Comparing Airway Analysis in Two-Time Points after Rapid Palatal Expansion: A CBCT Study

BACKGROUND

The aim of this study is to investigate the upper airway analysis at two-time points after the rapid maxillary expansion was performed, using cone-beam computed tomography.

METHODS

Subjects from the Orthodontic Department at the Aristotle University of Thessaloniki with unilateral or bilateral posterior crossbite were screened according to the selection criteria. A sample size calculation was performed, and a total of 14 subjects were recruited. All subjects received a rapid maxillary expansion with a Hyrax-type device as part of their comprehensive treatment. A CBCT was taken before the treatment (T1), immediately after the expansion was completed (T2), and 6 months after (T3). Their upper airway was measured using the CBCT images. Airway volume (V) and minimal cross-sectional area (MCS) were extracted and compared using SPSS to analyze the means.

RESULTS

A statistically significant difference was found between all time points regarding both V and MCS (p < 0.001, p = 0.001). There was a statistically significant increase in both V and MCS measurements immediately after RPE expansion (T1-T2) and six months after expansion (T1-T3). Between the end of expansion and 6 months after (T2-T3), there was a decrease in V and no statistical difference in MCS.

CONCLUSIONS

RPE can significantly increase the volume and minimal cross-sectional area of the nasal passage airway.

Three-Dimensional Cone-Beam Computed Tomography Evaluation of Changes in Naso-Maxillary Complex Associated with Rapid Palatal Expansion

The introduction of Cone-Beam Computed Tomography (CBCT) in orthodontics has added a new tool to diagnosis and treatment planning. The aim of this prospective clinical trial was to investigate the changes in the dimensions of the naso-maxillary complex in growing patients after RPE using CBCT. A total of 16 growing children (8 females, 6 males) with a mean age of 11, 12 ± 1 and 86 years underwent RPE as part of their comprehensive orthodontic treatment. CBCT scans were obtained before RPE (T1), immediately after RPE (T2) and 6 months after RPE (T3). The dimensions of the nasal width, nasal floor and the aperture of the midpalatal suture were calculated in different coronal slices of CBCT. Evaluation of the mean value variance per measurement at the three time intervals were performed using the paired Wilcoxon signed-rank test. Differences between the three time intervals were assessed by performing Multiple Pairwise Comparisons. A statistically significant increase in all measurements was seen immediately after RPE expansion (T2–T1) and six months after expansion (T3–T1). Between the end of expansion and 6 months in retention (T3–T2), a decrease was observed for all measurements. RPE can cause expansion of the nasal cavity in growing patients. The expansion of the midpalatal suture follows a triangular pattern of opening.

Results of nose breathing evaluation during orthodontic treatment in children

Relevance. In the modern practice of an orthodontist, distal occlusion caused by respiratory dysfunction is increasingly more common. It is especially evident in early mixed dentition, i.e., in 6-8-year-old children with diagnosed pathology of ENT organs, namely, adenoids.Objective. The study aimed to evaluate the relationship between respiratory dysfunction and distal occlusion in children with early mixed dentition.Materials and methods. The study performed conventional anterior and posterior rhinoscopy, endoscopic examination of ENT organs, anterior active rhinomanometry, and masticatory muscles’ electromyography. The orthodontic examination included an oral examination, impression-taking, occlusion assessment, morphometric analysis of the jaw models and lateral cephalometric image measurements.Conclusion. In modern medical practice, the pathology of ENT organs and maxillofacial anomalies are closely related. Therefore, the collaboration between an orthodontist and an ENT specialist is the key to the effective treatment of distal occlusion in early mixed dentition.

Rapid Maxillary Expansion (RME): An Otolaryngologic Perspective

Background. To evaluate the possible effects of Rapid Maxillary Expansion (RME), such as nasal breathing problems, middle ear function, Obstructive Sleep Apnea (OSA) in the otolaryngology field. RME has already been introduced in orthodontics to expand the maxilla of young patients affected by transversal maxillary constriction. Methods. A literature search was performed using different databases (Medline/PubMed, EMBASE, and CINAHL), from May 2005 to November 2021, according to the PRISMA guidelines. Results. The application of RME in children has shown good results on nasal function, reducing nasal resistances, independently from a previous adenotonsillectomy. These results are not only related to the increasing of nasal transverse diameters and volume, but also to the stiffening of airway muscles, enabling the nasal filtrum function and avoiding mouth opening, thereby decreasing respiratory infections. Positive effects have also been reported for the treatment of conductive hearing loss and of OSA, with the reduction of Apnea Hypopnea Index (AHI), possibly due to (i) an increased pharyngeal dimensions, (ii) a new tongue posture, and (iii) reduced nasal respiratory problems. Conclusions. Otolaryngologists should be aware of the indications and benefits of the RME treatment, considering its possible multiple beneficial effects.

