Tongue posture improvement and pharyngeal airway enlargement as secondary effects of rapid maxillary expansion: a cone-beam computed tomography study

Skeletal and dental effects of function-generating bite appliance compared to rapid palatal expander and untreated controls

INTRODUCTION

Maxillary expansion is a fundamental interceptive orthodontic treatment, which can be achieved through either a rapid expansion protocol or functional devices. However, no data exist about the efficacy of functional devices in achieving skeletal expansion. Therefore, the aim of this study was to compare the effects of the rapid palatal expander (RPE) and the function-generating bite type M (FGB-M) on the transversal dimension of the maxilla, and on the maxillary and mandibular dental arch width.

METHODS

One hundred eighty-one skeletal Class I patients, aged between 6 and 12 years and with a cervical vertebral maturation stage II or III, with maxillary transversal deficiency were retrospectively enrolled; among these 55 were treated with FGB-M, 73 were treated with RPE and 51 were untreated subjects retrieved from historical databases. The pre-treatment (T0) and post-treatment (T1) frontal cephalograms were retrieved, and the maxillary and mandibular widths, and the distance between upper and lower first molars were measured. T1-T0 interval was of 17.3 months (RPE), 24.6 months (FGB-M) and 18.2 months (controls).

RESULTS

The statistical analysis showed that there were no statistically significant differences between the RPE and FGB-M groups regarding skeletal and dental expansion, while the untreated control group differed significantly from the other two groups.

CONCLUSION

The comparison between patients treated with RPE and FGB-M showed that there were no statistically significant differences between the RPE and FGB-M groups regarding the amount of skeletal expansion and dental arch width, suggesting that both appliances can be used to achieve similar results.

Can rapid maxillary expansion affect speech sound production in growing patients? A systematic review

Rapid maxillary expansion (RME) may change speech sound parameters due to the enlargement of oral and nasal cavities. This study aimed to systematically review the current evidence on speech changes as a side effect of RME. An electronic search was conducted in nine databases, and two of them accessed the 'grey literature'. The eligibility criteria included clinical studies assessing orthodontic patients with maxillary transverse deficiency and the relationship with speech alterations without restricting publication year or language. Only interventional studies were included. The JBI Critical Appraisal Tool assessed the risk of bias. The initial search provided 4853 studies. Seven articles (n = 200 patients) met the inclusion criteria and were analysed. The primary source of bias was the absence of a control group in four studies. RME altered speech production by changing vowel fundamental frequency and fricative phoneme formant frequency. Shimmer and jitter rates changed in one and two studies, respectively. Two studies presented deterioration during orthodontic treatment, but speech improved after appliance removal. Despite the limited evidence, RME affects speech during and after treatment.

What changes in maxillary morphology from distraction osteogenesis maxillary expansion (DOME) correlate with subjective and objective OSA measures?

OBJECTIVES

To correlate skeletal and airway measures on imaging with polysomnographic and self-reported measures after distraction osteogenesis maxillary expansion (DOME), in the effort to identify clinically relevant sites of expansion to guide treatment for adult patients with obstructive sleep apnea (OSA).

MATERIALS AND METHODS

This is a retrospective study reviewing subjects who underwent DOME and had the complete set of the following data: peri-treatment cone-beam computed tomography (CBCT) scans, polysomnography (PSG), Epworth Sleepiness Scale (ESS), and nasal obstruction symptom (NOSE) scores.

RESULTS

Of 132 subjects who underwent DOME, 35 met inclusion criteria (71% men, mean age 27.7 ± 6.5 years, mean BMI 26.0 ± 6.4 kg/m2) and were enrolled in the study. There was a significant reduction in the NOSE score from 11.4 ± 5.5 to 3.6 ± 3.1, in the ESS score from 12.0 ± 4.6 to 7.1 ± 4.7, and in the apnea-hypopnea index (AHI) from 17.1 ± 15.8 to 7.01 ± 6.2 (p < 0.0001), after DOME. Nasal floor width at the nasopalatine canal level showed a statistically significant correlation with AHI reduction (p < .0001).

CONCLUSIONS

DOME is significantly associated with reduction of nasal obstruction, sleepiness, and severity of OSA. The findings suggest that expansion at the anterior third of the bony nasal passage, specifically where the nasopalatine canal is located predicts its clinical efficacy. This site may be a useful target anatomically via imaging.

Volumetric changes in the upper airway on CBCT after dentofacial orthopedic interventions - a systematic review

OBJECTIVE

To provide a critical overview of the effect of various orthodontic and/or dentofacial orthopedic interventions on three-dimensional volumetric changes in the upper airway.

MATERIALS AND METHODS

Four databases were searched for clinical studies concerning 3D volumetric assessments based on CBCT before and after orthodontics interventions. The quality of the studies was assessed using the quality assessment tool of the National Heart, Lung and Blood Institute. After the use of inclusion and exclusion criteria, the pre-and post-treatment volumes were used to visualize the effect of various orthodontics interventions.

RESULTS

A total of 48 studies were included in this review and none of which were RCTs. The quality of all included studies was assessed as medium. Overall, there is a tendency for an increase in airway volumes after various orthodontic interventions, except for studies concerning extraction therapy with fixed appliances in adults, in which both increases and decreases in airway volumes have been reported.

CONCLUSION

Orthodontic treatment by growth modification and non-extraction therapy with fixed appliances, regardless of the malocclusion, generally showed positive effects on the airway volume. Orthodontic treatment in combination with extractions does not provide an unambiguous insight. A consensus on the methodology of the airway measurement and nomenclature is urgently needed in order to gain insight into the effect of different interventions on three-dimensional airway changes.

CLINICAL RELEVANCE

Various orthodontic treatments do not negatively influence the upper airway volume. However, extraction therapy in adults should be chosen with caution, especially in subjects belonging to a group susceptible to airway obstruction.

Three-dimensional evaluation of the association between tongue position and upper airway morphology in adults: A cross-sectional study

Objective

This study aimed to evaluate the association between low tongue position (LTP) and the volume and dimensions of the nasopharyngeal, retropalatal, retroglossal, and hypopharyngeal segments of the upper airway.

Methods

A total of 194 subjects, including 91 males and 103 females were divided into a resting tongue position (RTP) group and a LTP group according to their tongue position. Subjects in the LTP group were divided into four subgroups (Q1, Q2, Q3, and Q4) according to the intraoral space volume. The 3D slicer software was used to measure the volume and minimum and average cross-sectional areas of each group. Airway differences between the RTP and LTP groups were analyzed to explore the association between tongue position and the upper airway.

Results

No significant differences were found in the airway dimensions between the RTP and LTP groups. For both retropalatal and retroglossal segments, the volume and average cross-sectional area were significantly greater in the patients with extremely low tongue position. Regression analysis showed that the retroglossal airway dimensions were positively correlated with the intraoral space volume and negatively correlated with A point-nasion-B point and palatal plane to mandibular plane. Males generally had larger retroglossal and hypopharyngeal airways than females.

Conclusions

Tongue position did not significantly influence upper airway volume or dimensions, except in the extremely LTP subgroup.

Evaluation of swallowing in transverse maxillary deficiency patients before and after rapid maxillary expansion

OBJECTIVES

To evaluate swallowing function in relation to oropharyngeal dysphagia (OD) in adolescents who had transverse maxillary deficiency with posterior crossbite and high-arched palate, before, and after rapid maxillary expansion (RME).

