Oropharyngeal Airway Dimensions Research Articles

Effect of premolar extraction and anchorage type for orthodontic space closure on upper airway dimensions and position of hyoid bone in adults: a retrospective cephalometric assessment.

This study aimed to assess the effect of premolar extraction and anchorage type for orthodontic space closure on upper airway dimensions and position of hyoid bone in adults by cephalometric assessment. This retrospective study was conducted on 142 cephalograms of patients who underwent orthodontic treatment with premolar extraction in four groups of (I) 40 class I patients with bimaxillary protrusion and maximum anchorage, (II) 40 class I patients with moderate crowding and anchorage, (III) 40 class II patients with maximum anchorage, and (IV) 22 skeletal class III patients with maximum anchorage. The dimensions of the nasopharynx, velopharynx, oropharynx, and hypopharynx, and hyoid bone position were assessed on pre- and postoperative lateral cephalograms using AudaxCeph v6.1.4.3951 software. Data were analyzed by the Chi-square test, paired t-test, and Pearson's correlation test (alpha = 0.05). A significant reduction in oropharyngeal, velopharyngeal, and hypopharyngeal airway dimensions was noted in groups I, III, and IV (P<0.001), which was correlated with the magnitude of retraction of upper and lower incisors (r=0.6-0.8). In group II, a significant increase was observed in oropharyngeal and velopharyngeal dimensions (P<0.001). A significant increase in nasopharyngeal dimensions occurred in all groups (P<0.001). Also, in groups I and III, the position of hyoid bone changed downwards and backwards, which was correlated with reduction in airway dimensions (r=0.4-0.6). According to the present results, extraction orthodontic treatment affects upper airway dimensions and hyoid bone position. Maximum anchorage decreases airway dimensions while moderate anchorage increases airway dimensions.

Evaluation of Hard Tissue, Soft Tissue and Airway Changes Post Twin Block Therapy: An In-vitro Study

Introduction: Aesthetic improvement happens to be one of the main reasons for seeking orthodontic treatment in patients with Angle’s Class II malocclusion. Prognathic maxilla, retrognathic mandible or a combination of both are the main aetiological factors for this malocclusion. Growth modification treatment with different methods can be performed in order to correct skeletal class II malocclusion. Appliance therapy to correct similar malocclusions should immaculately be directed towards addressing the dentoskeletal discord, in order to gain a favourable facial aesthetic result. Aim: To assess the effects of twin block on mandibular length, soft tissue profile and Oropharyngeal Airway (OAW) dimensions in skeletal class II malocclusion patients. Materials and Methods: An in-vitro study was carried out in the Department of Paedodontics at Sardar Patel Postgraduate Institute of Dental and Medical Sciences, Lucknow from June 2018 to March 2021. Study was done on lateral cephalograms of 15 growing children with Angle’s Class II Division 1 malocclusion in the age group of 9-12 years, who had undergone functional appliance therapy with twin block appliance. Standardised lateral cephalograms were evaluated at pretreatment (0 month) and postactive phase of twin-block therapy (9-12 months). Selected hard tissue, soft tissue and airway landmarks were marked and traced to evaluate hard tissue, soft tissue and airway changes. The data was analysed using statistical package for social sciences (SPSS) version 21. Results: There was a statistically significant increase in effective mandibular length (Condyle-Gnathion) and mandibular base length Gonion-Pogonion (Go-Pog) values (p&lt;0.001). Significant decrease in the facial convexity Glabella- Soft tissue Nasion (G-Sn) Soft tissue Nasion- Soft tissue Pogonion (Sn-Pog) was observed and airway dimensions showed significant increase after twin block therapy. Conclusion: Correction of Class II malocclusion by twin block appliance resulted in significant cephalometric changes in the hard tissue profile (increase in mandibular length), together with clinically favourable soft tissue changes and OAW dimensions.

