation were done using CBCT in vivo dental software 5.1 (ANATOMAGE, San Jose, CA). Intergroup comparison was done using independent t tests and level of significance (P < 0.05). Correlation of parameters were carried out using Pearson’s correlation test. RESULTS Significant increase in nasopharyngeal, velopharyngeal, glossopharyngeal, laryngopharyngeal, and total airway volume in Herbst group was observed. Velopharyngeal length, glossopharyngeal length and nasopharyngeal airway width showed significant increase in Herbst group. CONCLUSIONS Treatment of Class II patients with Herbst appliance resulted in increase in pharyngeal airway volume. Herbst therapy induced repositioning of tongue resulting in increased length due to posterior fall of uvula, and hence airway volume increased drastically. KEY WORDS Airway Volume, Herbst Appliance, Class II Malocclusion, Retrognathic Mandible

To evaluate the changes of maxillary expansion and upper airway structure after microimplant assisted rapid palatal expansion (MARPE) using cone-beam computed tomography (CBCT). This retrospective study included 19 subjects (15 females and 4 males) aged 15-29 years old (mean, 19.95±4.39 years) with maxillary transverse deficiency treated with MARPE. CBCT was performed at the initial diagnosis and 3 months after MARPE treatment. Measurements were taken to evaluate the amount of total expansion, skeletal expansion, and dental expansion at the maxillary first premolar (P1), second premolar (P2), first molar (M1), second molar (M2) regions and upper airway changes. After MARPE treatment, the maxillary skeletal base expansion, skeletal expansion, alveolar expansion and dental expansion were achieved at the P1, P2, M1, M2 region. The nasopharyngeal volume significantly increased 8.48% after MARPE treatment compared with that before the treatment (P < 0.05). The change of nasal lateral width (NLW) was also significantly different before and after MARPE (P < 0.05). However, there were no statistically significant change in the oropharyngeal, palatopharyngeal, glossopharyngeal and airway total volume (all P > 0.05). MARPE can produce more transverse bone expansion, relieve maxillary transverse deficiency and improve upper airway ventilation.

Background: Rapid maxillary expansion (RME) is a common orthodontic procedure that widens the maxillary arch to treat moderate to mild overcrowding and transverse skeletal and dental abnormalities. Orthodontic equipment applies lateral tension on posterior maxilla teeth or palate mucosa to the mid-palatal suture. The maxilla may grow transversely when force is applied at right angles to the mid-palatal suture, which is usually inactive in children and adolescents. This study used cone-beam computed tomography (CBCT) and an authorized upper respiratory airway volume measurement approach to compare RME cohort pharyngeal airway volume changes to healthy controls. Materials and Methods: This retrospective analysis included 52 RME patients and 52 healthy controls. The RME category's expansion regimen entailed twisting the screw of expansion on a tooth-attached Hyrax-type expansion equipment by 0.25 mm daily for at least 14 days. After six months, a few RME participants used fixed orthodontic gear. The comparison group used fixed orthodontic appliances for minor malocclusions without extractions (without RME). CBCT scans from 1021 orthodontic patients who visited a dental hospital between 2012 and 2022 were examined. The registry comprised only anonymized photographs. Volume, minimum cross-sectional area (MCA), molar width, and inter-molar width were measured before and after therapy. Results: The control group had 12227.12 mm3 at T0 and 15805.54 mm3 at T1. The control group's T0-T1 volume difference was statistically significant (p = 0.007). The RME group has 12884.84 mm3 at T0 and 17471.08mm3 at T1. The RME group had a significant volume difference at T0 and T1 (p = 0.002). The volume RME effect was ±1011.92and statistically insignificant. (p > 0.05). MCA in the control group was 126.04 mm2 at T0 and 170.61 mm2at T1. MCA at T0 and T1 in the control group was statistically significant (p = 0.041). RME group MCA was 126.53 mm3 at T0 and 164.69 mm2 at T1. The RME group had a significant volume difference at T0 and T1 (p = 0.002). The MCA, RME effect was 5.92 and statistically insignificant (p > 0.05). Both the control and RME groups had statistically significant volume and MCA differences at T0 and T1. However, the intergroup analysis showed no significant differences across the groups. Conclusion: Tooth-borne RME does not affect upper airway or MCA volume in children compared to controls. Upper airway changes were better with younger skeletal ages before treatment. The findings may aid RME for young children.

