Long-term Evaluation (10 Years) of the Outcomes of Herbst Functional Appliance in Pharyngeal Dimensions and Hyoid Bone Position in the Treatment of Class II Patients

Long-term Evaluation (10 Years) of the Outcomes of Herbst Functional Appliance in Pharyngeal Dimensions and Hyoid Bone Position in the Treatment of Class II Patients | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Long-term Evaluation (10 Years) of the Outcomes of Herbst Functional Appliance in Pharyngeal Dimensions and Hyoid Bone Position in the Treatment of Class II Patients Thagid Yasmin Leal Almeida, Tiago Fialho, Karina Maria Salvatore de Freitas, and 2 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-4536044/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract Objective: This study aimed to evaluate the long-term changes in the pharyngeal dimensions and hyoid bone position in Class II malocclusion patients treated with Herbst functional appliance. Design: Retrospective cohort study. Setting: Department of Orthodontics, Bauru Dental School, University of São Paulo – Brazil. Methods: The sample comprised 15 skeletal Class II malocclusion patients (13.00 years old ± 1.21) treated with Herbst functional appliance and followed for a mean period of 10 years (10.73 years ± 3.67). Lateral headfilms were used to evaluate the pharyngeal dimensions and hyoid bone position, and the measurements were performed with Dolphin® Imaging 11.9. Intragroup comparison between the evaluation stages was performed with repeated measures ANOVA, followed by Tukey tests if necessary. Results were considered statistically significant at p<0.05. Results: Regarding the pharyngeal cephalometric variables, only the lower airway space increased significantly in the treatment period, and all of them remained stable remained stable during follow-up period. The hyoid bone moved significantly forward and downward during the treatment period and even further forward during the long-term posttreatment period. Conclusion: The outcomes of Herbst functional appliance in pharyngeal dimensions and hyoid bone position are stable over the years. Malocclusion Angle Class II. Orthodontic Appliances Functional. Pharyngeal Airway. Hyoid Bone. Effects Long-Term Figures Figure 1 INTRODUCTION Class II malocclusion is one of the most prevalent orthodontic problems globally and represents approximately one-third of the patients seeking orthodontic treatment.[ 1 ] This malocclusion is present in about 15% of the United States population[ 1 ], and 38% of Brazilian children[ 2 ]. The relationship between sagittal skeletal pattern and airway space has been the subject of several studies, and the different anteroposterior skeletal patterns influence airway dimensions.[ 3 , 4 ] Compared to children with normal occlusions, children with skeletal Class II malocclusion have significantly smaller nasopharyngeal dimensions[ 5 ] and have a higher risk of future respiratory problems.[ 4 ] Functional Appliances (FAs) are routinely used to treat children with Class II skeletal malocclusion due to mandibular retrognathism[ 6 ], and it may help increase the airway dimensions, preventing respiratory disorders.[ 7 ] Thus, in some cases, orthodontic treatment can be chosen that improves not only the maxillomandibular relationship but also reduces the risk of acquiring Obstructive Sleep Apnea Syndrome (OSAS).[ 8 ] The Herbst appliance is a fixed functional orthopedic device for treating Class II malocclusion with several advantages compared to removable functional appliances.[ 9 ] Among its advantages, it may lead to changes in facial profile and muscle activity.[ 10 ] Many variations in Herbst design have occurred over the years. The Cantilever Bite Jumper (CBJ) marked a significant advancement in Herbst appliance designs, particularly in terms of facilitating dentition transition.[ 11 ] Previous studies have evaluated the association between fixed functional orthopedic appliances to treat Class II patients with mandibular retrognathism and changes in airway dimensions[ 12 , 13 ], and it is a controversial subject. Specifically, about the association between airway and Class II malocclusion treatment with Herbst functional appliance, some studies showed dimension improvement of specific regions of the upper airway[ 14 – 17 ] while others showed no significant changes in any of them.[ 13 , 18 ] Furthermore, it is important to realize that some studies of airway dimensions changes by Class II malocclusion treatment with Herbst appliance associated this protocol with rapid maxillary expansion (RME).[ 14 , 16 ] Modification of pharyngeal airway by RME is described in the literature[ 19 ], and these results must be carefully evaluated. Long-term follow-up of any orthodontic treatment is essential to assess the effectiveness of the treatment. Therefore, this study aimed to evaluate long-term changes in airway dimensions and hyoid bone position in patients with Class II malocclusion treated with the Herbst functional appliance. MATERIAL AND METHODS The present study was approved by the Ethics Committee in Human Research of Bauru Dental School, under protocol number CAAE: 22082219.0.0000.5417. The sample size was calculated with a statistical power of 0.80 and an alpha of 5% to detect a mean difference of 0.25 mm for the middle airway space (U-MPW) with a standard deviation of 0.32 mm, obtained in the study conducted by Göymen, Mourad, and Güleç.