Pharyngeal airway dimensions in Iranian female young adults with different skeletal patterns using cone-beam computed tomography

To assess the oropharyngeal airway in Iranian female young adults with different skeletal patterns using cone-beam computed tomography (CBCT).This descriptive, cross-sectional study evaluated 105 CBCT scans of female patients between 18 and 35 years retrieved from the archives of a radiology clinic. The images were evaluated in axial, sagittal, and frontal sections. In the axial plane, the maximum and minimum cross-sectional area (CSA) of the airways at the oropharynx, minimum width (anteroposteriorly), and minimum depth (laterally) were measured using Mimics Medical software. The oropharyngeal volume was measured by NemoFAB software. The values were compared among the groups with different sagittal, vertical, and transverse patterns. The correlation of indices with airway measurements was analyzed using Monte Carlo Chi-square and Pearson's correlation coefficient.No significant difference was noted in oropharyngeal airway dimensions and volume among cases with different skeletal sagittal, vertical, and transverse patterns (P > 0.05) except for class III patients with normal transverse pattern in whom maximum CSA in low-angle group was larger than that in normal-angle group (P < 0.05) and class I normal-angle patients in whom maximum CSA in transverse normal group was smaller than that in constriction group (P < 0.05).Oropharyngeal dimensions were not significantly different in Iranian female young adults with different skeletal patterns.

Tongue Adaptation and Airway Changes in Two Different Bracket Systems: A Randomised Clinical Trial

Introduction: Orthodontics apart from correcting the malocclusions provide an invariably indirect effects on surrounding musculature and airway by means of creating room for proper tongue posture which helps in improvement of oropharyngeal airway dimensions along with dentoalveolar corrections which in this study was experimented with two different bracket systemsMBT and Damon self-ligating systems. Aim: To assess the adaptation of tongue and oropharyngeal airway changes following treatment with two different bracket systems. Materials and Methods: This randomised clinical trial was conducted in the Department of Orthodontics, Saveetha Dental College and Hospital, Chennai, Tamil Nadu, India, and included 20 participants and categorised into two groups: Group 1 and group 2 included participants who underwent orthodontic treatment with Damon appliance therapy with Damon Copper NiTi (CuNiTi) wires and MBT prescription with Damon CuNiTi wires. Lateral cephalogram and intraoral scanning was done at the start of orthodontic treatment (T0) and after one year (T1). Cephalometric and occlusal model assessment to determine the adaptation of tongue and Oropharyngeal Dimensions (OD) were determined (T0-T1) using the Facad® and 3-shape software. Independent t-tests and paired t-tests were done to compare T0 and T1 for both the groups were done using Statistical Package for the Social Sciences (SPSS) software. Results: Results of paired t-tests showed a statistically significant difference at the Interpremolar distance (IPM1) region of both groups 1 and 2 between T0 and T1 (p=0.034, p=0.011), Intercanine distance (IC) of group 2 upper (p=0.043) and IPM2 of both the groups in the upper arch (p=0.042, p=0.022). Cephalometric results showed a significant increase in all the assessed parameters within the groups between T0 and T1 (p&lt;0.05). Oropharyngeal space did not show any difference in both the systems however comparatively increased in group 1 than in group 2. Conclusion: Treatment with Damon and MBT prescriptions with Damon Cuniti wires showed significant alterations in adaptation of tongue and oropharyngeal space and also in bringing about arch expansion in maxilla and mandible with the greatest expansion noted for first premolar of both the groups and IC and Interpremolar (2nd premolar) width of the upper arch of both the groups.

Three-dimensional evaluation of the effects of Bionator and Forsus appliances on oropharyngeal airway volume in patients with mandibular retrognathia

ABSTRACT Objective To evaluate whether there is a difference between the effects of Bionator and Forsus appliances on airway volume. Methods Forty patients with mandibular retrognathia were divided into two groups. The Bionator appliance was applied to Group 1, while the Forsus FRD EZ2 appliance was applied to Group 2. Three-dimensional images were captured before and after functional appliance use in both groups. Dolphin 3D software was used for airway measurements. Results No statistically significant difference was found between the groups in terms of volumetric and area measurements. There was a statistically significant difference between the minimum axial T and O-N border T measurements of the groups. Conclusion The use of functional appliances may contribute to an increase in oropharyngeal airway dimensions, but there was no difference between the Bionator and Forsus groups in terms of volumetric measurements.

