Effect of functional appliances on the airway dimensions in patients with skeletal class II malocclusion: A systematic review

The effect of different functional appliances on the sagittal pharyngeal airway dimension in skeletal class II: a retrospective study

The aim of this study was to compare the changes in the sagittal pharyngeal airway dimension (SPAD) in adolescents with Class II mandibular retrusion treated with Invisalign Mandibular Advancement (IMA), prefabricated Myobrace (MB), and Twin block (TB). For this retrospective study, the pre-treatment and post-treatment lateral cephalograms of 60 patients who underwent myofunctional treatment, using either one of the tested appliances were gathered from the files of treated patients. Changes in the SPAD were measured in each group, and comparisons were carried out between the three study groups. Additionally, sagittal skeletal measurements were carried out. Comparisons of the study variables at T0 and T1 between the three groups were performed using one-way ANOVA, while comparisons of the difference (T1-T0) were performed using Kruskal Wallis test. A significant SPAD increase has been reported using the three tested appliances (p < 0.05), with the least change documented with MB use (p < 0.05). Significant antero-posterior improvements have been found with IMA, MB, and TB with an increase in the SNB°, and a decrease in ANB° and Wits appraisal (p < 0.05). Non-significant FMA° changes have been observed post-treatment in the three test groups (p > 0.05). The IMA, MB, and TB generated significant SPAD and sagittal changes, with both IMA and TB surpassing MB in the airway area improvement post-treatment. Moreover, the three tested Class II functional appliances did not affect the vertical dimension.

Cervical spine changes with functional appliance treatment: A systematic review and meta-analysis

Objective

Cervical spine posture is related to craniofacial morphology, airway, gait and body posture. This posture may be influenced by the changes in the mandibular position brought about by functional appliance therapy. Therefore, this systematic review aimed to assess the changes in the cervical spine posture with functional appliance treatment in Skeletal Class II subjects.

Methods

A search of studies in six electronic databases - Medline (via Pubmed), the Cochrane Library, OVID, LILACS, Scopus and Web of Science were performed until January 18, 2024 without any restriction in date or language of publication. Eligibility screening, study selection, and data extraction were performed by two reviewers independently. The risk of bias assessment of the included studies was performed with the Newcastle Ottawa scale and Cochrane RoB 2.0. Meta-analysis was performed using random effects model for assessment of changes in the cervical spine with removable and fixed functional appliances.

Results

Twelve articles that satisfied the eligibility criteria were included for systematic review and nine articles for meta-analysis. Five studies showed a low risk of bias, one as moderate and six as high risk of bias. GRADE assessment revealed a low quality evidence. Meta-analysis revealed a decrease of the upper cervical inclination by 1.16° (95 % CI of -2.68 to 0.35, I2 = 6 %), an increase of the middle cervical inclination by 2.20° (95 % CI of 0.46-3.94, I2 = 49 %), an increase in cervical curvature angle by 1.60° (95 % CI of 0.12-3.09, I2 = 89 %) and a decrease in cervical lordosis angle by 1.54° (95 % CI of -4.16 to 1.08, I2 = 0 %).

Conclusions

Minimal uprighting of the cervical spine was noted with functional appliances. Fixed functional appliances exerted a greater effect than removable functional appliances. Cervical hyperlordosis was reduced with removable functional appliance treatment. Though these changes are minimal, the clinical orthodontist should be aware that functional therapy also influences cervical spine posture. Due to the heterogeneity and low quality of evidence, the results are to be considered critically.

