When static meets dynamic: Comparing cone-beam computed tomography and acoustic reflection for upper airway analysis

Three-dimensional evaluation of the airway morphology after miniscrew-supported en masse retraction in adult bimaxillary protrusion patients by using cone beam computed tomography: A single-arm clinical trial

OBJECTIVE

This study aimed to assess the changes in the pharyngeal airway morphology after premolar extraction and maximum anchorage retraction of the anterior segments in adult bimaxillary protrusion patients by using CBCT.

MATERIAL AND METHODS

Twenty-one subjects (mean age 23.8±4.6 years) requiring extraction of four first premolars and en masse retraction of the anterior segments using maximum anchorage participated in the study from July 2022 to May 2024 with an average treatment duration of 19.9 months. CBCT scans were taken before treatment (pre) and after en masse retraction (post). Airway volume was measured by using Relu software. The pre- and post-CBCT scans were superimposed by using Romexis 1 software. The cross-sectional area (CSA) was measured at the level of the hard palate, soft palate, and epiglottis. The most constricted area (MCA) was recorded. The hyoid bone position was evaluated by using 5 linear measurements. The upper and lower incisor angulations to the Frankfort horizontal plane (FH) were measured before and after retraction. Paired t-test was used to analyse the measurements and correlation analyses were made using Spearman's rank-order correlation coefficient (rs). The significance level was set at P<0.05 within all tests.

RESULTS

Twenty-one participants (16 females, 5 males) followed the inclusion criteria and enrolled in the analysis. There were no significant differences in airway volume, cross-sectional areas, or hyoid bone position between before treatment and after en masse retraction (P>0.05). There was a significant retraction of the incisors after treatment (P<0.001). The change in the most constricted area had a large positive correlation with the change in the airway volume (rs=0.509*) and the area of the soft palate (rs=0.653*).

CONCLUSION

Maximum anchorage retraction had no significant effect on airway volume, cross-sectional area, or hyoid bone position.

The orthodontic extraction of second premolars: The influence on airway volume

INTRODUCTION

The extraction of second premolars and associated changes in the volume of the airway have not been previously explored. This retrospective study aimed to compare the volumetric changes of the airway preorthodontic and postorthodontic treatment in relevant extraction and control samples and to identify variables that may influence the outcome.

METHODS

Cone-beam computed radiography scans of 54 patients with second premolar extraction and 59 nonextraction patients treated in a private orthodontic practice were matched for crowding. The average age for both samples was 15 years. The images were individually landmarked and measured by applying volumetric, linear, and angular parameters. The results were analyzed using repeated measures, such as variance analysis, correlation testing, and regression statistical analyses.

RESULTS

There was a statistically significant increase in the airway volume for both groups (P <0.05). The difference in increase between the groups was not statistically significant. Seven variables demonstrated a collectively significant effect on changes to airway volume (F[7,112] = 38.48; P <0.001; r2 = 0.701), with 70% of the variation predicted by the variables. Multiple regression analyses indicated that changes to the area of minimum constriction (B = 32.45; t = 11.95; P <0.001) and changes to airway length (B = 94.75; t = 7.79; P <0.001) had a statistically significant effect on airway volume.

CONCLUSIONS

The volume of the airway increased in both the extraction and nonextraction samples. The biggest contributors to the increase were an increase in airway length and an increase in the area of minimum constriction, which likely occurred as a result of natural growth.

Comparing CBCT to model scanner for dental model scanning. An in vitro imaging accuracy study

OBJECTIVE

The aim of this study is to compare the accuracy of cone beam computed tomography (CBCT) for dental model scanning to the accuracy of model scanners.

METHODS

Subjects from private practice were collected and scanned according to specific selection criteria. A total of 10 STL files were produced and used as reference files. They were printed with a three-dimensional (3D) printer and then scanned with CBCT and model scanner. For trueness evaluation, all models were scanned once with both equipments. Each file derived from each scan was compared with the corresponding reference model file. For the precision measurements, the physical model from the first master reference model file was scanned 10 times with each equipment and compared with the reference STL file. A reverse engineering software was used for all 3D best-fit comparisons.

RESULTS

With regard to the measurement of trueness of each method, the calculated mean root mean square (RMS) value was 0.06±0.01mm for the CBCT, and 0.15±0.02mm for the model scanner. There was a significant difference between the two methods (P<0.01). For the evaluation of precision of each scanner, the mean RMS value was 0.0056±0.001mm for the CBCT, and 0.153±0.002mm for model scanner. There was a significant difference between the two methods (P<0.01).

CONCLUSIONS

Cone Beam Computed Tomography seems to be an accurate method for scanning dental models. CBCT performs better than model scanners to scan dental models in terms of trueness and precision.