MATERIALS AND METHODS

Twenty patients (mean age: 13.0 ± 3.1) with bilateral posterior crossbite and high-arched palate (RME group: RMEG) and 20 volunteers (mean age: 13.4 ± 2.6) with Class I crowding without posterior crossbite or high-arched palate (control group: CG) were recruited. OD signs and symptoms were evaluated using the Eating Assessment Tool-10 (EAT-10) questionnaire, patient complaints, and physical examination of swallowing function before (T1) and 7 months after (T2) RME. Additionally, fiberoptic endoscopic evaluation of swallowing (FEES) with water, yogurt, and cracker was performed. In CG, evaluation of swallowing was performed only once, corresponding to T1 of RMEG.

RESULTS

Prevalence of OD signs and symptoms based on patient complaints and physical examination of swallowing was low (5%-15%), and nonsignificant differences were observed between CG and RMEG at T1 for these parameters as well as for EAT-10 scores. Total post-swallow pharyngeal residue with yogurt was significantly different between CG and RMEG at T1, with a prevalence of 60% in RMEG (P < .05). There was no significant difference regarding residue with yogurt between T1 and T2 in RMEG (P > .05).

CONCLUSION

Patients with a maxillary transverse deficiency were affected by pharyngeal residue as indicated by FEES, but it did not appear to improve in short-term follow-up in patients treated with RME.

Transverse Maxillary Deficiency Predicts Increased Upper Airway Collapsibility during Drug-Induced Sleep Endoscopy

OBJECTIVE

To examine the relationship between craniofacial skeletal anatomy and objective measures of pharyngeal collapse obtained during drug-induced sleep endoscopy. We hypothesized that transverse maxillary deficiency and an increased pharyngeal length will be associated with higher levels of pharyngeal collapsibility.

STUDY DESIGN

Cross-sectional analysis in a prospective cohort.

SETTING

University Hospital.

METHODS

A cross-sectional analysis was conducted in a cohort of consecutive patients from the positive airway pressure (PAP) alternatives clinic who underwent computed tomography (CT) analysis and drug-induced sleep endoscopy for characterization of upper airway collapsibility. PAP titration was used to determine pharyngeal critical pressure (PCRIT ) and pharyngeal opening pressure (PhOP). CT metrics included: Transverse maxillary dimensions (interpremolar and intermolar distances) and pharyngeal length (posterior nasal spine to hyoid distance).

RESULTS

The cohort (n = 103) of severe obstructive sleep apnea (Apnea and Hipopnea Index 32.1 ± 21.3 events/h) was predominantly male (71.8%), Caucasian (81.6%), middle-aged (54.4 ± 14.3 years), and obese (body mass index [BMI] = 30.0 ± 4.9 kg/m2 ). Reduced transverse maxillary dimensions were associated with higher PCRIT (intermolar distance: β [95% confidence interval, CI] = -.25 [-0.14, -0.36] cmH2 O/mm; p = .03) and PhOP (Interpremolar distance: β = -.25 [-0.14, -0.36] cmH2 O/mm; p = .02). Longer pharyngeal length was also associated with higher PCRIT (β = .11 [0.08, 0.14] cmH2 O/mm, p = .04) and PhOP (β [95% CI] = .06 [0.03, 0.09] cmH2 O/mm, p = .04). These associations persisted after adjustments for sex, age, height, and BMI.

CONCLUSION

Our results further the concept that skeletal restriction in the transverse dimension and hyoid descent are associated with elevations in pharyngeal collapsibility during sleep, suggesting a role of transverse deficiency in the pathogenesis of airway obstruction.

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.

Age-dependent effects on palate volume and morphology during orthodontic RME treatment

OBJECTIVES

Rapid maxillary expansion (RME) shows different age-dependent effects. It has been shown that RME leads to a parallel expansion prior to the age of 10, while later and especially from the age of 12, a V-shaped expansion happens (transverse, anterior > posterior; horizontal, inferior > superior). However, it is not clear to what extent these effects influence palatal volume and morphology and eventually maxillary functional space. The aim of the present study was to examine possible age-related effects of treatment with a dental anchored RME appliance upon volume and width/height ratio of the anterior and posterior palate.

MATERIALS AND METHODS

Sixty children and adolescents with documented treatment histories after RME were divided into three equal groups according to age at treatment begin (PG 1, < 10 years, n=20; PG 2, 10 ≤ 12 years, n=20; PG 3, > 12 years, n=20). Maxillary dental casts before and after therapy were digitised. Changes in palatal volume were determined using 3D analyses.

RESULTS

In all patients, the palatal volume increases significantly after RME. Older patients experienced smaller increases in total and posterior volume in absolute and percentage terms. The anterior palate volume increases are almost equal in all patients. Since palatal width increases more markedly than palatal height, the width/height ratio always increases. Except for the posterior region in PG 3, its increase is significant in all groups, both anteriorly and posteriorly. After successful RME, the palatal morphology appears normal anteriorly in PG 1, PG 2 and PG 3 and rather steep posteriorly in PG 3.

CONCLUSIONS

RME treatment with identical force application causes different, age-dependent effects upon palate volume and morphology. Width changes have a greater influence on palate volume than height changes.

CLINICAL RELEVANCE

It is preferable to use an RME prior to the age of 10 if homogeneous changes of the anterior and posterior palate regarding maxillary symmetry and functional space are desired.

Airway dimensional changes following bone anchored maxillary protraction: a systematic review

BACKGROUND

The introduction of skeletal anchorage utilized for maxillary protraction with a face mask or class III elastics has been developed for the management of class III malocclusions with minimal dental effect. The objective of the present review was to evaluate the current evidence regarding airway dimensional changes following bone-anchored maxillary protraction. A search was conducted by two authors (S.A & B.A) in the following databases: MEDLINE via PubMed, Cochrane Library, Web of Science, Scopus, Google Scholar and Open Grey; besides a hand search in references of selected articles and developing a search alert in electronic databases. Selection criteria comprised randomized as well as prospective clinical trials evaluating airway dimensional changes following bone-anchored maxillary protraction. Relevant data were extracted after studies retrieval and selection. The risk of bias was thereafter evaluated using the revised RoB 2 tool for randomized clinical trials and the ROBINS-I tool was used for non-randomized clinical trials. The quality of studies was assessed using the modified Jadad score. After examining (eligibility) full-text articles, four clinical trials were ultimately included. These studies evaluated the airway dimensional changes, following bone-anchored maxillary protraction in comparison to different control study groups. Based on the available evidence, all the bone-anchored maxillary protraction devices used in the eligible studies in the present systematic review resulted in an improvement in the airway dimensions. However, due to the few numbers of studies available and the guarded evidence due to the low quality of evidence of three out of four included articles, there is no strong evidence to support a significant increase in the airway dimensions following bone-anchored maxillary protraction. Therefore, there is a need for more randomized controlled clinical trials with similar bone-anchored protraction devices and similar assessment methods for more valid comparisons, excluding any confounding factors, on airway dimensional changes.

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.