Validation of a Finite Element Model for Clinical and Virtual Evaluation of the Changes in Airway Dimensions Following Class III Bimaxillary Orthognathic Surgery.

The aim of this study was to evaluate pharyngeal airway changes in adult skeletal Class III cases whose bimaxillary surgical treatments were planned with different amounts of maxillary and mandibular movement using lateral cephalometric radiographs and finite element analysis (FEA). Our null hypothesis was that bimaxillary orthognathic surgery in which maxillary forward movement (MF) is greater than mandibular backward movement (MB) will result in more expansion of the pharyngeal airway. A total of 31 individuals (11 females, 20 males) with class III skeletal deformity were included in the study. Patients who underwent bimaxillary orthognathic surgery with greater maxillary advancement (MF > MB) were categorized in Group 1 (n = 15), and those with greater mandibular set-back (MB > MF) as Group 2 (n = 16). Changes in airway dimensions were evaluated from lateral cephalometric radiographs. In addition, FEA modeling was used to determine pharyngeal airway changes with 5 different MF/MB combinations performed in skeletal class III bimaxillary surgeries. Nasopharyngeal and oropharyngeal airway dimensions increased in direct proportion to the amount of MF. Hypopharyngeal volume decreased compared to preoperative value in direct proportion to the decrease in MB. According to the FEA models, total pharyngeal airway volume decreased when MF was less than or equal to MB, was nearly unchanged when MF was 2mm greater than MB, and increased when MF was 4mm greater than MB. The results of FEA and lateral cephalometric analysis were compatible. Our results supported the null hypothesis. We concluded that when possible, planning slightly more maxillary advancement than mandibular set-back will not have an adverse impact on the airway. Although the skeletal deformity only causes forward displacement of the mandible, dividing the skeletal correction between the maxilla and mandible may be considered to avoid the risk to patients' quality of life in terms of respiratory function.

Does Combined Temporomandibular Joint Reconstruction With Patient-Fitted Total Joint Prosthesis and Orthognathic Surgery Provide Stable Skeletal and Occlusal Outcomes in Juvenile Idiopathic Arthritis Patients?

To determine skeletal and occlusal surgical changes and long-term stability outcomes for patients diagnosed with juvenile idiopathic arthritis (JIA) after TMJ reconstruction with TMJ Concepts patient-fitted total joint prostheses (TJP) and concomitant maxillary orthognathic surgery. A retrospective cohort study was conducted of all patients diagnosed with JIA, receiving TJP, and concomitant maxillary orthognathic surgery between 1991 and 2019, at Baylor University Medical Center treated by 1 surgeon. Patient evaluations presurgery (T1), immediate postsurgery (T2), and at longest follow-up (LFU) (T3) were analyzed using 20 cephalometric landmarks to compute 29 linear and angular measurements to determine surgical changes, long-term skeletal and occlusal stability, as well as oropharyngeal airway changes. Comparative data were tested for significance (α=0.05) using paired and unpaired t tests. Forty-two patients met the JIA inclusion criteria, with a median age of 17.5 years and median postsurgical follow-up of 26 months. There were significant surgical changes (T1-T2) (P ≤ .05) for all parameters associated with mandibular linear and angular surgical changes, except for the horizontal position of posterior nasal spine and the vertical/horizontal position of gonion, indicating highly stable surgical outcomes. There were significant improvements in the oropharyngeal airway dimensions. This study suggests that TMJ Concepts patient-fitted TJP for TMJ reconstruction in conjunction with maxillary orthognathic surgery for counterclockwise rotation of the maxillo-mandibular complex for the JIA patients provides long-term skeletal and occlusal stability as well as dimensional improvement in the oropharyngeal airway.