Dental Appliances for the Treatment of Obstructive Sleep Apnea in Children: A Systematic Review and Meta-Analysis

Background and objectives: Obstructive sleep apnea (OSA) in children is a debilitating disease, difficult to treat. Dental appliances have been proposed as a valid therapy for improving functional outcomes with good compliance rates. Herein, we aimed to perform a meta-analysis comparing clinical outcomes between OSA children treated with dental appliances versus controls. Materials Methods: The study was registered with PROSPERO. A systematic search was performed for all comparative studies examining outcomes in pediatric patients who underwent treatment of OSA with oral appliances versus controls. Data was extracted and analyzed using a random effects model via Rev Man 5.3. Results: Six studies including 180 patients were analyzed split into two groups: patients treated with dental appliances (n = 123) and the controls (n = 119). Therapy with dental appliances was shown to significantly improve the apnea-hypopnea index (p = 0.009) and enlarge the superior posterior airway space (p = 0.02). Maxilla-to-mandible measurements were not significantly different between the two groups, nor was the mean SO2 (p = 0.80). Conclusions: This is the most updated meta-analysis assessing the role of dental appliances for OSA in children; it shows that such devices can improve functional outcomes by decreasing the apnea-hypopnea index.

Comparing Airway Analysis in Two-Time Points after Rapid Palatal Expansion: A CBCT Study

BACKGROUND

The aim of this study is to investigate the upper airway analysis at two-time points after the rapid maxillary expansion was performed, using cone-beam computed tomography.

METHODS

Subjects from the Orthodontic Department at the Aristotle University of Thessaloniki with unilateral or bilateral posterior crossbite were screened according to the selection criteria. A sample size calculation was performed, and a total of 14 subjects were recruited. All subjects received a rapid maxillary expansion with a Hyrax-type device as part of their comprehensive treatment. A CBCT was taken before the treatment (T1), immediately after the expansion was completed (T2), and 6 months after (T3). Their upper airway was measured using the CBCT images. Airway volume (V) and minimal cross-sectional area (MCS) were extracted and compared using SPSS to analyze the means.

RESULTS

A statistically significant difference was found between all time points regarding both V and MCS (p < 0.001, p = 0.001). There was a statistically significant increase in both V and MCS measurements immediately after RPE expansion (T1-T2) and six months after expansion (T1-T3). Between the end of expansion and 6 months after (T2-T3), there was a decrease in V and no statistical difference in MCS.

CONCLUSIONS

RPE can significantly increase the volume and minimal cross-sectional area of the nasal passage airway.

Rapid maxillary expansion and nasal patency in mouth breathing children with maxillary atresia due to or not due to allergic rhinitis

AIM

To evaluate the effects of rapid maxillary expansion (RME) on nasal patency in mouth breathing (MB) children with maxillary atresia due to or not due to allergic rhinitis (AR) associated with asthma.

METHODS

Fifty-three MB children/adolescents (aged 7-14 years) with mixed or permanent dentition and maxillary atresia participated, with or without unilateral or bilateral crossbite. They formed the groups: RAD (AR + asthma; clinical treatment, RME); RAC (AR + asthma; clinical treatment, no RME); and D (mouth breathers; RME only). RAD and RAC patients received topical nasal corticosteroid and/or systemic H1 antihistamine (continuous use) and environmental exposure control. All were evaluated before RME (T1) and 6 months after (T2) with the CARATkids score, acoustic rhinometry, and nasal cavity computed tomography (CT). Patients RAD and D underwent RME (Hyrax® orthopedic appliance).

RESULTS

A significant reduction in the CARATkids score occurred in the RAD (-4.06; p < 0.05), similarly when patient and parent/guardian scores were evaluated (-3.28 and -3.16, respectively). Acoustic rhinometry (V5) showed increased nasal volume in all groups, significantly higher in RAD patients than in RAC and D (0.99 × 0.71 × 0.69 cm³, respectively). CT of the nasal cavity documented increased volume in all three groups, with no significant differences between them.

CONCLUSION

In MB patients with AR, asthma, and maxillary atresia, RME increased nasal cavity volume and improved respiratory symptoms. However, it should not be used as the only treatment for managing patients with respiratory allergies.

Airway dimensional changes following bone anchored maxillary protraction: a systematic review

BACKGROUND

The introduction of skeletal anchorage utilized for maxillary protraction with a face mask or class III elastics has been developed for the management of class III malocclusions with minimal dental effect. The objective of the present review was to evaluate the current evidence regarding airway dimensional changes following bone-anchored maxillary protraction. A search was conducted by two authors (S.A & B.A) in the following databases: MEDLINE via PubMed, Cochrane Library, Web of Science, Scopus, Google Scholar and Open Grey; besides a hand search in references of selected articles and developing a search alert in electronic databases. Selection criteria comprised randomized as well as prospective clinical trials evaluating airway dimensional changes following bone-anchored maxillary protraction. Relevant data were extracted after studies retrieval and selection. The risk of bias was thereafter evaluated using the revised RoB 2 tool for randomized clinical trials and the ROBINS-I tool was used for non-randomized clinical trials. The quality of studies was assessed using the modified Jadad score. After examining (eligibility) full-text articles, four clinical trials were ultimately included. These studies evaluated the airway dimensional changes, following bone-anchored maxillary protraction in comparison to different control study groups. Based on the available evidence, all the bone-anchored maxillary protraction devices used in the eligible studies in the present systematic review resulted in an improvement in the airway dimensions. However, due to the few numbers of studies available and the guarded evidence due to the low quality of evidence of three out of four included articles, there is no strong evidence to support a significant increase in the airway dimensions following bone-anchored maxillary protraction. Therefore, there is a need for more randomized controlled clinical trials with similar bone-anchored protraction devices and similar assessment methods for more valid comparisons, excluding any confounding factors, on airway dimensional changes.