Evaluation of the effects of different rapid maxillary expansion appliances on airway by acoustic rhinometry: A randomized clinical trial

OBJECTIVE

The purpose of this 3-arm parallel trial was to compare the effects of tooth tissue-borne (TTB), tooth-borne (TB) and bone-borne (BB) rapid maxillary expansion (RME) appliances on nasal airway with acoustic rhinometry (AR).

SETTING AND SAMPLE POPULATION

Forty-six 12- to 14-year-old patients with narrow maxilla were randomly allocated into 3 study groups accordingly the type of expander: TTB, TB and BB. The participants were recruited from the Department of Orthodontics, Izmir Katip Celebi University.

MATERIALS AND METHODS

All patients had RME with an initial activation of two-quarter turns a day (0.5 mm) for an average of 8 days followed by 1 quarter turns per day for an average of 10 days. Disguised group allocation using opaque sealed envelopes was made with a computer-generated randomization program. The primary outcome was changes on the minimal nasal cross-sectional area (MCA). Secondary outcome included the assessment of nasal cavity volume. AR measurements were obtained at baseline (T0), immediately after the expansion (T1), and at 3 months-follow-up (T2). One-way analysis of variance (ANOVA) and Bonferroni test were used for inter-group comparison and two-way ANOVA was used for intra-group evaluation.

RESULTS

There were significant increases in MCA 1, 2 and nasal Vol in all groups after the treatment (95% [CI], P < 0.05) whereas in inter-group comparisons; MCA 1, 2 and nasal Vol, the changes were found to be similar (95% [CI], P > 0.05).

HARMS

No serious harm was observed except for mild gingivitis due to plaque accumulation.

CONCLUSIONS

RME treatment increased minimal nasal cross-sectional areas and nasal volume irrespective of appliance design.

TRIAL REGISTRATION

This trial was registered at Clinicaltrials.gov (Identifier NCT04529057).

PROTOCOL

The protocol was not published.

FUNDING

This trial was financed by Izmir Katip Celebi University, Scientific Research Projects Unit [grant number 2016-TDR-SABE-0024].

Three-dimensional image study of accelerated maxillary expansion in oral breathing kids

OBJECTIVE

To evaluate, by a three-dimensional study, the volumetric and integumentary effects of rapid maxillary expansion on the nose, in mouth breathing kids with maxillary hypoplasia, in the short term, assessing the possible interference of gender, growth and age on the results achieved.

METHODS

120 mouth breathing patients with maxilla hypoplasia were divided into an Experimental Group treated by rapid maxillary expansion (n = 104, 62 males and 42 females, mean age 10.1 years, SD = 2.10, ranging from 5.1 to 13.9 years); and Control Group, constituted by 16 patients (9 males and 7 females, mean age 9.3 years, SD = 2.1 years, ranging from 6.1 to 13.2 years). Patients in the experimental group underwent multislice computed tomography examinations at two different times: (T1) pre-expansion and (T2) post-expansion. The control group was submitted to the same tests at the same time intervals. Six soft tissue variables of the nose were studied, besides the volume and area of the nasal cavity, and the measurement and comparison of data between T1 and T2 were performed using the Dolphin Imaging 11.7 Premium software.

RESULTS

The experimental group showed significant mean increases in all soft tissue variables studied (p < 0.005), yet there were no significant changes in the control group. In the comparison between groups, only inclination of the nasal dorsum did not present any significant change.

CONCLUSION

Rapid maxillary expansion may alter the nasal shape and physiology, by anatomical changes in the nose soft tissues, making it an important aid in the treatment of mouth breathing in childhood.

LEVEL OF EVIDENCE

The soft tissues of the nose play an important role in nasal shape and physiology and facial esthetics, and since they are directly related to the nasal valves, they are fundamental for maintenance and stability of the nasal breathing pattern.

Nasal ventilation and rapid maxillary expansion (RME): a randomized trial

OBJECTIVE

To assess three rapid maxillary expansion (RME) appliances in nasal ventilation.

TRIAL DESIGN

Three-arm parallel randomized clinical trial.