[ 12 ] The result showed the need for 15 patients. The sample for the study group was taken retrospectively from the Department of Orthodontics, __________________________________, and the patients selected had attended by graduate students. The inclusion criteria were patients aged between 11 and 15 years old, with initial Angle Class II, division 1 malocclusion and mandibular retrognathism; who underwent functional orthopedic treatment with Herbst, associated with fixed orthodontic appliance; ANB angle > 4º; SNB angle < 80º; complete orthodontic records, including lateral headfilms available in three moments: T1, pretreatment; T2, posttreatment (Herbst followed by fixed orthodontic appliance); and T3, long-term follow-up (at least seven years posttreatment). The exclusion criteria were history of previous orthodontic/orthopedic treatment; loss of any permanent teeth; palatal/lip cleft symptoms; chronic mouth breathing; permanent snoring; and tonsillectomy or adenoidectomy. The patients selected were treated without extractions with Herbst variation - Cantilever Bite Jumper (CBJ - Ormco Corporation, Orange, California, USA) orthopedic approach, followed by fixed appliances. After correction of Class II malocclusion, fixed orthodontic appliances were used to refine the occlusion (Roth prescription, Morelli, Sorocaba, Brazil). Patients wore a fixed mandibular retainer for at least five years after treatment and a Hawley maxillary plate for one year after treatment. The lateral headfilms were digitized and analyzed with Dolphin® Imaging 11.9 software (Patterson Dental Supply, Inc., Chatsworth, California, USA) by a single examiner (T.Y.). The software corrected the image magnification factors according to the respective X-ray unit's settings and instructions. The cephalometric landmarks and analysis of the pharyngeal structures and hyoid bone position were based on the methods described previously by Liu et al.[ 20 ] and Zong et al.[ 21 ] (Table 1 , Fig. 1 ). In addition, the cephalometric variables representing the dentoskeletal pattern were evaluated by Steiner analysis.[ 22 ] A customized cephalometric analysis generated 13 variables, six angular and seven linear, for each tracing (Table 2 ). Table 1 Definitions of the cephalometric landmarks used in the present study. Cephalometric landmarks Definition N The most anterior point of the frontonasal suture in the sagittal view S Center of the pituitary fossa A Point of maximum concavity in the midline of the alveolar process of the maxilla in the sagittal view B Point of maximum concavity in the midline of the alveolar process of the mandible in the sagittal view Me Most inferior point of the mandibular symphysis in the sagittal view Go The deepest point of the curvature of the angle of the mandible between the inferior border of corpus and posterior border of the ramus of mandible in sagittal view U1 Maxillary incisor tip L1 Mandibular incisor tip U The lower end of the soft palate V The most posteroinferior point on the base of the tongue SPP Point of intersection of a line from soft palate center perpendicular to the posterior pharyngeal wall and posterior margin of the soft palate SPPW Point of intersection of a line from soft palate center perpendicular to the posterior pharyngeal wall and posterior pharyngeal wall MPW Foot point of a perpendicular line from point U to the posterior pharyngeal wall LPW Foot point of a perpendicular line from point V to the posterior pharyngeal wall Hy The most anterior point on the hyoid bone C3 The most anteroinferior point on the corpus of the third cervical vertebra Table 2 Summary of the variables used for the cephalometric comparisons. Variable Interpretation Skeletal component SNA Angle between SN and NA SNB Angle between SN and NB ANB Angle between AN and NB SN.GoGn Angle between S-N and Go-Gn Dentoalveolar component U1-NA Distance between NA line and the most anterior point of the maxillary incisor crown U1.NA Angle between NA line and the long axis of the maxillary incisor L1-NB Distance between NB line and the most anterior point of the lower incisor crown L1.NB Angle between NB line and the long axis of the mandibular incisor Pharyngeal airway SPP-SPPW Superior airway space: Distance between SPP and SPPW (nasopharynx / palatopharynx) U-MPW Middle airway space: Distance between U and MPW V-LPW (mm) Inferior airway space: Distance between V and LPW Hyoid bone position Hy-C3 Distance between the most anterior point of the hyoid bone and the most anteroinferior point in the body of the third cervical vertebra Hy-MPperp Distance from the mandibular plane (Go-Me) perpendicular to the hyoid bone Error study Thirty percent of the headfilms were randomly selected, retraced, and remeasured by the single examiner (T.Y.) after a month interval. IntraClass Correlation Coefficient (ICC) was used for test reliability. Statistical analyses Normal distribution was evaluated and confirmed with Shapiro-Wilk tests. Intragroup comparison between the three evaluation stages was performed with repeated measures ANOVA, followed by Tukey tests if necessary. Results were considered statistically significant at P < 0.05. Statistical analyses were performed with Statistica software (Statistica for Windows 12.0; Statsoft, Tulsa, Okla, USA). RESULTS The sample was composed of 15 subjects (5 female; 10 male), with a mean age of 13.00 years (SD 1.21). Herbst appliance was used during a mean period of 1.18 years (SD 0.19), and the second period of treatment (comprehensive treatment) lasted a mean time of 3.01 years (SD 1.48) (Table 3 ). Post-treatment changes were evaluated 10.73 years (SD 3.67) after orthodontic treatment. Table 3 Descriptive characteristics of the sample. X n = 15 Stage/Period Mean S.D. T1 age 13.00 1.21 T2 age 18.02 1.78 T3 age 28.75 4.37 Total treatment period (T2-T1) 5.02 1.55 Long-term Posttreatment period (T3-T2) 10.73 3.67 Sex Male Female 10 (66.66%) 5 (33.33%) IntraClass correlation coefficients for the two separate measurements on the lateral headfilms ranged between 0.968 (Hy-Mp perp) and 0.997 (Md1.NB), indicating excellent reliability.[ 23 ] Regarding treatment changes, the skeletal components showed significant increase in the SNB angle, improvement in the maxillomandibular relationship, and mandibular counterclockwise rotation. There were no significant changes in the dentoalveolar components. The lower airway, the distance between the hyoid bone and the third cervical vertebra and the distance between the mandibular plane perpendicular to the hyoid bone have undergone significant changes, increasing in the treatment period (Table 4 ). Table 4 Intragroup comparisons of the cephalometric variables among the three stages (repeated measures ANOVA, followed by Tukey tests). Variables T1 T2 T3 p Mean (s.d.) Mean (s.d.) Mean (s.d.) Skeletal components SNA (°) 81.76 (2.66) 81.15 (2.99) 81.32 (3.14) 0.416 SNB (°) 76.22 (1.97) A 77.85 (2.23) B 78.32 (2.77) B 0.008* ANB (°) 5.51 (1.77) A 3.29 (1.89) B 2.99 (1.95) B 0.000* SN.GoGn (°) 31.54 (4.95) A 29.60 (3.77) B 29.04 (5.48) B 0.047* Dentoalveolar components U1-NA (mm) 4.18 (3.02) 4.61 (1.64) 4.74 (1.86) 0.672 U1.NA (°) 23.03 (10.20) 25.32 (6.64) 25.95 (7.29) 0.380 