Artificial Intelligence as an Aid in CBCT Airway Analysis: A Systematic Review

BACKGROUND

The use of artificial intelligence (AI) in health sciences is becoming increasingly popular among doctors nowadays. This study evaluated the literature regarding the use of AI for CBCT airway analysis. To our knowledge, this is the first systematic review that examines the performance of artificial intelligence in CBCT airway analysis.

METHODS

Electronic databases and the reference lists of the relevant research papers were searched for published and unpublished literature. Study selection, data extraction, and risk of bias evaluation were all carried out independently and twice. Finally, five articles were chosen.

RESULTS

The results suggested a high correlation between the automatic and manual airway measurements indicating that the airway measurements may be automatically and accurately calculated from CBCT images.

CONCLUSIONS

According to the present literature, automatic airway segmentation can be used for clinical purposes. The main key findings of this systematic review are that the automatic airway segmentation is accurate in the measurement of the airway and, at the same time, appears to be fast and easy to use. However, the present literature is really limited, and more studies in the future providing high-quality evidence are needed.

Change in the Constricted Airway in Patients after Clear Aligner Treatment: A Retrospective Study

This retrospective study evaluated changes in the pharyngeal portion of the upper airway in patients with constricted and normal airways treated with clear aligners (Invisalign, Align). Additionally, we assessed the change of tongue position in the oral cavity from a lateral view. Evaluation was performed with specialized software (Invivo 6.0, Anatomage) on pretreatment and post-treatment pairs of cone beam computed tomography imaging (CBCT) data. The level of airway constriction, volume, cross-section minimal area and tongue profile were evaluated. Patients with malocclusion, with pair or initial and finishing CBCT and without significant weight change between the scans, treated with Invisalign clear aligners were distributed into two groups. Group A consisted of fifty-five patients with orthodontic malocclusion and constricted upper airway. Control group B consisted of thirty-one patients with orthodontic malocclusions without any airway constriction. In the group with airway constriction there was a statistically significant increase in volume during therapy (p < 0.001). The surface of the most constricted cross-section of the airway did not change significantly after treatment in any of the groups. The final tongue position was different from the initial position in 62.2% of all clear aligner treatments. The position of the smallest clearance of the airway in the pharynx was similar for both groups localized at the level of 2nd cervical vertebra.

Effectiveness of Titratable Oral Appliance in Management of Moderate to Severe Obstructive Sleep Apnea-A Prospective Clinical Study with Acoustic Pharyngometry

To assess effectiveness of titratable Oral Appliance (OA) in management of moderate to severe cases of Obstructive Sleep Apnea (OSA). Thirty Polysomnography (PSG) diagnosed cases of moderate to severe OSA were subjected to a thorough cranio-facial-dental evaluation, a detailed sleep history and three dimensional assessment of upper airway geometry utilising Acoustic Pharyngometry (AP) (Eccovision, sleep group solutions). A titratable OA was delivered to all patients for mandibular advancement. Apnea Hypopnea Index (AHI), Oxygen Saturation (SPO2), Epworth's Sleepiness Scale (ESS), Mean area and volume of upper airway were recorded at Baseline (T0) and after 08 weeks of appliance delivery (T1). The mean AHI & ESS scores were significantly lower and SPO2 was significantly higher at T1 compared to T0 (P-value < 0.05 for all). The mean area and volume of upper airway at T1 were significantly higher compared to values at T0 (P-value < 0.05 for both). The mean area showed 19.51% increase at T1 whereas mean volume increased by 18.55%. OA therapy is highly efficacious in cases with moderate to severe OSA, especially, in those with retrognathic mandible. This modality should be considered as an effective alternate to Continuous Positive Airway Pressure (CPAP) therapy in non-compliant patients rather than no treatment. AP is an effective modality to predict airway changes after advancement with OA, to ascertain follow up changes and is highly recommended in routine clinical practice. Large scale, multicenter studies are recommended to elaborate the findings of the present study and to add better quality evidence in this regard.

Reliability of Acoustic Pharyngometry and Rhinometry Examination in Children and Adolescents

OBJECTIVES

The aim of this cross-sectional study was to examine the method error and reliability of acoustic pharyngometry and rhinometry in children and adolescents and to describe the feasibility of these methods in a young population.