Using a Portable Ventilatory Airway Screening (PVAS) Device to Evaluate the Difference Between Upper Airway Breathing Pressure and Respiratory Flow in Skeletal Class I and Class II Growing Individuals With Retrognathic Mandible

Background Upper airway obstruction (UAO) is a significant clinical concern due to its potential to lead to serious health issues, including obstructive sleep apnea (OSA) and cardiovascular diseases. Traditional diagnostic methods, such as spirometry, are often invasive and complex. This study aims to validate a portable ventilatory airway screening (PVAS) device as a non-invasive, cost-effective alternative for measuring upper airway breathing pressure and respiratory flow. Objectives To validate the accuracy of the PVAS device in measuring upper airway breathing pressure and respiratory flow by comparing its readings with those obtained from standard spirometry tests. Methods This cross-sectional analytical study involved 40 growing individuals aged 10-14 years, divided into two groups based on cephalometric analysis: Skeletal Class I (20 patients) and Skeletal Class II with retrognathic mandible (20 patients). Breathing pressure, volume, and velocity measurements were recorded using both the PVAS device and spirometry, and their accuracy was compared. Results The PVAS device showed high concordance with spirometry results, demonstrating significant accuracy in measuring breathing pressure, volume, and velocity. Skeletal Class II individuals exhibited significantly higher breathing pressure and reduced respiratory flow compared to Class I individuals, as measured by the PVAS device. Conclusion The PVAS device is a valid and accurate tool for non-invasive measurement of upper airway breathing pressure and respiratory flow. Its ease of use and reliability make it a valuable tool for clinical practice, particularly in the early diagnosis and management of airway obstructions.

Assessment of maximal inspiratory and expiratory pressures in skeletal Class II patients with different growth patterns

OBJECTIVES

To evaluate maximal inspiratory (MIP) and expiratory (MEP) pressures, which are reflective of respiratory muscle strength, in skeletal Class II patients with different growth patterns (horizontal, average, and vertical) and to correlate those with airway dimension.

MATERIALS AND METHODS

Patients with a Class II skeletal base seeking orthodontic treatment were assigned to the following groups: average, horizontal, and vertical growth pattern. The control group (n = 14) comprised patients with a Class I skeletal base and average growth pattern. Airway dimensions were obtained using cone-beam computed tomography scans, and a spirometer with a pressure transducer was used for assessment of MIP and MEP. Routine spirometry for assessment of lung function was also performed.

RESULTS

No significant differences were found in maximal inspiratory and expiratory pressures for the study groups in comparison with the control group. Class I patients had significantly greater oropharyngeal and nasopharyngeal airway volumes compared with the study groups. No significant difference in minimal cross-section area of the airway was observed among groups. A weak positive correlation between maximal inspiratory pressure and airway volume was observed.

CONCLUSIONS

Although Class I patients displayed significantly greater oropharyngeal and nasopharyngeal airway volumes, there was no significant difference in respiratory muscle strength or airway function between Class II patients with different growth patterns and the Class I control group. The findings underscore the significance of exploring factors beyond craniofacial growth patterns that may contribute to sleep-related breathing disorders.

Three-dimensional computed tomography analysis of airway volume in growing class II patients treated with Frankel II appliance

OBJECTIVE

The purpose of this retrospective study was to assess the airway volume changes associated with the use of Frankel appliance (FR II) in Class II malocclusion patients using three-dimensional cone beam computed tomography (3D CBCT) imaging.

MATERIALS AND METHODS

The sample consisted of 31 Class II malocclusion patients (mean age 9.24 ± 1.93 years old, 17 males (54.8%) and 14 females (45.2%)) treated with FR II appliance by the same orthodontist for an average of 9 months ± 20 days. CBCT images were taken before and after treatment and upper airway volume changes were measured using Dolphin 3D software version11.0 (Dolphin Imaging, Chatsworth, CA) and statistically compared.

RESULTS

Airway volume of nasal cavity, nasopharynx, oropharynx, hypopharynx and the total airway volume significantly increased after the use of FR II appliance. In addition, significant increase was reported in maxillary base, inter-molar, inter-premolar and inter-canine width. Significant increase in soft tissue thickness was only recorded opposite to CV2.

CONCLUSION

The use of the FR II appliance in growing subjects with Class II malocclusion led to a significant increase in the upper airway volume in addition to the anticipated dental and skeletal transverse expansion effects.

