Airway Length Research Articles

3D-CT measurements of airway morphology in severe CFM patients: A comparative study between ascending ramus distraction osteogenesis and bone grafting

This study investigated the differential effects of mandibular distraction osteogenesis (MDO) and bone grafting on upper airway morphology in pediatric patients with Pruzansky-Kaban type IIB and III craniofacial microsomia (CFM). A retrospective analysis was performed on medical records and three-dimensional computed tomography (3D-CT) scans of CFM patients who had undergone MDO or bone grafting as primary interventions. Preoperative and postoperative imaging data were evaluated to quantify and compare changes in airway dimensions between the two surgical groups. Parameters such as airway volume, surface area, length, mean and minimum cross-sectional areas, and sphericity were measured across the nasopharynx, oropharynx, and laryngopharynx. Data normality was assessed using the Shapiro-Wilk test, and statistical comparisons were made using either paired t-tests or the Wilcoxon signed-rank test, depending on distribution characteristics. Eighteen children with type IIB and III CFM were included in the study, with 11 undergoing MDO and 7 receiving bone grafting. In the MDO group, postoperative measurements revealed significant increases in nasopharyngeal length and surface area (P=0.001, P=0.036), along with notable improvements in oropharyngeal length, volume, surface area, mean and minimum cross-sectional areas, and sphericity (P<0.05). In contrast, the bone grafting group exhibited a significant increase only in nasopharyngeal length (P=0.019), without substantial postoperative changes in other airway parameters. These findings suggested that MDO leads to more pronounced improvements in upper airway morphology, particularly in the nasopharynx and oropharynx, compared to bone grafting, which demonstrated minimal impact on airway dimensions.

Mesenchymal Vangl1 and Vangl2 facilitate airway elongation and widening independently of the planar cell polarity complex.

Adult mammalian lungs exhibit a fractal pattern, as each successive generation of airways is a fraction of the size of the parental branch. Achieving this structure likely requires precise control of airway length and diameter, as the embryonic airways initially lack the fractal scaling observed in the adult. In monolayers and tubes, directional growth can be regulated by the planar cell polarity (PCP) complex. Here, we characterized the roles of PCP complex components in airway initiation, elongation and widening during branching morphogenesis of the lung. Using tissue-specific knockout mice, we surprisingly found that branching morphogenesis proceeds independently of PCP complex function in the lung epithelium. Instead, we found a previously unreported Celsr1-independent role for the PCP complex components Vangl1 and Vangl2 in the pulmonary mesenchyme, where they are required for branch initiation, elongation and widening. Our data thus reveal an explicit function for Vangl1 and Vangl2 that is independent of the core PCP complex, suggesting a functional diversification of PCP complex components in vertebrate development. These data also reveal an essential role for the embryonic mesenchyme in generating the fractal structure of airways in the mature lung.

Comparative Analysis of Pharyngeal Airway Changes Following All Four Versus All Five Premolar Extractions in Orthodontic Treatments: A Cephalometric Study.

Orthodontic treatment, particularly involving premolar extractions, has been a subject of ongoing debate within the orthodontic community. The impact of such interventions on the pharyngeal airway, a critical component of the respiratory system, remains a topic of exploration. This retrospective cephalometric study aims to investigate changes in pharyngeal airway dimensions following orthodontic treatment involving either all four or all five premolar extractions. A sample of 68 participants, extracted from orthodontic records, underwent cephalometric analysis to quantify changes in pharyngeal airway dimensions. The study compared two groups: those treated with all four premolar extractions (n=34) and those treated with all five premolar extractions (n=34). Cephalometric radiographs taken before and after treatment were analyzed, focusing on airway width, length, and volume. Preliminary findings indicate significant changes in airway dimensions within each group. In the all four premolar extraction group, there was a statistically significant decrease in airway width (p=0.02) and volume (p=0.04). Similarly, the all five premolar extraction group exhibited significant reductions in airway width (p=0.03) and volume (p=0.02). However, the between-group comparisons revealed no significant differences in changes between the two groups. This study sheds light on the intricate relationship between orthodontic interventions, specifically premolar extractions, and changes in pharyngeal airway dimensions. While significant changes were observed within each group, the lack of significant differences between the all fourand all five premolar extraction groups raises intriguing questions about the specific impact of premolar extraction patterns on the upper airway.