MATERIAL AND METHODS

The study sample included 35 healthy subjects in the age of 9 to 14 years. The subjects were randomly recruited for the present project in the period from June 2021 to February 2022. Repeated measurements of the upper airway dimensions in standing mirror position were performed by the use of Acoustic Pharyngometer and Rhinometer. Volume (cm³), calculated resistance (cm H₂O/L/min), mean area (cm²), minimum cross-sectional area (MCA, cm²) and distance to MCA (cm) were examined. Method errors and reliability coefficients were evaluated using Dahlberg's formula and the Houston reliability coefficient. The feasibility of the methods were analysed using paired t-test and estimated by difference in drop-out rates.

RESULTS

No systematic error exhibited in the repeated measurements except volume in the left nostril (P = 0.017). The method errors of the acoustic pharyngometry and rhinometry were betweeen 0.0002 to 0.069 and 0.001 to 0.082 respectively. The Houston reliability coefficient for both methods were between 0.952 to 0.999. The acoustic pharyngometry was significantly more feasible compared to rhinometry (P < 0.001).

CONCLUSIONS

The study shows that acoustic pharyngometry and rhinometry in the standing mirror position are reliable methods, with acoustic pharyngometry being even more feasible than rhinometry, which is why it is recommended to practice the methods with children and ensure reliability of results before registering measurements.

Dental and Skeletal Side Effects of Oral Appliances Used for the Treatment of Obstructive Sleep Apnea and Snoring in Adult Patients—A Systematic Review and Meta-Analysis

Background: Mandibular advancement devices for obstructive sleep apnea treatment are becoming increasingly popular among patients who do not prefer CPAP devices or surgery. Our study aims to evaluate the literature regarding potential dental and skeletal side effects caused by mandibular advancement appliances used for adult OSA treatment. Methods: Electronic databases were searched for published and unpublished literature along with the reference lists of the eligible studies. Randomized clinical trials and non-randomized trials assessing dental and skeletal changes by comparing cephalometric radiographs were selected. Study selection, data extraction, and risk of bias assessment were performed individually and in duplicate. Fourteen articles were finally selected (two randomized clinical trials and 12 non-randomized trials). Results: The results suggest that mandibular advancement devices used for OSA treatment increase the lower incisor proclination by 1.54 ± 0.16°, decrease overjet by 0.89 ± 0.04 mm and overbite by 0.68 ± 0.04 mm, rotate the mandible downward and forward, and increase the SNA angle by to 0.06 ± 0.03°. The meta-analysis revealed high statistical heterogeneity. Conclusions: The MADs affect the lower incisor proclination, overjet, overbite, the rotation of the mandible and the SNA angle. More randomized clinical trials providing high-quality evidence are needed to support those findings.

Upper airway changes in Class III patients using miniscrew-anchored maxillary protraction with hybrid and hyrax expanders: a randomized controlled trial

OBJECTIVES

The aim of this study was to compare the upper airway space changes after miniscrew-anchored maxillary protraction with hybrid (HH) and conventional hyrax (CH) expanders.

MATERIAL AND METHODS

The sample comprised Class III malocclusion growing patients that were randomized into two groups of miniscrew-anchored maxillary protraction. The group HH was treated with a hybrid hyrax appliance in the maxilla and two miniscrews distally to the canines in the mandible. Class III elastics were used from the maxillary first molar to the mandibular miniscrews until anterior crossbite correction. The group CH was treated with a similar protocol except for the conventional hyrax expander in the maxilla. Cone-beam computed tomography was obtained before (T1) and after 12 months of therapy (T2). The shape and size of upper airway were assessed. Intergroup comparisons were performed using Mann-Whitney U test (p < 0.05).

RESULTS

The group HH was composed of 20 patients (8 female, 12 male) with a mean age of 10.76 years. The group CH was composed of 15 patients (6 female, 9 male) with a mean age of 11.52 years. Anteroposterior and transverse increases of the upper airway were found for both groups. The oropharynx and the most constricted area increased similarly in both groups.

CONCLUSIONS

No differences in upper airway changes were observed using protraction anchored on hybrid or conventional hyrax expanders.

CLINICAL RELEVANCE

Maxillary protraction anchored on hybrid or conventional hyrax expanders may benefit patients with breathing disorders due to the increase of the upper airway volume and most constricted area. Registration: ClinicalTrials.gov (NCT03712007).

Effect of Mandibular Setback Surgery on Tongue Length and Height and Its Correlation with Upper Airway Dimensions

INTRODUCTION

The changes in length and height of tongue following mandibular setback (MS) surgery may affect pharyngeal airway dimensions. There is limited literature correlating tongue dimensional changes with linear and volumetric airway changes following MS with bilateral sagittal split ramus osteotomy (BSSRO) in skeletal class III patients.

