Nasopharyngeal Volume Research Articles

Retrospective analysis of the upper airway anatomy and Sella turcica morphology across different skeletal malocclusions: a computerized technique

ObjectiveThis study aimed to investigate the normal volumetric space and variations in the measurements of different landmarks in adults with different skeletal relations of the maxilla and the mandible based on CBCT data. The study also analyses these landmarks to locate any correlations.BackgroundNumerous studies in orthodontics have found a relationship between orthodontic treatment and changes in the anatomy and function of the airway. Severe changes in airway morphology can cause breathing difficulties, lower quality of life, and even result in life-threatening conditions such as obstructive sleep apnoea. Consequently, orthodontic diagnosis and treatment planning require a thorough understanding of the airway space and its function.MethodsThe present retrospective study was conducted using CBCT records of 120 adult patients, containing 40 samples of each skeletal class (20 males and 20 females). The boundaries were defined for the 3 major regions: the nasopharynx, the oropharynx, and the hypopharynx. Various measurements were recorded across these regions, as well as selective cephalometric landmarks. The obtained data was used to calculate average and standard deviation, while regression analysis was used to evaluate correlations and t-test was used to test statistical significance of gender differences.ResultsThe results demonstrate that skeletal Class III individuals exhibit a reduced airway volume in the nasopharynx compared to other groups, whereas skeletal Class II individuals displayed a diminished airway volume in the hypopharynx. A strong correlation was observed for Sella turcica parameters. There were no significant differences in skeletal parameters across genders. Nasopharynx cavity volume demonstrated significant differences between skeletal Class I–Class III as well as between skeletal Class II–Class III. Hypopharynx cavity volume also demonstrated significant differences between skeletal Class I–Class II and between skeletal Class II–Class III.ConclusionThe major findings are the presence of a reduced nasopharyngeal volume in skeletal Class III malocclusions while skeletal Class II individuals displayed a diminished hypopharyngeal volume, making these critical areas to consider during the diagnostic and orthodontic treatment planning stages. This study also revealed a consistent correlation between Sella turcica parameters across various facial skeletal profiles, with skeletal Class II patients exhibiting a distinct pattern and skeletal Class I and Class III demonstrating an average relationship.

A 3D-CBCT Volumetric Analysis of Cervical Vertebrae Angulation and Airway Dimensions

Aim: To evaluate the relationship between airway dimensions and cervical vertebrae angulations in dental patients using three-dimensional cone beam computed tomography (3D-CBCT) technology. Materials and Methods: Pre-treatment CBCT scans and cephalometric radiographs were measured for 59 patients (mean age 22±2.3yrs.) using the Dolphin3D software system (version 11.7; Dolphin Imaging & Management Solutions, Chatworth, CA) to record airway dimensions and cervical vertebral angulations. All CBCT images were acquired using the same standard protocol for collection using the iCAT CBCT Unit (Imaging Sciences International, Hatfield, PA): 13cm field of view, 0.4mm voxel size, 8.9sec scan time. Intraclass Correlations (ICC) were performed on duplicate measurements of 10 CBCT scans after a two-week interval to assess reliability. P-value and Pearson correlation coefficients were used to statistically assess the relationship between vertebral angulations and airway dimensions. Results: ICC values from the reliability assessment were >0.90. Pearson correlation coefficients were categorized based on confidence level as follows: high (>0.75 or <-0.75), moderate (0.5 to 0.74 or -0.5 to -0.74), or weak (0.3 to 0.49 or -0.3 to -0.49). No high/moderate correlations were observed. Weak correlations (p<0.05) were observed between the nasopharyngeal volume and the soft tissue thickness at CV1(-0.47) and CV2(-0.34). A weak correlation was observed between the nasal cavity volume and S-N (+0.41) as well as ANS-PNS(+0.38). A weak correlation was observed between the total airway volume and the soft tissue thickness at CV2(-0.34). Conclusion: The soft tissue thickness of the posterior wall of the airway at the level of cervical vertebrae-2 appears to have a weak, negative correlation with several upper airway parameters and total airway volume. Soft tissue thickness of the posterior pharyngeal wall is crucial for dental clinicians to analyze prior to some procedures such as orthognathic surgery and orthodontic treatment that involve growth modification and jaw positioning, as it may have an association with decreased airway volume. Clinical Significance: The relationship between cervical vertebrae angulation, airway, and craniofacial morphology is a complex aspect of human anatomy. In dentistry, it is crucial that clinicians recognize the vital role cervical vertebrae angulation and airway interact in relation to craniofacial morphology. Knowledge of these interconnections will significantly inform treatment planning for multiple oral health conditions such as malocclusions, jaw discrepancies, and temporomandibular joint disorders.