Evaluation of effect of PowerScopeTM class II corrector on skeletal, dental and Oro-pharyngeal airway dimension in Skeletal class II cases - A controlled prospective clinical study

: The aim of this study was to evaluate the effect of PowerScope (Class II Corrector) on skeletal, dental and oro-pharyngeal airway dimensions in class II malocclusion with retrusive mandible. Twenty patients with age group of 11 to 14 were selected for this study. Experimental group underwent Power scope class II corrector therapy and control group, alignment of only upper arch respectively. Lateral cephalometric radiographs were taken in both experimental group and control group before and after 6 month of treatment. Sixteen measurements in that eight skeletal, five dental and three pharyngeal airway were assessed to know the effect of PowerScope Class II corrector on skeletal, dental and pharyngeal airway PowerScope Class II corrector after treatment showed significant change in SNB (P = 0.01*), ANB (P=0.001*), Inferior airway space (IAS) (P=0.006*), lower incisors position (P=0.0001*) and overjet (P=0.0001*) where as these values were insignificant on comparison with control group except for lower incisors position (P=0.001*) and overjet (P=0.0001*) indicating that PowerScope corrects class II malocclusion mainly by dento alveolar changes not have significant effect on skeletal and oro-pharyngeal airway. Power Scope (Class II corrector) corrects skeletal class II malocclusion mainly by dental changes and has insignificant effect on skeletal and oro-pharyngeal airway.

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

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. 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. 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. 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.

Analysis of three dimensional oropharyngeal airway and hyoid position in retrognathic adolescent patients

ObjectiveTo test the null hypotheses that there is no significant difference in the three-dimensional size of the oropharyngeal space or hyoid position when comparing individuals with a normal jaw relationship with individuals with retrognathic mandibles. MethodsIn total, 226 skeletal class I (0.7° ≤ ANB < 4.7°) or class II (ANB > = 4.7°) adolescent patients were examined and categorized into two groups: normal group and retrognathic group. Group classifications were made based on SNA angle, SNB angle, ANB angle, and maxillary length (Ptm-ANS). From the total available cases, 60 subjects met the above classification criteria and had a normo-divergent facial pattern, with 30 cases in each group. Cone beam computed tomography (CBCT) images were collected for each participant and InVivoDental (Anatomage, San Jose, Calif) software was used to analyze 60 CBCT scans. Mimics 17.0 software was used to reconstruct the upper airway, and indices of oropharyngeal airway dimensions and hyoid position were calculated. ResultsThe oropharyngeal airway dimensions of adolescent patients in the retrognathic group were smaller than adolescent patients in the normal group. The hyoid was positioned more superior and posterior in the retrognathic group. With decreases in mandibular length and SNB angle, oropharyngeal space volume tended to decrease, the hyoid tended to be more superior and posterior. ConclusionThe null hypotheses were rejected. Significant differences in the three-dimensional size of the oropharyngeal space or hyoid position when comparing individuals with a normal jaw relationship with individuals with retrognathic mandibles.

Changes in sleep and airway variables in patients with obstructive sleep apnea after mandibular advancement splint treatment.

Obstructive sleep apnea (OSA) is an extensive public health problem that imposes considerable morbidity. Mandibular advancement splint (MAS) therapy is a well tolerated treatment, but success rates are difficult to predict. Our objective was to investigate the relationship of oropharyngeal airway dimensions, sleep characteristics, patient biometrics, and treatment response within an OSA patient sample. Records of 33 adults were assessed retrospectively with the use of Dolphin 3D and Image J to measure the airway on pretreatment supine cone-beam computed tomography images and derived lateral cephalograms. The patients used Somnodent (Somnomed; Crows Nest, Australia) MAS appliances, which were titrated over 6-8weeks. Appliance titration measurements and pre- and posttreatment polysomnograms were assessed. Respiratory disturbance index (RDI), absolute and percentage changes in RDI, non-rapid eye movement (NREM) RDI, rapid eye movement (REM) RDI, supine and nonsupine NREM and REM RDI, and minimal blood-oxygen saturation variables were evaluated. The associations of measurements from 2D and 3D minimal anterior-posterior linear distance and 3D airway variables with MAS treatment response were estimated. Combined effects of baseline total airway volume, body mass index, neck circumference, location of minimal cross sectional area, and OSA severity were associated with treatment response. Patients with higher initial OSA and more superiorly located airway constriction showed enhanced treatment response to MAS therapy. Airway constriction due to maxillofacial disproportions rather than soft tissue obstruction also showed better treatment response. No significant relationships were found in lateral cephalogram measurements.