Measurement of the lengths of different sections of the upper airway and their predictive factors.

No studies have been conducted to define the lengths of the upper airway's different segments in normal healthy adults. This study aimed to determine the length of the subglottis and extrathoracic trachea and the factors affecting it. This was an observational retrospective review study. Included 102 adult patients who underwent CT scan during the quiet inspiration phase of the upper airway. The results revealed significant positive linear relationships between height and both anterior and posterior subglottic measurements (p < 0.001). Additionally, a statistically significant, moderately strong negative correlation between age and extrathoracic tracheal measurements (p > 0.001) was observed. Men exhibited longer anterior (p < 0.001) and posterior (p > 0.001) subglottic measurements. In both sexes, the average length of the anterior subglottis was 14.16 (standard deviation [SD]: 2.72) mm, posterior subglottis was 14.51 (SD: 2.85) mm and extrathoracic trachea was 66.37 (SD: 13.71) mm. We concluded that a normal healthy adult's anterior subglottis length is 6.3-19.3 mm (mean: 14.16 [SD: 2.72] mm), posterior subglottis length is 6.1-20.0 mm (mean: 14.51 [SD: 2.85] mm) and extrathoracic trachea length is 25.2-98.5 mm (mean: 66.37 [SD: 13.71] mm). Age, height and sex affected the upper airway length.

Characteristics of lower airway parameters in an adult Asian population related to endotracheal tube design: a cadaveric study

The risk of endotracheal tube (ETT) placement includes endobronchial intubation and subglottic injury. This study aimed to describe the lengths of lower airway parameters related to cuff location and vocal cord markings in different adult-sized ETTs. Eighty cadavers were examined for the lengths of the lower airway, including their correlations and linear regressions with height. Thirty adult-sized ETTs from seven different brands were examined for Mark-Cuff and Mark-Tip distances. The depth of ETT placement was simulated for each brand using vocal cord marking. The mean (standard deviation) lengths from the subglottis, trachea, vocal cord to mid- trachea, and vocal cord to carina were 24.2 (3.5), 97.9 (8.6), 73.2 (5.3), and 122.1 (9.0) mm, respectively. Airway lengths were estimated as: (1) subglottis (mm) = 0.173 * (height in cm) − 3.547; (2) vocal cord to mid-trachea (mm) = 0.28 * (height in cm) + 28.391. There were variations in the Mark-Cuff and Mark-Tip distances among different ETTs. In the simulation, endobronchial intubation ranged between 2.5 and 5% and the cuff in the subglottis ranged between 2.5 and 97.5%. In summary, the lower airway parameters were height-related. ETT placement using vocal cord marking puts the patient at a high risk of cuff placement in the subglottis.

Analysis of airway structural parameters in Han Chinese adults: a prospective cross-sectional study

Introduction Establishing reference ranges for central airway parameters and exploring their influencing factors in Han Chinese non-smoking adults. Methods This prospective cross-sectional study was conducted on Han Chinese non-smoking adults who underwent chest CT scans at the Tongzhou Campus of Dongzhimen Hospital Affiliated with the Beijing University of Chinese Medicine between September 2022 and November 2022. The SYNAPSE 3D image analysis software was utilized, enabling the extraction of critical parameters such as central airway length, airway wall thickness (AWT), airway lumen area (ALA), and subcarinal angle (SCA). Pearson’s correlation coefficient analysis and multiple linear regression analysis methods were employed to evaluate the relationship between central airway parameters and age, sex, weight, and height. Results The study encompassed 888 Han Chinese non-smoking adults, comprising 456 females and 432 males. Significant sex differences were noted in central airway length, AWT, and ALA, with measurements in males exceeding those in females (p < 0.01) with no significant difference in SCA. Correlation analyses unveiled relationships between central airway parameters and age, sex, weight, and height. During multiple linear regression analyses, no conclusive evidence emerged to demonstrate the independent or combined explanatory or predictive capacity of the aforementioned variables for central airway length and SCA. Although sex has a significant impact on AWT and ALA, its capability in explanation or prediction remains limited. The conclusions drawn from the primary analysis receive reinforcement from the outcomes of sensitivity analyses. Conclusion Establishing the distribution range of central airway parameters in non-smoking Han Chinese adults. It observed significant sex differences in these parameters, except for the SCA. However, the study found that the predictive or explanatory power of age, sex, weight, and height for central airway parameters was either limited or non-significant.

