How has our interest in the airway changed over 100 years?

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

INTRODUCTION

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

A retrospective study of the influence of obesity on polysomnography and cephalometric parameters in males with obstructive sleep apnea

OBJECTIVE

Evaluate the influence of obesity on the polysomnographic and cephalometric parameters in obstructive sleep apnea (OSA).

METHODS

Fifty records of male patients with OSA, containing information on dental, medical, polysomnographic, and cephalometric exams were selected. The degree of obesity was based on Body Mass Index (BMI). Group I comprised normal or overweight individuals (BMI ≤ 29.9 kg/m2), whereas Group II consisted of obese individuals (BMI ≥ 29.9 kg/m2).

RESULTS

BMI significantly correlated with apnea and hypopnea index (p < 0.0005), minimal oxyhemoglobin saturation (p < 0.0005), and two cephalometric variables (soft palate length, p = 0.01 and width, p = 0.01). Group II showed a significant correlation with the position of the hyoid bone (p = 0.02). Soft palate length and width significantly differed between groups (p = 0.014; 0.016).

CONCLUSION

Obese males present wider and longer soft palate dimensions, and patients with a greater BMI present a more inferiorly positioned hyoid bone.

Effect of Craniofacial Morphology on Pharyngeal Airway Volume Measured Using Cone-Beam Computed Tomography (CBCT)-A Retrospective Pilot Study

Background: The present study aimed to determine the correlation between pharyngeal airway volume and craniofacial morphology through cone-beam computed tomography (CBCT). Additionally, the study analyzed the influence of gender on pharyngeal airway volume. (2) Methods: 80 CBCT scans of 40 male and 40 female patients (mean age: 15.38 + 1.10 years) fulfilling the eligibility criteria were included. CBCT scans were evaluated for pharyngeal airway volume using the In Vivo Dental 5.1 software. Additionally, CBCT-derived lateral cephalograms were used to assess various craniofacial morphology parameters. To examine the influences of gender on airway volume, T-test was carried out. Correlation between airway volume and craniofacial parameters were measured using Pearson correlation followed by regression analysis. The value of p < 0.05 was considered statistically significant. Results: The mean airway volume was significantly greater in males than in females. A statistically significant negative correlation was found between maxillary plane inclination and pharyngeal airway volume. In contrast, a positive correlation was observed between mandibular length and lower molar inclination with oropharyngeal and total pharyngeal airway volume. Females showed a statistically significant positive correlation between the pharyngeal airway volume and sagittal position of maxilla and mandible; they also showed a negative correlation between oropharyngeal airway volume and the mandibular plane angle. Conclusions: Overall, the pharyngeal airway space differs significantly between males and females. Craniofacial morphology does have a significant effect on the pharyngeal airway, especially on the oropharyngeal airway volume.

Treacher Collins syndrome: Orthodontic treatment with mandibular distraction osteogenesis and orthognathic surgery

Interdisciplinary treatment for patients with Treacher Collins syndrome is challenging because of the rarity of the condition and the wide variety of phenotypic expression. A 23-year-old male was diagnosed with Treacher Collins syndrome with a history of severe obstructive sleep apnea. He presented with a Pruzansky-Kaban classification grade I mandible, skeletal type II pattern with a hyperdivergent mandibular plane, severe convex profile, and Class II malocclusion with a missing mandibular incisor. Improvement of facial esthetics was achieved by a combination of orthodontics, mandibular distraction osteogenesis, and 2-jaw maxillomandibular advancement surgery. Presurgical orthodontic treatment involved permanent tooth extraction to relieve severe crowding, and Class III mechanics were employed to increase overjet. Correction of mandibular hypoplasia by increasing ramal height and the mandibular length was done by intraoral mandibular distraction osteogenesis. Counterclockwise rotation of the mandibular plane angle and a Class III occlusion with negative overjet were achieved after mandibular distraction osteogenesis. A postdistraction posterior open bite was maintained with a biteplane during the consolidation period. Subsequently, 2-jaw orthognathic surgery was performed. LeFort I osteotomy was done for maxillary advancement to correct an anterior crossbite, eliminate canting, and reestablish occlusal contact at the mandibular occlusal plane. Bilateral sagittal split ramus osteotomy was done to correct the residual mandibular deviation. A genioplasty was also performed to improve chin projection. Postoperatively, the oropharyngeal airway was enlarged. The patient's facial profile and obstructive sleep apnea problem were improved as a result of advancement and counterclockwise rotation of the maxillomandibular complex.

Cone beam computed tomographic evaluation of pharyngeal airway in North Indian children with different skeletal patterns

BACKGROUND

In growing patients with skeletal discrepancies, early assessment of functional factors can be vital for the restoration of normal craniofacial growth.

AIM

To compare airway volumes in patients with mandibular retrognathism with the normal anteroposterior skeletal relationship, thereby assessing the association between cephalometric variables and airway morphology.

METHODS

Cone-beam computed tomography volume scans, and lateral cephalograms, 3-dimensional airway volume and cross-sectional areas of 120 healthy children (54 boys and 66 girls mean age 15.19 ± 1.28) which were done for orthodontic assessment were evaluated. The subjects were divided into 2 groups based on the angle formed between point A, Nasion and point B (ANB) values and cephalometric variables (such as anterior and posterior facial height, gonial angle etc.) airway volumes, and cross-sectional measurements were compared using independent t tests. Pearson’s correlation coefficient test was used to detect any relationship of different parts of the airway and between airway volume and 2-dimensional cephalometric variables.