The role of rapid maxillary expansion in pediatric obstructive sleep apnea: Efficacy, mechanism and multidisciplinary collaboration

This review aims to provide current knowledge about the efficacy, mechanism, and multidisciplinary collaboration of rapid maxillary expansion (RME) treatment in pediatric obstructive sleep apnea (OSA). OSA is a chronic disease characterized by progressively increasing upper airway resistance, with various symptoms and signs. Increasingly the evidence indicates that RME is a non-invasive and effective therapy option for children with OSA. Besides, the therapeutic mechanism of RME includes increasing upper airway volume, reducing nasal resistance, and changing tongue posture. Recent clinical researches and case reports also show that a multidisciplinary approach improves sleep-disordered breathing in children. Applied with adenotonsillectomy, mandibular advancement, continuous positive airway pressure, and comprehensive orthodontic treatment, RME can be more effective in recurrent or residual OSA.

Effects of Rapid Palatal Expansion on the Upper Airway Space in Children with Obstructive Sleep Apnea (OSA): A Case-Control Study

Obstructive Sleep Apnea (OSA) in children needs a multidisciplinary approach. Even if the first-line treatment of pediatric OSA is adenotonsillectomy, nowadays rapid palatal expansion (RPE) is considered a valid additional treatment. The aim of this study is to evaluate cephalometric changes in upper airways dimensions after rapid palatal expansion (RPE) in children suffering from Obstructive Sleep Apnea (OSA). A total of 37 children (range age 4-10 years) with diagnosis of OSA referred to Dentistry Unit of Bambino Gesù Children's Research Hospital IRCCS (Rome, Italy) were included in this pre-post study and underwent lateral radiographs at the start (T0) and at the end (T1) of a RPE treatment. Inclusion criteria were: diagnosis of OSA confirmed by cardiorespiratory polygraphy (AHI > 1) or pulse oximetry (McGill = >2), skeletal maxillary contraction evaluated by presence of posterior crossbite. A control group of 39 untreated patients (range age 4-11 years), in good general health, was set up. A paired T-test was used to investigate the statistical differences between T0 and T1 values in both groups. The results showed a statistically significant increase of nasopharyngeal width in the treated group after RPE treatment. Moreover, the angle that identifies mandibular divergence compared to palatal plane (PP-MP°) was significantly reduced. In the control group, no statistically significant differences were observed. The present study showed that RPE treatment determines a significant sagittal space increase in the upper airways space and a counterclockwise mandibular growth in children with OSA compared to a control group. These results suggest that a widening of the nasal cavities induced by RPE may support a return to physiological nasal breathing and promote a counterclockwise mandibular growth in children. This evidence confirms the crucial role of the orthodontist in the management of OSA in pediatric patients.

Does surgically assisted maxillary expansion improve obstructive sleep apnoea in adults? A systematic review and meta-analysis

Introduction The aim of this systematic review and meta-analysis was to evaluate the effects of maxillary expansion on adults with obstructive sleep apnoea (OSA).Methods Electronic searches up to July 2021 in eight electronic databases were conducted. Study selection, data extraction, risk of bias evaluation using ROBINS-I, quality of evidence assessment using GRADE and meta-analyses were performed.Results The electronic searches yielded 1,007 studies. Following the application of the eligibility criteria, 15 articles were fully read and five studies were included. The studies evaluated the effects of surgically assisted rapid maxillary expansion in adults with OSA. The meta-analysis demonstrated an improvement in Apnoea-Hypopnea Index (AHI) (MD = -9.91, CI = -14.57 to -5.25), Oxygen Desaturation Index (ODI) (MD = -7.95, CI = -12.23 to -3.67), and Epworth Sleepiness Scale (ESS) (MD = -4.40, CI = -6.39 to -2.40). ROBINS-I indicated serious, no information and critical risk of bias for the included studies. The quality of the evidence was very low.Conclusion The findings herein suggest that maxillary expansion could improve OSA in adults in the short term.

Volumetric measurement of the tongue and oral cavity with cone-beam computed tomography: A systematic review

Purpose

The goal of this systematic review was to compare the use of cone-beam computed tomography (CBCT) with that of computed tomography (CT) for volumetric evaluations of the tongue and oral cavity.

Materials and Methods

A search for articles was conducted in accordance with the Preferred Reporting Items for Systematic Review and Meta-analyses guidelines. The PubMed, Scopus, ScienceDirect, and SAGE Journals databases were searched for articles published between 2011 and 2021. Articles were screened and assessed for eligibility. Screening involved checking for duplication, reading the title and abstract, and reading the full text.

Results

The initial search retrieved 25,780 articles. Application of the eligibility criteria yielded 16 articles for qualitative analysis. Multiple uses of CBCT were identified. In several studies, researchers assessed the volumetric correlation between tongue and oral cavity volumes, as well as other parameters. Post-treatment volumetric evaluations of the oral cavity were also reported, and the reliability of CBCT was assessed. The use of CT resembled that of CBCT.

Conclusion

CBCT has been used in the evaluation of tongue and oral cavity volumes to assess correlations between those volumes and with the upper airway. It has also been used for volumetric evaluation after surgical and non-surgical procedures and to assess the relationships between tongue volume, tooth position, occlusion, and body mass index. Participants with obstructive sleep apnea and malocclusion have been evaluated, and the reliability of CBCT has been assessed. In the included studies, CT was utilized for similar purposes as CBCT, but its reliability was not assessed.

Changes in hyoid bone and tongue position in Class I subjects after orthodontic treatment with rapid palatal expander

OBJECTIVE

To evaluate the effects of the rapid palatal expander (RPE) on the hyoid bone and tongue position in skeletal Class I patients, compared to control groups.

METHODS

Eighty-four Class I subjects, aged 6-14, were selected. Among these, 28 patients were treated with RPE, 28 with function-generating bite (FGB) appliance, and 28 were untreated. Lateral cephalograms taken before (T0) and after (T1) treatment were retrieved. Changes in the hyoid bone and tongue position were evaluated, and the area above the tongue was measured.

RESULTS

No significant difference in the hyoid and tongue posture was observed across the groups. However, there were significant differences for HC3 (distance from H-point to the third cervical vertebrae), H2H (distance from H-point to SN plane), and TT-Eb (tongue length) between T0 and T1 in all groups.

CONCLUSION

The results suggest that hyoid bone and tongue position changes were related to growth rather than treatment.

Three-dimensional volumetric changes in the airway of growing unilateral complete cleft lip and palate patients after bone-anchored maxillary protraction

INTRODUCTION

This prospective controlled study evaluates volumetric, length, and average cross-sectional area (aCSA) airway changes in growing patients with unilateral complete cleft lip and palate after 1.5 years of bone-anchored maxillary protraction therapy.

METHODS

Thirty-five growing unilateral complete cleft lip and palate patients with maxillary deficiency were included (aged 11.3 ± 0.5 years). Cone-beam computed tomography scans were obtained before bone-anchored maxillary protraction (BAMP) therapy and after 1.5 years. A growing group without cleft (n = 18) patients served as a control group at 1.5 years posttreatment (aged 13.1 ± 1.2 years). Volumetric, length, and aCSA changes of the total airway, nasopharynx (NP), middle pharynx, and inferior pharynx airway were evaluated.

RESULTS

After 1.5 years of BAMP therapy, a significant increase was observed in the total airway volume and the NP (P <0.01). The middle and inferior pharynx showed an insignificant tendency of volumetric increase. Compared with the control group, a significantly larger airway volume could be observed in the total airway and NP (P <0.05). The aCSA of the NP increased significantly compared with pretreatment.

