Assessment of upper airway size after orthopedic treatment for maxillary protrusion or mandibular retrusion

Long-term changes in skeletal and airway dimensions in patients treated with headgear compared with untreated control subjects

INTRODUCTION

The objective of this study was to evaluate the short-term and long-term skeletal and airway changes associated with the use of headgear and to compare these changes to a group of untreated control subjects.

METHODS

The sample included 2 Class II groups: a group treated with cervical headgear and a group of untreated control subjects, with 30 subjects in each group. Lateral cephalograms were taken at 3 time points: pretreatment (T1), posttreatment (T2), and long-term postretention (T3), and a single examiner performed skeletal and airway measurements. Paired samples t test was used to compare T1, T2, and T3 skeletal and airway measurements within the groups, and independent samples t test was used to compare treatment (T2 - T1), posttreatment (T3 - T2), and overall (T3 - T1) skeletal and airway changes in the treatment group compared with the control group.

RESULTS

There was a significant decrease in the SNA (3.1°) and an increase in the SN-PP (1.5°) in the treatment group at T2 (P <0.001), which remained significant at T3 (P <0.05). In addition, there was a significant short-term increase in the mandibular plane angle and a decrease in SNB (P <0.05). Paired t tests showed no significant change in airway width within the treatment group (P >0.05). The independent samples t test showed no significant differences in any of the changes in airway variables between the groups (P >0.05).

CONCLUSIONS

The use of headgear did not result in any change in airway width, both short-term and long-term. A decrease in SNA and an increase in SN-PP were found with the use of the headgear, and these changes remained stable for up to 8 years posttreatment.

How does changing the vector of transport disc distraction affect the outcomes of surgery in patients of temporomandibular joint ankylosis with obstructive sleep apnea?

PURPOSE

Temporomandibular joint ankylosis (TMJA) in children is associated with retrognathia, reduction in pharyngeal airway volume (PAV), and obstructive sleep apnea (OSA). Distraction-osteogenesis (DO) is the proven method in the management of OSA. There is paucity in literature about the effect of distraction vector on PAV. It can be expected that an oblique vector would improve PAV and relieve OSA. Thus, the study was designed to explore the feasibility, advantages, and disadvantages of this modified technique for managing TMJA and OSA simultaneously.

MATERIALS AND METHOD

The investigators designed a prospective study on patients of TMJA with retrognathia. Ethical approval was obtained (IECPG-547/14.11.2018). In all patients, simultaneous ankylosis release and mandibular distraction were performed. Primary outcome variables were improvement in 3-dimensional (3D) PAV and maximal interincisal opening (MIO). Secondary outcome variables were changed mandibular length, distraction relapse, and re-ankylosis. Paired t-test and multivariate ANOVA were used to assess all the parameters.

RESULT

The study included 13 joints in 8 patients of TMJA with retrognathia (2 unilateral and 6 bilateral ankylosis) with mean age of 14.25 ± 7.37 years. Mean distraction performed was 19 ± 4.0 mm. There was a statistically significant improvement of PAV by 225% (p = 0.002), a reduction in Epworth's scale (p = 0.017), an increase in MIO (p = 0.001), and an increase in mandibular length. Three patients had re-ankylosis at the 25-month follow-up.

CONCLUSION

The results of the present study conclude that modification of distraction vector improves 3D PAV and MIO in TMJA patients, with the added advantage of a reduction in overall treatment time and improved patient compliance.

Effects of maxillary expansion and protraction on pharyngeal airway dimensions in relation to changes in head posture and hyoid position : A retrospective cohort study

PURPOSE

To assess changes in pharyngeal airway dimensions, head posture and hyoid position after maxillary expansion and face mask (FM) treatment compared to untreated class III patients.

METHODS

This study examined 24 class III patients (10 girls, 14 boys, mean age: 10.97 ± 0.88 years) treated with expansion and a petit-type FM appliance and 24 untreated class III patients (16 girls, 8 boys, mean age: 10.50 ± 1.06 years). Pre- and posttreatment cephalometric radiographs were digitally analysed. Parametric data were analysed with paired and independent-samples t‑tests, nonparametric data were analysed with Wilcoxon signed-rank and Mann-Whitney U tests. Spearman's correlation analysis was used to examine the relationship between dental/skeletal treatment changes and those of craniocervical postural position, pharyngeal airway dimension and hyoid position.