L1-NB (mm) 4.64 (2.72) 6.07 (1.87) 5.74 (2.24) 0.066 L1.NB (°) 25.45 (8.48) 30.49 (5.81) 28.72 (5.63) 0.084 Pharyngeal airway SPP-SPPW (mm) 11.68 (2.41) 12.23 (2.12) 10.99 (2.32) 0.104 U-MPW (mm) 9.88 (2.63) 9.43 (2.53) 9.62 (2.58) 0.758 V-LPW (mm) 15.94 (2.53) A 18.32 (3.60) B 19.09 (3.93) B 0.007* Hyoid bone position Hy-C3 (mm) 31.45 (3.35) A 34.65 (4.88) B 36.48 (5.57) C 0.000* Hy-MPperp (mm) 15.14 (3.29) A 18.58 (3.88) B 21.07 (4.22) B 0.002* * Statistically significant at p < 0.05 Different letters in the same row indicate the presence of a statistically significant difference between the stages. In the long-term posttreatment period, only the distance between the hyoid bone and the third cervical vertebra suffered significant changes, increasing (Table 4 ). DISCUSSION Although previous studies evaluated the association between airways and functional appliances[ 3 , 24 – 26 ], the long-term follow-up is important to discuss the effectiveness and stability of the treatment and remains unclear. Our study assessed upper airway dimensions and hyoid bone position changes in Class II patients with mandibular retrognathism treated with Herbst CBJ functional appliance for an average of 10 years (10.73y ± 3.67) of follow-up. The sample size was sufficient to give reliability to the results. Statistical significance was achieved, indicating that the treatment effect was large enough to be detected in a limited sample. In addition, although a small sample size, it is substantial because the subjects were evaluated more than ten years post-treatment. Another study conducted similar research showed similar samples.[ 18 ] For ethical reasons, it seems obvious the impossibility of long-term follow-up of untreated Class II individuals. Moreover, most of the growth of airway structures finishes in early childhood, and only a slight continuous increase of about 1 mm was detected between 6 and 17 years of age.[ 27 ] Our sample was 18.02 years old (SD 1.78) at the end of treatment, then there was expected to be no increase in the airway dimensions from growth in the follow-up period. Although three-dimensional imaging (3D) using cone-beam computed tomography (CBCT) to evaluate changes in airway dimensions is preferred to a lateral cephalometric radiograph, CBCT is not a standard diagnosis method in Orthodontics and routine use is not recommended for legal and ethical reasons because of radiation exposure.[ 28 ] Furthermore, the literature shows a significant correlation between sagittal cephalometric measurements of the airway and 3D analysis with CBCT imaging.[ 29 ] Therefore, this method for analyzing the airway is still a valid tool as it is inexpensive, has minimal dose radiation, and gives accurate measurements.[ 30 ] Regarding the treatment changes in the skeletal components, the sample underwent an improvement in mandibular position, as previously reported for similar appliances, probably due to treatment and normal growth changes[ 31 ]; mandibular counterclockwise rotation which is in agreement with a previous study[ 16 ], and improvement in maxillomandibular relationship, as the literature has already shown[ 32 ], represented mainly by the changes in the mandibular component and growth.[ 6 ] There were no significant changes in the dentoalveolar variables with treatment and it is corroborated by previous studies that found that Herbst CBJ variation causes less mandibular incisor protrusion when compared to other designs of this appliance.[ 31 ] Concerning the airway variables, a significant change was observed only in the lower airway space during treatment, increasing. This find is in agreement with previous study that found that the hypopharynx region has the greatest dimensional increase in treatment with the Herbst appliance[ 15 ], and other studies that reported increase in hypopharynx with Herbst treatment.[ 14 , 16 , 33 ] This fact is probably related to the forward shift of the mandible, plus some growth effect.[ 15 , 16 ] Some studies that evaluated the effects of the Herbst device on the airways reported an increase in the oropharyngeal region, but this was not found in our study.[ 14 – 17 ] Dentoalveolar changes by functional orthopedic appliances, especially mandibular incisor protrusion, may be responsible for more anterior tongue position and increase in airways dimensions.[ 34 ] In our study the sample did not show significant changes in the dentoalveolar variables, which can explain the insignificant changes in the oropharynx. Most studies that evaluated the relationship between treatment with Herbst appliance and the maxillary airway did not evaluate the hyoid bone position. Changes in hyoid bone position are related to mandibular position changes.[ 35 ] In the present study hyoid bone was moved significantly forward and downward in the treatment period, which corroborates with previous studies that showed anterior displacement of the mandible by the functional appliances improving the horizontal position of the hyoid bone and, consequently, the position of the tongue, increasing upper airway dimensions.[ 14 , 25 ] The downward displacement of the hyoid bone after Class II functional treatment was also reported in the literature previously.[ 36 , 37 ] Change in the hyoid bone position in a superior direction was reported after functional advancement of the mandible, however, in the long term, it resumed its original position as a compensatory action.[ 38 ] More information about the long-term effects of fixed functional appliances in the airway dimension is needed. To the best of our knowledge, only one study has evaluated the long-term effects of fixed functional appliances on upper airway[ 18 ], and they did not analyze the changes in the hypopharynx dimension and hyoid bone position, and included patients treated with extraction in their sample. Tooth extraction can interfere with airway dimensions, although in different ways in different malocclusions. In Class II patients, after extraction of maxillary premolars, there was a reduction in the dimensions of the velopharynx.[ 39 ] In contrast, mesial movements of molars in Class I patients increased the posterior space of the tongue, consequently increasing the dimensions of the airway.