Surgery for tracheal and laryngotracheal stenosis: a historical case series.

Benign (laryngo-)tracheal stenosis is a relatively rare pathology and its surgical treatment is performed only at few specialized centres. This study aims to investigate outcomes after (laryngo-)tracheal resection-anastomosis, to explore potential risk factors for postoperative complications and to assess whether, over a 33-year period, there were major changes in surgical indications, techniques or outcomes. Retrospective, single-centre review of all consecutive patients who underwent tracheal or laryngo-tracheal resection/anastomosis for benign pathologies from 1990 to 2023. Overall, 211 patients underwent tracheal (149 patients, 70.6%) and laryngo-tracheal (62 patients, 29.4%) resection-anastomosis. Of these, 195 patients (93.8%) were affected by iatrogenic stenosis, while 13 (6.2%) suffered from idiopathic stenosis. The median length of stenosis was 25mm (interquartile range 1-3, 20-30). The overall morbidity rate was 27.5%, while major morbidity occurred in 10.5% of cases. One patient (0.5%) died in the postoperative period. Glottic oedema (17 patients, 8.1%), granulations (12 patients, 5.7%) and restenosis (10 patients, 4.7%) were the main complications. The only independent risk factor for postoperative complications was the length of the resected airway (P = 0.019). In the latest half of the study period, an older median age was observed, and no patient with idiopathic tracheal stenosis underwent surgery. Postoperative outcomes were comparable between surgical eras. Surgical treatment of (laryngo-)tracheal stenosis is challenging and should be performed by specialized centres. In our experience, morbidity and mortality rates were satisfactory, and in most cases, patients could breathe without tracheostomy. The length of the stenosis was the most significant risk factor for postoperative complications.

Correlation between cone-beam computed tomographic findings and the apnea-hypopnea index in obstructive sleep apnea patients: A cross-sectional study.

The aim of this study was to explore the correlations of cone-beam computed tomographic findings with the apnea-hypopnea index in patients with obstructive sleep apnea. Forty patients with obstructive sleep apnea were selected from the ear-nose-throat (ENT) outpatient clinic, Faculty of Medicine, Mansoura University. Cone-beam computed tomography was performed for each patient at the end of both inspiration and expiration. Polysomnography was carried out, and the apnea-hypopnea index was obtained. Linear measurements, including cross-sectional area and the SNA and SNB angles, were obtained. Four oral and maxillofacial radiologists categorized pharyngeal and retropalatal airway morphology and calculated the airway length and volume. Continuous data were tested for normality using the Kolmogorov-Smirnov test and reported as the mean and standard deviation or as the median and range. Categorical data were presented as numbers and percentages, and the significance level was set at P<0.05. The minimal value of the cross-sectional area, SNB angle, and airway morphology at the end of inspiration demonstrated a statistically significant association (P<0.05) with the apnea-hypopnea index, with excellent agreement. No statistically significant difference was found in the airway volume, other linear measurements, or retropalatal airway morphology. Cone-beam computed tomographic measurements in obstructive sleep apnea patients may be used as a supplement to a novel radiographic classification corresponding to the established clinical apnea-hypopnea index classification.

Craniofacial features of adult obese obstructive sleep apnoea patients in relation to the obesity onset - A pilot study.

Obesity and craniofacial structures are aetiologies of obstructive sleep apnoea (OSA). The effect of obesity onset on the craniofacial development and growth of obese OSA subjects has been suggested, but supporting data were lacking. This study aimed to assess the craniofacial features of adult obese OSA patients in relation to their obesity onset. A total of 62 adult OSA patients were included in the study, consisting of 12 early-onset (i.e. before puberty), 21 late-onset (i.e. after puberty) and 29 non-obese. All participants underwent a sleep study and cephalometric radiograph. Cephalometric analysis was conducted to measure the craniofacial features among the groups. The early obesity onset group (n = 12) showed a more prognathic mandible, longer lower facial height, protrusive incisors, a more caudal position of the hyoid bone and a wider lower airway. The late-onset group (n = 21) had more proclined and protrusive upper incisors, a shallower overbite, a more inferiorly positioned hyoid bone and an obtuse craniocervical angle. The overall obese group showed a combination of the findings above, plus a shorter soft palate and shorter airway length. There was no significant difference between early and late obesity onset groups. However, the early group showed a tendency for a shallower or decreased mandibular plane angle and deeper overbite. The current pilot study had many limitations but holds important information as a hypothesis generator. Craniofacial features of OSA patients with different obesity onset showed discrepancies and were distinguished from non-obese controls. Adult OSA patients with an early obesity onset showed a tendency for a more hypodivergent growth pattern than those with a late obesity onset.

