Comparison of anatomic and aerodynamic characteristics of the upper airway among edentulous mild, moderate, and severe obstructive sleep apnea in older adults.

STUDY OBJECTIVES: First, to compare the upper airway's anatomic and aerodynamic characteristics of the edentulous older adults who experience mild, moderate, and severe obstructive sleep apnea (OSA). Second, to examine the correlation between the severity of OSA and the anatomic and aerodynamic characteristic(s) of the upper airway in these edentulous individuals. METHODS: NewTom5G cone beam computed tomography scans of 58 edentulous individuals with mild, moderate, and severe OSA were included in this analysis. 1) Computational models of the upper airway were reconstructed based on cone beam computed tomography images and the anatomical and aerodynamic characteristics of the upper airway were examined by an observer blind to OSA severity. 2) Pearson correlation analysis was used to determine the correlation between apnea-hypopnea index and the anatomic and aerodynamic characteristics of the upper airway. RESULTS: Compared with edentulous patients with mild and moderate OSA, those with severe OSA have a more hourglass-shaped upper airway. The severity of OSA, namely, apnea-hypopnea index, was significantly correlated with the length, shape, and minimum cross-sectional area of the upper airway. During inspiration, the mean velocity of the airflow within the upper airway of the edentulous patients with severe OSA was higher than that of patients with mild and moderate OSA. During both inspiration and expiration, apnea-hypopnea index was found to be significantly correlated with maximum velocity (P = .05) and airway resistance (P = .024, 0.038). CONCLUSIONS: The edentulous patients with severe OSA have a more hourglass-shaped upper airway. The findings also suggest that, during inspiration, the airflow travels faster in edentulous patients with severe OSA than in those with mild or moderate OSA. CLINICAL TRIAL REGISTRATION: Registry: ClinicalTrials.gov; Name: The Effect of Nocturnal Wear of Dentures on Sleep and Oral Health Related Quality of Life; URL: https://clinicaltrials.gov/ct2/show/NCT01868295; Identifier: NCT01868295. CITATION: Chen H, Elham E, Li Y, et al. Comparison of anatomic and aerodynamic characteristics of the upper airway among edentulous mild, moderate, and severe obstructive sleep apnea in older adults. J Clin Sleep Med. 2022;18(3):759-768.

Phenotypes of responders to mandibular advancement device therapy in obstructive sleep apnea patients: A systematic review and meta-analysis.

Mandibular advancement device (MAD) therapy is the most commonly used non-continuous positive airway pressure (CPAP) treatment for obstructive sleep apnea (OSA). Although OSA patients prefer MAD over CPAP, on average over one third have minimal or no major reduction in OSA severity with MAD therapy. Improved understanding of responder characteristics (or "phenotypes") to MAD may facilitate more efficient use of limited medical resources and optimize treatment efficacy. The aim of this review is to describe the baseline phenotypic characteristics of responders to MAD therapy in OSA patients. Pubmed, Web of Science, EMBASE, Scopus were searched for eligible studies published until Feb 2019. A total of 650 studies were identified. 41 studies were included in this review and meta-analysis. The quality of the studies was assessed using the risk of bias assessment tool for non-randomized studies (RoBANS). Based on meta-analysis, the responders to MAD therapy had certain clinical phenotypic characteristics: lower age (95% CI: -4.55 to -1.62, p < 0.00001), female (95% CI: 0.56 to 0.91, p = 0.006), lower body mass index (95% CI: -2.80 to -1.11, p < 0.00001), smaller neck circumference (95% CI: -1.57 to -0.52, p < 0.00001), lower apnea-hypopnea index (95% CI: -7.23 to -1.89, p < 0.00001), a retracted maxilla and mandible, a narrower airway and a shorter soft palate than non-responders. The above-mentioned phenotypic responder characteristics provides useful information for the clinician when considering prescribing MAD therapy for OSA patients.

CBCT assessment of gubernacular canals in relation to eruption disturbance and pathologic condition associated with impacted/unerupted teeth.