MATERIALS AND METHODS

Treatment records of 18 patients who underwent MS with BSSRO were evaluated for changes in tongue and linear airway dimensions, mean airway volume and area at T1 (1-week pre-surgery), T2 (6-month post-surgery) and T3 (2-year post-surgery). Amount of MS was recorded from case sheets of patients. Mean tongue length reduced, whereas mean tongue height increased at T2 compared to T1 (P value = 0.001 for both). Linear, area and volumetric airway parameters at T2 were significantly reduced (P value = 0.001). All parameters showed statistically nonsignificant increase from T2 to T3 (P value > 0.05). Correlation analysis showed that change in tongue length at T3 did not show statistically significant correlation with amount of MS, changes in linear, area and volumetric airway parameters (P value > 0.05). However, the change in tongue height at T3 showed a significant (P value < 0.05) negative correlation (r value = - 0.742) with change in posterior airway space (PAS).

CONCLUSIONS

The appraisal of tongue length and height after MS surgery should be an integral part of diagnosis and treatment planning. The retro-positioning of tongue and increase in its height after MS surgery may compromise pharyngeal airway especially PAS. Additional options such as bi-jaw surgery, debulking of tongue volume and genioplasty should be explored to minimize adverse effects post-surgically.

Comparing different software packages for measuring the oropharynx and minimum cross-sectional area

INTRODUCTION

Several imaging software packages report the ability to measure the oropharynx and minimum cross-sectional area (MCA). This study aimed to compare 4 imaging software packages for measuring the oropharynx volume and MCA.

METHODS

Twenty-eight randomly selected cone-beam computed tomography scans had oropharynx volume and MCA calculated by 2 experienced operators using 4 different programs: Dolphin 3D (version 11.95.8.64; Dolphin Imaging & Management Solutions and Management Solutions, Chatsworth, Calif), InVivo Dental (version 6; Anatomage Inc, San Jose, Calif), OnDemand3D (version 1.0.10.7510; CyberMed, Seoul, South Korea), and ITK-SNAP (version 3.8.0; www.itksnap.org). The measurements were repeated after 2 weeks, and intraclass correlation coefficients were used for the reliability tests. Analysis of variance with the Tukey post-hoc test was used to compare the measurements of oropharynx and MCA with different software programs. Paired t tests were used to compare measurements of both investigators and software programs. Bland-Altman analysis was used to assess interexaminer reliability and agreement between the software programs.

RESULTS

The intraclass correlation coefficients revealed excellent repeatability for the 4 programs for both investigators. Analysis of variance showed no statistically significant difference between programs when comparing the oropharynx and MCA. There were no significant differences in software programs when measuring the airway. Bland-Altman showed the maximum difference as 4.1 cm³ for volume and 35 mm² for MCA. Those differences were below the standard deviations of 5.33 cm³ for volume and 73.75 mm² for MCA.

CONCLUSIONS

The use of 4 different software packages to measure the airway for oropharynx volume and MCA showed high intraoperator and interoperator reliability, no statistically significant difference when using analysis of variance, Tukey post-hoc, paired t tests, and variations within one standard deviation when using Bland-Altman.

Evaluation of the Average Nasal and Nasopharyngeal Volume in 10-13-year-old Children: A Preliminary CBCT Study

Aim and objective

Mouth breathing is one of the most common deleterious habits prevalent in children which leads to various skeletal and dental malocclusions. Due to the close relationship between nasal and nasopharyngeal cavity volume and maxilla, transverse maxillary deficiency causes reduced nasal and nasopharyngeal cavity volume leading to mouth breathing. Therefore, knowledge of average nasal and nasopharyngeal cavity volume is essential to accurately diagnose mouth breathing and to evaluate underlying causative factors.

Materials and methods

Cone-beam computed tomographic scans of 60 children were taken and nasal cavity and nasopharyngeal volumes were calculated using Planmeca Romexis 5.2.0.R software. Average volumes were computed using predetermined landmarks and compared among gender.

Results

The nasal cavity and nasopharyngeal volume showed significant differences among the gender (p value < 0.001 and 0.018, respectively).

Conclusion and clinical significance

Knowledge of the average nasal and nasopharyngeal cavity volumes can be a useful diagnostic aid for mouth breathing patients and also assess the causative factors and treatment outcomes in these patients.

How to cite this article

Kalaskar R, Balasubramanian S, Kalaskar A. Evaluation of the Average Nasal and Nasopharyngeal Volume in 10–13-year-old Children: A Preliminary CBCT Study. Int J Clin Pediatr Dent 2021;14(2):187–191.

Nasal ventilation and rapid maxillary expansion (RME): a randomized trial

OBJECTIVE

To assess three rapid maxillary expansion (RME) appliances in nasal ventilation.

TRIAL DESIGN

Three-arm parallel randomized clinical trial.