Characterization of upper airway and analysis of potential risk factor associated with OSA in patients with unilateral temporomandibular ankylosis and micrognathia deformities

ObjectiveTo ascertain the airway characteristics in patients with unilateral temporomandibular joint ankylosis and maxilla-mandibular deformities (UTMAMD) and investigate the potential risk factors associated with obstructive sleep apnea (OSA) among UTMAMD patients. MethodsAuthors conducted a retrospective single-center study to assess and compare study group consisting of a cohort of 32 patients diagnosed with UTMAMD between January 2011 and July 2022 with control group including 54 participants. The study group was further divided into two subgroups based on the presence or absence of OSA in patients. Parameters related to the upper airway were measured and analyzed using three-dimensional reconstruction of computed tomographic scans. The measurements of airway parameters were compared between study group and control group and between two subgroups. Pearson correlation analysis was used to identify the factors associated with the presence of OSA, and a multiple variable regression model was used to identify risk factors for OSA. ResultsAirway volume (VOL), Minimum cross-section area (min CSA), mean CSA, tilt in sagittal plane (TS), and tilt in sagittal plane (TC) in velopharynx; VOL, airway length (AL), min CSA, mean CSA, TS, TC, and airway deviation (AD) in glossopharynx; min CSA, TS, and AD in hypopharynx were found difference with significance between study group and control group. Lateral dimension/anterior-posterior dimension (LAT/AP) ratio in velopharynx and min CSA, TC, and LAT/AP ratio in glossopharynx were significant different between patients with UTMAMD with OSA and without OSA. ConclusionsThe upper airway of patients with UTMAMD exhibits significant narrowing and distortion, rendering them susceptible to suffer from OSA. Patients with UTMAMD and OSA demonstrate more elliptical airways, and the glossopharyngeal LAT/AP ratio is a predictive indicator for the occurrence of OSA.

Characteristics of genioglossus neuromuscular activity in patients with obstructive sleep apnea during drug-induced sleep

Objective: To analyze genioglossus (GG) activation responses to the negative pressure of upper airway cavity during awake and different sleep stages in patients with different obstructive sleep apnea (OSA) graduation. Methods: This prospective cohort study started from August 2019 to January 2021, recruited 42 male OSA patients aged from 21 to 59 (38.77±8.42) years. After completing whole night polysomnography (PSG) and upper airway CT, each subject underwent drug-induced sleep with simultaneous monitoring of genioglossal electromyography (GGEMG) and pressure of epiglottis (Pepi). Subjects were divided into three groups of mild OSA(7 males), moderate OSA(12 males), and severe OSA(23 males). The differences in upper airway CT measurements, parameters of GGEMG and Pepi during awake and induced sleep were compared. Statistical analysis was conducted by SPSS 21.0. Results: There was no significant difference in the GGEMG parameters between the mild and moderate groups. In wakefulness, the peak phasic GGEMG of the severe group was higher than the mild group (t=1.249, P=0.025), with no statistically difference in the corresponding Pepi. In the sleep onset, the GGEMG parameters and Pepi in severe group were higher than the other two groups. Linear regression analysis of the maximum GGEMG and maximum Pepi at the end of obstructive apnea (OA) in all moderate plus severe patients (n=35) was shown nonlinear correlation (r=0.28, P=0.694). The airway length of the glossopharyngeal cavity was linearly correlated with the maximum Pepi of OA (r=0.468, R2=0.219, P=0.005). Conclusions: The individual difference of GG activation in OSA patients is related to the severity of the disease (frequency of respiratory events) and negative pressure stimulation. In moderate and severe OSA patients, GG activity is not in harmony with the corresponding negative pressure stimulation, which may be one of the mechanisms leading to the aggravation of OSA.