Effect of Slow Maxillary Expansion and Alternative Rapid Maxillary Expansion Protocols on Airway Volume in Cleft Palate Cases: A Cone Beam Computed Tomography Based Study.

A total of 22 patients with cleft palate aged 8 to 12 years were selected and categorized into two groups: the first group was treated with alternate rapid maxillary expansion and constriction (Alt-RAMEC) using an expander with differential opening (EDO) and facemask, while the second group was treated using slow maxillary expansion (SME) using an EDO. Finally, the pharyngeal airway volume in the two groups was compared using cone beam computed tomography (CBCT). CBCT scans were performed before expansion and six months following the expansion. Alveolar crest level, maxillary breadth, nasal cavity width, arch width, inclination of the molar teeth, buccal and palatal alveolar bone thickness, and maxillary alveolar width were all assessed. Paired t-tests (p=0.05) were applied to compare interphase data. The two groups showed a non-significant difference in terms of nasopharyngeal volume (cm3), oropharyngeal volume (cm3), and overall pre- and post-treatment results (p>0.005). Results of comparison of pre- and post-treatment periods in the Alt-RAMEC group revealed a significantly higher cleft volume (cm3) (p=0.001). Results of comparison of pre- and post-treatment periods in the SME group revealed a substantial rise in cleft volume (cm3) (p=0.003).Results from a comparison of the cleft volume (cm3) between the two study groups pre- and post-intervention revealed a non-significant difference (p=0.200 and 0.054, respectively).

Postsurgical Volumetric Airway Changes in Class III Patients Receiving Bimaxillary Orthognathic Surgery.

The purpose of the present study was to investigate the pharyngeal airway space (PAS) changes in class III patients receiving bimaxillary orthognathic surgery and correlate the PAS volume and minimum axial section changes with the magnitude of the surgical movement. This research involved a retrospective sample composed of 38 patients with class III skeletal occlusions. Three-dimensional measurements of the PAS volume and minimum axial section were conducted. Cephalometric points were used to verify the extent of jaw-hyoid bone movement. No significant differences were found between pre and postoperative total PAS volume (P = 0.280), nasopharyngeal volume (P = 0.545), oropharyngeal volume (P = 0.297), and minimum axial section (P = 0.568). Anterior movement of point A and posterior nasal spine were significantly associated with an increase in total PAS volume, oropharyngeal volume, and minimum axial section (P < 0.05). However, the posterior movement of menton was significantly associated with a decrease in total PAS volume, oropharyngeal volume, and minimum axial section (P < 0.05). The results of the present study indicated that PAS is not negatively affected by bimaxillary surgery in class III patients. However, the planning of class III patients who are prone to the development of airway problems should be done carefully.

Adults with Treacher Collins Syndrome Share Comparable 3D Upper Airway Dimensions with Nonsyndromic Individuals.

Sleep apnea symptoms, such as snoring and daytime somnolence, are commonly observed in individuals with Treacher Collins Syndrome (TCS) and may be related to airway obstruction due to micro- and retro-gnathia. This study aims to three-dimensionally evaluate the upper airway using cone-beam computed tomography (CBCT) exams of adolescents (TCS-ADOL) and adults (TCS-ADUL) with TCS compared to a nonsyndromic group (CON). Twenty-six CBCT exams were divided into three groups: TCS-ADOL (n = 7) (13.14 ± 1.67 years): CBCT exams of TCS adolescents; TCS-ADUL (n = 10) (21.80 ± 4.39 years): CBCT exams of TCS adults; and CON (n = 9) (25.33 ± 8.57 years): CBCT exams of adult nonsyndromic individuals with Class II skeletal pattern. The variables analyzed were (1) total upper airway volume; (2) nasal cavity volume; (3) total pharyngeal volume; (4) nasopharyngeal volume; (5) oropharyngeal volume; (6) pharyngeal minimal cross-sectional area; (7) pharyngeal length; and (8) pharyngeal depth. Scans were analyzed by two examiners, and intra- and inter-rater agreement was calculated. A p-value of ≤0.05 was considered significant. Although not statistically significant, the TCS-ADUL group showed decreased airway volume and minimal cross-sectional areas compared to the CON group. There were also significant differences between TCS-ADOL and TCS-ADUL, with significantly lower airway volumes in the TCS-ADOL group. Strong positive correlations were found between certain airway measurements in the TCS-ADOL group, which were not observed in adults. The upper airways of adults with TCS are dimensionally similar to those of nonsyndromic individuals, despite absolute value reductions found in the syndromic group. The reduced airway in the adolescent population suggests significant potential for growth, mainly in pharyngeal dimensions.