Cephalometric changes in pharyngeal airway dimensions after functional treatment with twin block versus myobrace appliances in developing skeletal class II patients: a randomized clinical trial

BACKGROUND

Several appliances have been used for correction of developing skeletal Class II, including different myofunctional appliances as Twin block (TB)as well as the new pre-fabricated Myobrace (MB) appliance. However, the effects of these devices on the pharyngeal airways have not been compared in the literature. Thus, the aim of this study was to compare the effects of two Class II correction appliances; TB and MB on the sagittal pharyngeal airway dimension (SPAD), including the nasopharyngeal airway area (NPAA), the oropharyngeal airway area (OPAA), and the laryngopharyngeal airway area (LPAA).

METHODS

This is a two parallel arms randomized comparative clinical trial. Twenty-six children of 9-12 years with Skeletal Class II malocclusion due to mandibular deficiency and normal maxillary growth as confirmed by lateral cephalometric X-ray readings (ANB angle > 4° and SNB angle < 78) and Cervical vertebral maturational index (CVMI) 1 or 2 were randomly assigned into two equal groups. Group I: TB, Group II: MB (prefabricated functional appliance, Myofunctional Research Co., Australia). Lateral cephalograms were taken for all patients in both groups before treatment (T1) and after treatment (6 months later) (T2). The primary aim was to assess pre and post treatment changes in the SPAD in each group, and compare between the two study groups. The secondary aim was to evaluate the sagittal skeletal measurements such as the SNA, SNB, ANB, Wits appraisal, as well as vertical skeletal measurements represented by the Frankfurt-mandibular plane angle (FMA) measured pre- and post-treatment. The independent samples t-test was used to compare the two study groups, and the mean difference and 95% confidence intervals (CI) were computed. The paired samples t-test was used to compare various parameters between T1 and T2 within each group. The cutoff for significance was p-value < 0.05. Data were analyzed using IBM SPSS for Windows (Version 26.0).

RESULTS

By Comparing changes in airway measurements within each group, it was found that NPAA, OPAA, and LPAA increased significantly after treatment within each group of MB and TB. TB group showed significantly higher mean difference (T2-T1) in both NPAA and OPAA than MB group with 28.39 (± 56.75) and 40.46 (± 52.16) respectively. The increase in LPAA values was not statistically significant at (T2-T1) between both groups. Regarding skeletal changes, there was a significant increase in the SNB values between T1 and T2 within each group with 2.82 (± 3.32) for MB group and 3.79 (± 3.06) for TB group Moreover, there was a significant decrease in the ANB values between T1 and T2 within each group by 2.42 (± 2.70) for MB group and 3.06 (± 1.14) for TB group. Similarly, there was a significant decrease in the ANB values between T1 and T2 within each group by -2.13 (± 0.62) for MB group and - 2.46 (± 0.72) for TB group. No significant differences were found between both groups in SNA, SNB, ANB and Wits appraisal at p = 0.06, p = 0.45, p = 0.43 and p = 0.22 respectively. FMA did not show significant difference between T1 and T2 within each group, nor showed a significant mean difference between both groups at T2-T1.

CONCLUSIONS

TB was more effective than MB in improving the upper (NPAA) and middle (OPAA) airways, while no difference was found regarding the lower airway (LPAA). Both TB and MB reduced the severity of developing skeletal class II due to mandibular retrognathism by forward posturing of the mandible. Thus, patients with airway problems would benefit more from TB than MB.

Effectiveness of orthopaedic treatments on the enlargement of the upper airways: Overview of systematic reviews

OBJECTIVE

The aims of this overview are to evaluate the three-dimensional effects of orthopaedic treatment (OT) and myofunctional therapy (MT) on the enlargement of the upper airways (UA).

METHODS

A search of the MEDLINE/PubMed and EMBASE databases was conducted up to July 2022 and completed by hand search. After selection of the title and abstract, systematic reviews (SR) dealing with the impact of OT and/or MT on UA containing only controlled studies were included. The methodological quality of the SR was assessed by the AMSTAR-2, Glenny and ROBIS tools. A quantitative analysis was done with Review Manager 5.4.1.