Effects of twin-block appliance on upper airway parameters in OSA children with class II malocclusion and mandibular retrognathia: a CBCT study.

Correction of class II mandibular retrognathic skeletal malocclusion with twin-block appliance resulted in a significant increase in upper airway volume, MCA, anteroposterior and lateral distances of the MCA at the level of the oropharynx, MCA at the level of the hypopharynx and upper airway length, and a significant decrease in AHI, but it had no effect on nasopharynx parameters. • CBCT imaging has been shown to be an effective and precise diagnostic tool for analyzing the upper airways and craniofacial structures. • Twin block appliance may be an effective treatment modality in children with OSA. • Minimal cross-sectional area of upper ways may be the most relevant potential parameter when explaining how the upper airway anatomy plays role of in the pathogenesis of pediatric OSA. • Twin block appliance induced favorable changes in upper airway morphology (oropharynx area mainly) and respiratory parameters in OSA children with class II malocclusion.

Characteristics and outcomes of transoral robotic surgery with free-flap reconstruction for oropharyngeal cancer: a systematic review.

Transoral robotic surgery (TORS) approach for the treatment of oropharyngeal cancer allows for reduced patient morbidity, amongst other advantages over the traditional lip-splitting mandibulotomy method. Free-flap reconstruction is commonly utilized in head and neck cancer surgeries; however, safety and outcomes of this technique in TORS procedures have not been well studied. The objective of this study was to perform a systematic review to evaluate the efficacy and safety of TORS with free-flap reconstruction (TORS-FFR) for oropharyngeal cancer. A systematic search of Scopus, EMBASE, CINAHL and PubMed databases was completed. Following PRISMA guidelines, case series/reports, retrospective and prospective cohort studies were included. Primary outcomes measured were deaths and complication rates associated with TORS-FFR for oropharyngeal cancers. Secondary outcomes included functional swallowing and airway outcomes, operative time and length of hospital stay. Twenty-one studies met the inclusion criteria comprising a total of 132 patients. The mean patient age was 58.4years. The most frequent complication was infection (8.9%) followed by flap wound dehiscence (4.2%). The average total operative time was 710min (n = 48), while average length of hospital stay was 13.5days (n = 48). Reconstructions were most commonly fashioned from radial forearm free flaps (RFFF), with anterolateral thigh flaps (ALT) representing the second most common free-flap subtype. TORS-FFR procedures for oropharyngeal cancer are safe, with low serious complication rates. This surgical approach may be associated with decreased length of hospital stay; however, further studies are required to better characterize post-operative outcomes.Level of evidence 1a.

Upper airway dimensions and the skeletal parameters in orthodontic patients who developed moderate-severe COVID-19 symptoms during the pandemic.

Large airway dimensions are associated with a rapid decline in the lung function and a higher risk of hospitalization. Therefore, the airway dimensions of healthy subjects who tested positive for coronavirus disease 2019 (COVID-19) may be associated with the severity of COVID-19 symptoms. The objectives of this study were to measure the upper airway dimensions and the craniofacial skeletal parameters in patients who tested positive for COVID-19, to compare the upper airway dimensions and the craniofacial skeletal parameters between patients who developed no/mild symptoms and those with moderate-severe COVID-19 symptoms, and to assess any association of the skeletal relationships (anteroposterior (AP) and vertical) and the upper airway dimensions with the severity of COVID-19 symptoms in adult subjects. A total of 204 orthodontic patients who tested positive for COVID-19 were evaluated. Of these, only 137 met the inclusion criteria. The sample was further subdivided into 2 groups based on the severity of symptoms: cases (moderate-severe symptoms; n = 56); and controls (asymptomatic/ mild symptoms; n = 81). The upper airway dimensions and the skeletal parameters were measured on lateral cephalograms. The nonparametric Mann-Whitney U test was used to detect differences between the cases and the controls. Binary logistic regression analysis was used to evaluate the association between the studied variables and the severity of symptoms. The cases had a reduced lower face height (LFH) and a reduced perpendicular distance from the hyoid bone to the line connecting the anteroinferior limit of the 3rd cervical vertebra (C3) and the retrognathion point (RGN) (HH1) as compared to the controls. Regression analysis revealed a significant association of LFH (p = 0.013), the vertical airway length (VAL) (p = 0.002) and HH1 (p = 0.021) with the severity of COVID-19 symptoms. The types of malocclusion were similar in the cases and the controls. Patients with reduced LFH and VAL, and a superiorly positioned hyoid bone in relation to the mandible developed more severe COVID-19 symptoms.