METHODS

Sixty-six growing subjects (10-16 years old) needing RME as part of their orthodontic treatment were randomly allocated (1:1:1 ratio) to three groups of 22 patients receiving Hyrax (H), Hybrid-Hyrax (HH), or Keles keyless expander (K). The primary outcome of nasal ventilation (pressure and velocity) and secondary outcomes (skeletal, dental, soft tissue, and nasal obstruction changes) were blindly assessed on the initial (T0) and final (T1, 6 months at appliance removal) cone-beam computed tomography (CBCT) data by applying computational fluid dynamics (CFD) method. Differences across groups were assessed with crude and adjusted for baseline values and confounders (gender, age, skeletal maturation, expansion amount, mucosal/adenoid hypertrophy, nasal septum deviation) regression models with alpha = 5%.

RESULTS

Fifty-four patients were analysed (19H, 21HH, 14K). RME reduced both nasal pressure (H: -45.8%, HH: -75.5%, K: -63.2%) and velocity (H: -30%, HH: -58.5%, K: -35%) accompanied with nasal obstruction resolution (H: 26%, HH: 62%, K: 50%). Regressions accounting for baseline severity indicated HH expander performing better in terms of post-expansion maximum velocity (P = 0.03) and nasal obstruction resolution (P = 0.04), which was robust to confounders. Mucosal/adenoid hypertrophy and nasal septum deviation changes were variable, minimal, and similar across groups. The HH resulted in significantly greater increase in the nasal cross-sectional area (62.3%), anterior (14.6%), and posterior (10.5%) nasal widths. Nasal obstruction resolution was more probable among younger (P = 0.04), skeletally immature (P = 0.03), and male patients (P = 0.02) without pre-treatment mucosal hypertrophy (P = 0.04), while HH was associated with marginal greater probability for obstruction resolution.

CONCLUSIONS

RME resulted in improvement of nasal skeletal parameters and simulated ventilation with the former being in favour of the HH and the latter not showing significant differences among the three appliances.

LIMITATION

Attrition in the K group due to blocked activation rods possibly leading to limited sample to identify any existing group differences.

HARMS

Replacement of blocked Keles expanders for finalizing treatment.

PROTOCOL

The protocol was not published before the trial commencement.

REGISTRATION

Australian and New Zealand Clinical Trial Registry; ACTRN12617001136392.

Opening up on airways: the purported effect of nasorespiratory obstruction on dentofacial growth

Nasorespiratory obstruction has been purported to influence dentofacial growth adversely. This has sparked considerable debate for decades with a resurgence in interest in 'airway friendly orthodontics' among both general and specialist dental practitioners. This critical review aims to evaluate the current literature relating to two questions: does nasorespiratory obstruction alter dentofacial growth, and does early intervention targeted at alleviating nasorespiratory obstruction improve dentofacial growth? The strength of association between nasorespiratory obstruction, mouth breathing and a long face is weak. The common methodological flaws in research include unblinded and cross-sectional study designs, a lack of adequate controls, inadequate follow-up, subjective assessments and inadequate statistical power. Vertical dentofacial growth has a strong genetic influence, which implies a relatively minor contribution of environmental factors including airway obstruction. The current evidence does not support recommending procedures, such as adenotonsillectomy and maxillary expansion, with the singular aim of negating a hyperdivergent (vertical) dentofacial growth pattern. In light of low-quality evidence, both the World Health Organization guidelines and ethical principles dictate that greater emphasis is placed on avoiding harm and wastage of resources over alternative options. These findings call for quality improvement in undergraduate and postgraduate curricula and continuing professional development for health professionals.

The effect of rapid maxillary expansion in children: a meta-analysis

INTRODUCTION

Craniofacial growth is modified by chronic mouth breathing. Rapid maxillary expansion leads to separation of the mid-palatal suture, improving the occlusion and the upper airway size.

AIM

Systematically evaluate scientific articles on the effects of rapid maxillary expansion on airway dimensions and classify the quality of the evidence of the information.

METHODS

Searches on PUBMED, LILACS, EMBASE, SCOPUS, WEB OF SCIENCE and COCHRANE, as well as in the grey literature were performed. The articles found were selected and evaluated both for the risk of bias (ROBINS-I) and for the quality of evidence (GRADE).

RESULTS

Of the 309 works found, 26 papers were selected for full reading, of which 22 were excluded. Data compilation and analysis were performed in four papers, two being controlled non-randomized clinical trials and two non-randomized and uncontrolled clinical trials. No randomized clinical trial was found.

CONCLUSIONS

The meta-analysis found an increase in the internasal and inter-zygomatic distances and oropharyngeal volume after rapid maxillary expansion, which, together with clinical findings, makes the recommendation favorable to the intervention. The quality of the evidence for each outcome was considered very low.

Short-term and long-term effects of rapid maxillary expansion on the nasal soft and hard tissue

OBJECTIVES

To evaluate nasal soft and hard tissue changes immediately post-rapid maxillary expansion (RME) and to assess the stability of these changes using cone beam computed tomography (CBCT).

