Three-dimensional CT reconstructions of tongue and airway in adult subjects with obstructive sleep apnea

Evaluation of Minimum Axial Airway Area and Airway Volume in Orthognathic Surgery Patients

The aim of this study was to compare preoperative and postoperative linear, planar, and volumetric measurements in the pharyngeal airway in orthognathic surgery patients. Preoperative and postoperative cone beam computed tomography (CBCT) images of 60 patients, who underwent maxillary advancement with mandibular setback (Group I, n=25) and bimaxillary advancement (Group II, n=35), were compared. The airway was divided into 3 regions as nasopharynx, oropharynx, and hypopharynx. Linear and planar measurements were made on the reference sections of each region. The minimum axial airway area, the volume of 3 regions, and total airway volume were also measured. Regarding the linear, planar, and volumetric measurements, while there was a statistically significant increase in the measurements for all three regions in Group II, in Group I only the measurements in the nasopharyngeal region demonstrated a statistically significant increase postoperatively ( P <0.05). There was an increase in minimum axial airway areas in both groups; however, it was only statistically significant in Group II ( P <0.05). There was a statistically significant increase in total airway volumes in both groups ( P <0.05). A positive and good correlation was found between the percent increase in the minimum axial area and the percent increase in the total volume ( P <0.05). While bimaxillary advancement surgery results in a significant increase in the pharyngeal airway, mandibular setback with maxillary advancement caused an increase in the total airway. Changes that may occur in the airway should be considered while planning orthognathic surgery.

The effect of pharyngeal structures on the severity of obstructive sleep apnea

BACKGROUND/OBJECTIVE

Obstructive sleep apnea (OSA) is characterized by complete or partial cessation of breathing during sleep. The tongue is suggested as a possible anatomical site causing airway obstruction. However, the role of other pharyngeal structures in the development of OSA remains unclear. We designed a study using both the apnea-hypopnea index (AHI) and the oxygen saturation measurements to assess the severity of OSA. We aimed to identify critical anatomical structures of the upper airway that correlate with the severity of OSA and to evaluate the utility of magnetic resonance imaging (MRI) markers to detect possible OSA in patients without overt symptoms.

MATERIALS AND METHODS

The study included participants referred to the neurology outpatient clinic from the check-up unit. Participants were grouped as controls, mild, moderate, or severe OSA according to the AHI. A cranial MRI with a field of view (FOV) encompassing the upper airway structures was obtained from all participants. The areas of the tongue and the uvula were measured on the sagittal images by drawing the boundaries of the tissues manually. The posterior air space (PAS) area was evaluated from regions of interest in five parallel planes.

RESULTS

Of 105 participants, 30 were controls, 27 had mild, 25 had moderate, and 23 had severe OSA. The moderate and severe OSA groups did not differ in oxygen saturation levels during sleep. Therefore, patients with moderate and severe OSA were combined into one group (moderate/severe OSA). The area of the tongue was significantly larger in the moderate/severe OSA group compared to the control group. Both the tongue and the uvula areas showed a significant positive correlation with the AHI.

CONCLUSION

Our findings suggest that the tongue and uvula have prominent roles in the severity of OSAS. It may be useful to measure these structures with MRI to screen for at-risk individuals without overt OSA symptoms.

Is it possible to reveal a typical swallowing pattern for specific skeletal malocclusion types using M-mode sonographic imaging of tongue movements?

PURPOSE

The present study aims to compare the M‑mode ultrasound findings of different skeletal malocclusions and to evaluate whether sonographic parameters can be used for the diagnosis of malocclusions.

METHODS

Tongue movements of 36 adolescents aged between 10.37 and 17.29 years (mean 14.25 ± 1.78 years) were assessed using simultaneous two-dimensional real-time B‑mode and M‑mode sonography. The swallowing patterns of the subjects were visualized recording the motion of the tongue surface in the ultrasound images utilizing a fixed scan line through the middle of the tongue. M‑mode scans of tongue motion during empty deglutition were recorded. The parameters range, duration, and speed were computed for the entirety of the swallowing process using M‑mode examination. Findings were evaluated and statistically analyzed.

RESULTS

No clear intraindividual repeatability in the M‑mode imaging of the subjects' swallowing process could be observed. Considering the setup used in the study, it was not always possible to distinguish individual swallowing stages in the M‑mode images with regard to the chosen reference points. The average duration, range of motion, and speed of swallowing were found to be 2.43 s, 24.06 mm, and 10.34 mm/s, respectively. The findings showed both intra- and intersubject variability during empty swallowing.

CONCLUSION

With the help of the metrics that could be calculated based on the M‑mode images, it was not possible to differentiate the swallowing acts of different skeletal malocclusion types. It remains unclear whether M‑mode imaging can accurately visualize the swallowing pattern. Therefore, further progress in technology and multidisciplinary work is needed in order to establish diagnostic references regarding swallowing.

Quantification of pharyngeal airway space changes after two-jaw orthognathic surgery in skeletal class III patients

BACKGROUND

Skeletal class III malocclusion is a common dentofacial deformity. Orthognathic treatment changes the position of the jaws and affects the shape of the upper airway to some extent. The aim of this study was to use multislice spiral computer tomography data and orthognathic knowledge to quantify the relationship between the amount of surgical movement of the maxilla or mandible in all three spatial planes and the changes in airway volume that occurred.

METHODS

A retrospective study of 50 patients was conducted. Preoperative and postoperative linear changes related to skeletal movements of the maxilla and mandible were measured and compared to changes in the most constricted axial level (MCA) and its anteroposterior (MCA-AP) and transverse diameters (MCA-TV). Correlation tests and linear regression analysis were performed.

RESULTS

Significant interactions were observed between the anterior vertical movement of the maxilla and the MCA-AP. The anteroposterior movement distance of the mandible was significantly correlated with changes in the oropharyngeal, velopharyngeal, total airway volume, MCA, MCA-AP, and MCA-TV. The change in the mandibular plane angle was significantly correlated with the change in velopharyngeal volume, total airway volume (nasopharynx, oropharynx, velopharynx), and MCA. The linear regression model showed that oropharyngeal volume decreased by 350.04 mm³, velopharyngeal volume decreased by 311.50 mm³, total airway volume decreased by 790.46 mm³, MCA decreased by 10.96 mm² and MCA-AP decreased by 0.73 mm² when point B was setback by 1 mm.

CONCLUSIONS

Anteroposterior mandibular control is the key to successful airway management in all patients. This study provides estimates of volume change per millimeter of setback to guide surgeons in treatment planning.

A computed tomographic evaluation of effect of mandibular advancement device at two different horizontal jaw positions in patients with obstructive sleep apnea

Statement of problem

Studies pertaining to the objective assessments of the efficacy of mandibular advancement device in patients with obstructive sleep apnea are scarce.

Purpose

The purpose of this clinical study was to evaluate the effect of MAD at two different horizontal positions of mandible on upper airway dimensions through computed tomography.