OBJECTIVES: The aim of this study was to demonstrate the imaging characteristics of gubernacular canals (GCs) in impacted/unerupted permanent teeth and to determine whether these characteristics differ as a result of the presence of eruption disturbances or pathologic conditions associated with impacted/unerupted teeth. STUDY DESIGN: GCs were retrospectively analyzed by using cone beam computed tomography in 250 patients with 753 impacted/unerupted permanent teeth (105 males, 145 females; mean age, 21.09 ± 14.45 years; range 6-70 years). RESULTS: The rate of detection of GCs was significantly lower in cases with eruption disturbances than in those without eruption disturbances. An inverse correlation was observed between age and detection of GCs. Similarly, root resorption of adjacent teeth and resorption of impacted/unerupted teeth were associated with lower rates of detection of GCs. However, no association was found for widening of the follicular space. Regression analysis determined disturbed eruption pattern as the most important factor for the absence of GCs. CONCLUSIONS: The absence of GC may indicate a disturbed eruption pattern of the tooth and may increase the risk of complications related to impaction resulting in a tooth that is more likely to remain unerupted.

A novel imaging technique to evaluate airflow characteristics in the upper airway of an obstructive sleep apnea patient.

We report about a novel imaging technique for airflow analysis, particle image velocimetry (PIV), used in a moderate obstructive sleep apnea (OSA) patient. By measuring the airflow characteristics in the upper airway at different protrusion positions, the effect of mandibular advancement device (MAD) on OSA was further understood.

Reliability and accuracy of three imaging software packages used for 3D analysis of the upper airway on cone beam computed tomography images.

OBJECTIVES: The aim of this study was to assess the reliability and accuracy of three different imaging software packages for three-dimensional analysis of the upper airway using CBCT images. METHODS: To assess the reliability of the software packages, 15 NewTom 5G® (QR Systems, Verona, Italy) CBCT data sets were randomly and retrospectively selected. Two observers measured the volume, minimum cross-sectional area and the length of the upper airway using Amira® (Visage Imaging Inc., Carlsbad, CA), 3Diagnosys® (3diemme, Cantu, Italy) and OnDemand3D® (CyberMed, Seoul, Republic of Korea) software packages. The intra- and inter-observer reliability of the upper airway measurements were determined using intraclass correlation coefficients and Bland & Altman agreement tests. To assess the accuracy of the software packages, one NewTom 5G® CBCT data set was used to print a three-dimensional anthropomorphic phantom with known dimensions to be used as the "gold standard". This phantom was subsequently scanned using a NewTom 5G® scanner. Based on the CBCT data set of the phantom, one observer measured the volume, minimum cross-sectional area, and length of the upper airway using Amira®, 3Diagnosys®, and OnDemand3D®, and compared these measurements with the gold standard. RESULTS: The intra- and inter-observer reliability of the measurements of the upper airway using the different software packages were excellent (intraclass correlation coefficient ≥0.75). There was excellent agreement between all three software packages in volume, minimum cross-sectional area and length measurements. All software packages underestimated the upper airway volume by -8.8% to -12.3%, the minimum cross-sectional area by -6.2% to -14.6%, and the length by -1.6% to -2.9%. CONCLUSIONS: All three software packages offered reliable volume, minimum cross-sectional area and length measurements of the upper airway. The length measurements of the upper airway were the most accurate results in all software packages. All software packages underestimated the upper airway dimensions of the anthropomorphic phantom.

Venous malformation with multiple phleboliths: A case report.

Venous malformations are congenital, abnormally formed vessels, present at birth. They do not undergo regression with the growth of the patient. Due to the stagnation of blood flow in venous malformations, thrombosis and phlebolith formation may occur. Phleboliths are calcified thrombi which radiographically must be differentiated from calcified lymph nodes, sialoliths, foreign bodies, and other radiopacities. We report an extensive venous malformation in a 19-year-old woman with panoramic radiography demonstrating multiple phleboliths. Magnetic resonance imaging revealed the extension of the lesion into the hard palate and the masseter muscles superiorly, extending from the oropharynx to the tongue, inferiorly reaching the right clavicula and spreading between the right sternocleidomastoid muscle and strap muscles of the neck. The article is presented because the presence of phleboliths demonstrated on panoramic radiography is rarely described in the literature.