Measurement of Upper Airway Volume in Children with Craniofacial Abnormalities.

Previous literature has established a high prevalence of upper airway obstruction in children with craniofacial abnormalities. This study aims to perform quantitative airway volume measurements in patients with craniofacial abnormalities and compare them to age and sex-matched controls. We performed a retrospective review of the records of all children with craniofacial abnormalities who underwent head-and-neck computed tomography (CT) imaging at a single tertiary-care center between 1/1/13 and 12/31/20 using the ICD-10 codes Q75.1, Q75.4, and Q87.0. These patients were then matched by age and sex to patients with isolated craniosynostosis (Q75.0). CT scans were imported into Dolphin Imaging software, and airway volumes were measured for the nasal cavity, nasopharynx, oropharynx, and hypopharynx. The primary outcome was the total airway volume, defined as the sum of these measurements. Thirty subjects with craniofacial syndromes were matched to 30 patients with isolated craniosynostosis (controls). In both groups, 18 subjects (60%) were male (p = 0.99). The average ages for syndromic patients and controls were 12.1 and 12.9 months, respectively (p = 0.84). On average, the total airway volumes of syndromic patients were 25% lower than those of controls (p = 0.02). Syndromic patients had 39% smaller nasal cavity volumes (p < 0.001) and 32% smaller nasopharyngeal volumes (p < 0.01). Significant volume differences were not observed for the oropharynx or hypopharynx. We present a unique technique to measure airway volumes in patients with craniofacial abnormalities. These findings will help practitioners to further understand the anatomy and pathophysiology of disturbed breathing in children with craniofacial syndromes. III Laryngoscope, 134:2915-2921, 2024.

The short- and long-term changes of upper airway and alar in nongrowing patients treated with Mini-Implant Assisted Rapid Palatal Expansion (MARPE): a systematic review and meta-analysis

ObjectiveThis study aims to assess the short- and long-term changes in the upper airway and alar width after mini-implant -assisted rapid palatal expansion (MARPE) in nongrowing patients.MethodsFive electronic databases (PubMed, Scopus, Embase, Web of Science, and Cochrane Library) were searched up to 2 August, 2023 based on the PICOS principles. The main outcomes were classified into three groups: 1) nasal cavity changes, 2) upper airway changes and 3) alar changes. The mean difference (MD) and 95% confidence intervals (CI) were used to assess these changes. Heterogeneity tests, subgroup analyses, sensitivity analyses, and publication bias were also analyzed.ResultOverall, 22 articles were included for data analysis. Nasal cavity width (WMD: 2.05 mm; 95% CI: 1.10, 3.00) and nasal floor width (WMD: 2.13 mm; 95% CI: 1.16, 3.11) increased significantly. While palatopharyngeal volume (WMD: 0.29 cm3, 95% CI: -0.44, 1.01), glossopharyngeal volume (WMD: 0.30 cm3, 95% CI: -0.29, 0.89) and hypopharyngeal volume (WMD: -0.90 cm3; 95% CI: -1.86, 0.06) remained unchanged, nasal cavity volume (WMD: 1.24 cm3, 95% CI: 0.68, 1.81), nasopharyngeal volume (MD: 0.75 cm3, 95% CI: 0.44, 1.06), oropharyngeal volume (WMD: 0.61 cm3, 95% CI: 0.35, 0.87), and total volume of the upper airway (WMD: 1.67 cm3, 95% CI: 0.68, 2.66) increased significantly. Alar width (WMD: 1.47 mm; 95% CI: 0.40, 2.55) and alar base width (WMD: 1.54 mm; 95% CI: 1.21, 1.87) also increased.ConclusionMARPE can increase nasal cavity width, nasal cavity volume, nasopharyngeal volume and oropharyngeal volume for nongrowing patients, but has no significant effect on hypopharyngeal volume. In addition, the alar width also increased. However, the studies included in this meta-analysis were mainly retrospective, nonrandomized and small in number, so the findings should be interpreted with caution and high-quality RCTs need to be studied.