Material and methods

Twenty-nine consenting participants satisfying predetermined inclusion and exclusion criteria were enrolled and an adjustable two-piece MAD was fabricated at 50% maximum mandibular protrusion and after 4 weeks was adjusted to 70% protrusion. CT scans were obtained at baseline, 4 weeks after delivering MAD with 50% mandibular protrusion, and then after 4 weeks with 70% mandibular protrusion. Cross sectional area with diameters (lateral and anteroposterior) of upper airway was measured at three specific anatomic levels (retropalatal-RP, retroglossal-RG, and epiglottal-EG). Data were analyzed using the Student t-test for parametric analysis.

Results

Intragroup comparison revealed a statistically significant increase in lateral & anteroposterior dimensions as well as cross sectional area at all three anatomical levels at 4 weeks after MAD with 50% mandibular protrusion compared with baseline and 4 weeks after MAD with 70% mandibular protrusion compared with baseline. However, the difference between lateral and anteroposterior dimensions with MAD at 70% protrusion compared with MAD at 50% protrusion was not statistically significant. The difference between cross-sectional area was found to be statistically significant.

Conclusion

Mandibular advancement device at 70% mandibular protrusion is more effective compared with the device at 50% protrusion in relieving oropharyngeal obstruction seen in OSA.

The integrated brain network that controls respiration

Respiration is a brain function on which our lives essentially depend. Control of respiration ensures that the frequency and depth of breathing adapt continuously to metabolic needs. In addition, the respiratory control network of the brain has to organize muscular synergies that integrate ventilation with posture and body movement. Finally, respiration is coupled to cardiovascular function and emotion. Here, we argue that the brain can handle this all by integrating a brainstem central pattern generator circuit in a larger network that also comprises the cerebellum. Although currently not generally recognized as a respiratory control center, the cerebellum is well known for its coordinating and modulating role in motor behavior, as well as for its role in the autonomic nervous system. In this review, we discuss the role of brain regions involved in the control of respiration, and their anatomical and functional interactions. We discuss how sensory feedback can result in adaptation of respiration, and how these mechanisms can be compromised by various neurological and psychological disorders. Finally, we demonstrate how the respiratory pattern generators are part of a larger and integrated network of respiratory brain regions.

Does Head and Neck Posture Affect Cone-Beam Computed Tomography Assessment of the Upper Airway?

PURPOSE

Radiographic analysis is often used as a screening tool to assess for risk of sleep-related breathing disorders. This study aimed to address 2 questions: (1) Does head posture significantly affect the minimum cross-sectional area (MCA)? and (2) Is the NBC3 (nasion-basion-C3) angle a reliable measurement to control for alteration of head position in cone-beam computed tomography (CBCT) scans?

METHODS

Study design: prospective cohort study.

SETTING

Private practices affiliated with a research institution.

PARTICIPANTS

convenience sample of adult volunteers.

VARIABLES

CBCT scans were taken in 2 conditions: baseline (natural head position, NHP) and 1 of 5 experimental conditions (head tilted up, head tilted down, sitting vs standing, use of chin-rest, and swallow variation). For the primary aim of our study, the primary predictor variable was head posture and the main outcome variable was percentage change in MCA. For the secondary aim, the primary predictor variable was head posture and the main outcome variable was degree change in NBC3 angle.

RESULTS

Ninety subjects were included (age 40.7 ± 13.7 years, 70% female). Mean NBC3 at baseline was 112.4 ± 8.3°. Head tilted down significantly decreased (-41.4 ± 18.5 mm², P = .03∗) and head tilted up significantly increased MCA (+147.4 ± 43.3 mm², P = .0018∗). Head tilted down significantly reduced the NBC3 angle measurement (-10.5 ± 6.8°, P = .006) and head tilted up significantly increased the NBC3 angle measurement (+14.4 ± 5.8°, P = .0004). A quadratic regression model was fitted with moderately strong correlation (R² = 0.54) showing an exponential effect of small changes in the NBC3 angle on MCA, P < .0001. The model predicts that increasing NBC3 by +5 and + 10° resulted in MCA changes of +25% and +88%, whereas a decrease in NBC3 by -5 and -10° results in MCA changes of -21% and -23%, respectively.

CONCLUSION

Alterations in head posture significantly affect the MCA of the upper airway on CBCT. The NBC3 angle can be used to reliably assess changes in cranio-cervical extension and validate comparisons of MCA between CBCT scans for the same patient. A standardized protocol for CBCT acquisition is proposed.

Restricted upper airway dimensions in patients with dentofacial deformity from juvenile idiopathic arthritis

BACKGROUND

This retrospective, cross-sectional study aimed to assess the pharyngeal airway dimensions of patients with juvenile idiopathic arthritis (JIA) and moderate/severe JIA-related dentofacial deformity (mandibular retrognathia/micrognathia), and compare the results with JIA patients with a normal mandibular appearance and a group of non-JIA patients.

METHODS

Seventy-eight patients were retrospectively included in a 1:1:1 manner as specified below. All patients had previously been treated at the Section of Orthodontics, Aarhus University, Denmark. All had a pretreatment cone beam computed tomography (CBCT). Group 1 (JIA+); 26 JIA patients with severe arthritis-related dentofacial deformity and mandibular retrognathia/micrognathia. Group 2 (JIA-); 26 JIA patients with normal mandibular morphology/position. Group 3 (Controls); 26 non-JIA subjects. Dentofacial morphology and upper airway dimensions, excluding the nasal cavity, were assessed in a validated three-dimensional (3D) fashion. Assessment of dentofacial deformity comprised six morphometric measures. Assessment of airway dimensions comprised nine measures.

RESULTS

Five morphometric measures of dentofacial deformity were significantly deviating in the JIA+ group compared with the JIA- and control groups: Posterior mandibular height, anterior facial height, mandibular inclination, mandibular occlusal inclination, and mandibular sagittal position. Five of the airway measurements showed significant inter-group differences: JIA+ had a significantly smaller nasopharyngeal airway dimension (ad2-PNS), a smaller velopharyngeal volume, a smaller minimal cross-sectional area and a smaller minimal hydraulic diameter than JIA- and controls. No significant differences in upper airway dimensions were seen between JIA- and controls.

CONCLUSION

JIA patients with severe arthritis-related dentofacial deformity and mandibular micrognathia had significantly restricted upper airway dimensions compared with JIA patients without dentofacial deformity and controls. The restrictions of upper airway dimension seen in the JIA+ group herein were previously associated with sleep-disordered breathing in the non-JIA background population. Further studies are needed to elucidate the role of dentofacial deformity and restricted airways in the development of sleep-disordered breathing in JIA.

Assessment of the Effect of Complete Dentures on Respiratory Performance: A Spirometric Analysis

Background

Among the vital functions, respiration can be claimed to be one of the most important. A thorough understanding of the patient should be an important aspect a prosthodontist should dwell into so as to predispose patients to acknowledge the kind of prosthesis they require. Hence, the present study was conducted for assessing the effect of complete dentures on respiratory performance.