Residents' journal review

Residents' journal review

The effects of sex, skeletal age, and sagittal skeletal pattern on pharyngeal airway dimensions and related structures in growing Thai orthodontic patients

PurposeTo evaluate the effects of sex, skeletal age, sagittal skeletal pattern, and the interaction among these three factors on the pharyngeal airway widths and areas, and the positions and dimensions of surrounding structures. Materials and methodsPretreatment lateral cephalometric radiographs of 418 growing orthodontic patients (183 males, 235 females); 6–20 years old (mean age, 13.95±3.62 years), were collected from 2007–2014, Department of Radiology, Faculty of Dentistry, and divided into 3 skeletal ages according to cervical vertebral maturation stages, pre-pubertal (cervical stages (CS) 1,2), pubertal (CS 3,4), and post-pubertal (CS 5,6). Ten angular, 13 linear, and 3 cephalometric area measurements were analyzed. Three-way ANOVA and Factor analysis were applied to compare sex, skeletal age, and sagittal skeletal pattern differences in the pharyngeal airway dimensions and the surrounding structure dimensions and positions. ResultsSex–skeletal age interactions existed in the nasopharyngeal and oropharyngeal airway dimensions, and dimensions and positions (vertical, horizontal) of surrounding structures. Skeletal age–sagittal skeletal pattern interactions also affected the pharyngeal airway dimensions. In the post-pubertal period, male and skeletal Class III subjects tended to have larger pharyngeal airway, tongue, and soft palate dimensions; more anterior positions of the hyoid and tongue; and less obtuse soft palate angulation. The post-pubertal males also had more inferior positions of the hyoid and tongue. ConclusionInteractions between sex–skeletal age and skeletal age–sagittal skeletal pattern affected the pharyngeal airway dimensions. The surrounding structure positions and dimensions varied according to sex–skeletal age interaction and sagittal skeletal difference.

Evaluations of the tongue and hyoid bone positions and pharyngeal airway dimensions after maxillary protraction treatment

ObjectiveTo assess changes in the tongue and hyoid bone positions and airway dimensions after maxillary protraction using lateral cephalograms.MethodsLateral cephalograms were obtained before (C0) and after (C1) an observation period for untreated children with skeletal Class I malocclusion and before (T0), immediately after (T1), and one year after (T2) maxillary protraction in children with skeletal Class III malocclusion. Cephalometric measurements were compared between the time points in both patient groups.ResultsImmediately after maxillary protraction, the tongue moved superiorly and the nasopharyngeal and superior oropharyngeal airway dimensions increased. No significant changes in the middle or inferior oropharyngeal airway dimensions or in the hyoid bone position were noted after treatment.ConclusionsMaxillary protraction improved tongue posture and modified the nasopharyngeal and superior oropharyngeal airway dimensions in patients with skeletal Class III malocclusion. Consequently, maxillary protraction may restore the intra- and extraoral balance and improve respiratory function.

Effects of mandibular setback with or without maxillary advancement osteotomies on pharyngeal airways: An overview of systematic reviews.