Role of Nasal Ventilation Function in Obstructive Sleep Apnea Syndrome in Children.

Background: The association between increased nasal resistance (NR) and obstructive sleep apnea syndrome (OSAS) is controversial. The purpose of this study was to examine nasal ventilation function (NVF) in children with OSAS, with a focus on its pathogenetic role. Methods: Children were recruited and divided into the OSAS group (n = 109) and control group (n = 116). The participants underwent polysomnography (PSG), measurement of NR, and acoustic rhinometry (AR). A combination of intranasal corticosteroids (ICS) and oral montelukast (OM) was administered to 90 children with mild to moderate OSAS for 12 weeks. After excluding participants who dropped out or were lost to follow-up, there were 58 children who responded to the treatment, who were divided into 2 groups-A and B. We compared the size of the tonsil adenoids, the PSG, NR, and AR before and after treatment in the 2 groups. Results: Children aged 6 to 12 years with OSAS had significantly higher NR than the control group (P < .05). The OSAS group had a smaller nasal minimal cross-sectional area (NMCA), nasal cavity volume (NCV) from 0 to 5 cm, and nasopharyngeal volume (NPV) from 6 to 8 cm than the control group, and the difference was statistically significant (P < .05 or P < .01). A total of 58 (84.1%) children responded to the 12-week ICS+OM treatment and 11 (15.9%) children did not respond to the treatment. Effective treatment was achieved in 32 children, as evidenced by a significant reduction in tonsil adenoid size and variations in NR and AR values. There were significant improvements in NR, NMCA, and NCV in the remaining 26 children who were successfully treated, but there was no change in tonsil adenoids and NPV value. Conclusion: NVF may play an important pathogenetic role in children with OSAS.

Reliability of parental reporting of child snoring in children referred for obstructive sleep apnea.

Despite the high number of studies based on subjective reports of snoring, self-reported snoring has hardly been validated at all. As there is no "gold-standard" for objective snoring measurements, studies must evaluate whether the presence of snoring based on parental judgement is linked to objective measurements of nasal and/or pharyngeal obstruction in children referred for obstructive sleep apnea. A total of 146 children (median age 11 years) underwent polysomnography (with snoring recording using nasal cannula signal), acoustic rhinometry and pharyngometry, while their parents filled out the Spruyt-Gozal questionnaire assessing both frequency and loudness of subjective snoring. Three categories were further differentiated (null, low and high) for both frequency and loudness. The apnea-hypopnea index was significantly different in the three groups for both frequency (p=0.04) and loudness (p=0.01) of subjective snoring. Children in the low or high groups (frequency or loudness), compared with those in the null group, experienced a decline in both pharyngeal (sitting and supine positions) and nasopharyngeal (supine position) volumes (frequency, pharynx sitting: p=0.03; supine: 0.005 and nasopharynx: p=0.002; loudness, p=0.03; p=0.007 and p=0.03; three group comparisons). Objective snoring frequency during the night obtained with cannula was weakly related to loudness of subjective snoring but not to subjective snoring frequency during the week, and was biased by nasal obstruction. In conclusion, our study showed that parental assessment of snoring is related to a reduction in both pharyngeal and nasopharyngeal volumes in snorers, arguing for the adequacy of their evaluation of both snoring frequency and loudness.

A 3-Dimensional Evaluation of the Effects of Unilateral Vertical Mandibular Distraction Osteogenesis on Airway Volume Among Patients With Hemifacial Microsomia.