METHODS

Sixty-six growing subjects (10-16 years old) needing RME as part of their orthodontic treatment were randomly allocated (1:1:1 ratio) to three groups of 22 patients receiving Hyrax (H), Hybrid-Hyrax (HH), or Keles keyless expander (K). The primary outcome of nasal ventilation (pressure and velocity) and secondary outcomes (skeletal, dental, soft tissue, and nasal obstruction changes) were blindly assessed on the initial (T0) and final (T1, 6 months at appliance removal) cone-beam computed tomography (CBCT) data by applying computational fluid dynamics (CFD) method. Differences across groups were assessed with crude and adjusted for baseline values and confounders (gender, age, skeletal maturation, expansion amount, mucosal/adenoid hypertrophy, nasal septum deviation) regression models with alpha = 5%.

RESULTS

Fifty-four patients were analysed (19H, 21HH, 14K). RME reduced both nasal pressure (H: -45.8%, HH: -75.5%, K: -63.2%) and velocity (H: -30%, HH: -58.5%, K: -35%) accompanied with nasal obstruction resolution (H: 26%, HH: 62%, K: 50%). Regressions accounting for baseline severity indicated HH expander performing better in terms of post-expansion maximum velocity (P = 0.03) and nasal obstruction resolution (P = 0.04), which was robust to confounders. Mucosal/adenoid hypertrophy and nasal septum deviation changes were variable, minimal, and similar across groups. The HH resulted in significantly greater increase in the nasal cross-sectional area (62.3%), anterior (14.6%), and posterior (10.5%) nasal widths. Nasal obstruction resolution was more probable among younger (P = 0.04), skeletally immature (P = 0.03), and male patients (P = 0.02) without pre-treatment mucosal hypertrophy (P = 0.04), while HH was associated with marginal greater probability for obstruction resolution.

CONCLUSIONS

RME resulted in improvement of nasal skeletal parameters and simulated ventilation with the former being in favour of the HH and the latter not showing significant differences among the three appliances.

LIMITATION

Attrition in the K group due to blocked activation rods possibly leading to limited sample to identify any existing group differences.

HARMS

Replacement of blocked Keles expanders for finalizing treatment.

PROTOCOL

The protocol was not published before the trial commencement.

REGISTRATION

Australian and New Zealand Clinical Trial Registry; ACTRN12617001136392.

Internal nasal dimensions of children with unilateral cleft lip and palate and maxillary atresia: comparison between acoustic rhinometry technique and cone-beam computed tomography

PURPOSE

To compare the nasal cavity geometry of children and teenagers with cleft lip and palate and maxillary atresia by two methods: cone-beam computed tomography, considered the gold standard, and acoustic rhinometry.

METHODS

Data on cone-beam computed tomography and acoustic rhinometry examinations of 17 children and teenagers with cleft lip and palate and maxillary atresia, previously obtained for orthodontic planning purposes, were evaluated prospectively. Using Dolphin Imaging 11.8 software, the nasal cavity was reconstructed by two evaluators, and the internal nasal volumes were obtained. Using rhinometry, the volumes of regions V1 and V2 were measured. The values of each examination were then compared at a significance level of 5%.

RESULTS

Statistical analysis showed high intra- and inter-rater reproducibility in the cone-beam computed tomography analysis. The mean internal nasal volumes (± standard deviation) obtained using acoustic rhinometry and cone-beam computed tomography corresponded to 6.6 ± 1.9 cm3 and 8.1 ± 1.5 cm3, respectively. The difference between the examinations was 17.7%, which was considered statistically significant (p = 0.006).

CONCLUSION

The nasal volumes measured via the two methods were different; that is, they presented discrepancies in the measurements. The gold standard technique identified larger volumes than acoustic rhinometry in the nasal cavity. Therefore, determining which test reflects clinical reality is an essential future step.

Three-dimensional tomographic assessment of the upper airway using 2 different imaging software programs: A comparison study

INTRODUCTION

Several imaging software programs with different tools are available for upper airway (UAW) analysis by means of cone beam computed tomography. Because of this wide variability, this study aimed to compare the reproducibility of two of the most used software programs on UAW segmentation, that is, Dolphin Imaging (Dolphin Imaging and Management Solutions, Chatsworth, Calif) and Mimics Research (Materialise, Leuven, Belgium).

METHODS

The sample consisted of 50 scans of adult subjects with Class III malocclusion; pharyngeal volume and minimal cross-sectional area (mCSA) were assessed twice by 2 experienced evaluators using both software programs. Intra- and intersoftware and/or evaluator agreement were calculated using the intraclass correlation coefficient (ICC). Bland-Altman analysis was used to visualize the intersoftware and interevaluator agreement.

RESULTS

Using Mimics Research and Dolphin Imaging, the respective mean values of volume (cm³) were 27.1 ± 8.4 and 24.7 ± 8.1 (P < 0.05) and of mCSA (mm²) were 167.8 ± 95.5 and 176.5 ± 102.3 (P < 0.05). Although differences between software packages were observed on both the analyzed variables, the results showed a high intersoftware agreement, with ICC of 0.87 (volume) and 0.97 (mCSA) and mean bias of 24.6 (volume) and -8.8 (mCSA). A high intrasoftware agreement was also observed, with values varying from 0.83 to 0.99. Excellent intra- and interevaluator agreement was also obtained, with ICC values from 0.93 to 0.99.