RESULTS

Ten SR were included. The risk of bias was judged low for one SR according to ROBIS. Two SR presented a high level of evidence according to AMSTAR-2. In the quantitative analysis and about the orthopaedic mandibular advancement therapies (OMA), while a significant increase in superior (SPS) [(Mean difference (MD): 1.19; CI 95% [0.59; 1.78]; P<0.0001)] and middle (MPS) pharyngeal space [(MD: 1.10; CI 95% [0.22; 1.98]; P=0.01)] existed in the short-term for both OMA, it was greater for removable. On the other hand, there was no significant change in the inferior pharyngeal space (IPS). Four other SR targeted the short-term efficacy of class III OT. Only treatments with face mask (FM) or face mask+rapid maxillary expansion (FM+RME) allowed a significant increase in SPS [(MD FM: 0.97; CI 95% [0.14; 1.81]; P=0.02/MD FM+RME: 1.54; CI 95% [0.43; 2.66]; P=0.006)]. This was neither the case for chin cup nor in all cases in IPS. The last two SR explored the effectiveness of RME, whether or not associated with bone anchorage, on the dimensions of the UA or on the reduction of the apnoea/hypopnea index (AHI). A significant superiority of the effects of the devices with mixed or only bone anchorages existed concerning the width of the nasal cavity, the nasal airflow and the reduction of the nasal resistance. But, the qualitative analysis showed no significant reduction in AHI after RME.

CONCLUSIONS

Despite the heterogeneity of the included systematic reviews and their unfortunately not always low risk of bias, this synthesis showed that orthopaedics could provide some short-term improvement in AU dimensions, mainly in the upper and middle areas. Indeed, no devices improved the IPS. Class II orthopaedics improved SPS and MPS; class III orthopaedics, except for the chin cup, improved only SPS. RME, optimised with bone or mixed anchors, mostly improved the nasal floor.

Dentoalveolar, skeletal, pharyngeal airway, cervical posture, hyoid bone position, and soft palate changes with Myobrace and Twin-block: a retrospective study

BACKGROUND

The primary aim of this study was to evaluate the dentoalveolar, skeletal, pharyngeal airway, cervical posture, hyoid bone position, and soft palate effects of the Myobrace and Twin-block appliances. The second was to compare them in terms of ease of use by assessing the factors that may influence patient compliance.

METHODS

The study included thirty-six Class II division 1 patients (19 females, 17 males; mean age, 12.14 ± 1.23) who had previously been treated in the Orthodontic Clinic at Sivas Cumhuriyet University Faculty of Dentistry. The patients were divided into two groups: Group 1: Myobrace (n = 18), and Group 2: twin block (n = 18). The effects of the appliances on the skeletal, dentoalveolar, soft tissue, craniocervical, and other anatomic structures were assessed using 46 measurements (22 linear and 24 angular), on pre and post-treatment cephalometric radiographs. AudaxCeph 5.0 software (Ljubljana, Slovenia) was used for the analysis. To analyze the changes after one year of treatment, a paired sample t-test and Wilcoxon signed-rank test were used. Intergroup comparison was performed using the Student t-test and the Mann-Whitney U test.

RESULTS

In the Myobrace and Twin-block groups, there was a significant increase in SNB (°) (p = 0.004, p = 0.001), IMPA (°) (p = 0.005, p = 0.001) and a significant drop in U1/SN (°) (p = 0.021, p = 0.005). The lengths of Cd-Gn (mm), Go-Pg (mm), and Cd-Go (mm) increased significantly in the Twin-block group (p = 0.003, p = 0.010, p = 0.001), whereas the Myobrace group did not change. Similarly, there was no significant difference in pharyngeal and soft palate measurements in the Myobrace group but a statistically significant decrease in SP length and angle in the Twin-block group (p = 0.001, p = 0.006). Increases in SN/OPT (°) (p = 0.032, p = 0.001) and SN/CVT (°) (p = 0.012, p = 0.001) were statistically significant in both groups. Myobrace was more difficult to use while sleeping, whereas the twin block caused more nausea.