CONCLUSIONS

The total airway and NP volumes significantly increased in growing subjects with cleft lip and palate after 1.5 years of BAMP therapy to a level comparable to a control group without cleft. Volumetric increase in the NP in the BAMP group is mainly attributed to the increase in its cross-sectional area. BAMP can therefore be recommended as an effective therapy for patients with cleft lip and palate with positive effects on airway development.

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.

Craniofacial treatment protocol for a pediatric patient with obstructive sleep apnea and skeletal Class III malocclusion: A 13-year follow-up

This report aimed to describe the long-term effects of craniofacial growth modification treatment on sleep and breathing functions in a 7-year-old girl diagnosed with skeletal Class III malocclusion and sleep-disordered breathing. Based on the flowchart of orthodontic intervention protocol that we proposed for phenotype-based patient selection and skeletal target-based treatment selection for pediatric patients with sleep-disordered breathing, a 2-phase treatment targeting the nasomaxillary complex was performed. Posttreatment 3-dimensional changes in the skeletal structure and upper airway were evaluated in association with functional assessment using a validated pediatric sleep questionnaire and home sleep test. Esthetic improvement and obstructive sleep apnea cure were achieved without skeletal surgery. The 2-year retention records showed stable occlusion and improved facial profile with normal breathing and sleep.

Evaluation and Management of Snoring

Snoring can be harmless (primary) or a symptom of sleep-disordered breathing (secondary) and should alert the physician to evaluate the patient for risks thereof. Phenotypes of snoring and sleep-disordered breathing (SDB) are anatomic and nonanatomic and identifying these phenotypes and their interrelationships are critical to effective therapy. Mouth breathing alerts the physician to nasal airway obstruction, signals orofacial growth changes in children, and heralds the progression of SDB. Systematic evaluation to establish phenotypes includes assessing sleep habits, comorbidities, upper airway examination, polysomnography, and drug-induced sleep endoscopy. Strategies for treatment should be personalized and precise to the phenotype(s) to achieve the most benefit.

Upper airway changes in Class III patients using miniscrew-anchored maxillary protraction with hybrid and hyrax expanders: a randomized controlled trial

OBJECTIVES

The aim of this study was to compare the upper airway space changes after miniscrew-anchored maxillary protraction with hybrid (HH) and conventional hyrax (CH) expanders.

MATERIAL AND METHODS

The sample comprised Class III malocclusion growing patients that were randomized into two groups of miniscrew-anchored maxillary protraction. The group HH was treated with a hybrid hyrax appliance in the maxilla and two miniscrews distally to the canines in the mandible. Class III elastics were used from the maxillary first molar to the mandibular miniscrews until anterior crossbite correction. The group CH was treated with a similar protocol except for the conventional hyrax expander in the maxilla. Cone-beam computed tomography was obtained before (T1) and after 12 months of therapy (T2). The shape and size of upper airway were assessed. Intergroup comparisons were performed using Mann-Whitney U test (p < 0.05).

RESULTS

The group HH was composed of 20 patients (8 female, 12 male) with a mean age of 10.76 years. The group CH was composed of 15 patients (6 female, 9 male) with a mean age of 11.52 years. Anteroposterior and transverse increases of the upper airway were found for both groups. The oropharynx and the most constricted area increased similarly in both groups.

CONCLUSIONS

No differences in upper airway changes were observed using protraction anchored on hybrid or conventional hyrax expanders.

CLINICAL RELEVANCE

Maxillary protraction anchored on hybrid or conventional hyrax expanders may benefit patients with breathing disorders due to the increase of the upper airway volume and most constricted area. Registration: ClinicalTrials.gov (NCT03712007).

Three-dimensional evaluation of upper airway changes following rapid maxillary expansion: A retrospective comparison with propensity score matched controls

BACKGROUND

The aim of this study is to evaluate upper airway changes three-dimensionally following rapid maxillary expansion (RME) and compare the changes with matched controls.

MATERIALS AND METHODS

Seventeen patients (mean age 12.6 ± 1.8 years) with maxillary transverse deficiency were treated with RME. Using the propensity score matching method, 17 patients (mean age 12.3 ± 1.5 years) were selected from a non-RME control group of 33. Case-control matching was performed based on 5 covariates: age, gender, CBCT scan interval, sagittal skeletal pattern, and tongue posture. Airway volumes of nasopharynx and oropharynx and minimum cross-sectional areas (MCA) of oropharynx were measured and compared between the case and control groups in CBCT scan images.

RESULTS

In the case group, significant increases from before to after RME were found in all measurements except MCA of the retroglossal segment of oropharynx. Before treatment, there were no significant differences between case group and control group. While comparing the case group with the control group after treatment showed overall greater increases in the case group. In particular, MCA of retropalatal segment showed statistically significant differences.

CONCLUSION

The results of this study indicate that RME causes an increase in upper airway dimensions.

The role of the dentist in the diagnosis and management of pediatric obstructive sleep apnea

The objective of this article is to review the role of the dentist in the early diagnosis of pediatric obstructive sleep apnea (OSA) and to provide an in-depth review of the best evidence-based practices available to treat and/or to refer these patients for intervention.

Material and methods

A narrative review was performed using indexed data bases (PubMed, Medline, EMBASE, OVID, Scopus and Cochrane) up to year 2020, and approximately 1000 articles were reviewed. The articles included were those with the best information provided.

Results

Detailed review of the literature suggests that the role of the dentist has been redefined owing to their expertise in the orofacial region. Every patient consulting a dental practice is not merely a dental patient; he/she also requires a comprehensive medical review. The role of the dentist is pivotal in pediatric patients once diagnosed with OSA; as the patients grow, growth modification can be achieved, and future management will be easier. Initiating dental treatments during growth can benefit patients two-fold, saving them from malocclusion, and intervening in orofacial structural growth can help to avoid cumbersome treatments, such as CPAP and various surgeries. Proper diagnosis and management of systemic illnesses can prevent compromised quality of life, delays in treatment, morbidity and, in some cases, mortality.

Rapid maxillary expansion may increase the upper airway volume of growing patients with maxillary transverse deficiency

ARTICLE TITLE AND BIBLIOGRAPHIC INFORMATION

Niu X, Di Carlo G, Cornelis MA, Cattaneo PM. Three-dimensional analyses of short- and long-term effects of rapid maxillary expansion on nasal cavity and upper airway: A systematic review and meta-analysis. Orthod Craniofac Res. 2020 Aug;23(3):250-276. doi: 10.1111/ocr.12378. Epub 2020 May 5. PMID: 32248642.

SOURCE OF FUNDING

China Scholar Council TYPE OF STUDY/DESIGN: Systematic review with meta-analysis.

Cone beam CT evaluation of skeletal and nasomaxillary complex volume changes after rapid maxillary expansion in OSA children

OBJECTIVE

The first objective of this study was to evaluate skeletal changes and changes in dimensions and volume of the upper airways before and after rapid maxillary expansion (RME) therapy in children with obstructive sleep apnoea (OSA), by Cone Beam computed tomography (CBCT). The second objective was to evaluate if RME therapy could improve both the patency of the nasal airways and the Obstructive Sleep Apnoea Syndrome (OSAS).