Materials and Methods

Fifty patients with the presence of complete edentulous arch and who had a history of complete denture usage for at least 5 years were enrolled. All the spirometric procedures were performed by trained technicians. A diagnostic spirometer was employed for performing the spirometric test. Testing was carried out in the following steps: Stage 1: testing in the absence of denture, Stage 2: testing in the presence of both dentures, Stage 3: testing in the presence of maxillary denture only, and Stage 4: testing in the presence of mandibular dentures only. Forced vital capacity (FVC) value, peak expiratory flow (PEF) value, forced expiratory volume in 1 s (FEV1) value, and forced expiratory flow 25%-75% (FEF_25-75) value were recorded with the spirometric test. Analysis of all the results was done by SPSS software.

Results

The spirometric value of FVC, PEF, FEV1, and FEF_25-75 in the absence of both maxillary and mandibular dentures (Stage 1) was found to be 3.18, 5.83, 2.44, and 2.80, respectively. The spirometric value of FVC, PEF, FEV1, and FEF_25-75 in the presence of both maxillary and mandibular dentures (Stage 2) was found to be 3.09, 5.67, 2.41, and 2.67, respectively. While analyzing statistically, it was seen that there was a significant decrease in the value of spirometric variables in the presence of dentures.

Conclusion

Chronic denture wearer edentulous patients are subjected to the risk of development of spirometric alterations. Hence, these patients should be given timely instructions about the various respiratory exercise protocols.

Three-Dimensional Evaluation of the Tongue Volume in Different Dentoskeletal Patterns - A Cone Beam Computed Tomographic Study

AIM

The aim of this study is to evaluate tongue volume using cone-beam computed tomographic (CBCT) and its correlation to different growth patterns in patients.

MATERIALS AND METHODS

Sixty preorthodontic records of CBCT scans of subjects ranging from 14 to 25 age group from retrospective data of department were selected for the study. Patients were classified into three groups based on angle FMA; Group I (n = 20) with average growth pattern (FMA 22°-28°); Group II (n = 20) vertical growth pattern (FMA >28°); Group III (n = 25) horizontal growth pattern (FMA <20°). Tongue volume evaluation was done using Myrian® Software. Dentoskeletal features and parameters related to archform such as palatal vault depth, interpremolar, and intermolar distance were evaluated in all the subjects. ANOVA test was used for intergroup comparison of tongue volume and dentoskeletal parameters in all three groups. Correlation of the tongue volume to dentoskeletal parameters was done using Pearson's correlation test.

RESULTS

Mean tongue volume in Group I was 66.10 cm3, Group II, 66.04 cm3 and Group III was 66.72 cm3. There was a statistically significant correlation (P < 0.5) of tongue volume with palatal vault width, maxillary length, and mandibular interpremolar and intermolar distance among dentoskeletal parameters.

CONCLUSION

Tongue volume was found equal in all groups despite the variation in growth patterns. Skeletal differences leading to different growth patterns were found to be related to mandibular morphology. The results indicate the indirect role of the tongue in causing malocclusion in orthodontic patients.

A consideration of factors affecting palliative oral appliance effectiveness for obstructive sleep apnea: a scoping review

STUDY OBJECTIVES

This scoping review allows physicians, researchers, and others interested in obstructive sleep apnea to consider effectiveness of oral appliances (OAs). The intent is to improve understanding of OA effectiveness by considering morphologic interaction in patients with obstructive sleep apnea.

METHODS

Morphologic and biomechanical criteria for positional alterations of the mandible assessed success rates of OA appliances. Searches of databases (Medline, PubMed, The Cochrane Library, EBSCO) using terms: OA treatment effectiveness and positive and/or negative outcome predictors. Craniofacial predictors of OAs and obstructive sleep apnea biomechanical factors of anatomical traits associated with OA effectiveness were included. Databases searched radiographic cephalometric imaging for morphology/phenotypes and apnea-hypopnea index responses. Articles were excluded if title or abstract was not relevant or a case report. If the analysis did not report mean or standard deviation for apnea-hypoxia index, it was excluded. No language, age, or sex restrictions were applied.

RESULTS

Analysis of 135 articles included in searched literature indicated alterations in musculature and pharyngeal airway structure through OA use. These alterations were individually unpredictable with wide variability 61.81% ± 12.29 (apnea-hypoxia index mean ± standard deviation). Morphologic variations as predictors were typically weak and idiosyncratic. Biomechanical factors and wide variations in the metrics of appliance application were unclear, identifying gaps in knowledge and practice of OAs.

CONCLUSIONS

An integrated basis to identify morphologic and biomechanical elements of phenotypic expressions of sleep-disordered breathing in the design and application of OAs is needed. Current knowledge is heterogeneous and shows high variability. Identification of subgroups of patients with obstructive sleep apnea responding to OAs is needed.

Evaluation of oral air space volume in obstructive sleep apnea syndrome using clinical and postmortem CT imaging

OBJECTIVES

Obstructive sleep apnea syndrome (OSAS) induces upper airway occlusion and may cause sudden death during sleep. This study sought to clarify the relationship between oral air space volume and OSAS onset, which is influenced by multiple factors, such as jawbone, dentition morphology, and oral soft-tissue volume.

METHODS

(1) 50 subjects from deceased cases were divided into two groups: OSAS (25 subjects) and controls (25 subjects). (2) 28 subjects from clinical cases were divided into two groups: OSAS (9 subjects) and controls (19 subjects). In all cases, the Computed Tomography (CT) images of the facial region were obtained, and four parameters of oral area volume were analyzed in deceased and clinical cases, and comparisons and analyses were performed between OSAS and control cases. In addition, the efficiency of measurement of these parameters was evaluated using Receiver Operating Characteristic (ROC) curves in OSAS.

RESULTS

(1) In deceased cases, oral soft-tissue volume (OSV), oral air-space volume (OAV), and the ratio of OAV to OSV (%air) showed a significant correlation. (2) In clinical cases, OAV and %air showed a significant correlation. In both postmortem and clinical images, a small %air value indicates a high risk of developing OSAS and a high probability of OSAS-related sudden death.

CONCLUSIONS

It was shown that the %air is an index to evaluate OSAS by CT imaging of the oral region. OSAS may be indicated when the %air value is ≦ 16.0% in deceased cases and ≦ 6.6% in clinical cases.

Evaluation of volume change in oral cavity proper before and after mandibular advancement

OBJECTIVES

To evaluate the tongue and oral cavity proper volume in pre- and post-bilateral sagittal split osteotomy (BSSO) patients, and to establish whether there was a correlation between them.

MATERIALS AND METHODS

A retrospective study that evaluated 12 patients' pre- and post-surgical computed tomography records satisfying the inclusion criteria. Borders were defined for measurement of tongue and oral cavity proper volume. The volume assessment was carried out using 3D slice software.