CONCLUSIONS

Both appliances can be used for mandibular advancement. The Twin-block appliance, on the other hand, was more effective and patient-friendly.

Pharyngeal airway and hyoid bone position changes of skeletal anchored Forsus Fatigue Resistant Device and activator appliances

OBJECTIVES

To evaluate the effects of miniplate anchored Forsus Fatigue Resistant Device (MAF) and activator treatments in the pharyngeal airway dimensions and hyoid bone position.

MATERIALS AND METHODS

Thirty-eight patients with mandibular retrusion who were treated with either MAF or activator were selected retrospectively and compared with an untreated control group. The data of 114 lateral cephalograms, comprising those taken before treatment (T1) and at the end of functional treatment (T2), were evaluated with regard to their linear, angular, and area measurements.

RESULTS

The mandibular length increased and the hyoid bone moved forward with both treatments (P < 0.05). The horizontal change in the hyoid bone position with MAF treatment was correlated with changes in the point B and ANB angle. Increases of 1.8 mm, 1.4 mm, and 1.8 mm in the pharyngeal airway dimensions were obtained at the levels of the second, third, and fourth cervical vertebra, respectively, with the MAF treatment. On the other hand, an increase of 1.9 mm was found at the level of the fourth cervical vertebra with the activator treatment. The greatest vertical movement in the Menton and the highest increase in the oropharyngeal area were observed in the MAF group (P < 0.05).

CONCLUSION

Both the MAF and activator treatments caused favorable maxillomandibular changes; however, the MAF treatment provided a greater increase in the oropharyngeal area according to both the increase in mandibular length and the change in the vertical position of the mandible.

CLINICAL RELEVANCE

Functional appliances were found to be useful in increasing the pharyngeal airway dimensions in the short-term. The skeletal anchored fixed functional appliance caused a greater increase in the oropharyngeal airway area that may be beneficial for Class II patients who carry a risk of having respiratory problems.

Pharyngeal airway, hyoid bone, and soft palate changes after Class II treatment with Twin-block and Forsus appliances during the postpeak growth period

INTRODUCTION

This study aimed to compare cephalometrically the pharyngeal airway, hyoid bone, and soft palate (SP) changes after Class II malocclusion treatments using Twin-block (TWB) and Forsus Fatigue Resistant Device (FFRD) (3M Unitek Corp, 3M Dental Products, Monrovia, Calif) during the postpeak growth period.

METHODS

Forty-two patients with Class II malocclusion treated during the postpeak growth period were randomly and retrospectively included in this study. These patients were divided into 2 treatment groups: TWB and FFRD. The skeletal, dental, pharyngeal airway, hyoid bone position, and SP measurements were obtained from the lateral cephalometric radiographs taken at the beginning and at the end of the treatment. Paired-samples and independent-samples t tests were used for the intragroup and intergroup comparisons, respectively.

RESULTS

In the TWB group, the SNB (°), Md1-NB (mm), Md1-NB (°), and McNamara upper and lower pharyngeal airway dimensions significantly increased, whereas the ANB (°), AD1-Ba (mm), AD2-H (mm), adenoidal nasopharyngeal area, and SP angle decreased (P < 0.05). In the FFRD group, the SNB (°), Md1-NB (mm), Md1-NB (°), Ptm-Ba (mm), and McNamara upper airway dimensions significantly increased, whereas the ANB (°), AD2-H (mm), and interincisor angle decreased (P < 0.05). Moreover, there were statistically significant differences in the Md1-NB angles and SP thicknesses between the 2 groups (P < 0.05).

CONCLUSIONS

The effects of TWB and FFRD treatment on the airway during the postpeak growth period were similar. However, the FFRD caused a greater mandibular incisor protrusion.