The aim of this study was to evaluate the volumetric airway changes using three-dimensional images following unilateral vertical mandibular distraction osteogenesis (uVMD) among patients with hemifacial microsomia (HFM). This retrospective study analyzed cone-beam computed tomography (CBCT) scans of patients with HFM at three different timepoints; pretreatment (T0), posttreatment (T1), and at least 6 months post-distraction (T2). The individuals underwent uVMD between December 2018-Januaray 2021. The nasopharyngeal (NP) volume, oropharyngeal (OP) volume, and the area of maximum constriction (MC) were measured. Wilcoxon signed-rank test was used to compare the airway volumes between T0-T1, T1-T2, and T0-T2. Five patients met the inclusion criteria (mean age = 10.4 years; 1 female, 4 males). Intraclass correlation analysis showed excellent interrater reliability (r > .86, P < .001). Posttreatment, the OP airway volume exhibited a significant mean increase of 56% (P = .043) from T0 to T1, but decreased from T1-T2 by 13%. Likewise, the total airway volume presented with a significant mean increase of 48% between T0-T1 (P = .044), and a decrease of 7% from T1-T2. The changes in the NP airway volume and area of MC were not statistically significant (P > .05), but an increase in the mean values were observed. Surgical intervention with uVMD may significantly increase the OP airway volume and the total airway volume among patients with HFM immediately after distraction. However, the statistical significance diminished after six months post-consolidation, but the mean percent change may remain of clinical significance. The NP volume did not seem to show significant changes in response to uVMD.

Three-Dimensional Evaluation Effects of Microimplant-Assisted Rapid Palatal Expansion on the Upper Airway Volume: A Systematic Review and Meta-Analysis

Microimplant-assisted rapid palatal expansion is increasingly used clinically; however, the effect on the upper airway volume in patients with maxillary transverse deficiency has not been thoroughly evaluated yet. The following electronic databases were searched up to August 2022: Medline via Ovid, Scopus, Embase, Web of Science, Cochrane Library, Google Scholar, and ProQuest. The reference lists of related articles were also reviewed by manual search. The Revised Cochrane Risk of Bias Tool for randomized trials (ROB2) and the Risk of Bias in non-randomized Studies of Interventions (ROBINS-I) tool were used to evaluate the risks of bias of the included studies. The mean differences (MD) and 95% confidence intervals (CI) of changes in nasal cavity and upper airway volume were analyzed using a random-effects model, and subgroup and sensitivity analyses were also performed. Two reviewers independently completed the process of screening studies, extracting data, and assessing the quality of studies. In total, twenty-one studies met the inclusion criteria. After assessing the full texts, only thirteen studies were included, with nine studies selected for quantitative synthesis. Oropharynx volume increased significantly after immediate expansion (WMD: 3156.84; 95% CI: 83.63, 6230.06); however, there was no significant change in nasal volume (WMD: 2527.23; 95% CI: -92.53, 5147.00) and nasopharynx volume (WMD: 1138.29; 95% CI: -52.04, 2328.61). After retention a period, significant increases were found in nasal volume (WMD: 3646.27; 95% CI: 1082.77, 6209.77) and nasopharynx volume (WMD: 1021.10; 95% CI: 597.11, 1445.08). However, there was no significant change after retention in oropharynx volume (WMD: 789.26; 95% CI: -171.25, 1749.76), palatopharynx volume (WMD: 795.13; 95% CI: -583.97, 2174.22), glossopharynx volume (WMD: 184.50; 95% CI: -1745.97, 2114.96), and hypopharynx volume (WMD: 39.85; 95% CI: -809.77, 889.46). MARPE appears to be linked with long-term increases in nasal and nasopharyngeal volume. However, high-quality clinical trials are required to further verify the effects of MARPE treatment on the upper airway.

Effect of Maxillary Expansion Treatment Protocols On Maxillary Sinus Volume, Pharyngeal Airway Volume, and Hyoid Bone Position: A Prospective, Cone Beam Computed Tomography (CBCT) Study