RESULTS

The mean difference of tongue volume was 5.7 ± 1.7 cm3, which showed high statistical significance. The mean difference of oral cavity proper volume (OCVP) was 6.9 ± 3.4 cm3 and indicated high statistical significance. A very strong positive correlation existed between pre- and post-surgical tongue volume. Positive correlation was also evident between pre and post - surgical OCVP. Medium positive correlation was noted when the difference between pre- and post-surgical tongue and OCVP were assessed.

CONCLUSIONS

There was a significant change in volume of tongue and oral cavity proper after BSSO advancement surgery. The space around the tongue, position of tongue, and maxillary and mandibular relationship influence the volume of tongue and oral cavity proper.

Decreased maxillary sinus volume is a potential predictor of obstructive sleep apnea

OBJECTIVES

To investigate the associations between nasal airway volume and the presence and severity of obstructive sleep apnea (OSA) in adults.

MATERIALS AND METHODS

The medical records of adult patients who visited the sleep clinic at University Hospital between June 2013 and April 2017 and underwent overnight polysomnography for the diagnosis of obstructive sleep apnea were reviewed retrospectively. Using computed tomography, the volumes of the nasal airways and maxillary sinuses were measured, and associations with the presence and severity of OSA were analyzed while controlling for the effects of possible confounders such as lateral cephalometric variables, maxillary widths, tongue/hyoid position, and soft palate dimensions.

RESULTS

Comparison between normal subjects and patients with OSA revealed that the latter had decreased ratios of maxillary sinus volume to whole nasal airway volume (P = .029) than normal subjects. OSA severity was greater in those with inferior positions of the hyoid (P = .010), in older patients (P = .011), and in those with high body mass index (P = .001). The volume of the total nasal airway or maxillary sinuses were not associated with OSA severity.

CONCLUSIONS

A decreased ratio of maxillary sinus volume to whole nasal airway volume is associated with adult OSA. However, OSA severity is not associated with either maxillary sinus volume or whole nasal airway volume.

Comparative assessment of changes in pharyngeal airway space in cases of obstructive sleep apnoea with a customized mandibular repositioning appliance - a clinical study

Objectives

The present study aims at evaluating the effects of a customized mandibular repositioning appliance on the pharyngeal airway, nocturnal sleep patterns, daytime discomfort and occlusal changes in established cases of adult obstructive sleep apnoea.

Material and Methods

Ten consecutive patients with a complaint of snoring and disturbed sleep were included in the study. The primary diagnosis was established by the Epworth sleepiness scale, clinical examination, history and subsequently the diagnosis was substantiated through assessment of the pharyngeal airway space on a lateral cephalogram and polysomnography. A customized mandibular repositioning appliance was used to advance the mandible sequentially every 6 months, using 4 sets of the appliance. Pre and post-treatment evaluations were performed to establish, effects and changes in the outcome of obstructive sleep apnoea.

Results

The study revealed significant increase in the mean pharyngeal widths of upper airway and velum dimension with antero-superior repositioning of hyoid bone. Epworth sleepiness scale score improved significantly from baseline with clinically evident change in daytime discomforts. Significant decline in the mean apnoea/hypopnea index, oxygen desaturation index, respiratory disturbance index, heart rate, snoring and a significant increase in mean oxygen saturation of arterial blood was observed. No evident change noticed in occlusion except lower incisor inclination.

Conclusion

The customized mandibular repositioning appliances are effective in the management of adult obstructive sleep apnoea with a significant improvement observed in the airway patency and polysomnography parameters with clinically non-significant effects on dental occlusion..

3D evaluation of the morphological and volumetric changes of the tongue and oral cavity before and after orthognathic surgery for mandibular prognathism: a preliminary study

BACKGROUND

The volumetric ratio of the tongue to the oral cavity has been recognized to be one of the important factors for the maintenance of stable occlusion. Oral cavity capacity is changed after orthognathic surgery in patients with mandibular prognathism; however, the volumetric changes of the oral cavity including the tongue before and after surgery have not been analyzed. The purpose of this study was to evaluate the morphological and volumetric changes of the tongue and oral cavity following orthognathic surgery using a newly developed vinyl polysiloxane impression method.

MATERIALS AND METHODS

The study was performed in fifteen subjects who underwent surgical orthognathic treatment. Impressions of the tongue together with the oral cavity were obtained before orthognathic surgery and 1, 3, and 6 months after orthognathic surgery. These impression patterns were scanned using cone-beam computed tomography (CT), and three-dimensional (3D) images of the oral cavity including the tongue, and the upper and lower dental arches were reconstructed. The morphological and volumetric changes in the oral cavity capacity and the tongue volume were examined.

RESULTS

The volume of the tongue with the volume of the oral cavity decreased after orthognathic surgery. There was a correlation between the decrease in the oral cavity capacity and tongue volume. The volumetric ratio of the tongue to the oral cavity seems to be maintained before and after orthognathic surgery.

CONCLUSION

VPS method, free from radiation exposure, may be useful for investigating the morphological and volumetric changes of the tongue and oral cavity, which may possibly influence the stability of the dental arch and occlusion during surgical orthodontic treatment.

Use of cone beam computed tomography imaging for airway measurement to predict obstructive sleep apnea

Objective: This retrospective chart review examined whether airway parameters were correlated with scores on the STOP-Bang questionnaireMethods: Minimal upper airway area, upper airway volume, minimal retropalatal area, retropalatal volume, minimal retroglossal area, and retroglossal volume were calculated from cone beam computed tomography (CBCT) images. Patients were grouped based on their STOP-Bang scores (<3 or ≥3) for obstructive sleep apnea (OSA), and airway parameters were compared across the 2 groups.Results: Thirty-one (43%) of 72 patients with a minimal upper airway area of <110 mm² had STOP-Bang scores of ≥3. Most patients (90%) with STOP-Bang scores of ≥3 had minimal retropalatal areas of <110 mm². Differences were found between groups for minimal upper airway area (P=.03), upper airway volume (P=.04), and minimal retropalatal area (P=.001).Discussion: To assess OSA risk, dentists should compare CBCT images with STOP-Bang scores.

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

INTRODUCTION

This study aimed to determine the volumetric effects on the upper airways of growing patients with Class II malocclusion treated with the Herbst appliance (HA).

METHODS

Volumetric measurements of the upper airways of 42 skeletal Class II malocclusion patients (mean age: 13.8 ± 1.2 years; ranging from 12.0 to 16.9 years) were assessed using cone-beam computed tomography scans acquired before treatment (T0) and approximately 1 year later (T1). The sample comprised a Herbst appliance group (HA group [HAG]; n = 24), and a comparison group (comparison group [CG]; n = 18) of orthodontic patients who had received dental treatments other than mandibular advancement with dentofacial orthopedics.