Three-dimensional imaging of the upper airway anatomy in obstructive sleep apnea: a systematic review.

INTRODUCTION: The pathogenesis of upper airway collapse in people with obstructive sleep apnea (OSA) is not fully understood. The aim of this study was to systematically review the literature in order to assess the most relevant anatomical characteristics of the upper airway related to the pathogenesis of OSA by analyzing the three-dimensional upper airway anatomy. METHOD: A PICO (population/patient, intervention, comparison, outcome) search strategy, focusing on the upper airway anatomy of people with OSA, was conducted using the following databases: MEDLINE (PubMed), Excerpta Medica database (EMBASE), Web of Science, and Cochrane Library. The studies in which three-dimensional images were made from the participants who were awake and in the supine position during quiet breathing were selected in this systematic review. RESULTS: Of the 758 unique retrieved studies, eight fulfilled the criteria for this systematic review. The minimum cross-sectional area of the upper airways of people with OSA, which is influenced by many factors such as hard and soft tissues surrounding the upper airway, was significantly smaller than that of those without OSA. CONCLUSION: Within the limitation of the selected studies, this systematic review suggested that a small minimum cross-sectional area is the most relevant anatomical characteristic of the upper airway related to the pathogenesis of OSA.

Reliability of three-dimensional measurements of the upper airway on cone beam computed tomography images.

OBJECTIVES: The aim of this study was (1) to assess intra- and interobserver reliability of the localization of anatomic landmarks of the upper airway on cone beam computed tomography (CBCT) images; and (2) to assess intra- and interobserver reliability of the three-dimensional measurements of the upper airway based on these landmarks. STUDY DESIGN: Fifteen NewTom 5G (QR systems, Verona, Italy) CBCT data sets were randomly selected from the archives of the Department of Oral Radiology, Academic Centre for Dentistry (ACTA) at University of Amsterdam and VU University, Amsterdam, The Netherlands. Three observers localized six anatomic landmarks that are relevant for upper airway analysis twice, with a 10-day interval, using 3Diagnosys software (v5.3.1, 3diemme, Cantu, Italy). Subsequently, the observers performed upper airway volume measurement based on those landmarks twice as well, again with a 10-day interval, using Amira software (v4.1, Visage Imaging Inc., Carlsbad, CA). The upper airway measurements also included the minimum cross-sectional area (CSAmin), location of the CSAmin, and anteroposterior and lateral dimensions of the CSAmin. RESULTS: Both intraobserver reliability and interobserver reliability were excellent for the localization of the anatomic landmarks of the upper airway (intraclass correlation coefficients = 0.97-1.00) as well as for the three-dimensional upper airway measurements (intraclass correlation coefficients = 0.78-1.00). CONCLUSIONS: The methodology of landmark localization and upper airway measurements, as used in this study, showed an excellent reliability and can thus be recommended for upper airway analysis on CBCT images.

Radiographic features of mandibular trabecular bone structure in hypodontia.

PURPOSE: Radiographic parameters of mandibular trabecular bone structure between 67 subjects having hypodontia and those without were studied on digital panoramic radiographs. MATERIALS AND METHODS: Three regions of interest (ROI) were defined: the ascending ramus, apical of the mandibular molar and mesial of the first mandibular molar. The effects of the presence of hypodontia and the ROI on the mandibular trabecular bone structure were tested for statistical significance by means of multivariate analysis. RESULTS: Radiographic parameters of trabecular bone architecture were found to differ between various regions of the mandible (p = 0.000), but not between the group of hypodontia subjects and their controls (p = 0.23). There was no interaction effect between the ROIs and the two groups (p = 0.79). For people having hypodontia, some directional parameters of trabecular bone have a reverse correlation with the number of missing teeth. The fractal dimension and the number and perimeter of white segments in the binarized image correlate positively with the number of congenitally missing teeth. CONCLUSIONS: A limited number of parameters of radiographic mandibular trabecular bone structure correlate with the number of missing teeth. However, a markable difference in radiographic parameters of mandibular trabecular bone structure between hypodontia and non-hypodontia subjects could not be demonstrated.