Background and Objectives: Obstructive sleep apnea (OSA) is a sleep-related breathing disorder, characterized by disrupted snoring and repetitive upper airway obstructions. Continuous positive airway pressure (CPAP) is considered the therapeutic mainstay for OSA patients. However, CPAP therapy has compliance limitations. An alternative treatment options is maxillomandibular advancement (MMA) surgical procedure. Genial tubercle advancement (GTA) is often performed concomitant with MMA for esthetic purposes. Cone-beam computed tomography (CBCT) provides the ability to visualize the upper airway and perform three-dimensional (3D) reconstructions. The purpose of this study is to evaluate the impact of MMA procedure with or without GTA on oropharyngeal airway space in OSA patients and the stability after completion of orthodontic treatment. Methods: A total of 25 patients (18 females and 7 males) with a mean age of 37.1 ± 17.3 years were included in the study. CBCT scans were taken before treatment (T1); after pre-surgical orthodontic treatment (T2); immediately after MMA procedure (T3); and at 10 months follow-up visit (T4). Thus, (T2-T1) represented changes due to orthodontic treatment only; (T3–T2) represented changes due to MMA procedure; and (T4-T3) represented changes due to follow-up after surgery. Each patient served as his/her own control. Fifteen of the individuals underwent MMA with GTA. All DICOM files were analyzed using Dolphin 3D Imaging software program to determine total airway volume (TAV), airway area (AA) and minimum axial area (MAA) at explicit regions along the posterior airway space. Dolphin 3D voxel-based superimposition was used to determine the amount of skeletal advancement with MMA and changes after surgery. Results: Significant increase in TAV, AA and MAA was found with MMA treatment (40.61%; 28.77%; and 56.40%, respectively, p Conclusions: Significant increase in OPAS can be expected with MMA surgery with or without GTA procedure in patients diagnosed with OSA. Significant forward movement of the maxilla, mandible and chin positions can be obtained with MMA procedure. A partial loss in OPAS was found during the 10 months follow-up period. The surgical movements were found to be stable with less than 1 mm of relapse during the follow-up period, which was not clinically significant.

3D analysis of upper airway morphology related to obstructive sleep apnea severity

IntroductionMouth breathing (MB) is a dysfunctional respiratory pattern that may affect craniofacial development by altering maxillary arch width and upper pharyngeal airway morphology. Early identification is critical to prevent long-term dentofacial and airway complications. This study aimed to compare maxillary arch width and upper airway morphology between mouth- and nasal-breathing children aged 10–12 years using Cone Beam Computed Tomography (CBCT).Materials and methodsIn this cross-sectional study, 30 children (15 mouth breathers and 15 nasal breathers) underwent CBCT imaging. Transverse maxillary arch dimensions were measured at four points: maxillary width at molars (MWM), intermolar width (IMW), maxillary width at canines (MWC), and intercanine width (ICW). Upper airway morphology was assessed using volumetric (nasopharyngeal volume [NPV], oropharyngeal volume [OPV]) and cross-sectional area (nasopharyngeal area [NPA], oropharyngeal area [OPA]) measurements. Independent t-tests were used to compare group differences with 95 % confidence level.ResultsThe MB group showed significantly reduced maxillary arch widths (MWM, IMW, MWC, ICW) and diminished upper airway volume and area (NPV, OPV, NPA, OPA) compared to nasal breathers (p < 0.001 for all parameters).ConclusionMouth breathing in school-aged children is associated with measurable reductions in maxillary arch width and upper pharyngeal airway dimensions.

This study analyzed the differences in the upper airway of patients with skeletal Class III high-angle malocclusion with and without mandibular deviation, and further investigated whether there are differences in the changes in upper airway space after orthognathic surgery between the two groups. 15 patients with skeletal Class III high-angle malocclusion and mandibular deviation, and 15 patients without mandibular deviation were selected to explore the impact of mandibular deviation on the upper airway. Additionally, 16 patients with mandibular deviation undergoing orthodontic-orthognathic combined treatment, and 13 patients without mandibular deviation, were selected to investigate the differences in the changes in upper airway space after orthognathic surgery between the two groups. In patients with skeletal Class III high-angle malocclusion, the deviation group showed significantly smaller sagittal diameter/maximum transverse diameter, cross-sectional area, volumes of oropharynx and hypopharynx, and total volume compared to the normal group, with all differences being statistically significant. After orthognathic surgery, the postoperative sagittal diameter/maximum transverse diameter of the oropharyngeal airway increased in the deviation group, while it decreased in the normal group. The postoperative reductions in cross-sectional area, volumes, and total volume of the oropharynx and hypopharynx were more pronounced in the normal group. In patients with skeletal Class III high-angle malocclusion, mandibular deviation results in narrowing of the lower portion of the upper airway. The orthognathic surgical correction of mandibular deviation compensates to some extent for the reduction in the cross-sectional area and volume of the upper airway caused by the surgery itself. For patients with skeletal Class III high-angle malocclusion with mandibular deviation, a thorough assessment of the upper airway should precede the selection of orthognathic surgery procedures. For patients with normal preoperative upper airway morphology, consideration may prioritize correction of facial aesthetics and occlusion. For patients with pre-existing narrow upper airways, as mandibular setback exacerbates narrowing and the compensatory effect of mandibular deviation correction on the airway is limited, it is suggested that these patients prioritize bimaxillary surgery or reduce the amount of mandibular setback to better promote postoperative respiratory function health.