METHODS

19 children with OSA and malocclusion took CBCT scans with a Dentascan and 3D reconstruction program before (T0) and 4 months after (T1) RME. Patients underwent an ENT visit with auditory and respiratory tests, including a daytime sleepiness questionnaire, a 19-channel polysomnography, and an orthognatodontic examination before orthodontic therapy (T0), after 2 months (T1) with the device still on, and 4 months after the end of the orthodontic treatment (T2).

RESULTS

In all cases opening of the mid-palatal suture was demonstrated. Nasal osseous width, volume of the total upper airways, nasal cavity and nasopharynx and oropharynx increased significantly (P, .001). The increased W-ANS, W-mid and WPNS were closed linked to the enlarged midpalatal suture (P, .001). The increased WPNS were closed linked to the enlarged pterygoid processes (P, .001). The increased V-NC and V-NPA was closely linked to the enlarged W-PNS (P, .001) as well as VOPA and consequently to the enlarged midpalatal suture and pterygoid processes.

CONCLUSION

RME treatment had a positive effect on children affected by chronic snoring and OSA, causing an increase in volume of the nasal cavity and nasopharynx, with expansion of the nasal osseous width and maxillary width. Enlarged nasal width at the PNS plane contributed to the increase in nasopharynx volume. Enlarged maxillary width showed a direct correlation to increased airways volume, bringing a functional improvement. The results show that the RME therapy can restore and improve a normal nasal airflow with disappearance of obstructive sleep breathing disorder.

Analysis of nasal airway symmetry and upper airway changes after rapid maxillary expansion

INTRODUCTION

The objectives of this study were to assess the changes in right vs left nasal cavity volumes and minimum cross-sectional width, nasopharyngeal, and oropharyngeal volumes of the upper airway in response to rapid maxillary expansion (RME).

METHODS

Pretreatment and posttreatment cone-beam computed tomography scans of 28 patients with a mean age of 9.86 ± 2.43 years and 20 age- and sex-matched controls were digitized and linear, angular, and volumetric measurements were obtained.

RESULTS

Nasopharyngeal volume, right, and left nasal cavity volumes, and minimum cross-sectional widths increased significantly 2 years post RME (P <0.05). These measurements did not show any significant increase in the control group (P >0.05), whereas the oropharyngeal volume increase for both groups was comparable (P = 0.92). In the experimental group, the right and left nasal cavity volumes were not significantly different at baseline or posttreatment. However, the change that occurred was significantly larger for the left nasal cavity. This change for the control group was more significant for the right nasal cavity. Maxillary right and left molar inclinations were positively correlated to the nasal cavity volume, showing that the more buccally inclined the maxillary molars were, the smaller the nasal cavity volume.

CONCLUSIONS

Nasopharyngeal and right and left nasal cavity volumes and minimum cross-sectional widths increase significantly after RME in young children. Expansion decreases the degree of difference in volume between the right and left nasal cavities. The buccal inclination of maxillary molars is correlated with nasal cavity volume.

Correlation between the transverse dimension of the maxilla, upper airway obstructive site, and OSA severity

STUDY OBJECTIVES

Acquiring a better comprehension of obstructive sleep apnea physiopathology can contribute to improving patient selection for surgical treatments. We hypothesize that maxillary transverse deficiency restricts the space available for the tongue, leading to upper airway obstruction during sleep. Our primary hypothesis was that maxillary transverse deficiency increases the prevalence of tongue collapse during drug-induced sleep endoscopy (DISE). The secondary hypothesis was that maxillary transverse deficiency will also increase the prevalence of circumferential collapse at the velopharynx. The exploratory hypothesis was that maxillary transverse deficiency is associated with increased obstructive sleep apnea severity. The objectives of this study were to correlate maxillary morphometric measurements with (1) the anatomic level of obstruction during DISE and (2) the apnea-hypopnea index on polysomnography.

METHODS

We made a cross-sectional analysis of patients with obstructive sleep apnea undergoing DISE in search of positive airway pressure alternative treatment. Maxillary measurements were collected from a computed tomography scan (interpremolar distance, intermolar distance [IMD] and sella-nasion A point angle), findings from DISE, and sleep study variables from polysomnography. Correlation between computed tomography, DISE, and polysomnography data was assessed using Pearson's correlation, and receiver operating characteristic curves were determined for each facial measurement.

RESULTS

Sixty-nine patients were included in the study. The group with velopharyngeal circumferential collapse had mean IMD = 26.30 mm (25.5-31.45), and the group with anteroposterior collapse had mean IMD = 29.20 mm (26.8-33.10; P = .040). The group with complete tongue-base obstruction had mean interpremolar distance = 26.40 mm (25.1-28) and IMD = 26.30 mm (25.6-28.4), and the group without obstruction had mean interpremolar distance = 28.7 mm (27.2-30; P = .003) and IMD = 34.06 mm (32.1-37; P < .001). The receiver operating characteristic curve determined an IMD cutoff of 29.8 mm for predicting tongue-base obstruction.

CONCLUSIONS

The maxillary transverse deficiency, identified by reduction in interpremolar distance and IMD, predicted the occurrence of complete tongue-base obstruction, complete concentric collapse at the velopharynx, and multilevel obstruction during DISE. We did not find an association between the maxillary measurements and obstructive sleep apnea severity. These associations hold some promise in ultimately supplanting insights previously available only through DISE.

Does rapid maxillary expansion enlarge the nasal cavity and pharyngeal airway? A three-dimensional assessment based on validated analyses

OBJECTIVES

To evaluate the three-dimensional changes following rapid maxillary expansion (RME) of the nasal cavity (NC) and pharyngeal airway (PA) in growing patients, using innovative and validated evaluation methods and to investigate whether a correlation between skeletal expansion and increase in airway volume exists.

SETTINGS AND SAMPLE POPULATION

Records of patients who had cone beam computed tomography taken before and after orthodontic treatment with or without RME were retrospectively collected and divided into two groups: (a) RME, 39 patients (mean age 10.40 ± 1.74 years); and (b) control, 29 patients, matched for age (mean age 11.07 ± 1.45 years) and follow-up period.

MATERIAL AND METHODS

Total and partial volumes of the NC and the PA were calculated. The PA centerline was determined to assess the minimal cross-sectional area and hydraulic diameter. Paired and unpaired t test were applied to compare the difference between time points and between groups. One-way ANOVA and post hoc Tukey's tests were used to compare subgroups with respect to changes in palatal width and lacrimal ducts distance.

RESULTS

All of the NC, PA and skeletal parameters were significantly enlarged after RME. The NC volume and inter-molar distance in the RME were significantly larger compared to the control group. The initially lower mean values of minimal cross-sectional area and hydraulic diameter in the RME group when compared to the control group normalized after RME treatment.

CONCLUSIONS

Based on validated analyses, the NC volume increase was evident after RME in the long term after controlling for growth.

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.

Rapid maxillary expansion on oral breathing children: effects on tongue location, hyoid position and breathing. A pilot study

BACKGROUND

Oral breathing and downward tongue position are generally associated with transverse hypo-development of the upper maxilla. Rapid maxillary expansion aims to expand the upper maxilla transversely. This pilot retrospective clinical study evaluates the effects of rapid maxillary expansion therapy on the resting position of the tongue, on the position of the hyoid bone and on clinical respiratory pattern in a group of mouth breathing patients with mono- or bilateral cross-bites due to transversal deficits of the maxilla.