BackgroundMandibular setback osteotomies potentially lead to narrowing of the pharyngeal airways, subsequently resulting in post-surgical obstructive sleep apnea (OSA).ObjectiveTo summarize current evidence from systematic reviews that has evaluated pharyngeal airway changes after mandibular setback with or without concomitant upper jaw osteotomies.MethodologyPubMed, EMBASE, Web of Science, and Cochrane Library databases were searched with no restriction of language or date. Systematic reviews studying changes in pharyngeal airway dimensions and respiratory parameters after mandibular setback with or without concomitant upper jaw osteotomies have been identified, screened for eligibility, included and analyzed in this study.ResultsSix systematic reviews have been included. While isolated mandibular setback osteotomies result in reduced oropharyngeal airway dimensions, the reduction is lesser in cases with concomitant upper jaw osteotomies. Only scarce evidence exists currently to what happens to naso- and hypo-pharyngeal airways. There is no evidence for post-surgical OSA, even though some studies reported reduced respiratory parameters after single-jaw mandibular setback with or without concomitant upper jaw osteotomies.ConclusionAlthough mandibular setback osteotomies reduce pharyngeal airway dimensions, evidence confirming post-surgical OSA was not found. Nevertheless, potential post-surgical OSA should be taken into serious consideration during the treatment planning of particular orthognathic cases. As moderate evidence exists that double-jaw surgeries lead to less compromised post-surgical pharyngeal airways, they should be considered as the method of choice especially in cases with severe dentoskeletal Class III deformity.Study registrationPROSPERO (registration number: CRD42016046484).

Assessment and Comparison of Oropharyngeal Airway Dimensions in Skeletal Class II Cases Treated With Forsus FRD and Twin Block Appliances

Abstract Aims: To assess the changes in the oropharyngeal airway (OAW) dimensions in individuals with retrognathic mandible treated with Forsus FRD and Twin Block appliance to correct the skeletal Class II mal relationship. Methodology: 40 individuals, with Class II skeletal pattern were selected as per inclusion criteria. Pre-treatment lateral cephalograms and hand wrist radiographs were obtained and analyzed. Group 1 with 20 individuals were treated with Forsus FRD and Group 2 with 20 individuals were treated with conventional Twin Block Appliance. Post treatment records were taken after the Class I molar relationship had been obtained. Pre and post treatment cephalograms were compared and analyzed. The data obtained was statistically evaluated using paired t test and unpaired t test. Results: On comparison of pre-treatment and post-treatment cephalograms, increase in Oropharyngeal Airway (OAW) measurements, such as Superior posterior airway space (SPAS), Middle airway space (MAS) and Inferior airway space (IAS) was very highly significant. Conclusion: Our results suggest the existence of a relationship between functional-orthopaedic treatment and increases in OAW dimensions in skeletal Class II growing subjects.

Dentoskeletal and airway effects of the X-Bow applian ce versus removable functional appliances (Frankel-2 and Trainer) in prepubertal Class II division 1 malocclusion patients

Abstract Objectives The aim of the present study was to evaluate the dentoskeletal and airway effects of three different functional appliances (Frankel-2, Trainer and X-Bow) in prepubertal Class II division 1 patients. Methods The sample consisted of 54 patients with a Class II relationship as a result of mandibular retrognathia and relative maxillary constriction. Group I included 15 patients treated with a Frankel-2 appliance. Group II consisted of 14 patients treated with a T4-K Trainer. Group III consisted of 15 patients treated with the X-Bow appliance. Group IV consisted of 10 untreated Class II patients who served as a control group. Pretreatment (T1) and post-treatment (T2) cephalograms were used to evaluate dentoskeletal and airway changes. Parametric one-way variance analysis (ANOVA) and a paired t-test were used to perform statistical analysis. Results The decrease in SNA angle was significant in groups I and III, compared with the control group (p &lt; 0.05). SNB angle and Co-GN length changes from T1 to T2 were statistically significant in groups I and II (p &lt; 0.05), but not relative to the control group. The upper and lower incisors were significantly retruded and protruded, respectively, in all treatment groups (p &lt; 0.05). Except PNS-AD2 and MAS measurements in group I, nasopharyngeal and oropharyngeal airway dimensions did not significantly change from T1 to T2 in all groups. Conclusions The Frankel-2 and X-Bow appliances were efficient in restricting the forward growth of the maxilla. The Frankel-2 and Trainer appliances produced a larger sagittal increase in mandibular length than the X-Bow appliance. Lower incisor proclination was more pronounced in the X-Bow group. The effect of the treatment protocols was similar and matched the control group with respect to the airway.