Objective:To investigate the pathogenesis of OSA-related through 128-slice spiral CT measurements of adult male patients with moderate to severe OSA at different respiratory phases, and to optimize treatment options for patients with OSA. Method:128-slice spiral CT was used to scan the upper airway in 52 adult male patients with moderate to severe OSA and 20 normal controls under two different breathing states: calm breathing and Müller maneuver. The plane diameter and length of each area of the upper airway were measured. Area size, soft palate length, thickness, airway volume, airway length, total thickness of the pharyngeal wall, and calculate the compliance of the pharyngeal cavity, including the compliance of the pharyngeal wall, the compliance of the anterior and posterior pharyngeal wall, and the total pharyngeal compliance. Comparison of measurement results and correlation analysis with related parameters.Result: In the OSA group, the length and area of the smallest plane of each airway area（except the posterior epiglottic area） during calm breathing are greater than Müller's movement, and the difference was statistically significant（P<0.05）. The soft palate length and thickness of the OSA group during calm breathing were significantly larger than those of the normal group, and the difference was statistically significant（P<0.01）, In the OSA group, the total thickness of the soft palate region and the posterior lingual area of the pharyngeal wall in the Müller group was significantly greater than the calm breathing state, and the difference was statistically significant（P<0.01）. The volume of the nasopharynx, posterior epiglottic area and airway length in the OSA group during calm breathing were significantly larger than those in the normal group, and the difference was statistically significant（P<0.01）. The compliance of the pharyngeal cavity in the OSA group was greater than that in the normal group, and the difference was statistically significant（P<0.05）. In the OSA group, the volume of the posterior soft palate, posterior tongue, and total airway volume during Müller movement were significantly smaller than those of calm breathing, and the differences were statistically significant（P<0.01）. In the OSA group, the compliance of the pharyngeal wall in the posterior region of the soft palate was greater than the compliance of the anterior and posterior wall of the pharynx, while the compliance of the posterior region of the pharynx in the posterior region of the pharynx was greater than the compliance of the pharynx. There was a significant positive correlation between BMI and AHI in OSA patients（P<0.05）, which was statistically significant. Conclusion:Through MSCT measurement of the upper airways of adult male patients with moderate to severe OSA, the morphological structure and compliance of the upper airways can be observed intuitively, and the degree and location of upper airway stenosis can be accurately assessed, and the measurement indicators and related parameters can be combined. The correlation can optimize the clinical treatment options for adult male patients with OSA.

Three-dimensional changes of the upper airway in patients with Class II malocclusion treated with the Herbst appliance: A cone-beam computed tomography study

The Pharyngeal Airway: Is Bigger Really Better?

Herbst appliance anchored with miniscrews: Some unsettled questions

Background:Obstructive sleep apnea (OSA) is caused by narrowing or obstruction of the airway lumen at single or multiple levels of the airway, starting from the nasal cavity up to the larynx. Oral appliance therapy for the management of OSA is prescribed as an alternative treatment option for patients with mild to moderate OSA who fail to adhere to Continuous Positive Airway Pressure (CPAP) therapy. Treatment with oral appliances addresses the craniofacial deficiencies that cause OSA by providing means to mandibular advancement and palatal expansion, thus opening the airways and potentially preventing airway collapse during sleep. Imaging the upper airway is employed to investigate the narrowing or the obstruction in the airway. Three-dimensional imaging modalities such as cone beam computed tomography (CBCT) allow for detecting obstructions before commencing treatment and for evaluating changes in the upper airway dimensions after treatment. To evaluate the effect of the biomimetic oral appliance therapy (BOAT) device on the airway measurements taken from a CBCT before and after treatment in correlation with the changes in the AHI.Trial design:A non-randomized clinical trial.Methods:About 17 patients with mild-moderate OSA (9 males, 8 females; age, mean [SD]: 45.76 [10.31]) underwent BOAT therapy. Subjects had 2 months of follow-up visits, including examinations for progress and adjustment of the appliances. The mean apnea–hypopnea index (AHI) with no appliance in the mouth before BOAT and after treatment was recorded. The midpalate screw mechanism of the appliance was advanced once per week. The subjects were asked to wear the appliance for 10 to 12 h/d and night. Pre and Post CBCT were taken. Paired T-test was used to analyze the results.Results:The treatment duration was 15.4 ± 6.3 months. Before treatment, at the diagnosis stage, the mean AHI of the sample (n = 17) was 24.0. After treatment, the mean AHI fell by 5% to 22.8% (P = .019), indicating enhanced upper airway functions. Airway measurements from the CBCT were not statistically significant despite improvement in the polysomnographic parameters.Conclusion:CBCT is a valuable tool for airway assessment and the determination of upper airway anatomic risk factors for OSA.