METHODS

A total of 39 prepubertal oral breathing subjects with posterior cross-bite (mean age 8.5 year) have been studied. Before (T0) and after treatment (T1), changes in the position of the hyoid bone and tongue were evaluated by comparing latero-lateral radiographs (TLL), while the modification of respiratory patterns by a clinical and anamnestic assessment.

RESULTS

After the treatment, the dorsum of tongue moved closer to the palatine vault, the position of the hyoid bone did not undergo significant variations and the respiratory pattern clinically improved in 64% of subjects.

CONCLUSIONS

In patients in early stages of oral respiratory development, rapid maxillary expansion promoted correct tongue position but did not produce significant changes in the position of the hyoid bone. It has been observed a general improvement of the breathing pattern.

The upper airway volume effects produced by Hyrax, Hybrid-Hyrax, and Keles keyless expanders: a single-centre randomized controlled trial

OBJECTIVE

To assess upper airway volume changes after rapid maxillary expansion (RME) with three different expanders.

TRIAL DESIGN

Three-arm parallel randomized clinical trial.

METHODS

Sixty-six patients, 10-16 years old, in permanent dentition, with maxillary transverse deficiency were recruited and assigned with block randomization (1:1:1 ratio) and allocation concealment to three groups of 22 patients each (Hyrax, Hybrid-Hyrax, and Keles keyless expander). The primary outcome (overall upper airway volume change) and secondary outcomes (volume changes in the nasal cavity, nasopharynx, oropharynx, and hypopharynx) were blindly assessed on the initial (T0) and final (T1, 6 months at appliance removal) cone beam computed tomography. Differences across groups were assessed with crude or adjusted for confounders (gender, age, growth stage, skeletal pattern, baseline airway volume, and amount of expansion) linear regression models.

RESULTS

Fifty-one patients were analysed (19, 19, and 13 in the Hyrax, Hybrid-Hyrax, and Keles groups). Maxillary expansion resulted in considerable increases in total airway volume in the Hybrid-Hyrax group (+5902.1 mm3) and less in the Hyrax group (+2537.9 mm3) or the Keles group (+3001.4 mm3). However, treatment-induced changes for the primary and all secondary outcomes were of small magnitude and no significant difference was seen among the three expanderes in the total airway volume in either crude or adjusted analyses (P > 0.05 in all instances). Finally, among pre-peak patients (CVM 1-3), the Hybrid-Hyrax expander was associated with significantly greater increases in total airway volume compared to the Hyrax expander (P = 0.02).

CONCLUSIONS

RME resulted in relatively small increases in total upper airway volume and its separate compartments, with mostly no statistically significant differences across the Hyrax, Hybrid-Hyrax, and Keles groups.

LIMITATIONS

Significantly greater attrition was found in the Keles group due to appliance failure. The current trial might possibly be under-powered to detect differences between groups, if such exist.

HARMS

Keles expanders blocked during activations and required substitution for completion of treatment.

PROTOCOL

The protocol was not published before trial commencement.

REGISTRATION

Australian and New Zealand Clinical Trial Registry (ACTRN12617001136392).

Effect of extraction treatment on upper airway dimensions in patients with bimaxillary skeletal protrusion relative to their vertical skeletal pattern

Objective

To investigate dimensional changes in regional pharyngeal airway spaces after premolar extraction in bimaxillary skeletal protrusion (BSP) patients according to vertical skeletal pattern, and to further identify dentoskeletal risk factors to predict posttreatment pharyngeal changes.

Methods

Fifty-five adults showing BSP treated with microimplant anchorage after four premolar extractions were included in this retrospective study. The subjects were divided into two groups according to the mandibular plane steepness hyperdivergent (Frankfort horizontal plane to mandibular plane [FH-MP] ≥ 30) and nonhyperdivergent groups (FH-MP < 30). The control group consisted of 20 untreated adults with skeletal Class I normodivergent pattern and favorable profile. Treatment changes in cephalometric variables were evaluated and compared. The association between posttreatment changes in the dentoskeletal and upper airway variables were analyzed using linear regression analysis.

Results

The BSP patients showed no significant decrease in the pharyngeal dimensions to the lower level in comparison with controls, except for middle airway space (MAS, p < 0.01). The upper airway variable representing greater decrease in the hyperdivergent group than in the nonhyperdivergent group was the MAS (p < 0.01). Posttreatment changes in FH-MP had negative correlation with changes in MAS (β = –0.42, p < 0.01) and inferior airway space (β = –0.52, p < 0.01) as a result of multivariable regression analysis adjusted for sagittal skeletal relationship.

Conclusions

Decreased pharyngeal dimensions after treatment in BSP patients showed no significant difference from the normal range of pharyngeal dimensions. However, the glossopharyngeal airway space may be susceptible to treatment when vertical dimension increased in hyperdivergent BSP patients.

Computational Fluid Dynamics Analysis of Nasal Airway Changes after Treatment with C-Expander

The use of the C-expander is an effective treatment modality for maxillary skeletal deficiencies which can cause ailments and significantly reduce life expectancy in late adolescents and young adults. However, the morphological and dynamic effects on the nasal airway have not been reported. The main goal of this study was to evaluate the nasal airway changes after the implementation of a C-expander. A sample of nine patients (8 females, 1 male, age range from 15 to 29 years) was included. The morphology parameters and nasal airway ventilation parameters of pretreatment and posttreatment were measured. All study data were normally distributed. A paired t-test was used to evaluate the changes before and after treatment. After expansion, the mean and standard deviation values of intercanine maxillary width (CMW) and intermolar maxillary width (MMW) increased from 35.75 ± 2.48 mm and 54.20 ± 3.17 mm to 37.87 ± 2.26 mm (P < 0.05) and 56.65 ± 3.10 mm (P < 0.05), respectively. The nasal cavity volume increased from 20320.00 ± 3468.25 mm³ to 23134.70 ± 3918.84 mm³ (P < 0.05). The nasal pressure drop decreased from 36.34 ± 3.99 Pa to 30.70 ± 3.17 Pa (P < 0.05), while the value of the maximum velocity decreased from 6.50 ± 0.31 m/s to 5.85 ± 0.37 m/s (P < 0.05). Nasal resistance dropped remarkably from 0.16 ± 0.14 Pa/ml/s to 0.08 ± 0.06 Pa/ml/s (P < 0.05). The use of C-expander can effectively broaden the area and volume of the nasal airway, having a positive effect in the reduction of nasal resistance and improvement of nasal airway ventilation. For patients suffering from maxillary width deficiency and respiratory disorders, a C-expander may be an alternative method to treat the disease.

Oropharyngeal 3-dimensional changes after maxillary expansion with 2 different orthodontic approaches

INTRODUCTION

The objective of this research was to compare the oropharyngeal volume and minimal cross-sectional area (MCA) changes after maxillary expansion using either the Damon system or Hyrax appliances as assessed through cone-beam computed tomography (CBCT) imaging.

METHODS

Patients aged between 11 and 17 years with skeletal maxillary transverse discrepancy in need of maxillary expansion were included and allocated randomly into 1 of the 2 treatment groups, Damon or Hyrax. Patients underwent CBCT imaging at 2 time points: T1, after initial clinical evaluation before treatment, and T2, after completion of full orthodontic treatment. The CBCT data were assessed using Dolphin software (Dolphin Imaging & Management Solutions, Chatsworth, Calif). In addition, a qualitative assessment of breathing function was done using the modified Nasal Obstruction and Septoplasty Effectiveness Scale questionnaire.