RESULTS

In CG, nasopharynx and oropharynx volumes decreased slightly during the observation period (9% and 3%, respectively), whereas the nasal cavity volume increased significantly (12%; P = 0.046). In HAG, there was an increase in the volume of all regions (nasal cavity, 5.5%; nasopharynx, 11.7%; and oropharynx, 29.7%). However, only the oropharynx showed a statistically significant increase (P = 0.003), presenting significant volumetric changes along the time (T1-T0) in HAG.

CONCLUSION

Mandibular advancement with the HA significantly increased the volume of the oropharynx, but no significant volumetric modifications were observed in the nasal cavity and nasopharynx.

Obstructive sleep apnea severity and dental arches dimensions in children with late primary dentition: An observational study

Objective: The aim of this study was to compare the dimensions of the upper and lower arches in children affected by OSAS with different levels of severity of obstruction.Methods: Twenty-seven Caucasian children (14 males, 13 females; mean age 6, range 5.2-6.1 years) with a diagnosis of OSAS determined by polysomnography were enrolled in this study. The dimensions of both dental arches were measured, and the data were compared among children affected by severe, moderate, and mild OSAS.Results: Statistically significant differences among the three groups revealed that children with severe OSAS had the highest values of upper intercanine and intermolar distances in the sample.Discussion: A severe OSAS grade (AHI > 10) is associated with statistically significantly higher upper intercanine and intermolar distances compared with mild and moderate grades. An early approach to OSAS in children with late primary dentition is auspicated in order to prevent an influence on dental arches growth.

Genioglossus Advancement and Hyoid Surgery

The structure and dimensions of the mandible, tongue, and hyoid complex are important variables in the pathophysiology of obstructive sleep apnea at the hypopharyngeal level. Genioglossus advancement is based on mandibular osteotomy, which brings the genioglossus muscle (GGM) forward and prevents posterior collapse during sleep. The genioglossus advancement technique has recently undergone several modifications; each has attempted to minimize surgical morbidity while improving the incorporation and advancement of the GGM. The hyoid bone has been of interest in sleep apnea and apnea-related surgical procedures because of its integral relationship with the tongue base and hypopharynx. Hyothyroidopexy is illustrated.

Trans-Oral Robotic Tongue Reduction for OSA: Does Lingual Anatomy Influence the Surgical Outcome?

STUDY OBJECTIVES

To evaluate both the influence of the volume of the excised base of tongue (BOT) on the surgical outcome after robotic tongue reduction in patients affected by obstructive sleep apnea (OSA) and the role of the lymphatic or muscular predominance within the removed tissue.

METHODS

Fifty-one patients with OSA were included in this study. All patients were treated with a robotic tongue base reduction. Data registered for the analysis were: age, sex, preoperative body mass index, preoperative and postoperative apnea-hypopnea index (AHI), delta AHI (preoperative AHI - postoperative AHI), total volume of the excised BOT, total thickness of excised BOT, isolated lymphatic thickness and soft tissue thickness (including muscular component) of the excised BOT, and lymphatic/soft tissue ratio (lymphatic thickness / soft tissue thickness).

RESULTS

A statistically significant reduction of AHI values was seen postoperatively, and a success rate of 74.5% was recorded. However, no significant correlations between delta AHI and tongue volume in cubic centimeters, lymphatic/soft tissue ratio, and total thickness were found.

CONCLUSIONS

These findings reinforce the general opinion that OSA is not only influenced by anatomic factors but other phenomena may play a fundamental role in its genesis. A deeper understanding of OSA pathogenesis is needed in order to tailor an individual treatment strategy that could lead to a more effective therapy.

Post-Stroke Sleep-Disordered Breathing-Pathophysiology and Therapy Options

Sleep-disordered breathing (SDB), encompassing both obstructive and central sleep apnea, is prevalent in at least 50% of stroke patients. Small studies have shown vast improvements in post-stroke functional recovery outcomes after the treatment of SDB by continuous positive airway pressure. However, compliance to this therapy is very poor in this complex patient group. There are alternative therapy options for SDB that may be more amenable for use in at least some post-stroke patients, including mandibular advancement, supine avoidance, and oxygen therapy. There are few studies, however, that demonstrate efficacy and compliance with these alternative therapies currently. Furthermore, novel SDB-phenotyping approaches may help to provide important clinical information to direct therapy selection in individual patients. Prior to realizing individualized therapy, we need a better understanding of the pathophysiology of SDB in post-stroke patients, including the role of inherent phenotypic traits, as well as the contribution of stroke size and location. This review summarizes the available literature on SDB pathophysiology and treatment in post-stroke patients, identifies gaps in the literature, and sets out areas for further research.

Evaluation of tongue volume and oral cavity capacity using cone-beam computed tomography

The aims of this study were to reveal the usefulness of a newly developed method for measuring tongue volume (TV) and oral cavity capacity (OCC) and to assess the relationship between them. The tongue was coated with a contrast agent, and the TV and OCC were determined using cone-beam computed tomography (CBCT). We enrolled 20 adults who were scheduled to undergo CBCT to evaluate the relationship of the third molar roots to the alveolar nerve before molar extraction. Each participant’s tongue was coated with a contrast agent, and CBCT of the tongue and oral cavity was performed. Using computer software, we evaluated reconstructed 3D images of the TV, oral cavity proper volume (OCPV), and OCC. The mean TV was 47.07 ± 7.08 cm³. The mean OCPV and OCC were 4.40 ± 2.78 cm³ and 51.47 ± 6.46 cm³, respectively. There was a significant correlation between TV and OCC (r = 0.920; p < 0.01) but not between TV and OCPV. The mean TV/OCC ratio was 91 ± 5%. The proposed method produced CBCT images that enabled effective measurement of TV and OCC. This simple method of measuring TV and OCC will be useful in the diagnosis on the tongues with abnormal size.

Spirometric Assessment of Impact of Complete Dentures on Respiratory Performance: An in vitro Study

INTRODUCTION

Edentulism is one of the debilitating states affecting a significant portion of the geriatric population. It is often considered as the ultimate marker for predicting the pressure and burden on oral health. Respiration is also a routine vital function running continuously through the human body and most commonly assessed by a spirometer. Hence, we planned the present study to assess the impact of complete dentures on the functioning of the respiratory system.

MATERIALS AND METHODS

In the present study, a spirometric assessment of the effect of complete dentures on respiratory performance was done. A total of 100 subjects were included, and diagnostic spirometer was used for carrying out the spiro-metric test at different stages of each subject. The spirometric test was carried out at four different stages: In the absence of both the denture (AODs), with both the dentures (maxillary and mandibular) inserted in the patient's mouth (BDs), with only maxillary denture inserted in the oral cavity (UDs), and finally, by inserting only the mandibular dentures in the oral cavity (LDs). Forced vital capacity (FVC), peak expiratory flow (PEF), forced expiratory volume in 1 second (FEV1), and forced expiratory flow between 25 and 75% (FEF_25-75) were evaluated. All the results were compiled and assessed using Statistical Package for the Social Sciences (SPSS) software.