RESULTS

Means and standard deviations for cephalometric, cross-sectional, and volumetric variables were compared. ANB, mandibular body length and facial convexity were statistically highly significant (P < 0.01) whereas condylion to point A, nasal airway and total airway volume (P < 0.05) were statistically significant. The nasal airway volume and the superior pharyngeal airway volume had a positive correlation (P < 0.01), nasal airway was correlated to middle (P < 0.05) and total airway superior had a relation with middle (P < 0.05), inferior and total airway (P < 0.05), middle was related to all other airways; inferior was also related to all the airways except nasal. Lateral cephalometric values were positively correlated with the airway volume with Frankfurt Mandibular Plane Angle and facial convexity showed significant correlations with total airway volume (P < 0.05). Additionally, ANB angle was significantly correlated with total airway volume and superior airway (P < 0.05).

CONCLUSION

The mean total airway volume in patients with retrognathic mandible was significantly smaller than that of patients with a normal mandible.

Effect of functional appliances on the airway in Class II malocclusions

The proximity of the orofacial structures to the upper airway has led to enormous interest in their influence on the airway maintenance mechanism. The recognition of Sleep disorders and the evolution of dental sleep medicine has fueled further interest in the role of orthodontic treatment on the airway particularly in Class II malocclusions. With abundant literature on class II malocclusions and growth modification, it is natural that focus would shift on the effect of functional appliances on the airway. Most studies on the subject show an improvement in the airway in response to functional appliances and these include both two dimensional and three dimensional study of the airway. This review showcases the most significant literature on this field of study against the background of the information that is needed to gauge its clinical relevance.

Diagnostic paths for a mouth-breathing patient

INTRODUCTION

The clinical choice of diagnostic tests or treatment options is determined by the probability that the value of their execution (called the warrant for the test) exceeds their cost, and by their usefulness. The purpose of this study was to determine the warrant and usefulness of STOP-Bang, an obstructive sleep apnea screening questionnaire, and cone-beam computed tomography (CBCT) information about the minimal cross-sectional area for referring a mouth-breathing patient to a sleep specialist and for modifying planned orthodontic treatment.

METHODS

A branching survey was used to identify the prominence of paths between the presenting situation, 2 diagnostic tests, and 2 referral and/or treatment options. A description was given of a hypothetical patient: an overweight, mouth-breathing female teenager. Path analysis was used as a method for quantifying diagnostic warrant and usefulness.

RESULTS

There was a wide variation among the 125 orthodontists who responded to the survey. All paths were chosen. The use of tests altered the referral (χ² = 8.039; P = 0.03) and/or treatment decisions (χ² = 12.636; P = 0.005). Ownership of a CBCT system significantly influenced the use of this diagnostic test, with owning a CBCT system resulting in greater use in-office (χ² = 50.416; P <0.001) and greater use in the study (χ² = 22.959; P <0.001). The usefulness of the diagnostic tests could not be determined directly because common values were used for each test, but the variation in the use of this standard stimulus was very large, indicating personal differences in the interpretation of actual data.

CONCLUSIONS

Wide variation in the choice and interpretation of diagnostic tests for referral and orthodontic treatment modification relative to airway condition exists among orthodontists. Diagnostic path analysis is a potentially useful model for studying how practitioners make decisions independent of research evidence.

Association between snoring and deciduous dental development and soft tissue profile in 3-year-old children

INTRODUCTION

The aim was to study the association between snoring and development of occlusion, maxillary dental arch, and soft tissue profile in children with newly completed deciduous dentition.

METHODS

Thirty-two (18 female, 14 male) parent-reported snorers (snoring ≥3 nights/week) and 19 (14 female, 6 male) nonsnorers were recruited. Breathing preference (nose or mouth) was assessed at the mean age of 27 months by otorhinolaryngologist. At the mean age of 33 months, an orthodontic examination was performed, including sagittal relationship of second deciduous molars, overjet, overbite, and occurrence of crowding and lateral crossbite. Bite index was obtained to measure maxillary dental arch dimensions (intercanine and intermolar width, arch length). A profile photograph was obtained to measure facial convexity.

RESULTS

No significant differences were found between nonsnorers and snorers in any of the studied occlusal characteristics or in measurements of maxillary dental arch dimensions. Snorers were found to have a more convex profile than nonsnorers. Occurrence of mouth breathing was more common among snorers.

CONCLUSIONS

Parent-reported snoring (≥3 nights/week) does not seem to be associated with an adverse effect on the early development of deciduous dentition, but snoring children seem to have more convex profile than nonsnorers. Snoring is a mild sign of sleep-disordered breathing, and in the present study its short time lapse may not have had adequate functional impact on occlusion.

Reliability and validity of two software systems used to measure the pharyngeal airway space in three-dimensional analysis

The aim of this study was to test the reliability and validity of two software systems used to measure the pharyngeal airway space three-dimensionally. A sample of 40 cone beam computed tomography images from adult patients was taken from a database. The cone beam computed tomography images were analysed by InVivoDental and Dolphin 3D software systems by two calibrated examiners. Three nasopharynx and oropharynx prototypes were used as a reference standard to validate the software systems. The volume, minimum area and minimum area localization were the measurements tested. Measurements were compared using a paired t-test; correlated using Pearson's correlation and linear regression. Bland-Altman analysis was also used. We found significant differences in the oropharynx volume (P=0.002) and nasopharynx minimum area localization (P=0.009). The Dolphin 3D software presented higher-volume values than the ones found in the prototype, while the InVivoDental software presented lower values. Strong (r>0.7; P>0.001) or very strong (r>0.9; P>0.001) correlations were observed between the software systems. Bland-Altman analysis found good agreement between prototypes and the software systems. The measurements obtained from the Dolphin 3D and InVivoDental software systems are both reliable, strongly correlated, but should not be assumed as equal. Dolphin 3D software overestimates the nasopharynx and oropharynx volumes, while the InVivoDental software underestimates them.