Advanced interdisciplinary treatment protocol for pediatric obstructive sleep apnea including medical, surgical, and orthodontic care: a narrative review

OBJECTIVE

To suggest an updated interdisciplinary treatment protocol for pediatric obstructive sleep apnea (POSA) based on the integration of craniofacial growth modification into medical and surgical sleep practice.

METHODS

PubMed, Scopus, and Cochrane library were searched up to February 2020 using keywords. Among 184 articles, 80 studies were finally included. An integrated treatment protocol for POSA encompassing craniofacial skeletal management as well as medical and surgical care was attempted.

RESULTS

A differential diagnostic workflow for identifying the phenotype of POSA was suggested, and a phenotype-based treatment protocol for POSA was proposed. Despite the lack of high level of evidence, timely skeletal growth modification in three dimensions using craniofacial growth potential could be valuable treatment for upper airway development in POSA patients with craniofacial phenotypic cause.

CONCLUSION

A novel precision treatment protocol will advance clinicians to determine the primary option or to apply the combined strategy for POSA patients.

Effect of functional appliances on the airway in Class II malocclusions

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

Short-term effects of the Sander bite-jumping appliance on the pharyngeal airways in subjects with skeletal Class II malocclusion: A retrospective case-control study

BACKGROUND

Skeletal Class II subjects present often a retruded mandible that might increase the probability of breathing disorders.

OBJECTIVE

To evaluate the effects of functional treatment by means of the Sander bite-jumping appliance (BJA) on the upper airways of growing subjects.

METHODS

Thirty-four subjects (21 males, 13 females; mean age 11.1 ± 1.2 years) with skeletal Class II malocclusion due to mandibular retrusion were treated with the Sander BJA (BJA group). The control group consisted of thirty-four untreated subjects with skeletal Class II malocclusion (25 males, 9 females; 10.4 ± 1.2 years; CTR group). The effect of the Sander BJA appliance on the airway dimensions was evaluated by comparing lateral cephalograms recorded before (T0) and after (T1) the period of observation/treatment. Within- and between-group comparisons were statistically evaluated according to the distribution of the data (P < .05).

RESULTS

The oropharyngeal region (ph_pph) increased in the BJA group (1.8 ± 3.2; P = .001) but the difference respect to the CTR group was not statistically significant (0.73 ± 4.0; P = .314; P = .077). The tongue height (th) increased in the BJA group (2.8 ± 3.7; P < .001), and this increase was statistically significant respect to the CTR group (0.6 ± 4.7; P = .461; P = .038). In the BJA, the Ans_Pns_P angle showed a statistically significant decrease (-3.8 ± 7.8; P = .007) compared to the CTR group (-0.1 ± 5.4; P = .705; P = .026).

CONCLUSIONS

The airway dimensions increased for both control subjects and Class II patients treated with Sander BJA due to physiological growth. The Sander BJA induced a statistically significant change in the tongue and soft palate position, but the clinically relevant of these changes is questionable.

Changes in Upper Airway Dimensions Following Orthodontic Treatment of Skeletal Class II Malocclusion with Twin Block Appliance: A Systematic Review

Objective

This systematic review intends to evaluate the dimensional changes in upper airway dimensions (UAD) of the respiratory tract subsequent to orthodontic treatment of skeletal Class II malocclusion with Twin Block Appliance (TBA).

Methods

The quality of reporting systematic reviews and meta-analyses was decided by the PRISMA standards with PROSPERO registration number CRD42017060317. The systematic search included EMBASE, MEDLINE, Psych INFO, Scopus, CINAHL, and other reference journals and review articles. The article search was performed from March 2017 until November 2017. Cochrane's risk of bias in non-randomized studies - of interventions (ROBINS-I) was used to grade the methodological quality of the included studies.

Results

The screening procedure identified 302 studies, among which seven studies satisfied the inclusion criteria for eligibility. The UAD at the pretreatment time varied from 7.2 mm to 41.9 mm with a mean of 14.16 mm. The post-treatment change in UAD ranged from 8.2 mm to 43.7 mm with a mean of 15.6 mm.