CONCLUSIONS

Dolphin Imaging and Mimics Research individually provide highly reproducible results, with clinically acceptable agreement between them for UAW segmentation, providing consistent values for volume and mCSA.

Evaluation and quantification of airway changes in Class II division 1 patients undergoing myofunctional therapy using twin block appliance

Background

The purpose of the present study was to determine the airway changes in skeletal class II division 1 malocclusion patients with mandibular retrognathism, treated with Twin-Block (TB) appliance.

Methods

Airway assessment was carried for twelve patients (mean age 11.7 ± 1.1 years) who underwent myofunctional therapy using TB appliance for correction of skeletal class II division 1 malocclusion with mandibular retrognathism. Acoustic pharyngometry (AP) was used to assess and quantify the comparative changes in the upper airway, pretreatment and posttreatment.

Results

Data acquired was subjected to appropriate statistical analysis. The paired 't' test was used to compare pre-treatment (T0) and after the positive pterygoid response (T1). TB appliance increased mean minimum airway area by 0.28 ± 0.25 cm² and mean airway by 0.47 ± 0.44 cm² with 95% CI. Posttreatment minimum airway and mean area changes were found to be statistically significant (P-value<0.01).

Conclusion

TB appliance therapy has a positive effect on upper airway and is beneficial for the treatment of sleep-related disorders associated with Class II division 1 malocclusion for achieving positive functional changes, esthetics, and healthier quality of life.

Evaluation of Airway Dimensions Following Mandibular Setback with Surgery-First Orthognathic Versus Conventional Orthognathic Approach

Background

To evaluate changes in airway dimensions following mandibular setback with conventional orthognathic approach (COA) and surgery-first orthognathic approach (SFOA).

Materials and Methods

Treatment records of 20 patients who underwent mandibular setback with SFOA/COA were divided into two groups (COA and SFOA, ten patients in each group). Acoustic pharyngometry values were obtained at T0 (01 week prior to surgery), T1 (01-month post-surgery) and T2 (01-year post-surgery). Percentage change in mean volume and area was obtained at T1 (T1-T0) to evaluate airway changes and at T2 (T2-T1) to compare relapse of airway changes in both groups. Changes in airway per mm setback at T1 (T1-T0) and T2 (T2-T1) were also obtained in both groups.

Results

For both parameters, SFOA showed greater reduction at T1 and greater relapse at T2 as compared to COA. The reduction in airway volume at T1 was 0.56 mm/mm setback in COA compared to 1.06 mm/mm setback in SFOA (P-value > 0.05). The relapse in airway volume at T2 was 0.15 mm/mm setback in COA compared to 0.25 mm/mm setback in SFOA (P-value > 0.05). The reduction in area at T1 was 0.062 mm/mm setback in COA compared to 0.110 mm/mm setback in SFOA (P-value > 0.05). The relapse in area at T2 was 0.016 mm/mm setback in COA compared to 0.034/mm setback in SFOA (P-value < 0.05).

Conclusion

In setback cases, SFOA has greater airway reduction immediate post-surgically and greater relapse at 01-year follow-up. Predicting these changes at diagnostic and treatment planning stage may prevent potential adverse events on airway.

A new segmentation algorithm for measuring CBCT images of nasal airway: a pilot study

Background

Three-dimensional (3D) modeling of the nasal airway space is becoming increasingly important for assessment in breathing disorders. Processing cone beam computed tomography (CBCT) scans of this region is complicated, however, by the intricate anatomy of the sinuses compared to the simpler nasopharynx. A gold standard for these measures also is lacking. Previous work has shown that software programs can vary in accuracy and reproducibility outcomes of these measurements. This study reports the reproducibility and accuracy of an algorithm, airway segmentor (AS), designed for nasal airway space analysis using a 3D printed anthropomorphic nasal airway model.

Methods

To test reproducibility, two examiners independently used AS to edit and segment 10 nasal airway CBCT scans. The intra- and inter-examiner reproducibility of the nasal airway volume was evaluated using paired t-tests and intraclass correlation coefficients. For accuracy testing, the CBCT data for pairs of nasal cavities were 3D printed to form hollow shell models. The water-equivalent method was used to calculate the inner volume as the gold standard, and the models were then embedded into a dry human skull as a phantom and subjected to CBCT. AS, along with the software programs MIMICS 19.0 and INVIVO 5, was applied to calculate the inner volume of the models from the CBCT scan of the phantom. The accuracy was reported as a percentage of the gold standard.

Results

The intra-examiner reproducibility was high, and the inter-examiner reproducibility was clinically acceptable. AS and MIMICS presented accurate volume calculations, while INVIVO 5 significantly overestimated the mockup of the nasal airway volume.

Conclusion

With the aid of a 3D printing technique, the new algorithm AS was found to be a clinically reliable and accurate tool for the segmentation and reconstruction of the nasal airway space.