MATERIALS AND METHODS

A total of 35 treatment group (TG) patients (18 girls, 17 boys; 9.39 ± 1.4) had a pre-RME CBCT and a post-RME CBCT approximately 66 days after expansion, and 25 patients had a follow-up CBCT 2.84 years later. A total of 28 control group (CG; no RME) patients (16 girls, 12 boys; 8.81 ± 1.6) had an initial CBCT and a CBCT an average of 2.25 years later. Soft and hard tissue nasal landmarks were measured in transverse, sagittal, and coronal planes of space on CBCT scans. Differences within the same group were evaluated by paired t-tests or Wilcoxon signed-rank tests. Long-term comparisons between TG and CG were evaluated by independent-sample t-tests or Wilcoxon rank-sum tests.

RESULTS

Immediately post-RME, there were statistically significant mean increases of 1.6 mm of alar base width, 1.77 mm of pyriform height, and 3.57 mm of pyriform width (P < .05). CG showed the significant increases over 2.25 years (P < .001). Compared with CG, the long-term evaluation of TG demonstrated only pyriform height and pyriform width showed a statistically significant difference (P < .01).

CONCLUSIONS

Although RME produced some significant increase on the nasal soft tissue immediately after expansion, it regressed to the mean of normal growth and development over time. However, long-term evaluation of TG compared with CG showed only pyriform height and pyriform width to be affected by RME.

The role of pediatric maxillary expansion on nasal breathing. A systematic review and metanalysis

OBJECTIVE

A reduced transversal dimension of the maxilla leads to narrower nasal cavities, which may reduce airflow to the lungs. Maxillary expansion widens nasal floor. However, there is huge controversy regarding whether this increase does actually lead to increased airflow. In this systematic review and meta-analysis we aim to resolve this question by evaluating studies that have undertaken rhinomanometric measurements.

REVIEW METHODS

Pubmed (Medline), the Cochrane Library, EMBASE and Trip Database were checked by two authors. Two authors extracted the data. Main outcome was expressed as the difference between resistance before and after treatment and the 95% confidence interval.

RESULTS

30 studies were selected for full text reading. A total of 12 studies (301 patients) met the inclusion criteria. All selected articles found reduced resistance after palatal expansion. The data pooled in the meta-analysis reveals a statistically significant difference of 0.12 Pa s/cm³ mean reduction after palatal expansion (CI 95% 0.06, 0.18) for nine uncontrolled studies. Regarding nasal airflow, the pooled data show a statistically significant difference of 29.9 cm³/s increase after palatal expansion (CI 95% 9.17, 50.64).

CONCLUSION

According to the available evidence, palatal expansion in pediatric patients decreases nasal resistance and increases nasal flow.

Volumetric Changes in the Upper Airways after Rapid and Slow Maxillary Expansion in Growing Patients: A Case-Control Study

The aim is to evaluate changes in the volume of the upper airways before and after slow maxillary expansion (SME) obtained with the flexible properties of a nickel titanium leaf spring and rapid maxillary expansion (RME) with a conventional Hyrax appliance in growing patients. The records of 1200 orthodontic patients undergoing maxillary expansion from 2018 to 2019 were analyzed; among these pre and post treatment CBCT scans of 22 patients (mean age 8.2 ± 0.6 years old) treated by SME were compared with those obtained from 22 patients (mean age 8.1 ± 0.7 years old) treated by RME banded on the second primary molars. The following inclusion criteria were used: Maxillary transverse constriction, good general health, and no previous orthodontic treatment. Volumes of nasal cavity (NCavV), nasopharynx (NsPxV), and right and left maxillary sinuses (MSV) were calculated with ITK-SNAP. Shapiro–Wilk test revealed a normal distribution of data in each group. Paired t-test was used for within-group comparisons and independent t-test for between-group comparisons. Statistically significant increases occurred in NCavV, NsPxV, and MSVs after treatment with both appliances. No statistically significant difference between the appliances occurred in NCavV, NsPxV, and MSVs. Method error was considered negligible (mean intra-operator and inter-operator intraclass correlation coefficient were 0.928 and 0.911, respectively). It appears that both appliances produce similar effects on the different segments of the upper airway tract.

Effects of symmetric and asymmetric rapid maxillary expansion treatments on pharyngeal airway and sinus volume

OBJECTIVE

To evaluate pharyngeal airway and maxillary sinus volumes following symmetric rapid maxillary expansion (RME) and asymmetric rapid maxillary expansion (ARME) treatment using cone-beam computed tomography (CBCT).