Three-dimensional evaluation of the pharyngeal airway space in patients with anterior open bite.

: This study aimed to three-dimensionally evaluate the pharyngeal airway space (PAS) of patients with anterior open bite (AOB) by using cone-beam computed tomography (CBCT) and compare the findings with those obtained in individuals with normal occlusion. : The open bite group (OBG, n = 25) consisted of patients with an anterior overbite of -3 mm or less, while the control group (n = 25) consisted of age- and sex-matched individuals with an anterior overbite of 1-3 mm, Angle Class I malocclusion (1° ≤ point A-nasion-point B angle ≤ 4°), and a normodivergent profile (22° ≤ Frankfort mandibular plane angle ≤ 28°). After the CBCT data were reconstructed into a three-dimensional image, the PAS was segmented into four parts, and the volume of each part was measured. Pharyngeal airway length (PAL) and the area and transverse width of the part showing minimal constriction were also measured. Pearson's correlation analysis was used to evaluate the correlation between changes in the PAS and the amount of anterior overbite. : The OBG showed a significantly narrower airway space in the nasopharyngeal, hypopharyngeal, and total airway volumes. The OBG also showed a significantly smaller area and transverse width of the part with minimal constriction. The OBG showed a significantly longer PAL, but there was no correlation between the amount of anterior overbite and the changes in PAS. : The PAS was associated with AOB. Patients with AOB had a narrower PAS and a smaller part showing minimal constriction.

Evaluation of changes in tongue pressure with twin-block appliance therapy in growing Class II Div 1 malocclusion. An in vivo study.

Twin-block appliance therapy in patients with Class II Div 1 malocclusion positions the mandible anteroinferior leading to possible alterations in tongue pressure, tongue length, and the oropharynx. To evaluate the changes in tongue pressure, tongue length and dimension of the pharyngeal airway in Class II Division 1 subjects before and after twin-block therapy. Twenty-four subjects were selected, in the range of 10-14 years (mean-12 years). The tongue pressure was recorded at three regions with sensors placed at the incisive papilla and bilaterally at the molar region of the palate for four minutes. The root mean square (RMS) values were recorded and used for further analysis. Evaluation of tongue length and pharyngeal airway dimension was done using a lateral cephalogram. All the measurements were done before and after twin-block appliance therapy. The paired t-test was performed to compare the changes. Resting tongue pressures decreased from pre-treatment levels to post-treatment at all three regions. Change in ANB angle was found to have a significant negative correlation with tongue length, and pharyngeal airway dimension, a significant positive correlation with pressure at incisive papilla and left molar region and no correlation at right molar region. There was a decrease in resting tongue pressure as the malocclusion was corrected from Class II to Class I. Hence, this decrease in pressure could be a contributory factor in the maintenance of the dental equilibrium as lighter forces exist in the oral cavity.

Effect of Orthodontic Treatment on Pharyngeal Airway and adjacent Soft Tissues

Background: There is inconsistent data on the effect of fixed orthodontic treatment on the pharyngeal airway dimensions. Aim: The present study aimed to evaluate the effect of orthodontic treatment on airway. Methods: Fifty patients who completed their fixed orthodontic treatment were selected for the study. Pre- and post-treatment lateral cephalograms were collected. The airway parameters studied were Superior Posterior Airway Space, Middle Airway Space, Inferior Airway Space, and Vertical Airway Length, while the soft tissues analysed were the height of the tongue, length of the tongue, thickness of soft palate, and length of the soft palate. The measurements of these parameters were done on all the cephalograms and were tabulated and statistically analysed. Results: There was a significant decrease in the middle airway space in the non-extraction group, while the remaining parameters did not show any significant variation. In the extraction group, there was no significant variation in any of the parameters analysed. Conclusion: There was a significant reduction in the middle airway space, while no significant variation in the upper, lower airway, and vertical airway length in non-extraction cases after the orthodontic treatment. None of the airway parameters and adjacent soft tissues showed any significant variation post-orthodontic treatment in extraction cases.