Conclusion

There was a significant increase in UAD following the TBA treatment in the patient group as compared to the control group.

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

INTRODUCTION

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

METHODS

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

RESULTS

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

CONCLUSION

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

[Obstructive sleep disordered breathing and orthodontics: primum non nocere]

Obstructive sleep apnoea syndrome is a widespread and under-diagnosed condition, making it a major public health and safety issue. The objective of this article was to clarify some of the evidence-based elements of therapeutic decision-making and the information provided to the patient and family on the benefit-cost-security ratio of several of his therapeutic options. Published data on the effectiveness of oral appliances and functional orthopaedic appliances for obstructive sleep apnea (OSA) in children, the durability of their effects, the therapeutic possibilities of maxillary or bimaxillary expansion, and the interrelationships between permanent teeth extractions and obstructive sleep disordered breathing, were researched and analyzed. Based on available evidence, in growing patients with Class II malocclusion, treatment with functional orthopedic devices can increase the volume of the pharyngeal airway and thus hopefully reduce the risk of developing OSA. An improvement in the apnea-hypopnea index and lower oxygen saturation was observed in children treated with rapid maxillary expansion. Permanent teeth extractions prescribed for the treatment of teeth crowding in an orthodontic age patient do not result in any significant change in the upper airway. The role of the orthodontist in the multidisciplinary team in the screening and management of Obstructive Sleep Disordered Breathing (OSDB) is essential. By combining clinical experience with published data on various therapeutic approaches, the orthodontist helps the patient to benefit from better adapted care and a more sustainable outcome, while taking into account his or her preferences.

[Upper airways: tridimensional analysis and effect of treatment by functional appliances]

This article revolves around three questions summarizing the main lines of research into the upper airways conducted at Aarhus University. 1. Can the upper airway be reliably evaluated by Cone Beam CT (CBCT)? 2. Is there a link between airway dimension and craniofacial morphology? 3. Do functional appliances increase the volume of the upper airway? 1. The CBCTs of 34 patients were used for this three-dimensional assessment of the upper airway, comparing linear measurements, surfaces and volumes. 2. CBCTs of 90 healthy adults with skeletal class I, II or III were compared. The dimensions of the upper airway were correlated with the cephalometric measurements in 3D. 3. A retrospective CBCT study investigated changes in the upper airway after functional appliance therapy in 20 patients. 1. The upper airway cannot be correctly described using linear measurements. 2. No correlation could be identified between the size and morphology of the upper airway and the morphology of sagittal skeletal class I, II or III malocclusions. 3. An increase in volume of the upper airway was observed after treatment with functional appliances, mainly at the level of the oropharynx. A three-dimensional analysis by CBCT gives a better representation of the anatomical characteristics of the upper airway. This type of 3D analysis revealed a positive effect of treatment by functional appliances on the oropharynx in healthy, growing patients.

Effects of functional appliance treatment on pharyngeal airway passage dimensions in Class II malocclusion subjects with retrognathic mandibles: A systematic review

Objective:

The objective of this study was to assess the pharyngeal airway passage (PAP) dimension changes following functional appliance treatment in Class II malocclusion subjects with retrognathic mandibles.

Materials and Methods:

Two authors independently searched various electronic databases such as PubMed, Cochrane Database of Systematic Reviews, Cochrane Central Register of Controlled Trials, Scopus, NCBI, and Google Scholar for the available literature within the period from January 1, 2001, to December 31, 2018. On the basis of population, intervention, comparison, and outcome, “changes in PAP dimensions following functional appliance therapy in skeletal Class II malocclusion subjects associated with mandibular retrusion” was considered as search question of the study. After the selection and removal of duplicate articles, assessment for risk of bias was calculated and the data from the included articles were extracted by two authors independently.