MATERIALS AND METHODS

The study consisted of 60 patients presenting to the orthodontics clinic with an indication that they required symmetric or asymmetric rapid maxillary expansion treatment. Individuals were included if they were aged 12-15 years and had symmetric (RME group; 14 girls, 16 boys) or asymmetric (ARME group; 16 girls, 14 boys) maxillary deficiency. Maxillary sinus volume (mm3) and pharyngeal airway volume (upper, lower, and total; mm3) were evaluated using CBCT records. The parameters were compared before treatment (T1) and after 3 months in retention (T2).

RESULTS

All measurements at T2 were increased significantly compared with T1 in the RME group (P < .05). In the ARME group, changes in the lower pharyngeal airway and the nonaffected maxillary sinus volumes (non-affected side of maxillary sinus volumes) were not significant; however, the other measurements increased significantly from T1 to T2 (P < .05). Intergroup comparisons revealed that total pharyngeal airway volume and total maxillary sinus volume changes were significantly greater in the RME group.

CONCLUSIONS

Pharyngeal airway and maxillary sinus volumes increased with both RME and ARME treatment. Both were found to be effective for treating transverse maxillary deficiency.

Effects of Maxillary Skeletal Expansion on Upper Airway Airflow: A Computational Fluid Dynamics Analysis

The effect of maxillary skeletal expansion (MSE) on upper airway in adolescent patients is not clear. The purpose of this study was to determine the upper airway airflow with MSE treatment using computational fluid dynamics analysis. Three-dimensional upper airway finite element models fabricated from cone beam computed tomography images were obtained before and after treatment in an adolescent patient with maxillary constriction. Turbulent analyses were applied. The nasal cavity (NC) was divided into 6 planes along the y-axis and the pharynx was divided into 7 planes in the z-axis. Changes in cross-sectional area, airflow velocity, pressure, and total resistance at maximum expiration and maximum inspiration were determined at each plane after MSE treatment. The greatest increase in area occurred in the oropharynx which was around 40.65%. The average increase in area was 7.42% in the NC and 22.04% in the pharynx. The middle part of pharynx showed the greatest increase of 212.81 mm and 217.99 mm or 36.58% and 40.66%, respectively. During both inspiration and expiration, airflow pressure decreased in both the NC and pharynx, which ranged from -11.34% to -23.68%. In the NC, the average velocity decrease was -0.18 m/s at maximum expiration (ME) and -0.13 m/s at maximum inspiration (MI). In the pharynx, the average velocity decrease was -0.07 m/s for both ME and MI. These results suggest that treatment of maxillary constriction using MSE appliance may show positive effects in improvement of upper airway cross-sectional areas and reduction of upper airway resistance and velocity.

Effects of non-surgical rapid maxillary expansion on nasal structures and breathing: A systematic review

OBJECTIVE

This systematic review aims to determine the effects of non-surgical rapid maxillary expansion (RME) on breathing and upper airway structures.

MATERIALS AND METHODS

An electronic search of the scientific literature from January 2005 to June 2016 was done using Web of Science, Dentistry & Oral Sciences Source and PubMed databases. A combination of search terms "rapid maxillary expansion", "nasal", "airway" and "breathing" were used. Studies that involved surgical or combined RME-surgical treatments and patients with craniofacial anomalies were excluded.

RESULTS

The initial screening yielded a total of 183 articles. After evaluation of the titles, abstracts and accessing the full text, a total of 20 articles fulfilled both inclusion/exclusion criteria and possessed adequate evidence to be incorporated into this review.

CONCLUSIONS

Non-surgical RME was found to improve breathing, increase nasal cavity geometry and decrease nasal airway resistance in children and adolescents.

Three-dimensional evaluation of airway volume changes in two expansion activation protocols

The purpose of this study was to evaluate the airway volume changes associated with rapid maxillary expansion (RME) protocols using different activation rates. A sample of forty RME treated cases was classified into two groups according to the rate of RME activation (Group A: 0.8mm per day and Group B: 0.5mm per day). Three-dimensional images were obtained for each case before and three months after expansion. Dolphin imaging software was used to identify landmarks and calculate airway volumes. Intraclass correlation coefficient was used to confirm reliability and Wilcoxon signed rank tests were used for comparison between the initial and final measurements within each group and between groups. Significant increase in the nasal cavity volume for both groups was observed (P<0.0001 and P=0.001 for groups A and B respectively). The increase in nasopharynx volume was significant in the group with a more rapid activation rate (P=0.0006). Significant differences between the two groups in post-treatment changes were detected in the nasal cavity volume (P<0.0001), nasopharynx volume (P=0.0035), and soft palate area (P=0.0081). A more rapid activation rate results in a higher volume increase for the nasal cavity and nasopharynx than a slower activation rate.