RESULTS

Of the total 100 subjects included in the study, 42 were males and 58 were females. The mean FVC values of AOD, BD, LD, and UD group were 3.10, 3.02, 2.90, and 2.93 respectively. The mean PEF values of AOD, BD, LD, and UD group were 5.79, 5.60, 5.40, and 5.48 respectively; 2.39, 2.35, 2.33, and 2.32 were the mean FEV1 values observed in AOD, BD, LD, and UD group respectively. Statistically significant results were obtained while comparing AOD-FVC and BD-FVC and other oral conditions.

CONCLUSION

Spirometric values of respiratory functional tests in edentulous patients might be unfavorably affected by wearing complete dentures.

CLINICAL SIGNIFICANCE

Since subjects without complete dentures exhibited a maximum value of respiratory functional test, respiratory exercise protocols should also be carried in denture-wearing edentulous patients for increasing the performance of the respiratory system.

Three-dimensional evaluation of maxillary dentoalveolar changes and airway space after distalization in adults

OBJECTIVES

To evaluate the changes in position of the maxillary dentition and the airway space after distalization using a modified C-palatal plate (MCPP) in adult patients through CBCT images and to analyze the relationship between the amount of distalization and the changes in the airway space.

MATERIALS AND METHODS

CBCT images of 33 adult Class II patients (22.2 ± 4.0 years old; 27 women and 6 men) treated by total maxillary arch distalization using the MCPP were evaluated before and after distalization. The patients were divided into nonextraction and extraction groups. The changes in the airway space as well as the changes in the positions of the maxillary dentition were evaluated. The distalization effects were calculated and assessed using paired t-tests.

RESULTS

After distalization, the first molar showed significant distalization and intrusion ( P < .001) with no significant rotation of the crown and no significant buccal displacement of its root in the transverse dimension. There were no significant changes in the airway volume or the minimum cross-sectional area of the oropharynx.

CONCLUSIONS

The application of the MCPP resulted in significant total arch distalization without a significant effect on the transverse dimensions or changes in the oropharynx airway space. The MCPP can be considered a viable treatment option for patients with Class II malocclusion.

Maxillary Expansion and Mandibular Setback Surgery With and Without Mandibular Anterior Segment Osteotomy to Correct Mandibular Prognathism With Obstructive Sleep Apnea

Mandibular prognathism is usually treated with mandibular setback surgery. However, this approach reduces the pharyngeal airway space, and can aggravate obstructive phenomena in patients with obstructive sleep apnea (OSA). While maxillary expansion is known to lead to an increase in the pharyngeal airway volume (PAS), its effect on the PAS in mandibular setback surgery has not yet been reported. The authors report a surgical approach with maxillary expansion in 2 patients with mandibular prognathism that was accompanied by OSA: maxillary midsagittal expansion with minimum maxillary advancement and minor mandibular setback without mandibular anterior segmental osteotomy (ASO) or major mandibular setback with mandibular ASO. Preoperative and postoperative computed tomography and polysomnography indicated that OSA was improved and pharyngeal airway space was increased or sustained, and the prognathic profile could be corrected to an acceptable facial esthetic profile. In summary, maxillary transversal expansion and mandibular setback with or without mandibular ASO can be successfully applied to treat mandibular prognathism with OSA.

Is Ultrasound a Valid and Reliable Imaging Modality for Airway Evaluation?: An Observational Computed Tomographic Validation Study Using Submandibular Scanning of the Mouth and Oropharynx

OBJECTIVES

Ultrasound (US) imaging of the airway may be useful in predicting difficulty of airway management (DAM); but its use is limited by lack of proof of its validity and reliability. We sought to validate US imaging of the airway by comparison to CT-scan, and to assess its inter- and intra-observer reliability. We used submandibular sonographic imaging of the mouth and oropharynx to examine how well the ratio of tongue thickness to oral cavity height correlates with the ratio of tongue volume to oral cavity volume, an established tomographic measure of DAM.

METHODS

A cohort of 34 patients undergoing CT-scan was recruited. Study standardized assessments included CT-measured ratios of tongue volume to oropharyngeal cavity volume; tongue thickness to oral cavity height; and US-measured ratio of tongue thickness to oral cavity height. Two sonographers independently performed US imaging of the airway before and after CT-scan.

RESULTS

Our findings indicate that the US-measured ratio of tongue thickness to oral cavity height highly correlates with the CT-measured ratio of tongue volume to oral cavity volume. US measurements also demonstrated strong inter- and intra-observer reliability.

CONCLUSIONS

This study suggests that US is a valid and reliable tool for imaging the oral and oropharyngeal parts of the airway, as well as for measuring the volumetric relationship between the tongue and oral cavity, and may therefore be a useful predictor of DAM.

Changes in Upper Airway Volume Following Orthognathic Surgery

Reduced volume of the internal skeletal dimensions of the face is 1 of the main causes of obstructive sleep apnea, and attention to patients' airways is necessary when planning orthognathic treatment. This study aims to describe changes in upper airway volume following virtually planned orthognathic surgery.A retrospective pilot study was designed with 30 randomly selected patients (10 men and 20 women, aged 23.1 ± 6.8 years, molar-relations: 15 neutral, 8 distal, and 7 mesial). Cone-beam computed tomography scans were performed before surgery and 1 week following surgery. The authors did total upper airway volume measurements and obtained 1-mm slices at vertical levels in the velo-, oro-, and hypopharynx and at the smallest visible cross-section.Measurements before and after surgery were compared using Student t test.After orthognathic surgery, the minimum cross-sectional area at the vertical level increased from 83 mm ± 33 before surgery to 102 mm ± 36 after surgery (P = 0.019). In patients with neutral and distal occlusions, the minimum cross-sectional slice volume increased in 87% but in only 57% with mesial occlusion.The present findings suggest that orthognathic surgery increases upper airway volume parameters, but a few patients have continued impairment of the airways following orthognathic surgery. Further studies are needed to confirm an individual surgical planning approach that potentially could bring the minimum cross sectional area out of the risk zone.

Three-dimensional analysis of craniofacial bones and soft tissues in obstructive sleep apnea using cone beam computed tomography

A total of 154 adult patients with sleep complaints underwent a polysomnography and a craniofacial cone beam computed tomography (CBCT). OSA was defined as an apnea and hypopnea index (AHI) or an oxygen desaturation index (ODI) ≥ 10. Soft tissues and craniofacial bones volumes were prospectively measured by CBCT and collected blindly from sleep polysomnography. Among the study patients, 127 (83%) suffered from OSA and 27 (17%) did not. OSA patients demonstrated a narrower maxillo-palatine core volume (11.7±3.2 vs 14.6±4.9cm³) even when adjusting for age, gender, height, neck circumference and body mass index. These upper airway measures provide a comprehensive analysis of bony structures and soft tissues, which can be involved in OSA.