Results:

From six databases and additional hand searching, a total of 5784 articles were extracted. Of 5784 articles, 3754 articles were screened after removal of 2030 duplicates. After going through the title and abstract, 3197 articles were excluded and 40 articles were assessed for full text. From these 40 articles, eight articles fulfilled our inclusion and exclusion criteria for the qualitative synthesis review.

Conclusions:

The correction of mandibular deficiency by functional appliances has minimum effect on the nasopharynx. Functional appliance treatment has a significant effect on the improvement of the oropharyngeal airway. Changes of hypopharyngeal airway passage need to be studied further among Class II malocclusion subjects with retrognathic mandibles.

Pharyngeal dimensional changes in class II malocclusion treatment when using Forsus® or intermaxillary elastics - An exploratory study

OBJECTIVE

Pharyngeal airway obstruction can facilitate some forms of sleep disorder breathing (SDB) in susceptible children, especially in those having class II malocclusion. Changes in the anatomic areas surrounding the pharyngeal region during orthodontic treatment could hypothetically impact the pharyngeal airway dimensions. Management of a class II malocclusion on a growing individual with either intermaxillary elastics or different removable or fixed class II appliance designs have been proposed over the last century. The objective of this retrospective exploratory cohort study is to investigate to what extent the class II malocclusion treatment with either intermaxillary elastics (IME) or Forsus® fatigue resistance device (FFRD) leads to changes in oropharyngeal airway dimensions.

MATERIALS AND METHODS

Twenty-nine patients diagnosed as class II with an average age of 12.7years were included in this study, (11 males, 18 females). The sample was divided into group 1: IME and group 2: FFRD. CBCT's scans before (T1) and after treatment (T2) were obtained and analysed using Dolphin software. Reliability was obtained using Intraclass Correlation Coefficient (ICC). Descriptive statistics, ANOVA and paired t-test were used for analysis.

RESULTS

Intra-rater reliability test was excellent in all measurements for both groups. There were no statistically significant differences in pharyngeal airway dimensions between both groups (P=0.919). A statistically significant correlation was found for sex, where male patients had the highest increase in oro-space area (ORS), and in oropharyngeal volume. Children under 14-year-old in IME group showed statistically negative correlation for sub-mandibular (SM) and for ORS, meaning the younger the greatest increase. Additionally, individuals younger than 14years had a statistically significant increase in the vertical dimension.

CONCLUSIONS

Both orthodontic treatment approaches appear to be associated with a similar increase in oropharyngeal airway dimensions. Male patients under 14-year-old had a greater significant increase compared to female patients and older children. Normal pharyngeal dimensions changes were not accounted for.

Three-dimensional evaluation of changes in upper airway volume in growing skeletal Class II patients following mandibular advancement treatment with functional orthopedic appliances

OBJECTIVES

The aim of this study was to assess three-dimensionally the upper airway changes following functional appliance treatment in growing Class II patients.

MATERIALS AND METHODS

Pre-and post-treatment Cone beam computed tomography scans of 20 patients (age range: 9 to 12; mean: 11.4 ± 1.0 years) were retrieved from the list of patients previously treated with functional appliances in the Postgraduate Clinic at the Section of Orthodontics, Aarhus University, Denmark. Total and partial volumes of the upper airway (ie, lower nasopharynx, velopharynx, and oropharynx) were calculated. To rule out the effect of growth, the changes in the functional appliance group were compared to an age-matched Class I group of 18 patients (age range: 8 to 14; mean: 11.8 ± 1.4 years).

RESULTS

In the functional appliance group, all the partial and total volumes were significantly larger at the end of treatment when compared to the start of treatment ( P < .003). On the other hand, when comparing the changes for the total and partial volumes of the upper airway in the functional appliance group with the Class I group, a statistical difference was seen only for the oropharynx ( P = .022) and total volume ( P = .025), with the functional appliance group showing a larger volume increment.

CONCLUSIONS

An increase in the upper airway volume was found after treatment with functional appliances. This difference was mainly related to the changes at the oropharynx level, which differed significantly from what was observed in the Class I group.