PurposeTo compare the anatomical balance and shape of the upper airway in the supine position between adults with positional obstructive sleep apnea (POSA) and adults with non-positional OSA (NPOSA).MethodsAdults diagnosed with OSA (apnea-hypopnea index (AHI) > 10 events/h) were assessed for eligibility. POSA was defined as the supine AHI more than twice the AHI in non-supine positions; otherwise, patients were classified as NPOSA. Cone beam computed tomography (CBCT) imaging was performed for every participant while awake in the supine position. The anatomical balance was calculated as the ratio of the tongue size to the maxillomandibular enclosure size. The upper airway shape was calculated as the ratio of the anteroposterior dimension to the lateral dimension at the location of the minimal cross-sectional area of the upper airway (CSAmin-shape).ResultsOf 47 participants (28 males, median age [interquartile range] 56 [46 to 63] years, median AHI 27.8 [15.0 to 33.8]), 34 participants were classified as having POSA (72%). The POSA group tended to have a higher proportion of males and a lower AHI than the NPOSA group (P = 0.07 and 0.07, respectively). After controlling for both sex and AHI, the anatomical balance and CSAmin-shape were not significantly different between both groups (P = 0.18 and 0.73, respectively).ConclusionAdults with POSA and adults with NPOSA have similar anatomical balance and shape of their upper airway in the supine position.Trial registrationThis study was registered with the Australian New Zealand Clinical Trials Registry (ANZCTR Trial ACTRN12611000409976).

The main aim of this study was to analyze the volume and area of the pharyngeal airway among different sagittal skeletal relationships. The secondary aim was to study the association between the upper airway volume and upper airway cross-sections among the three sagittal skeletal relationships. A retrospective study of 90 cone beam computed tomography (CBCT) scans of patients reporting for dental treatment to University Dental Hospital, Sharjah was conducted. Among the 90 CBCT scans, 30 scans were of patients with class I skeletal pattern, 30 with class II skeletal pattern, and 30 with class III skeletal pattern. The extract airway module of Romexis software 6.2.1 was used for segmentation of the upper airway. The maximum cross-sectional area (MACA), minimum cross-sectional area (MICA), cross-sectional area at the level of the hard palate cross-sectional area (PCA), and cross-sectional area at the level of the epiglottis cross-sectional area (ECA) of the airway way and volume (Vol) were obtained. There was a significant difference in the cross-sectional airway variables (MACA, MICA, ECA) and volume among patients with class I, II, and III skeletal malocclusion (p &lt; 0.001). The PCA did not show any significant difference among the three study groups (p = 0.13). Patients with skeletal class II malocclusion had the lowest cross-sectional airway variables and volume values among all the study groups. The MICA of the airway was a reliable predictor for airway volume.

The Twin Block (TWB) appliance is widely employed for treating Class II malocclusion in children and adolescents. This study aimed to evaluate the three-dimensional treatment effects of the TWB on the upper airway and temporomandibular joint (TMJ), and to investigate the association between airway changes and TMJ alterations. This retrospective study examined 24 cone-beam computed tomography (CBCT) scans from 12 patients (mean age, 12.30 ± 1.24 years) diagnosed with Class II Division 1 malocclusion and treated with the TWB appliance. CBCT scans were acquired both at pretreatment (T0) and posttreatment (T1). Romexis 6.2.1 imaging software was used to assess changes in the upper airway and TMJ. The paired t-test was used to compare the pretreatment and posttreatment measurements, while Pearson correlation coefficient analysis evaluated the relationship between the upper airway and TMJ measurements. A statistically significant increase was observed in the upper airway volume, condylar volume, and condylar dimensions after treatment. No significant correlation was detected between the upper airway and TMJ measurements at T0, T1, or in the net changes (T1-T0) during TWB therapy. Growing patients treated with the TWB appliance demonstrated a statistically significant increase in upper airway volume. In addition, there was a significant increase in condylar volume, width, and length, with the condyle repositioned more anteriorly within the glenoid fossa. However, no statistically significant correlation was found between the TMJ and upper airway measurements.