RESULTS

A statistically significant increase in the oropharyngeal volume (2.23 mL; P = 0.005) and MCA (29.72 mm²; P = 0.007) after the completion of treatment (T2 - T1) for the Hyrax group was suggested. No statistically significant difference was found in the Damon group for volume (1 mL; P = 0.311) and for MCA (7.32 mm²; P = 0.643). In addition, no statistically significant difference was found in the breathing function in both treatment groups (P >0.05).

CONCLUSIONS

Hyrax expansion followed by fixed appliances produced more dimensional upper airway changes at the oropharyngeal level than the Damon system approach. No breathing functional changes were noted in either samples.

Evaluating the effect of midpalatal corticotomy-assisted rapid maxillary expansion on the upper airway in young adults using computational fluid dynamics

Midpalatal corticotomy-assisted rapid maxillary expansion (MCRME) is a minimally invasive treatment of maxillary transverse deficiency (MTD) in young adults. However, the effect of MCRME on respiratory function still needs to be determined. In this study, we evaluated the changes in maxillary morphology and the upper airway following MCRME using computational fluid dynamics (CFD). Twenty patients with MTD (8 males, 12 females; mean age 20.55 years) had cone-beam computed tomography (CBCT) images taken before and after MCRME. The CBCT data were used to construct a three-dimensional (3D) upper airway model. The upper airway flow characteristics were simulated using CFD, and measurements were made based on the CBCT images and CFD. The results showed that the widths of the palatal bone and nasal cavity, and the intermolar width were increased significantly after MCRME. The volume of the nasal cavity and nasopharynx increased significantly, while there were no obvious changes in the volumes of the oropharynx and hypopharynx. CFD simulation of the upper airway showed that the pressure drop and maximum velocity of the upper airway decreased significantly after treatment. Our results suggest that in these young adults with MTD, increasing the maxillary width, upper airway volume, and quantity of airflow by MCRME substantially improved upper airway ventilation.

Total maxillary arch distalization with modified C-palatal plates in adolescents: A long-term study using cone-beam computed tomography

INTRODUCTION

The aims of this study were to evaluate the long-term skeletodental effects, the volume of maxillary tuberosity, and airway space changes after maxillary molar distalization using modified C-palatal plate (MCPP) in adolescents with Class II malocclusion.

METHODS

The sample consisted of 20 adolescent patients (MCPP group; mean age, 12.9 ± 1.0 year) who underwent bilateral distalization of their maxillary dentition and 20 subjects as a control group. In the MCPP group, cone-beam computed tomography images were taken before distalization, at the end of the treatment, and during retention with a minimum of a 3-year posttreatment follow up period. Repeated measures ANOVA followed by post-hoc analysis with the Bonferroni test were used to identify significant differences between time points.

RESULTS

After the long-term observation period, sagittal skeletal and dental relationships were maintained (there were no significant changes in ANB, occlusal plane angle, and overjet postretention). The vertical skeletal dimension did not change during treatment and was stable at the long-term follow-up (the mandibular plane angle and ANS-Me were relatively well maintained). The volume of the maxillary tuberosity showed no significant change during long-term retention. However, the volume was significantly smaller in the treatment group than in the control group (P <0.0001). There were no significant airway space changes after distalization and the postretention period. In addition, there was no significant difference between the MCPP and control groups.

CONCLUSIONS

Improved sagittal skeletal and dental relationships because of treatment were maintained in the long-term evaluation. There was no negative long-term effect on airway space associated with the maxillary arch distalization. Therefore, these findings might be beneficial for clinicians in diagnosis and treatment planning for Class II malocclusion in adolescents.

[Protocol of cone beam computed tomography analysis for patients with craniomandibular dysfunction]

The article presents a detailed protocol of cone beam computed tomography (CBCT), which includes not only the classic analysis of dentoalveolar and skeletal disorders, but diagnosis of cranial patterns (craniocervical cephalometric analysis by M. Rocabado, cephalometric diagnosis by Sassouni PLUS), analysis of transverse jaw sizes (Penn analysis) and measuring the volume of the airway for screening of obstructive sleep apnea. The literature review was conducted using the PubMed in the Scopus and Medline electronic databases through April 2020. Combining several methods of interpretation of CBCT in a single protocol will allow doctors to obtain a more complete amount of information to make a complete plan of comprehensive treatment.

Relationship between olfaction and maxillofacial morphology in children with malocclusion

OBJECTIVES

Functional problems, including nasal flow problems, are associated with specific skeletal and dental features. Further, maxillary expansion has been associated with nasal airway resistance alterations. This study aimed to investigate whether there is a correlation between skeletal features and nasal airflow- and olfaction-related problems.

MATERIALS AND METHODS

This prospective study included 68 patients (30 boys, 38 girls; mean age 9 ± 2 years) examined at the Ohu University Hospital. We classified patients into three skeletal Classes (Class I, II, and III) based on the ANB angle. Olfactory disorder history was collected from the guardians. Maxillofacial measurements, nasal airflow assessments, and olfactory tests were performed using cephalometric analysis, rhinomanometry, and T&T olfactometer, respectively.

RESULTS

Malocclusion, resulting from skeletal mandibular protrusion and smaller maxilla, was associated with reduced olfaction in children. The detection and recognition thresholds of skeletal Class III were significantly higher than those of Classes I (p = .01) and II (p = .01). Significant correlations were observed between SNA and the detection threshold (r = -.50) as well as between nasion perpendicular-point A and the recognition threshold (r = -.53). The detection and recognition thresholds were significantly higher in Class III than in Classes I (r = .3) and II (r = -.1).

CONCLUSIONS

Maxillary growth and development may be associated with olfaction in children. Changing the maxillofacial morphology may improve olfactory function. In the future, we will investigate how malocclusion treatment affects olfactory function.

Changes in the hyoid bone, tongue, and oropharyngeal airway space after mandibular setback surgery evaluated by cone-beam computed tomography

Background

Mandibular setback surgery can change the position of the mandible which improves occlusion and facial profile. Surgical movement of the mandible affects the base of the tongue, hyoid bone, and associated tissues, resulting in changes in the pharyngeal airway space. The aim of this study was to analyze the 3-dimensional (3D) changes in the hyoid bone and tongue positions and oropharyngeal airway space after mandibular setback surgery.

Methods

A total of 30 pairs of cone-beam computed tomography (CBCT) images taken before and 1 month after surgery were analyzed by measuring changes in the hyoid bone and tongue positions and oropharyngeal airway space. The CBCT images were reoriented using InVivo 5.3 software (Anatomage, San Jose, USA) and landmarks were assigned to establish coordinates in a three-dimensional plane. The mean age of the patients was 21.7 years and the mean amount of mandibular setback was 5.94 mm measured from the B-point.

Results

The hyoid bone showed significant posterior and inferior displacement (P < 0.001, P < 0.001, respectively). Significant superior and posterior movements of the tongue were observed (P < 0.05, P < 0.05, respectively). Regarding the velopharyngeal and glossopharyngeal spaces, there were significant reductions in the volume and minimal cross-sectional area (P < 0.001). The anteroposterior and transverse widths of the minimal cross-sectional area were decreased (P < 0.001, P < 0.001, respectively). In addition, the amount of mandibular setback positively correlated with the amount of posterior and inferior movement of the hyoid bone (P < 0.05, P < 0.05, respectively).