Upper airway changes following single-step or stepwise advancement using the Functional Mandibular Advancer.

Purpose of the present study was to determine and compare possible changes in the dimensions of the pharyngeal airway, morphology of the soft palate, and position of the tongue and hyoid bone after single-step or stepwise mandibular advancement using the Functional Mandibular Advancer (FMA). The sample included 51 peak-pubertal Class II subjects. In all, 34patients were allocated to two groups using matched randomization: a single-step mandibular advancement group (SSG) and a stepwise mandibular advancement group (SWG). Both groups were treated with FMA followed by fixed appliance therapy; the remaining 17 subjects who underwent only fixed appliance therapy constituted the control group (CG). The study was conducted using pre- and posttreatment lateral cephalometric radiographs. Data were analyzed by paired t test, one-way analysis of variance, and Pearson's correlation coefficient. In the SWG and SSG, although increases in nasopharyngeal airway dimensions were not significant compared with those in the CG, enlargements in the oropharyngeal airway dimensions at the level of the soft palate tip and behind the tongue, and decreases in soft palate angulation, were significant. Tongue height increased significantly only in the SWG. Compared with the CG, while forward movement of the hyoid was more prominent in SSG and SWG, the change in the vertical movement of the hyoid was not significant. No significant difference between SWG and SSG was observed in pharyngeal airway, soft palate, tongue or hyoid measurements. The mode of mandibular advancement in FMA treatment did not significantly affect changes in the pharyngeal airway, soft palate, tongue, and hyoid bone.

Effects of Two-Phase Treatment with the Herbst and Preadjusted Edgewise Appliances on the Upper Airway Dimensions.

Aims. To assess the effects of two-phase treatment with the Herbst and the preadjusted edgewise appliances on upper airway dimensions and to investigate the correlation between changes in the upper airway dimensions and skeletal morphologies. Methods. A total of 27 Chinese male adolescents aged 12.8 ± 1.3 years were selected. Lateral cephalograms were collected to assess the skeletal morphology and upper airway dimensions. Results. Following Herbst appliance treatment, the upper airway space was significantly enlarged, with the retropalatal (U-MPW) increasing by 1.1 ± 1.6 mm (P < 0.001), the retroglossal (PASmin) increasing by 1.3 ± 2.9 mm (P < 0.05), and the hypopharynx (V-LPW) enlarging by 1.6 ± 3.0 mm (P < 0.01). PASmin was found to show a negative correlation to the mandibular plane angle (MnPl-SN) by r = −0.413 (P < 0.05). There was no significant change (P > 0.05) in upper airway dimensions during the second-phase treatment. Conclusions. Herbst appliance treatment increased the oropharyngeal and hypopharyngeal airway dimensions among adolescents with Class II malocclusion, and the effects were maintained throughout the second treatment phase with a preadjusted edgewise appliance. There was a negative correlation between the change in the depth of the retroglossal pharynx and the mandibular plane angle.

Changes in the oropharyngeal airway of Class II patients treated with the mandibular anterior repositioning appliance.

To evaluate the effects of functional appliance treatment on the oropharyngeal airway volume, airway dimensions, and anteroposterior hyoid bone position of growing Class II patients. Twenty Class II white patients (mean age, 11.7 ± 1.75 years) treated with the MARA followed by fixed appliances were matched to an untreated control sample by cervical vertebrae maturation stage at pretreatment (T1) and posttreatment (T2) time points. Cone beam computed tomography scans were taken at T1 and T2. Dolphin3D imaging software was used to determine oropharyngeal airway volume, dimensions, and anteroposterior hyoid bone position. Multivariate ANOVA was used to evaluate changes between T1 and T2. Oropharyngeal airway volume, airway dimensions, and A-P position of the hyoid bone increased significantly with functional appliance treatment. SNA and ANB decreased significantly in the experimental group (P ≤ .05). Changes in SNB and Sn-GoGn failed to reach statistical significance. Functional appliance therapy increases oropharyngeal airway volume, airway dimensions, and anteroposterior hyoid bone position in growing patients.