Aim: This study aimed to investigate the changes in maxillary sinus volume, pharyngeal airway volume, and hyoid bone position in patients treated with Rapid Maxillary Expansion (RME) and Alternate Rapid Maxillary Expansion and Constriction (AltRaMEC) – Facemask therapy and compare between the groups. Materials and Methods: The records of 15 patients between the age group of 8-14 years with Class I and Class III malocclusion were collected, and the patients were assigned into two groups. The first group comprised of 8patients (4 girls and 4 boys) who were treated with Rapid Maxillary Expansion. The second group comprised 7 patients (5 boys and 2 girls) treated with expansion devices using Alt-RaMEC protocol followed by maxillary protraction using a facemask. Pre and post-treatment CBCT scans were obtained and analyzed for changes in the pharyngeal airway, maxillary sinus volume, and hyoid bone position. The maxillary sinus volume was calculated in 3 dimensions by measuring the craniocaudal height, anteroposterior depth, and mediolateral width. Measurements were taken before and after the procedure to compare the groups and between the groups. The data were analyzed using Paired t-test and an Independent t-test. Results: In the RME group, a significant increase in the total maxillary sinus volume (mean difference = 520±576.57mm3), especially in the craniocaudal height, was seen, but no changes were noted in the pharyngeal airway and hyoid position. The AltRAMEC group showed a statistically significant increase in the maxillary sinus volume (anteroposteriorly) and nasopharyngeal volume with a p-value &lt;0.005. Comparing the maxillary sinus volume changes in RME and AltRAMEC groups showed a statistically significant increase in the volume of the maxillary sinuses in both groups, significantly higher in the RME group. Conclusion: RME and AltRAMEC protocol followed by facemask therapy caused a significant increase in the maxillary sinus volume, while no changes were noted in the nasopharynx, oropharynx, hypopharynx, and hyoid bone position. While comparing the treatment effects between the groups, RME showed a greater increase in maxillary sinus volume (p &lt; 0.05), specifically in the anteroposterior dimension. Since there are no changes in airway volume and hyoid position with the skeletal expansion protocols, there will be no difference in nasal resistance to airflow.

Influences of Airway Obstruction Caused by Adenoid Hypertrophy on Growth and Development of Craniomaxillofacial Structure and Respiratory Function in Children.

Adenoid hypertrophy (AH) is a common disease in otorhinolaryngology. Children with chronic snoring and hypoxia are susceptible to long-term nasal obstruction, while long-term open-mouth breathing may cause craniofacial bone development disorders and dull facial expressions, the so-called adenoid face. The purpose of this work is to analyze the influence of AH-induced airway obstruction (AO) on the growth and development of craniomaxillofacial structure and respiratory function (RF) in children. The clinical data of 56 AH children (observation group) and 42 healthy children with physical examination (control group) who visited the Hebei Eye Hospital during the same period were retrospectively analyzed. All children received acoustic rhinometry and X-ray cephalometric measurements. The upper airway structure, sleep disorder score, and A/N value of nasopharyngeal lateral X-ray images were compared between cases and controls. For AH children, sleep tests were also performed to assess their RF. X-ray cephalometric measurements of facial morphology showed obvious vertical growth, mandibular retrognathia, and enlarged mandibular angle in AH children. AH mainly affects the size of the nasopharyngeal and oropharyngeal airway. AH children presented with higher nasal airway resistance (5.11 ± 1.95 cmH2O/L min) and lower nasopharyngeal volume (NPV) (16.86 ± 3.93 cm3) than controls. Of the AH children, 45 had abnormal RF, including 4 with obstructive sleep apnea syndrome. The A/N value of nasopharyngeal lateral X-ray images was significantly higher in AH children than in controls. Besides, worse sleep quality was found in AH children. The above differences were all of statistical significance. The above indicates that AH can affect the size of the nasopharyngeal and oropharyngeal airway, change children's respiratory mode and RF, increase nasal resistance, and decrease NPV, resulting in upper respiratory tract stenosis, as well as craniomaxillofacial and oral malformations, which affects children's normal growth and development.

Assessment of pharyngeal airway in Korean adolescents according to skeletal pattern, sex, and cervical vertebral maturation: A cross-sectional CBCT study.