Evaluation of Dent aluation of Dentoskeletal and Phar eletal and Pharyngeal Air yngeal Airway Changes after y Changes after Treatment with Twin Block and Monoblock Appliance in Growing Patients

Objective: To compare of pharyngeal airway dimensions and dentoskeletal changes after treatment with twin block (TWB) and monoblock (MB) appliance in growing patients. Methods: The sample was comprised of a total of 72 patients at the ages of 10 to 13. The TWB group consisted of 36 patients (22 females, 14 males, mean age: 11.9±1.5) and MB group consisted of 36 patients (18 females, 18 males, mean age: 11.8±1.2). The linear and angular measurements were evaluated on lateral cephalometric radiographs at beginning (T0) and end of treatment (T1). Results: The amounts of increase in the inferior airway space, L1xNB, IMPA and FMA measurements from T0 to T1 in the TWB group were significantly higher (p &lt; 0.05).In the TWB group, the amounts of the increase in the soft palate thickness, distance between hyoid and C3, Co-A and Co-Gn measurements from T0 to T1 in the female patients were significantly higher (p &lt; 0.05).In the MB group, the amounts of increase in the Upper adenoid thickness and Vertical airway length measurements from T0 to T1 in the female patients were significantly higher (p &lt; 0.05). Conclusion: Both the MB and TWB appliances increase the pharyngeal airway dimensions, and the lower airway is most affected by the appliance type. The effects of the MB and TWB appliances on tongue dimensions and hyoid bone movements are different.

Relationship between premolar extraction on the dimension of upper airway and tongue posture in skeletal class II malocclusion

Correction of skeletal Class II malocclusion with camouflage orthodontic treatment generally requires the extraction of the maxillary first premolars to provide space for retraction of the maxillary incisors. Retraction of incisors changes the position of the incisors and the dimensions of the dental arch, which can cause changes in tongue posture and affect the upper airway. The purpose of this study was to determine the relationship between premolar extraction on the dimensions of upper airway and tongue posture in skeletal Class II malocclusion. This study was designed as a retrospective cohort using lateral cephalometric radiographs before and after orthodontic treatment. The samples in this study consisted of 44 samples of adult patients (n = 44) aged 18-40 years, who were divided into 2 groups: 22 subjects treated without premolar extraction and 22 subjects treated with premolar extraction. Lateral cephalometric radiographic analysis were used to measure the dimensions of the upper airway by analyzing superior posterior airway space (SPAS), middle airway space (MAS), inferior airway space (IAS), vertical airway length (VAL), and tongue posture (tongue length and height tongue) using imageJ software. No Statistically significant different changes were observed as seen from the following results: SPAS (p = 0.709), MAS (p = 0.365), IAS (p = 0.562), (p = 0.401), tongue length (p = 0.578), tongue height (p = 0.086) in the sample group without extraction premolar. No significant alterations in the upper airway and tongue posture measurement were observed in the sample group with extraction premolar. Premolar extraction with retraction on upper incisors did not affect upper airway dimensions and toung posture in skeletal Class II malocclusion.

Modeling of the respiratory system of the long-necked Triassic reptile Tanystropheus (Archosauromorpha).

All known species of the Triassic archosauromorph genus Tanystropheus are known to have had the longest neck in proportion to their torso. This feature is related to a series of ventilatory challenges since an increase in neck length also increases airway length and, therefore, the volume of stagnant air that does not reach the lungs, the dead space volume. Based on this challenge, the objective of the present study was to model the type of respiratory system of Tanystropheus able to meet its metabolic demands during the early Triassic period. The modeling was based on allometric relations for morphological and physiological ventilatory and metabolic variables, and to do so, the mean body mass of Tanystropheus was estimated based on three different methods. In addition, the tracheal airflow was also estimated based on the proportions of Tanystropheus elongated neck, the results of allometric modeling, and fundamental equations of fluid mechanics. The estimation of the body mass indicated that an animal of 3.6m would possess a body mass of 50.6 ± 21.6kg. Allometric modeling suggested that the respiratory system best suited to Tanystropheus' oxygen demands, especially during activity, would be a generic reptilian-like respiratory system composed of multicameral lungs. The best respiratory pattern to maintain adequate tracheal flow rates and effective pulmonary ventilation would be one ventilating the relatively narrower trachea at lower frequencies to deal with tracheal dead space volume.