Detecting bone loss along dental implants by subtraction of panoramic radiographs.

OBJECTIVES: To test an extended subtraction method for measuring changes in bone along dental implants depicted on non-standardized panoramic radiographs. MATERIAL AND METHODS: The measuring method consisted of a subtraction module extended with modules correcting gray values, correcting geometry and defining the region of interest mesial and distal of dental implants. It was applied to an archive of panoramic radiographs of implant patients who had been monitored up to 16 years. RESULTS: Significant loss of gray value was demonstrated at a constant rate of 0.6 units per month throughout the study. This indicates gradual bone loss on the mesial and/or distal sides of the implants. Females were found to lose bone at a higher rate than males. Smokers and non-smokers, and various implant strategies yielded the same rate of bone loss. CONCLUSIONS: The measuring method is a helpful tool to monitor changes around implants even when non-standardized radiographs are being used. Whereas changes of marginal bone level are increased five to eight times during the first year after surgery, the present method shows gradual loss of bone during 15 years after surgery.

Evaluation of the visibility and the course of the mandibular incisive canal and the lingual foramen using cone-beam computed tomography.

OBJECTIVES: To assess the visibility and the course of the incisive canal and the visibility and the location of the lingual foramen using cone-beam computed tomography (CBCT). METHODS: In total, 100 CBCT examinations of patients for preoperative planning were used for this study. The examinations were taken using the NewTom 3G CBCT unit, applying a standardized exposure protocol. Image reconstruction from the raw data was performed using the NewTom software. Three experts were asked to assess the visibility of the incisive canal using a four-point rating scale. The position of the incisive canal was recorded in relation to the lower, buccal and lingual border of the mandible using the application provided by the CBCT software. RESULTS: The incisive canal was definitely visible in 83.5% of the scans and the mean endpoint was approximately 15 mm anterior to the mental foramen. The mean distance from the lower border of the mandible was 11.5 mm and its course was closer to the buccal border of the mandible in 87% of the scans. The lingual foramen was definitely visible in 81% of the scans. CONCLUSIONS: The high detection rate of the incisive canal and the lingual foramen in the anterior region of the mandible using CBCT indicates the potential high preoperative value of CBCT scan for surgical procedures in the anterior mandible.

Is self-reported alcohol consumption associated with osteoporotic mandibular bone loss in women?

The aim of this study was to determine whether alcohol consumption would predict mandibular bone quality and quantity in a large European female population. In total, 672 middle-aged and elderly women (45-70 yr of age; standard deviation = 6) were recruited in the study. Alcohol consumption was recorded through a self-reported questionnaire. Mandibular cortical width was measured, by five observers, in the mental foramen region on panoramic radiographs. Mandibular bone density, expressed as aluminium thickness, was recorded on intra-oral radiographs. Alcohol consumption was associated with a reduction of mandibular bone density and cortical width. This association was higher in subjects with excessive alcohol consumption, defined in the present study as > 14 units consumed per week. This study showed reduced jaw-bone quality in older individuals and in those with increased alcohol consumption.

Pilot study: digital subtraction radiography as a tool to assess alveolar bone changes in periodontitis patients under treatment with subantimicrobial doses of doxycycline.

BACKGROUND: Subtle changes in marginal alveolar bone level can be demonstrated using digital subtraction of sequential radiographs. OBJECTIVE: We aimed to evaluate the practical application of geometrically corrected digital subtraction in a clinical study of alveolar bone response to a drug previously shown to inhibit alveolar bone loss. STUDY DESIGN: Selected periapical radiographs were acquired with projective standardization of patients with clinical marginal alveolar bone loss. Subsequently, patients received a 6-month regimen of subantimicrobial doxycycline or placebo. Standardized radiographs of the same alveolar regions were acquired after 3 and 6 months, and baseline radiographs were subtracted from these images. RESULTS: Blinded digital subtraction analysis indicated various levels of marginal bone gain in 3 of the 6 patients in the experimental group, whereas in 3 of the 5 placebo patients the method showed bone loss. CONCLUSION: These results suggest that geometrically corrected digital subtraction possibly agrees with clinical predictors of bone loss severity.