ObjectiveTo investigate airway volumes using cone-beam computed tomography (CBCT) by skeletal patterns, sex, and cervical vertebral maturation (CVM) stages in Korean adolescents.MethodsThe sample consisted of pretreatment CBCT and cephalograms of 95 adolescents (aged 12–19) obtained out of 1,611 patients examined for orthodontic treatment from 2018 to 2020 in Kyungpook National University Dental Hospital. The samples were classified into two sex groups; three skeletal pattern groups, four chronological age groups and four CVM stages. Nasopharyngeal volumes (NPV), oropharyngeal volumes (OPV), total pharyngeal airway volume (TAV) and minimum cross-sectional area (MCA) measurements were taken from the CBCT. Multiple linear regression analyses to find out which one of the independent variables are good predictors for airway variables. Significant factors were analyzed by two-way multivariate analysis of variance (MANOVA) then multiple comparisons were analyzed using a t-test, and Fisher least significant difference.ResultsAge, sex, CVM, and Sella-Nasion-B point have significant influence on airway variable. Males and females showed similar patterns of change in chronological age groups 1–3; however, males had larger NPV, OPV, and MCA at CVM in group 4. According to CVM stages, males had larger OPV, TAV, and MCA at CVM stage 6 (p-value 0.019, 0.021, 0.015, respectively) and no sex differences at CVM stages 3, 4, and 5.ConclusionsSkeletal patterns have an effect on airway volume. Sex differences were found in CVM 6.

From SARS-CoV-2 infection to COVID-19 morbidity: an in silico projection of virion flow rates to the lower airway via nasopharyngeal fluid boluses

Background: While the nasopharynx is initially the dominant upper airway infection site for SARS-CoV-2, the physiologic mechanism launching the infection at the lower airway is still not well-understood. Based on the rapidity of infection progression to the lungs, it has been hypothesized that the nasopharynx may be acting as the primary seeding zone for subsequent contamination of the lower airway via aspiration of virus-laden boluses of nasopharyngeal fluids. Methodology: To examine the plausibility of the aspiration-driven mechanism, we have computationally tracked the inhalation process in three anatomic airway reconstructions and have quantified the nasopharyngeal liquid volume transmitted to the lower airspace during each aspiration. Results: Extending the numerical trends on aspiration volume to earlier records on aspiration frequencies indicates a total aspirated nasopharyngeal liquid volume of 0.3 – 0.76 ml/day. Subsequently, for mean sputum viral load, our modeling projects that the number of virions reaching the lower airway will range over 2.1×106 – 5.3×106 /day; for peak viral load, the corresponding number hovers between 7.1×108 – 1.8×109. Conclusions: The virion transmission findings fill in a key piece of the mechanistic puzzle on the systemic progression of SARS-CoV-2, and subjectively point to health conditions like dysphagia, with proclivity to increased aspiration, as some of the potential underlying risk factors for aggressive lung infections.

Obstructive sleep apnoea in pycnodysostosis: A three-dimensional upper airway analysis.

To assess the upper airway (UA) morphology in patients with pycnodysostosis with a 3D analysis, compare results with normative data and investigate the correlation of the total volume (TV) with other UA morphology variables. Cone beam computed tomography (CBCT) images of eight Danish patients with pycnodysostosis (4 males and 4 females with a mean age of 31.8years, SD: 16.3years) were analyzed using Mimics® (Materialise® ) and compared with a sex- and age-matched control group (6 males and 8 females with a mean age of 33.6years, SD: 18.6years). The distance from the tip of the epiglottis (E) to the Frankfurt horizontal plane (Fp) was significantly shorter in the pycnodysostosis group (P<.042). Regarding the cross-sectional measurements, at the 'maximum constriction' (P<.005), the 'upper airway limit' (P<.001) and the 'lower airway limit' (P<.035) cross-sections were significantly smaller in the pycnodysostosis group. The volumes 'nasopharynx' (P<.002) and 'total airway' (TV) (P<.01) were also significantly smaller. Patients with pycnodysostosis have a reduced total airway as well as nasopharyngeal volume compared with matched controls. Additionally, they have a reduced cross-sectional area in the upper and lower borders of the UA, and the area of maximum constriction is also reduced. These factors might explain the high prevalence of obstructive sleep apnoea in pycnodysostosis. Total airway is positively correlated with total length and cross-sections at all levels including the maximum constriction area as well as the anteroposterior dimension at the upper and lower airway borders.