Airway compartments volume and oxygen saturation changes after rapid maxillary expansion: a longitudinal correlation study

OBJECTIVE

To evaluate changes in airway volumes and respiratory performance in patients undergoing rapid maxillary expansion and determine whether any correlations exist between the morphological and respiratory functional modifications induced by rapid maxillary expansion and pretreatment airway stenosis.

MATERIALS AND METHODS

Fifteen patients (11 females and 4 males; mean age, 7.5 ± 0.3 years) were enrolled in the study. Each patient underwent cone beam computed tomography and polysomnography examination before rapid maxillary expansion and after the removal of the maxillary expander 12 months later. The airway regions were segmented and the volumes were computed.

RESULTS

The upper, middle, and lower airway volumes were significantly increased 2305 mm(3), 1144 mm(3), and 1915 mm(3), respectively. Similarly, oxygen saturation was increased (+5.3%) and the apnea/hypopnea index was improved (-4.2 events). All the observed modifications were statistically significant (P < .05). Baseline middle and lower airway volume showed a significant negative correlation with the oxygen saturation modification.

CONCLUSIONS

The results of this study showed that when rapid maxillary expansion is performed in subjects having posterior crossbite, oxygen saturation is improved. The improvement is greater in subjects having more reduced middle and lower airway volumes.

Correlation between acoustic rhinometry, computed rhinomanometry and cone-beam computed tomography in mouth breathers with transverse maxillary deficiency

INTRODUCTION

To provide clinical information and diagnosis in mouth breathers with transverse maxillary deficiency with posterior crossbite, numerous exams can be performed; however, the correlation among these exams remains unclear.

OBJECTIVE

To evaluate the correlation between acoustic rhinometry, computed rhinomanometry, and cone-beam computed tomography in mouth breathers with transverse maxillary deficiency.

METHODS

A cross-sectional study was conducted in 30 mouth breathers with transverse maxillary deficiency (7-13 y.o.) patients with posterior crossbite. The examinations assessed: (i) acoustic rhinometry: nasal volumes (0-5cm and 2-5cm) and minimum cross-sectional areas 1 and 2 of nasal cavity; (ii) computed rhinomanometry: flow and average inspiratory and expiratory resistance; (iii) cone-beam computed tomography: coronal section on the head of inferior turbinate (Widths 1 and 2), middle turbinate (Widths 3 and 4) and maxilla levels (Width 5). Acoustic rhinometry and computed rhinomanometry were evaluated before and after administration of vasoconstrictor. Results were compared by Spearman's correlation and Mann-Whitney tests (α=0.05).

RESULTS

Positive correlations were observed between: (i) flow evaluated before administration of vasoconstrictor and Width 4 (Rho=0.380) and Width 5 (Rho=0.371); (ii) Width 2 and minimum cross-sectional areas 1 evaluated before administration of vasoconstrictor (Rho=0.380); (iii) flow evaluated before administration of vasoconstrictor and nasal volumes of 0-5cm (Rho=0.421), nasal volumes of 2-5cm (Rho=0.393) and minimum cross-sectional areas 1 (Rho=0.375); (iv) Width 4 and nasal volumes of 0-5cm evaluated before administration of vasoconstrictor (Rho=0.376), nasal volumes of 2-5cm evaluated before administration of vasoconstrictor (Rho=0.376), minimum cross-sectional areas 1 evaluated before administration of vasoconstrictor (Rho=0.410) and minimum cross-sectional areas 1 after administration of vasoconstrictor (Rho=0.426); (v) Width 5 and Width 1 (Rho=0.542), Width 2 (Rho=0.411), and Width 4 (Rho=0.429). Negative correlations were observed between: (i) Width 4 and average inspiratory resistance (Rho=-0.385); (ii) average inspiratory resistance evaluated before administration of vasoconstrictor and nasal volumes of 0-5cm (Rho=-0.382), and average expiratory resistance evaluated before administration of vasoconstrictor and minimum cross-sectional areas 1 (Rho=-0.362).

CONCLUSION

There were correlations between acoustic rhinometry, computed rhinomanometry, and cone-beam computed tomography in mouth breathers with transverse maxillary deficiency.

Impact of genioplasty during puberty on the upper airways

AIM

Mouth breathing is a functional disorder that affects craniofacial and dento-alveolar growth and also upper airway (UA) anatomy. This is apparent mainly in dimensional abnormalities of the UA caused by hypertrophy of Waldeyer's ring and excessive vertical development of the lower part, giving rise to labial incompetence that perpetuates the functional disorder. The main aim of this study was to evaluate the development of the oropharyngeal structures in young hyperdivergent patients who had undergone functional genioplasty in the context of orthodontic treatment.