Better imaging: the advantages of digital radiography.

BACKGROUND: Digital radiography has been available in dentistry for more than 25 years, but it has not replaced conventional film-based radiography completely. This could be because of the costs involved in replacing conventional radiographic equipment with a digital imaging system, or because implementing new technology in the dental practice requires a bit of courage. When the practitioner is fully aware of the new possibilities offered by digital radiography, he or she can make a more informed decision about adopting it. This article offers information about digital radiography, not just as a replacement of conventional radiography, but also as a concept offering benefits beyond those of conventional radiography. OVERVIEW: Digital radiographs are composed of a set of numbers arranged as a grid of rows and columns. The dentist can perform mathematical operations on these numbers to create a new image in which certain characteristics are enhanced, thus making interpretation of the image easier. The dentist also can correct, to some extent, overexposed or underexposed images and can optimize contrast and brightness for specific diagnostic procedures, such as caries detection and bone level assessment. More advanced procedures are available as well, such as digital subtraction radiography and computer-aided recognition of image features. CONCLUSIONS AND CLINICAL IMPLICATIONS: The author presents a selection of the advantages of digital radiography that are not achievable with conventional film-based radiography. Implementing digital radiography in the dental office requires additional training. However, once members of the dental team have gone through this initial phase, they have the benefits of several new diagnostic possibilities. With a digital system, information from radiographic images is collected more easily and in a more objective way, which will improve the performance of the diagnostic process.

Detecting reduced bone mineral density from dental radiographs using statistical shape models.

We describe a novel method of estimating reduced bone mineral density (BMD) from dental panoramic tomograms (DPTs), which show the entire mandible. Careful expert width measurement of the inferior mandibular cortex has been shown to be predictive of BMD in hip and spine osteopenia and osteoporosis. We have implemented a method of automatic measurement of the width by active shape model search, using as training data 132 DPTs of female subjects whose BMD has been established by dual-energy X-ray absorptiometry. We demonstrate that widths measured after fully automatic search are significantly correlated with BMD, and exhibit less variability than manual measurements made by different experts. The correlation is highest towards the lateral region of the mandible, in a position different from that previously employed for manual width measurement. An receiver-operator characterstic (ROC) analysis for identifying osteopenia (T < -1: BMD more than one standard deviation below that of young healthy females) gives an area under curve (AUC) value of 0.64. Using a minimal interaction to initiate active shape model (ASM) search, the measurement can be made at the optimum region of the mandible, resulting in an AUC value of 0.71. Using an independent test set, AUC for detection of osteoporosis (T < -2.5) is 0.81.

Filmless imaging: the uses of digital radiography in dental practice.

BACKGROUND: As use of digital radiography becomes more common, many dentists are wondering if and how they can replace conventional film-based imaging with a digital system. This article briefly describes the different technologies used for digital radiography in dentistry. The article provides general practitioners with a broad overview of the benefits and limitations of digital radiography to help them understand the role the technology can play in their practices. OVERVIEW: The two technologies now available are solid-state systems and phosphor plate systems. Each has its strong points, and the choice of which to use depends on the type of dental practice. Image processing improves the diagnostic quality of the radiographic information. Advanced image-processing techniques, such as subtraction radiography, are available for specialized clinics. CONCLUSIONS AND CLINICAL IMPLICATIONS: Digital radiography no longer is an experimental modality. It is a reliable and versatile technology that expands the diagnostic and image-sharing possibilities of radiography in dentistry. Optimization of brightness and contrast, task-specific image processing and sensor-independent archiving are important advantages that digital radiography has over conventional film-based imaging.