[ 39 ] Some authors have researched the long-term effects of removable functional appliances in the upper airway[ 37 , 40 ], however it is important to note that different functional appliances may affect the dentoalveolar and skeletal structures[ 24 ], as well in the upper airway and hyoid bone position.[ 25 , 41 ] In the present study, only the horizontal position of the hyoid bone changed significantly in the long-term posttreatment period, moving forward, which agrees with the study by Ulusoy.[ 37 ] All other variables remained stable during this period, converging with results from previous long-term follow-up studies with functional appliances.[ 37 , 40 ] Our results have a relevant clinical impact, considering that Orthodontists can ensure that the outcomes of Herbst functional appliance in pharyngeal dimensions and hyoid bone position are stable over the years. As this is a retrospective study, we do not know if special instruction was given to the patient about the tongue and head position in the lateral cephalogram records, affecting our findings. Another limitation of this study was that a retrospective study design could not include body mass index (BMI). Body mass index has been shown to impact the airway dimensions in children[ 42 ] and adults[ 43 ] and may have influenced the airway measurements. Future studies should be conducted to correlate dimensional changes in the airways and the impact on respiratory problems and sleep disorders. CONCLUSION During treatment, the sample showed a significant increase in the hypopharynx, which may be related to the forward shift of the mandible, plus some growth effect. The hyoid bone was moved forward and downward as a treatment effect. All studied variables remained stable in long-term follow-up, except for the horizontal position of the hyoid bone which changed significantly, moving forward. Declarations Conflicts of interest: All authors of this study declare no conflicts of interest or other relationships/conditions/circumstances that present a potential relationship of conflict of interest. Funding: This work was supported by the Coordination for the Improvement of Higher Education Personnel (CAPES) [finance code 001]. Author Contribution Thagid Yasmin Leal Almeida: Study concept and design, data acquisition and analysis, validation, manuscript draft, manuscript review & editing.Tiago Fialho: Study concept and design, manuscript draft, manuscript review & editing.Karina Maria Salvatore Freitas: Data acquisition and analysis, manuscript draft, data curation, English revision.José Fernando Castanha Henriques: Study concept and design, data acquisition and analysis, scientific revision.Marcos Roberto de Freitas: Study concept and design, statistical analysis, validation, visualization, manuscript review& editing, project administration, scientific revision. 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Thorax 73:538–545 Mayer P, Pépin JL, Bettega G, Veale D, Ferretti G, Deschaux C, Lévy P (1996) Relationship between body mass index, age and upper airway measurements in snorers and sleep apnoea patients. Eur Respir J 9:1801–1809 Additional Declarations No competing interests reported. Cite Share Download PDF Status: Posted Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-4536044","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":318893007,"identity":"f25af13c-141a-4090-876b-27952fdfb52d","order_by":0,"name":"Thagid Yasmin Leal Almeida","email":"","orcid":"","institution":"Bauru Dental School","correspondingAuthor":false,"prefix":"","firstName":"Thagid","middleName":"Yasmin Leal","lastName":"Almeida","suffix":""},{"id":318893008,"identity":"231c3010-84d2-4fd1-91d5-3cc5ee438252","order_by":1,"name":"Tiago Fialho","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA20lEQVRIiWNgGAWjYDACZsYHBxgKDjDwS4C5EjIEdfAwMxscYAAiyRkMjA1ALTyEtTAwGzCAtBjcAGthIKzFnp2Z8cAPgztyxrebjz+6UWPBw8B++OgGAg5jONhj8MzY7M6xxOacY0CH8aSl3cCvhf/AAR6Dw4nbbuQYNuewAbVI8JgR0AK05Q9Qy+YZIC3/iNRyGGTLBgmgltw2YrQcBmqRMThsLHEjLXF2bp8EDxshv7D3H2b++KbisBz/jOQDn3O+1cnxsx8+hlcLJmAjTfkoGAWjYBSMAmwAAIivRdNv1EsUAAAAAElFTkSuQmCC","orcid":"","institution":"Bauru Dental School","correspondingAuthor":true,"prefix":"","firstName":"Tiago","middleName":"","lastName":"Fialho","suffix":""},{"id":318893009,"identity":"2d07ca5f-a257-42d1-9375-8117ceed3a41","order_by":2,"name":"Karina Maria Salvatore de Freitas","email":"","orcid":"","institution":"Ingá University Center","correspondingAuthor":false,"prefix":"","firstName":"Karina","middleName":"Maria Salvatore","lastName":"de Freitas","suffix":""},{"id":318893010,"identity":"853e9101-206f-4064-b320-3c91f180c42c","order_by":3,"name":"José Fernando Castanha Henriques","email":"","orcid":"","institution":"Bauru Dental School","correspondingAuthor":false,"prefix":"","firstName":"José","middleName":"Fernando Castanha","lastName":"Henriques","suffix":""},{"id":318893011,"identity":"0b06a631-d7d0-49b3-9845-9a39e00533d6","order_by":4,"name":"Marcos Roberto de Freitas","email":"","orcid":"","institution":"Bauru Dental School","correspondingAuthor":false,"prefix":"","firstName":"Marcos","middleName":"Roberto","lastName":"de Freitas","suffix":""}],"badges":[],"createdAt":"2024-06-05 19:59:22","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-4536044/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-4536044/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":59870375,"identity":"f6f923ea-a8fb-499d-b223-2e83b4b4c662","added_by":"auto","created_at":"2024-07-08 16:58:43","extension":"jpg","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":228574,"visible":true,"origin":"","legend":"\u003cp\u003eDiagram of landmarks and variables associated with upper airway and hyoid bone.\u003c/p\u003e","description":"","filename":"Figure1.jpg","url":"https://assets-eu.researchsquare.com/files/rs-4536044/v1/98f75f7c84623c91929620d5.jpg"},{"id":60466543,"identity":"48553e09-413e-4c53-834f-3dbabd976479","added_by":"auto","created_at":"2024-07-17 05:29:21","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":809917,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-4536044/v1/87898011-d51c-4823-b7f8-723114a411f3.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"\u003cp\u003eLong-term Evaluation (10 Years) of the Outcomes of Herbst Functional Appliance in Pharyngeal Dimensions and Hyoid Bone Position in the Treatment of Class II Patients\u003c/p\u003e","fulltext":[{"header":"INTRODUCTION","content":"\u003cp\u003eClass II malocclusion is one of the most prevalent orthodontic problems globally and represents approximately one-third of the patients seeking orthodontic treatment.