METHODS

This is a comparative retrospective study performed on 47 adolescents who were hyperdivergent, non-obese and exclusive or diurnal mouth breathers, treated at the Centre de soins, d'enseignement et de recherche dentaires (CSERD) in Montpellier, France. All were candidates for early genioplasty for vertical reduction, and were undergoing or at the end of treatment: 23 had been treated surgically (functional genioplasty), and 24 controls had received orthodontic treatment alone. Inter-group comparison of the changes in cephalometric measurements of the oro- and nasopharyngeal zones and maxillomandibular measurements was performed using covariance analysis (ANCOVA) to adjust for confounding factors.

RESULTS

Concerning the skeletal structures: in the sagittal dimension, genioplasty led to significantly greater projection of the symphysis in the surgical group than in the control group (P<0.001). However, the sagittal position of the hyoid bone was unchanged. Similarly, in the vertical dimension, the reduction in divergence of the bony base was significantly greater in the surgical group (P<0.001), but with no change in the vertical position of the hyoid bone. Concerning the upper airways: at the level of the nasopharynx, there was a significantly greater increase in the velopharyngeal space in the surgical group (P<0.033). The same observation can be made on the level of the oropharynx, where there was a significant increase in the linguopharyngeal space in the surgical group (P<0.05), which was not the case in the control group. The change in the depth of the pharynx did not differ significantly between the two groups.

CONCLUSION

Early genioplasty performed on adolescents during the growth phase helps to recalibrate the UA by encouraging spontaneous lip closure.

Physiological correction of lingual dysfunction with the "Tongue Right Positioner": Beneficial effects on the upper airways

Several studies have demonstrated the beneficial role of functional tongue therapy in stabilizing treatments for dental malocclusion and treating sleep-disordered breathing (SDB). The aim of this retrospective study was to evaluate the effect on the upper airways of the Tongue Right Positioner device (TRP) used for the correction of atypical swallowing. We analyzed lateral headfilms of 94 orthodontic patients aged between 11 and 17, before the start of treatment and after establishment of mature swallowing, treated with the TRP (TRP group) or by reeducation exercises (control group). In the TRP group, the establishment of mature swallowing occurs twice as fast as in the control group. This led to thinning of the floor of the mouth (-8.38%, P<0.001) linked to anteroposterior enlargement of the pharynx (+10.48%, P<0.01), both probably due to an increase in genioglossal and styloglossal muscle tone and correction of cranio-cervical posture (+2.52%, P<0.01). These results are not dependent on the type of orthodontic treatment. They suggest that the TRP could be used in the treatment of SDB.

Dental treatment for paediatric obstructive sleep apnea

Paediatric obstructive sleep apnea (OSA) is common and its prevalence is expected to increase due to the rise in childhood obesity. Recent research has shown that many children, both syndromic and non-syndromic, who exhibit mouth breathing as a result of upper airway obstruction, may also exhibit dentofacial anomalies. Although adenotonsillectomy and continuous positive airway pressure have been classically proposed as the primary treatment modalities for paediatric OSA, there are significant limitations to both therapies. Therefore newer treatment modalities are needed. Current research has focused on emerging dental treatment options for paediatric OSA, such as rapid maxillary expansion, oral appliances and distraction osteogenesis. However, there are few randomized trials assessing the effectiveness of these novel dental therapies for paediatric OSA, and hence further research is required to advance the field.

Computational fluid dynamics analysis of the upper airway after rapid maxillary expansion: a case report

Background

Assessment of the upper airway volume, morphology, and mechanics is of great importance for the orthodontic patient. We hypothesize that upper airway dimensions have significant effects on the dynamics of the airway flow and that both the dimensions and mechanics of the upper airway are greatly affected by orthodontic and orthopedic procedures such as rapid maxillary expansion (RME). The aim of the current study was to assess the effect of RME on the airway flow rate and pattern by comparing the fluid dynamics results of pre- and post-treatment finite element models.

Methods

Customized pre- and post-treatment computational fluid dynamics models of the patient’s upper airway were built for comparison based on three-dimensional computed tomogram. The inhalation process was simulated using a constant volume flow rate for both models, and the wall was set to be rigid and stationary. Laminar and turbulent analyses were applied.

Results

Comparisons between before and after RME airway volume measurements showed that increases were only detected in nasal cavity volume, nasopharynx volume, and the most constricted area of the airway. Pressure, velocity, and turbulent kinetic energy decreased after dental expansion for laminar and turbulent flow. Turbulent flow shows relatively larger velocity and pressure than laminar flow.