Detection on pharyngeal wall floppiness in patients with nonstructural factor-induced obstructive sleep apnea-hypopnea syndrome: Difference in position detection

OBJECTIVES/HYPOTHESIS

To evaluate changes in pharyngeal wall floppiness (PWF) between patients with obstructive sleep apnea-hypopnea syndrome induced by non-upper-airway structural factors and normal subjects, as well as the clinical significance using acoustic pharyngealmetry technology.

STUDY DESIGN

Cohort study.

METHODS

The obstructive sleep apnea (OSA) group (n = 102) and the normal control group (n = 50) were identified using the Eccovision Acoustic Pharyngometer measuring instrument. The volume of the pharyngeal cavity in the sitting and supine positions during expiration and inspiration was recorded, respectively, and the PWF index in the sitting and supine positions was calculated for further statistical analysis.

RESULTS

PWF in the sitting (P < .001) and supine positions (P < .001) in the OSA group was notably higher than that in the control group. PWF in the supine position in both the OSA group and control group was remarkably higher than that in the sitting position (P < .001, P = .025, respectively). The difference in PWF between the supine and sitting positions (ΔPWF) (PWF_supine-PWF_sit) was distinctly higher than in control group (P < .01). PWF was positively correlated with age (P < .001) but not with body mass index (P > .05).

CONCLUSIONS

PWF, quantified as elevated PWF, is an important nonstructural factor for the pathogenesis of OSA patients. PWF in the supine position can more accurately reflect airway collapsibility in OSA patients. Our pilot study of a novel observation may help us in the choice of proper surgical candidates for OSA procedures.

LEVEL OF EVIDENCE

3b Laryngoscope, 128:2200-2205, 2018.

3D Biometrics for Hindfoot Alignment Using Weightbearing CT

BACKGROUND

Hindfoot alignment on 2D radiographs can present anatomical and operator-related bias. In this study, software designed for weightbearing computed tomography (WBCT) was used to calculate a new 3D biometric tool: the Foot and Ankle Offset (FAO). We described the distribution of FAO in a series of data sets from clinically normal, varus, and valgus cases, hypothesizing that FAO values would be significantly different in the 3 groups.

METHODS

In this retrospective cohort study, 135 data sets (57 normal, 38 varus, 40 valgus) from WBCT (PedCAT; CurveBeam LLC, Warrington, PA) were obtained from a specialized foot and ankle unit. 3D coordinates of specific anatomical landmarks (weightbearing points of the calcaneus, of the first and fifth metatarsal heads and the highest and centermost point on the talar dome) were collected. These data were processed with the TALAS system (CurveBeam), which resulted in an FAO value for each case. Intraobserver and interobserver reliability were also assessed.

RESULTS

In normal cases, the mean value for FAO was 2.3% ± 2.9%, whereas in varus and valgus cases, the mean was -11.6% ± 6.9% and 11.4% ± 5.7%, respectively, with a statistically significant difference among groups ( P < .001). The distribution of the normal population was Gaussian. The inter- and intraobserver reliability were 0.99 +/- 0.00 and 0.97 +/-0.02 Conclusions: This pilot study suggests that the FAO is an efficient tool for measuring hindfoot alignment using WBCT. Previously published research in this field has looked at WBCT by adapting 2D biometrics. The present study introduces the concept of 3D biometrics and describes an efficient, semiautomatic tool for measuring hindfoot alignment.

LEVEL OF EVIDENCE

Level III, retrospective comparative study.

Does pterygomaxillary disjunction in surgically assisted rapid maxillary expansion influence upper airway volume? A prospective study using Dolphin Imaging 3D

Surgically assisted rapid maxillary expansion has been used for the treatment of transverse maxillary deficiency. This prospective study aimed to evaluate the effect of this surgery (with or without pterygomaxillary disjunction) on the upper airway volume. The patients were randomly divided into two groups: without pterygomaxillary disjunction (-PD) and with pterygomaxillary disjunction (+PD). Eleven patients per group were estimated to obtain a representative sample (90% of power and 95% of confidence level). Volumetric images of cone beam computed tomography scans were obtained preoperatively, immediately after Hyrax screw stabilization and 6 months after Hyrax screw stabilization. Volumetric measurements of the nasal cavity, maxillary sinuses, nasopharynx, and oropharynx, and of the minimum oropharynx cross-sectional area were obtained using Dolphin 3D Imaging Software. The final sample consisted of 25 adult individuals (+PD group, n=12; -PD group, n=13). In the +PD group, we observed a statistically significant increase immediately after Hyrax screw stabilization for the nasopharynx volume (P=0.003), oropharynx volume (P=0.007) and oropharynx cross-sectional area (P=0.001). Pterygomaxillary disjunction resulted in a significant (P <0.05) increase in volumetric measurements of the nasopharynx and minimum oropharynx cross-sectional area 6 months after the expander device stabilization.