[\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e] This malocclusion is present in about 15% of the United States population[\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e], and 38% of Brazilian children[\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eThe relationship between sagittal skeletal pattern and airway space has been the subject of several studies, and the different anteroposterior skeletal patterns influence airway dimensions.[\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e, \u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e] Compared to children with normal occlusions, children with skeletal Class II malocclusion have significantly smaller nasopharyngeal dimensions[\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e] and have a higher risk of future respiratory problems.[\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e]\u003c/p\u003e \u003cp\u003eFunctional Appliances (FAs) are routinely used to treat children with Class II skeletal malocclusion due to mandibular retrognathism[\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e], and it may help increase the airway dimensions, preventing respiratory disorders.[\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e] Thus, in some cases, orthodontic treatment can be chosen that improves not only the maxillomandibular relationship but also reduces the risk of acquiring Obstructive Sleep Apnea Syndrome (OSAS).[\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e]\u003c/p\u003e \u003cp\u003eThe Herbst appliance is a fixed functional orthopedic device for treating Class II malocclusion with several advantages compared to removable functional appliances.[\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e] Among its advantages, it may lead to changes in facial profile and muscle activity.[\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e] Many variations in Herbst design have occurred over the years. The Cantilever Bite Jumper (CBJ) marked a significant advancement in Herbst appliance designs, particularly in terms of facilitating dentition transition.[\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e]\u003c/p\u003e \u003cp\u003ePrevious studies have evaluated the association between fixed functional orthopedic appliances to treat Class II patients with mandibular retrognathism and changes in airway dimensions[\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e, \u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e], and it is a controversial subject. Specifically, about the association between airway and Class II malocclusion treatment with Herbst functional appliance, some studies showed dimension improvement of specific regions of the upper airway[\u003cspan additionalcitationids=\"CR15 CR16\" citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e] while others showed no significant changes in any of them.[\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e, \u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e] Furthermore, it is important to realize that some studies of airway dimensions changes by Class II malocclusion treatment with Herbst appliance associated this protocol with rapid maxillary expansion (RME).[\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e, \u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e] Modification of pharyngeal airway by RME is described in the literature[\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e], and these results must be carefully evaluated.\u003c/p\u003e \u003cp\u003eLong-term follow-up of any orthodontic treatment is essential to assess the effectiveness of the treatment. Therefore, this study aimed to evaluate long-term changes in airway dimensions and hyoid bone position in patients with Class II malocclusion treated with the Herbst functional appliance.\u003c/p\u003e"},{"header":"MATERIAL AND METHODS","content":"\u003cp\u003e The present study was approved by the Ethics Committee in Human Research of Bauru Dental School, under protocol number CAAE: 22082219.0.0000.5417.\u003c/p\u003e \u003cp\u003eThe sample size was calculated with a statistical power of 0.80 and an alpha of 5% to detect a mean difference of 0.25 mm for the middle airway space (U-MPW) with a standard deviation of 0.32 mm, obtained in the study conducted by G\u0026ouml;ymen, Mourad, and G\u0026uuml;le\u0026ccedil;.[\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e] The result showed the need for 15 patients.\u003c/p\u003e \u003cp\u003eThe sample for the study group was taken retrospectively from the Department of Orthodontics, __________________________________, and the patients selected had attended by graduate students. The inclusion criteria were patients aged between 11 and 15 years old, with initial Angle Class II, division 1 malocclusion and mandibular retrognathism; who underwent functional orthopedic treatment with Herbst, associated with fixed orthodontic appliance; ANB angle\u0026thinsp;\u0026gt;\u0026thinsp;4\u0026ordm;; SNB angle\u0026thinsp;\u0026lt;\u0026thinsp;80\u0026ordm;; complete orthodontic records, including lateral headfilms available in three moments: T1, pretreatment; T2, posttreatment (Herbst followed by fixed orthodontic appliance); and T3, long-term follow-up (at least seven years posttreatment). The exclusion criteria were history of previous orthodontic/orthopedic treatment; loss of any permanent teeth; palatal/lip cleft symptoms; chronic mouth breathing; permanent snoring; and tonsillectomy or adenoidectomy.\u003c/p\u003e \u003cp\u003eThe patients selected were treated without extractions with Herbst variation - Cantilever Bite Jumper (CBJ - Ormco Corporation, Orange, California, USA) orthopedic approach, followed by fixed appliances. After correction of Class II malocclusion, fixed orthodontic appliances were used to refine the occlusion (Roth prescription, Morelli, Sorocaba, Brazil). Patients wore a fixed mandibular retainer for at least five years after treatment and a Hawley maxillary plate for one year after treatment.