Volumes of Velopharyngeal and Glossopharyngeal Airway Were Not Changed after Uvulopalatopharyngoplasty: Report of Three Cases

Objective. The aim of this study was to investigate the changes in velopharyngeal and glossopharyngeal airway morphology and volume after uvulopalatopharyngoplasty in three adult obstructive sleep apnea syndrome patients who had bilateral large tonsils using three-dimensional computed tomography. Case Report. All three patients (one male and two females) who presented with a history of heavy snoring and excessive daytime sleepiness were examined with overnight nocturnal polysomnography, which indicated moderate-to-severe obstructive sleep apnea syndrome. Because all patients had large tonsils, uvulopalatopharyngoplasty was expected to enlarge the pharyngeal airway. Polysomnography and three-dimensional computed tomography scanning were performed and compared, both before and 3 months after uvulopalatopharyngoplasty. Results. Unexpectedly, although the morphology of the glossopharyngeal airway clearly changed after UPPP, the volume changes in the velopharyngeal and glossopharyngeal airways were negligible.

Tongue Volume Influences Lowest Oxygen Saturation but Not Apnea-Hypopnea Index in Obstructive Sleep Apnea

Objectives

The aim of this study was to identify correlations between sleep apnea severity and tongue volume or posterior airway space measured via three-dimensional reconstruction of volumetric computerized tomography (CT) images in patients with obstructive sleep apnea (OSA) for use in predicting OSA severity and in surgical treatment. We also assessed associations between tongue volume and Mallampati score.

Methods

Snoring/OSA male patients (n = 64) who underwent polysomnography, cephalometry, and CT scans were enrolled in this retrospective study. OSA was diagnosed when the apnea-hypopnea index (AHI) was greater than 5 (mild 5–14; moderate 15–29; severe>30). The patients were also categorized into the normal-mild group (n = 22) and the moderate-severe group (n = 42). Using volumetric CT images with the three-dimensional reconstruction technique, the volume of the tongue, posterior airway space volume, and intra-mandibular space were measured. The volumes, polysomnographic parameters, and physical examination findings were compared, and independent factors that are related to OSA were analysed.

Results

No associations between tongue volume or posterior airway space and the AHI were observed. However, multivariate linear analyses showed that tongue volume had significantly negative association with lowest O₂ saturation (r = 0.365, p = 0.027). High BMI was related to an increase in tongue volume. Modified Mallampati scores showed borderline significant positive correlations with absolute tongue volume (r = 0.251, p = 0.046) and standardized tongue volume (absolute tongue volume / intramandibular area; r = 0.266, p = 0.034). Between the normal-mild and moderate-severe groups, absolute tongue volumes were not different, although the standardized tongue volume in the moderate-severe group was significantly higher.

Conclusion

Absolute tongue volume showed stronger associations with lowest O₂ saturation during sleep than with the severity of AHI. We also found that high BMI was a relevant factor for an increase in absolute tongue volume and modified Mallampati grading was a useful physical examination to predict tongue size.

Cephalometric norms for the upper airway in a healthy North Indian population

Objective:

The aim was to obtain normative data for cephalometric measurements of the upper airway in the North Indian population.

Design:

Observational study. Setting: University department and teaching hospital out-patient clinic.

Subjects and Methods:

A total of 180 healthy patients were included out of which 90 were males (age range, 8-16 years), and 90 were females (age range, 8-16 years), with normal skeletal facial profile, no history of snoring, sleep apnea, upper airway disease, tonsillectomy or adenoidectomy, obesity, or pathology in the pharynx. Twenty cephalometric airway measurements, including size of the tongue, soft palate, nasopharynx, oropharynx, hypopharynx, and relative position of the hyoid bone and valleculae were obtained. Landmarks on cephalometric radiographs were digitized and measurements were made using a specially designed computer program. Error analysis of measurements was performed and comparison of measurements according to sex was made.

Results:

Significant sex dimorphism was seen for the majority of measurements, with the exception of minimal depth of the airway, oropharyngeal depth of the airway, and the soft palate angle with the hard palate.

Conclusion:

A minimum sagittal dimension of the upper airway was evident despite differences in measurements between sexes. Findings from this study should be a useful reference for the assessment of sleep apnea in the North Indian population.

Craniofacial characteristics related to daytime sleepiness screened by the paediatric daytime sleepiness scale

The present cross-sectional study aimed to assess daytime sleepiness in Chinese adolescents using the Paediatric Daytime Sleepiness Scale (PDSS) and to identify associations between PDSS answers and craniofacial characteristics. A group of 265 Chinese adolescents aged 11-17 years self-completed the PDSS, and their extra- and intra-oral craniofacial characteristics were recorded. Among the participants, 59.7% (157) experienced one or more daytime sleepiness events. No significant associations were found between total PDSS scores and the craniofacial parameters, but when PDSS answers were assessed at the item level, several craniofacial characteristics were found to be positively associated with daytime sleepiness, such as hypertrophic tonsils (P = 0.05), a relatively large tongue (P < 0.01), a bilateral Class II molar relationship (P < 0.05) and increased overjet (P < 0.05). A short lower face (P < 0.01) and a convex profile (P < 0.01) were found to be negatively associated with daytime sleepiness. Daytime sleepiness is commonly reported among Chinese adolescents seeking orthodontic treatment and there are potential associations between the condition and craniofacial characteristics. An assessment of daytime sleepiness is recommended to orthodontists in young patients presenting with hypertrophic tonsils, relative large tongues and Class II tendency malocclusions, and appropriate medical referrals should also be considered.

The relationship of vertical skeletofacial morphology to oropharyngeal airway shape using cone beam computed tomography: possible implications for airway restriction

OBJECTIVE

To determine if the shape of the oropharyngeal airway is related to the vertical morphology of the skeletofacial complex, including the hyoid bone.

MATERIALS AND METHODS

Cone beam computed tomography scans from 50 pretreatment adult orthodontic records were used to obtain skeletal and airway measurements. Linear regression statistics were used to compare soft tissue variables to hard tissue predictor variables.

RESULTS

Transverse airway widening was significantly increased when the distance between the hyoid and vertebrae was reduced; when the three-dimensional (3D) facial axis angle decreased (became more vertical); when the 3D mandibular plane angle increased; when the width of the hyoid increased, or when the calculated length of the geniohyoid decreased.

CONCLUSIONS

A laterally elliptical airway-found when the face is more vertical and when the hyoid is closer to the cervical vertebrae-is hypothetically more resistant to collapse. Patients with a retrognathic, skeletal deep bite and a rounded oropharynx should be identified and corrected early to prevent potential airway problems.

Pharyngeal airway dimensions: a cephalometric, growth-study-based analysis of physiological variations in children aged 6-17

OBJECTIVE

The aim was to assess pharyngeal airway dimensions and physiological changes based on lateral cephalometric radiographs from healthy untreated children aged 6-17 years.