Conclusions

RME showed positive effects that may help understand the key reasons behind relieving the symptom of breathing disorders in this patient. Turbulence occurs at both nasal and oropharynx areas, and it showed relatively larger pressure and velocity compared to laminar flow.

Rapid maxillary expansion in growing patients: correspondence between 3-dimensional airway changes and polysomnography

OBJECTIVES

The aim of the present prospective study was to investigate the effects of rapid maxillary expansion on the airway correlating airway volumes computed on cone beam computed tomography and polysomnography evaluation of oxygen saturation and apnea/hypopnea index.

METHODS

The study group comprised 14 caucasian patients (mean age 7.1 ± 0.6 years) undergone to rapid maxillary expansion with Haas type expander banded on second deciduous upper molars. Cone beam computed tomography scans and polysomnography exams were collected before placing the appliance (T0) and after 12 months (T1). Landmarks localization and airway semiautomatic segmentation on cone beam computed tomography scans allowed airway volume computing and measurements.

RESULTS

Increases of total airway volume, oxygen saturation and apnea/hypopnea index were statistically significant. No correlation was found among total airway volume, oxygen saturation and apnea/hypopnea index changes between the examined timepoints.

CONCLUSIONS

Computing airway volume on cone beam computed tomography allow to measure the amount of air that flows through nasal cavity, nasopharynx and oropharynx while oxygen saturation and apnea/hypopnea index could give information about functional parameters. In the present study all three variables investigated showed statistically significant differences between T0 and T1 but no correlation was found between increases of the different variables tested.

Three-dimensional computed tomography analysis of airway volume changes after rapid maxillary expansion

INTRODUCTION

In this retrospective study with 3-dimensional computed tomography, we evaluated airway volume, soft-palate area, and soft-tissue thickness changes before and after rapid maxillary expansion in adolescents. Another purpose was to determine whether rapid maxillary expansion caused changes in the palatal and mandibular planes and facial height.

METHODS

The sample comprised 20 patients who were treated with rapid maxillary expansion. Spiral tomographs were taken before and 3 months after treatment. Reliability studies were performed, and then volumetric, soft-palate area, soft-tissue thickness, and cephalometric parameters were compared on the tomographs. Intraclass correlations were performed on the reliability measurements. Before and after rapid maxillary expansion measurements were compared by using Wilcoxon signed rank tests. Spearman correlation coefficients were used to evaluate the associations among the airway volume, soft-palate area, soft-tissue thickness, and cephalometric measurements. Significance was accepted at P ≤0.05 for all tests.

RESULTS

Intraclass correlation coefficients were ≥0.90 for all reliability measures. Significant increases from before to after rapid maxillary expansion were found in nasal cavity and nasopharynx volumes, and for the measurements of MP-SN, S-PNS, N-ANS, ANS-Me, and N-Me. Significant positive correlations existed between changes in PP-SN and N-ANS, and ANS-Me and N-Me.

CONCLUSIONS

Rapid maxillary expansion causes significant increases in nasal cavity volume, nasopharynx volume, anterior and posterior facial heights, and palatal and mandibular planes.

Does rapid maxillary expansion have long-term effects on airway dimensions and breathing?

INTRODUCTION

In this systematic review, we identified and qualified the evidence of long-term reports on the effects of rapid maxillary expansion (RME) on airway dimensions and functions.

METHODS

Electronic databases (Ovid, Scirus, Scopus, Virtual Health Library, and Cochrane Library) were searched from 1900 to September 2010. Clinical trials that assessed airway changes at least 6 months after RME in growing children with rhinomanometry, acoustic rhinometry, computed tomography, or posteroanterior and lateral radiographs were selected. Studies that used surgically assisted RME and evaluated other simultaneous treatments during expansion, systemically compromised subjects, or cleft patients were excluded. A methodologic-quality scoring process was used to identify which studies would be most valuable.

RESULTS

Fifteen articles fulfilled the inclusion criteria, and full texts were assessed. Three were excluded, and 12 were assessed for eligibility. Four articles with low methodologic quality were not considered. The remaining 8 were qualified as moderate. The posteroanterior radiographs showed that nasal cavity width increases; in the lateral radiographs, decreased craniocervical angulation was associated with increases of posterior nasal space. Cone-beam computed tomography did not show significant increases of nasal cavity volume. Rhinomanometry showed reduction of nasal airway resistance and increase of total nasal flow, and acoustic rhinometry detected increases of minimal cross-sectional area and nasal cavity volume.

CONCLUSIONS

There is moderate evidence that changes after RME in growing children improve the conditions for nasal breathing and the results can be expected to be stable for at least 11 months after therapy.