\u003c/p\u003e \u003cp\u003eThe lateral headfilms were digitized and analyzed with Dolphin\u0026reg; Imaging 11.9 software (Patterson Dental Supply, Inc., Chatsworth, California, USA) by a single examiner (T.Y.). The software corrected the image magnification factors according to the respective X-ray unit's settings and instructions.\u003c/p\u003e \u003cp\u003eThe cephalometric landmarks and analysis of the pharyngeal structures and hyoid bone position were based on the methods described previously by Liu et al.[\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e] and Zong et al.[\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e] (Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e, Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). In addition, the cephalometric variables representing the dentoskeletal pattern were evaluated by Steiner analysis.[\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e] A customized cephalometric analysis generated 13 variables, six angular and seven linear, for each tracing (Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e).\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eDefinitions of the cephalometric landmarks used in the present study.\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"2\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCephalometric landmarks\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eDefinition\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eN\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eThe most anterior point of the frontonasal suture in the sagittal view\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eS\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eCenter of the pituitary fossa\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eA\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003ePoint of maximum concavity in the midline of the alveolar process of the maxilla in the sagittal view\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eB\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003ePoint of maximum concavity in the midline of the alveolar process of the mandible in the sagittal view\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eMe\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eMost inferior point of the mandibular symphysis in the sagittal view\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eGo\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eThe deepest point of the curvature of the angle of the mandible between the inferior border of corpus and posterior border of the ramus of mandible in sagittal view\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eU1\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eMaxillary incisor tip\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eL1\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eMandibular incisor tip\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eU\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eThe lower end of the soft palate\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eV\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eThe most posteroinferior point on the base of the tongue\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eSPP\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003ePoint of intersection of a line from soft palate center perpendicular to the posterior pharyngeal wall and posterior margin of the soft palate\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eSPPW\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003ePoint of intersection of a line from soft palate center perpendicular to the posterior pharyngeal wall and posterior pharyngeal wall\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eMPW\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eFoot point of a perpendicular line from point U to the posterior pharyngeal wall\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eLPW\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eFoot point of a perpendicular line from point V to the posterior pharyngeal wall\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eHy\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eThe most anterior point on the hyoid bone\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eC3\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eThe most anteroinferior point on the corpus of the third cervical vertebra\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab2\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eSummary of the variables used for the cephalometric comparisons.\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"2\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eVariable\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eInterpretation\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003ctr\u003e \u003cth align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e \u003cp\u003eSkeletal component\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eSNA\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eAngle between SN and NA\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eSNB\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eAngle between SN and NB\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eANB\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eAngle between AN and NB\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eSN.GoGn\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eAngle between S-N and Go-Gn\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e \u003cp\u003e\u003cb\u003eDentoalveolar component\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eU1-NA\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eDistance between NA line and the most anterior point of the\u003c/p\u003e \u003cp\u003emaxillary incisor crown\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eU1.NA\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eAngle between NA line and the long axis of the maxillary\u003c/p\u003e \u003cp\u003eincisor\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eL1-NB\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eDistance between NB line and the most anterior point of the\u003c/p\u003e \u003cp\u003elower incisor crown\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eL1.NB\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eAngle between NB