Three-dimensional assessment of airway volumes in patients with unilateral cleft lip and palate

BackgroundConsidering the adverse consequences of respiratory insufficiency in cleft lip and palate (CLP) patients, this study aimed to assess the pharyngeal airway dimensions in 9–12-year-old patients with unilateral CLP. This historical cohort evaluated the cone-beam computed tomography (CBCT) scans of 30 patients with non-syndromic unilateral CLP between 9 and 12 years and 30 age- and sex-matched non-cleft controls. Three-dimensional (3D) images were reconstructed by the Mimics software, and the nasopharyngeal, oropharyngeal, and total airway volumes, as well as the minimal cross-sectional area of the airway (minAx), and posterior airway length (PAL) were all measured in the sagittal plane. Data were analyzed by the Student’s t test.ResultsThe oropharyngeal and the total airway volumes, as well as the minAx and PAL in CLP patients, were significantly smaller than the corresponding values in the control group (P < 0.05). Despite smaller nasopharyngeal airway volume in CLP patients than controls, this difference was not statistically significant (P > 0.05).ConclusionsNine- to twelve-year-old non-syndromic unilateral CLP patients have smaller pharyngeal airway dimensions than non-cleft controls, and are therefore at higher risk of respiratory insufficiency.

RELATION BETWEEN SAGITTAL POSITION OF THE MANDIBLE AND PHARYNGEAL AIRWAY VOLUME IN ADULTS USING CONE BEAM COMPUTED TOMOGRAPHY

Introduction: Many authors have discussed the relationship between craniofacial morphology and pharyngeal airway spaces in different malocclusions and skeletal patterns. So the aim of this work was to study the relation between sagittal position of the mandible and pharyngeal airway volume in adults using CBCT. Materials And Methods:Twentyone CBCT radiographs were collected from the archive of Radiology Department at Suez Canal University and were divided into 3 groups according to the measured SNB angle. Group 1 normal mandibular position, group 2 retrognathic mandible and group 3 prognathic mandible. Dolphin 3D imaging software was used to measure the airway volume for all the radiographs. Nasopharyngeal, oropharyngeal, hypopharyngeal and total pharyngeal airway volumes were measured for all the radiographs. F-test (ANOVA) was used for comparison between groups and Tukey test for pairwise comparisons. Correlations between variables were tested using PearsonÂ’s correlation coefficient. Results: there was statistically significant difference in the mean total pharyngeal airway volume and oropharyngeal airway volumes between the three groups. Nasopharyngeal airway volume and hypopharyngeal airway volume had non-significant difference between groups. There was a significant positive correlation between total pharyngeal airway volume (mm3) and SNB angle. Conclusion: Pharyngeal airway volume differs with different sagittal positions of the mandible. Pharyngeal airway volume decreases with mandibular retrognathism and increases with mandibular prognathism.

Analysis of nasal airway symmetry and upper airway changes after rapid maxillary expansion

The objectives of this study were to assess the changes in right vs left nasal cavity volumes and minimum cross-sectional width, nasopharyngeal, and oropharyngeal volumes of the upper airway in response to rapid maxillary expansion (RME). Pretreatment and posttreatment cone-beam computed tomography scans of 28 patients with a mean age of 9.86±2.43years and 20 age- and sex-matched controls were digitized and linear, angular, and volumetric measurements were obtained. Nasopharyngeal volume, right, and left nasal cavity volumes, and minimum cross-sectional widths increased significantly 2years post RME (P<0.05). These measurements did not show any significant increase in the control group (P>0.05), whereas the oropharyngeal volume increase for both groups was comparable (P=0.92). In the experimental group, the right and left nasal cavity volumes were not significantly different at baseline or posttreatment. However, the change that occurred was significantly larger for the left nasal cavity. This change for the control group was more significant for the right nasal cavity. Maxillary right and left molar inclinations were positively correlated to the nasal cavity volume, showing that the more buccally inclined the maxillary molars were, the smaller the nasal cavity volume. Nasopharyngeal and right and left nasal cavity volumes and minimum cross-sectional widths increase significantly after RME in young children. Expansion decreases the degree of difference in volume between the right and left nasal cavities. The buccal inclination of maxillary molars is correlated with nasal cavity volume.

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

Aim and objectiveMouth 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 methodsCone-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.ResultsThe nasal cavity and nasopharyngeal volume showed significant differences among the gender (p value < 0.001 and 0.018, respectively).Conclusion and clinical significanceKnowledge 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 articleKalaskar 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.