Conclusion

There were significant changes in the hyoid bone, tongue, and airway space after mandibular setback surgery.

Preliminary study: evaluating the reliability of CBCT images for tongue space measurements in the field of orthodontics

INTRODUCTION

Accurately measuring tongue space is challenging, but this information can be useful to many dental specialties. This study was intended to estimate the reliability of using cone-beam computed tomography (CBCT) to measure tongue space, which includes tongue volume and the oral cavity air capacity.

METHODS

For this preliminary study, CBCT images from ten participants (five females and five males, mean age of 29.8 ± 3.3 years) were available for evaluation. Each participant was radiographed two times (T0 and T1). The average time between T0 and T1 was 15.8 ± 3.7 days. CBCT scans were standardized to reduce variability. Three-dimensional landmarks were established to identify tongue space and 3D image analysis software (SimPlant^® 17 Pro; Materialise Dental, Leuven, Belgium) was used to measure the volume circumscribed by the landmarks. Two investigators independently calculated airway, tongue dimensions, and total tongue space for CBCT image T0 twice (day 1 and day 14), and T1 once. Intraclass correlation coefficients (ICCs) were used to estimate intra-rater and inter-rater reliability. Bland-Altman charts were constructed to demonstrate agreement within and between raters.

RESULTS

The intra-rater and inter-rater ICCs of the CBCT measurements at T0 were excellent (> 0.90). Measurements for T0 vs. T1 show good (0.75-0.90) intra-rater and excellent (> 0.90) inter-rater reliability. Bland-Altman charts show that 90-95% of the total measurements fall within the 95% limits of agreement for both intra- and inter-rater pairs CONCLUSIONS: The results of this preliminary study suggest that the landmarks chosen to measure the overall tongue space are reproducible and can be measured clearly using CBCT.

Three-dimensional analyses of short- and long-term effects of rapid maxillary expansion on nasal cavity and upper airway: A systematic review and meta-analysis

INTRODUCTION

The purpose of this systematic review was to evaluate the three-dimensional (3D) changes occurring at short- and long-term follow-up after rapid maxillary expansion (RME) in nasal cavity (NC) and upper airway (UA) in growing patients.

METHODS

A literature search up to 1 July 2019 was performed. Randomized and non-randomized clinical trials and cohort studies comparing the effects of RME in a paediatric population using 3D analyses based on computed tomography (CT), cone-beam CT and MRI were included. The risks of bias of the included studies were assessed using the Cochrane Collaboration's risk of bias tool, the GRADE approach and a customized tool. The random-effects meta-analyses of the mean differences and 95% confidence intervals of NC and UA volume changes were carried out, followed by subgroup analyses.

RESULTS

Twenty-seven studies were included, with 18 selected for quantitative synthesis. Immediately after expansion, the nasopharynx and oropharynx increased significantly. After 3 months of retention, only the NC and nasopharynx showed a significant volume increase. Two studies mentioned the use of a sleep-disordered breathing questionnaire, and one study reported the difference before and after RME. None of the 27 articles included assessed the correlation between the skeletal widening and NC or UA volume changes after RME.

CONCLUSIONS

The existing evidence confirmed only the short-term positive effect of RME on expanding the volume of the NC and the upper part of the UA. However, long-term stability could not be sustained.

Skeletal Surgery for Obstructive Sleep Apnea

This article focuses on the role of skeletal surgery within the modified Stanford protocol with particular attention focused on the evolved role of MMA. First, surgery in patients presenting with congenital dentofacial deformity or characteristic drug-induced sleep endoscopy findings, then the growing role of maxillary expansion in a newly identified patient phenotype, and finally genioglossus advancement, are discussed. Less commonly used and validated techniques, such as isolated mandibular advancement and maxillomandibular expansion are not discussed in this article.

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 surgically assisted rapid maxillary expansion on the modification of the pharynx and hard palate and on obstructive sleep apnea, and their correlations

PURPOSE

To investigate the changes induced by surgically assisted rapid maxillary expansion (SARME) on palate and pharynx morphology as well as the correlation of these changes with the improvement of obstructive sleep apnea (OSA).

MATERIALS AND METHODS

The study was conducted in 16 patients, seven women and nine men, aged on average 40.23 ± 10.23 years, all of them with OSA confirmed by polysomnography (PSG) and with posterior crossbite. All participants underwent computed tomography (CT) and PSG before and after SARME. The CT scans were used to determine the dimensions of the palate and pharynx before and after surgery. Data were analyzed statistically by the paired t-test, Wilcoxon test and Pearson correlation, with the level of significance set at P < 0.05.

RESULTS

A 56.24% reduction in apnea and hypopnea index was detected (from 33.23 ± 39.54 to 14.54 ± 19.48: P = 0.001). The total airway area increased on average by 23.99% (P = 0.016), although in a more expressive manner in its lower half (28.63%, P = 0.008). A 24% transverse bone increase was observed in the palate in the region of the first premolars and an 18% increase in the region of the first molars (from 2.42 ± 0.31 to 2.99 ± 0.26. P < 0.001, and from 3.11 ± 0.32 to 3.70 ± 0.41, P < 0.001, respectively), and a mean 15% reduction of its depth (from 1.07 ± 0.33 to 0.89 ± 0.18, P = 0.014). A moderate correlation was detected between palate depth and width and OSA severity, as well as a correlation of the reduction of palate depth and its transverse increase with the improvement of OSA, especially among patients with severe OSA.

CONCLUSION

It appears that narrowing of the palate, especially in the premolar region, and its greater depth may be related to the severity of OSA. SARME promotes transverse maxillary widening and lowering of palate depth, thus reducing OSA among adults and expanding the airway, especially in its lower half.

Changes of the upper airway and bone in microimplant-assisted rapid palatal expansion: A cone-beam computed tomography (CBCT) study

OBJECTIVE

To evaluate the changes of maxillary expansion and upper airway structure after microimplant assisted rapid palatal expansion (MARPE) using cone-beam computed tomography (CBCT).

METHODS

This retrospective study included 19 subjects (15 females and 4 males) aged 15-29 years old (mean, 19.95±4.39 years) with maxillary transverse deficiency treated with MARPE. CBCT was performed at the initial diagnosis and 3 months after MARPE treatment. Measurements were taken to evaluate the amount of total expansion, skeletal expansion, and dental expansion at the maxillary first premolar (P1), second premolar (P2), first molar (M1), second molar (M2) regions and upper airway changes.

RESULTS

After MARPE treatment, the maxillary skeletal base expansion, skeletal expansion, alveolar expansion and dental expansion were achieved at the P1, P2, M1, M2 region. The nasopharyngeal volume significantly increased 8.48% after MARPE treatment compared with that before the treatment (P < 0.05). The change of nasal lateral width (NLW) was also significantly different before and after MARPE (P < 0.05). However, there were no statistically significant change in the oropharyngeal, palatopharyngeal, glossopharyngeal and airway total volume (all P > 0.05).

CONCLUSIONS

MARPE can produce more transverse bone expansion, relieve maxillary transverse deficiency and improve upper airway ventilation.