RESULTS

With respect to the hypopharyngeal airway dimension, the hypopharyngeal sagittal length (CV3'-LPW), velar angle (HRL/U-PNS) and velar length (U-PNS) significantly increased in the treatment group. All the parameters describing head posture and those describing the distances of the hyoid bone to the HRL changed significantly after treatment, but these changes were not significantly different from the control group. In the treatment group, there also occurred a significant increase in the sagittal growth of the maxilla (SNA, Co‑A, Na-Perp A, Wits), vertical growth of the maxillomandibular complex (SN-GoGN, N‑ANS, N‑Me), counterclockwise rotation of the maxilla (SN-PP) and overjet, while a clockwise rotation (y-axis) and a nonsignificant inhibition of the sagittal growth (Co-Gn) of the mandible were observed. The treatment induced increases of hypopharyngeal sagittal length (CV3'-LPW), soft palate thickness and anteroposterior movement of hyoid bone (H-CV3) demonstrated a positive correlation with changes of craniocervical angles (NSL/OPT, NSL/CVT) and a negative correlation with craniohorizontal angles (OPT/HOR, CVT/HOR). The change of the anteroposterior movement of hyoid bone (H-CV3) was also positively correlated with oropharyngeal sagittal length (CV2'-MPW), the hypopharyngeal sagittal length (CV3'-LPW) and the minimal dimension of the pharyngeal airway space (PASmin).

CONCLUSION

While expansion and FM treatment did not affect the head posture and hyoid bone position, positive effects were observed in the hypopharyngeal airway region.

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.

Comparison of oropharyngeal airway dimensional changes in patients with skeletal Class II and Class III malocclusions after orthognathic surgery and functional appliance treatment: A systematic review

Objective

To compare the dimensional changes in the oropharyngeal airway in patients with skeletal Class II and Class III malocclusion before and after orthognathic surgery and treatment with a functional appliance.

Methods

The protocol was developed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analysis Protocols (PRISMA-P) and was registered to the International Prospective Register of Systematic Reviews (PROSPERO) under the registration number CRD42020170901. Furthermore, the reporting of the present SR was performed based on the PRISMA checklist.

Results

The use of removable functional appliances increased the volume of the oropharyngeal airway in patients with skeletal Class II malocclusion. Furthermore, the increase in the volume of the oropharyngeal airway following the removable functional appliance treatment was more than that observed after fixed functional appliance treatment in growing patients. For patients with skeletal Class III malocclusion, who underwent the bimaxillary orthognathic surgery, resulted in no change in the dimensions of the oropharyngeal airway.

Conclusion

Growing patients who receive removable functional appliance treatment have a more favorable long-term prognosis with regard to the oropharyngeal airway when compared with those who receive fixed functional appliance. Alternatively, in patients aged from (18–22) years with skeletal class III malocclusion Bimaxillary orthognathic surgery was found to be the recomended and superior method of treatment.

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.

Orthopedic Treatment for Class II Malocclusion with Functional Appliances and Its Effect on Upper Airways: A Systematic Review with Meta-Analysis

Aim of this systematic review was to assess the effects of orthopedic treatment for Class II malocclusion with Functional Appliances (FAs) on the dimensions of the upper airways. Eight databases were searched up to October 2020 for randomized or nonrandomized clinical studies on FA treatment of Class II patients with untreated control groups. After duplicate study selection, data extraction, and risk of bias assessment according to Cochrane guidelines, random effects meta-analyses of mean differences (MDs) and their 95% confidence intervals (CIs) were performed, followed by subgroup/meta-regression analyses and assessment of the quality of evidence. A total of 20 nonrandomized clinical studies (4 prospective/16 retrospective) including 969 patients (47.9% male; mean age 10.9 years) were identified. Orthopedic treatment with FAs was associated with increased oropharynx volume (MD = 2356.14 mm³; 95% CI = 1276.36 to 3435.92 mm³; p < 0.001) compared to natural growth. Additionally, significant increases in nasopharynx volume, minimal constricted axial area of pharyngeal airway, and airway were seen, while removable FAs showed considerably greater effects than fixed FAs (p = 0.04). Finally, patient age and treatment duration had a significant influence in the effect of FAs on airways, as had baseline matching and sample size adequacy. Clinical evidence on orthopedic Class II treatment with FAs is associated with increased upper airway dimensions. However, the quality of evidence is very low due to methodological issues of existing studies, while the clinical relevance of increases in airway dimensions remains unclear.

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 airway spaces in different skeletal malocclusions: a CBCT 3D assessment

Objective: To three-dimensionally evaluate the upper pharyngeal airway spaces in adults with different anteroposterior and vertical skeletal malocclusions.Methods: In this retrospective study, three-dimensional airway volume and the minimum constricted areas of 120 adults were measured from cone beam computed tomography volume scans. The sample was divided into skeletal Class I and Class II and subdivided into average and long face malocclusions in each skeletal Class. Airway volumes of the naso-, palato-, and glossopharynx, and the minimum constricted area were measured and compared.Results: Skeletal Class II reduced glossopharyngeal airway volume and larger total minimum constricted area in average faces and more nasal minimum constricted area in long faces. Skeletal Class II with long face significantly increased palatopharyngeal and glossopharyngeal airway volumes as well as larger palatopharyngeal minimum constricted area (p < 0.05).Conclusion: This paper found a likely association between jaw skeletal classification and airway dimensions.