line and the long axis of the mandibular\u003c/p\u003e \u003cp\u003eincisor\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e \u003cp\u003e\u003cb\u003ePharyngeal airway\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eSPP-SPPW\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eSuperior airway space: Distance between SPP and SPPW (nasopharynx / palatopharynx)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eU-MPW\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eMiddle airway space: Distance between U and MPW\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eV-LPW (mm)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eInferior airway space: Distance between V and LPW\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e \u003cp\u003e\u003cb\u003eHyoid bone position\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eHy-C3\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eDistance between the most anterior point of the hyoid bone and the most anteroinferior point in the body of the third cervical vertebra\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eHy-MPperp\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eDistance from the mandibular plane (Go-Me) perpendicular to the hyoid bone\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003eError study\u003c/h2\u003e \u003cp\u003eThirty percent of the headfilms were randomly selected, retraced, and remeasured by the single examiner (T.Y.) after a month interval. IntraClass Correlation Coefficient (ICC) was used for test reliability.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec4\" class=\"Section2\"\u003e \u003ch2\u003eStatistical analyses\u003c/h2\u003e \u003cp\u003eNormal distribution was evaluated and confirmed with Shapiro-Wilk tests.\u003c/p\u003e \u003cp\u003e Intragroup comparison between the three evaluation stages was performed with repeated measures ANOVA, followed by Tukey tests if necessary.\u003c/p\u003e \u003cp\u003eResults were considered statistically significant at \u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.05. Statistical analyses were performed with Statistica software (Statistica for Windows 12.0; Statsoft, Tulsa, Okla, USA).\u003c/p\u003e \u003c/div\u003e"},{"header":"RESULTS","content":"\u003cp\u003eThe sample was composed of 15 subjects (5 female; 10 male), with a mean age of 13.00 years (SD 1.21). Herbst appliance was used during a mean period of 1.18 years (SD 0.19), and the second period of treatment (comprehensive treatment) lasted a mean time of 3.01 years (SD 1.48) (Table\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003e). Post-treatment changes were evaluated 10.73 years (SD 3.67) after orthodontic treatment.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab3\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 3\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eDescriptive characteristics of the sample.\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"3\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eX\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e \u003cp\u003en\u0026thinsp;=\u0026thinsp;15\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eStage/Period\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eMean\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eS.D.\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eT1 age\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e13.00\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1.21\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eT2 age\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e18.02\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1.78\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eT3 age\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e28.75\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e4.37\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eTotal treatment period (T2-T1)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e5.02\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1.55\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eLong-term Posttreatment period (T3-T2)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e10.73\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e3.67\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003e\u003cb\u003eSex\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eMale\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eFemale\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e10 (66.66%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e5 (33.33%)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003eIntraClass correlation coefficients for the two separate measurements on the lateral headfilms ranged between 0.968 (Hy-Mp perp) and 0.997 (Md1.NB), indicating excellent reliability.[\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e]\u003c/p\u003e \u003cp\u003eRegarding treatment changes, the skeletal components showed significant increase in the SNB angle, improvement in the maxillomandibular relationship, and mandibular counterclockwise rotation. There were no significant changes in the dentoalveolar components. The lower airway, the distance between the hyoid bone and the third cervical vertebra and the distance between the mandibular plane perpendicular to the hyoid bone have undergone significant changes, increasing in the treatment period (Table\u0026nbsp;\u003cspan refid=\"Tab4\" class=\"InternalRef\"\u003e4\u003c/span\u003e).\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab4\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 4\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eIntragroup comparisons of the cephalometric variables among the three stages (repeated measures ANOVA, followed by Tukey tests).\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"5\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eVariables\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eT1\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eT2\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eT3\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003ep\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eMean (s.d.)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eMean (s.d.)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eMean (s.d.)