MATERIALS/METHODS

The sample consisted of 880 lateral cephalograms (412 females and 468 males) of the Zurich Craniofacial Growth Study. Statistical analyses on cephalometric measurements of airway dimensions (distances 'p': shortest distance between soft palate and posterior pharyngeal wall and 't': shortest distance between tongue and posterior pharyngeal wall) and craniofacial parameters were performed. To disclose differences between different age groups, a Kruskal-Wallis test was applied. The influence of gender on 'p' and 't' was analysed by a Mann-Whitney U-test for each age group separately. The Spearman correlation was computed in order to investigate associations between craniofacial parameters. Variables associated with 'p' and 't' were chosen for multiple regression model investigation.

RESULTS

The results demonstrated high interindividual variations. A slight influence of age on 'p' (P = 0.034) could be attested (+1.03 mm) but not on 't' (P = 0.208). With the exception of the 9-year age group, no significant differences between the genders were found. Correlation analysis revealed several statistically significant correlations between 't' or 'p' and antero-posterior cephalometric variables. All correlation coefficients were, however, very low and the adjusted coefficient of determination also revealed the regression model to be very weak.

CONCLUSIONS

The high interindividual variations of 'p' and 't' render the use of reference values problematic. Contrary to other craniofacial structures, neither age-related changes nor sexual dimorphism were found for 'p' and 't'. Any associations to antero-posterior cephalometric characteristics seem low.

Three-dimensional evaluation of upper airway in patients with different anteroposterior skeletal patterns

OBJECTIVES

To investigate variability in the upper airway of subjects with different anteroposterior skeletal patterns by evaluating the volume and the most constricted cross-sectional area of the pharyngeal airway and defining correlations between the different variables.

MATERIAL AND METHODS

The study sample consisted of 60 patients (29 boys, 31 girls) divided into three groups: Class I (1 ≤ ANB ≤ 3), Class II (ANB>3), and Class III (ANB<1), to evaluate how the jaw relationship affects the airway volume and the most constricted cross-sectional area (Min-CSA). Differences between groups were determined using the Tukey-Kramer test. Correlations between variables were tested using Pearson's correlation coefficient.

RESULTS

The volume and the Min-CSA of the pharyngeal airway (PA) were significantly related to anteroposterior skeletal patterns (p < 0.05). The nasopharyngeal airway (NA) volume of Class I and Class III subjects was significantly larger than that of Class II subjects (p < 0.05). The Min-CSA and the length of PA were significantly related to the volume of PA (p < 0.05). The site and the size of the Min-CSA varied among the three groups.

CONCLUSIONS

The volume and the most constricted cross-sectional area of the airway varied with different anteroposterior skeletal patterns. The NA volume of Class I and Class III subjects was significantly larger than that of patients with a Class II skeletal pattern.

A 2D ultrasound evaluation of swallowing in children with unilateral posterior crossbite

BACKGROUND

Swallowing pattern is important in the aetiology of unilateral posterior crossbite (ULCB). The aim of this study was to assess the swallowing pattern and tongue function during swallowing in children with ULCB in deciduous dentition using B-mode and M-mode ultrasonography.

MATERIALS AND METHODS

Twenty-three children with ULCB, aged 4.1-6.6 years, and 22 children without ULCB, 5.7-6.7 years, were examined with simultaneous B- and M-mode ultrasonography. The swallowing pattern was assessed according to the action of genioglossus muscle in ultrasound images with the scan line of the ultrasound transducer set through the tongue tip. The tongue movements (duration, range, and speed) were compared within each subphase (I, IIa, IIb, IIIa, and IIIb) and in the entire swallowing cycle between the children with ULCB and without ULCB.

RESULTS

The visceral swallowing pattern was found in 83 per cent of children with ULCB and in 36 per cent of children without ULCB; the difference was statistically significant. The duration of phase IIb and the entire swallowing act was found to be statistically significantly prolonged in the ULCB group. Furthermore, the range of the tongue movement in phases and in the entire swallowing act was statistically significantly larger in the ULCB group. The speed of the tongue movement was statistically significantly higher in the ULCB group in phase IIa.

CONCLUSIONS

The 2D ultrasonography was used to evaluate the prevalent type of swallowing in children with ULCB. Visceral type of swallowing pattern and the changed tongue function during swallowing seem to be important factors in the aetiology of ULCB.

Recent advances in the management of obstructive sleep apnea: The dental perspective

Obstructive sleep apnea (OSA) is common in adult population. OSA shows detrimental effects on health, neuropsychological development, quality-of-life, and economic potential and now it is recognized as a public health problem. Despite the availability of expanded therapeutic options, polysomnography and nasal continuous positive airway pressure (CPAP) are the gold standards for the diagnosis and treatment for OSA. Recently, American Academy of Sleep Medicine has recommended oral appliances for OSA. Hence the therapeutic interventions that are directed at the site of airway obstruction in the maxillofacial region are within the scope of dentistry. Treatment of OSA can improve vitality, social and daytime functioning, family life and mental health of a person and hence the quality-of-life. Obesity is the main predisposing factor for OSA. Other than obesity, craniofacial abnormalities such as micrognathia and retrognathia, age, ethnic background and genetic predisposition, consumption of alcohol, smoking, and sedatives may also predispose to OSA. Treatment modalities for OSA are behavior modification, diet and medication, CPAP devices, surgical (maxillo-mandibular advancement surgery), and oral appliances. Treatment of a patient with OSA not only improves the physical health of the patients but also the mental and social well-being.

Comparative Evaluation of Nasopharyngeal Airways of Unilateral Cleft Lip and Palate Patients Using Three-Dimensional and Two-Dimensional Methods

Aim

Comparison of nasopharyngeal airway dimensions among UCLP patients and the control group.

Materials and Methods

Computed tomography imaging data and cephalometric films of 20 patients with UCLP and 20 controls were acquired prior to treatment. Three-dimensional (3D) reconstructions of nasal, superior, middle, and inferior pharyngeal airways were carried out from dicom data, and volumes of these compartments were calculated. Nasal width and superior, middle, and inferior nasopharyngeal areas were calculated from cephalometric films.

Results

The only statistically significant difference among the cleft and noncleft patients was detected in nasal volume ( p < .01). Upper and middle pharyngeal airway areas were found to display significant larger areas in the noncleft group on cephalometric appraisal. Nonsignificantly larger nasal widths were measured in the cleft group.

Discussion and Conclusion

Evaluation of the nasopharyngeal airways of cleft and noncleft patients was done, resulting in only the nasal region showing statistically significant difference. Our results showed significantly lower nasal volume measurements of cleft patients when compared with the healthy individuals (p < .01). This inadequacy can be interpreted as an outcome of the deficiency. The controversy among results of cephalometric appraisal and 3D imaging can be associated with superimpositions, density, and contrast inadequacies and obscured landmarks. When 2D data are compared with 3D data, the former can be insufficient and therefore deceiving. Consequently, although the radiation dose of 3D imaging systems is greater, they have the advantage of superior diagnostic outputs.