\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003ctr\u003e \u003cth align=\"left\" colspan=\"5\" nameend=\"c5\" namest=\"c1\"\u003e \u003cp\u003eSkeletal components\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eSNA (\u0026deg;)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e81.76 (2.66)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e81.15 (2.99)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e81.32 (3.14)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.416\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eSNB (\u0026deg;)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e76.22 (1.97) A\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e77.85 (2.23) B\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e78.32 (2.77) B\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e\u003cb\u003e0.008*\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eANB (\u0026deg;)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e5.51 (1.77) A\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e3.29 (1.89) B\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e2.99 (1.95) B\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e\u003cb\u003e0.000*\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eSN.GoGn (\u0026deg;)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e31.54 (4.95) A\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e29.60 (3.77) B\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e29.04 (5.48) B\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e\u003cb\u003e0.047*\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"5\" nameend=\"c5\" namest=\"c1\"\u003e \u003cp\u003e\u003cb\u003eDentoalveolar components\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eU1-NA (mm)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e4.18 (3.02)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e4.61 (1.64)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e4.74 (1.86)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.672\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eU1.NA (\u0026deg;)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e23.03 (10.20)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e25.32 (6.64)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e25.95 (7.29)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.380\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eL1-NB (mm)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e4.64 (2.72)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e6.07 (1.87)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e5.74 (2.24)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.066\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eL1.NB (\u0026deg;)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e25.45 (8.48)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e30.49 (5.81)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e28.72 (5.63)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.084\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"5\" nameend=\"c5\" namest=\"c1\"\u003e \u003cp\u003e\u003cb\u003ePharyngeal airway\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eSPP-SPPW (mm)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e11.68 (2.41)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e12.23 (2.12)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e10.99 (2.32)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.104\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eU-MPW (mm)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e9.88 (2.63)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e9.43 (2.53)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e9.62 (2.58)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.758\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eV-LPW (mm)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e15.94 (2.53) A\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e18.32 (3.60) B\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e19.09 (3.93) B\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e\u003cb\u003e0.007*\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"5\" nameend=\"c5\" namest=\"c1\"\u003e \u003cp\u003e\u003cb\u003eHyoid bone position\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eHy-C3 (mm)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e31.45 (3.35) A\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e34.65 (4.88) B\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e36.48 (5.57) C\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e\u003cb\u003e0.000*\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eHy-MPperp (mm)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e15.14 (3.29) A\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e18.58 (3.88) B\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e21.07 (4.22) B\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e\u003cb\u003e0.002*\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003ctfoot\u003e \u003ctr\u003e\u003ctd colspan=\"5\"\u003e* Statistically significant at p\u0026thinsp;\u0026lt;\u0026thinsp;0.05\u003c/td\u003e\u003c/tr\u003e \u003ctr\u003e\u003ctd colspan=\"5\"\u003eDifferent letters in the same row indicate the presence of a statistically significant difference between the stages.\u003c/td\u003e\u003c/tr\u003e \u003c/tfoot\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003eIn the long-term posttreatment period, only the distance between the hyoid bone and the third cervical vertebra suffered significant changes, increasing (Table\u0026nbsp;\u003cspan refid=\"Tab4\" class=\"InternalRef\"\u003e4\u003c/span\u003e).\u003c/p\u003e"},{"header":"DISCUSSION","content":"\u003cp\u003eAlthough previous studies evaluated the association between airways and functional appliances[\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e, \u003cspan additionalcitationids=\"CR25\" citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e], the long-term follow-up is important to discuss the effectiveness and stability of the treatment and remains unclear. Our study assessed upper airway dimensions and hyoid bone position changes in Class II patients with mandibular retrognathism treated with Herbst CBJ functional appliance for an average of 10 years (10.73y\u0026thinsp;\u0026plusmn;\u0026thinsp;3.67) of follow-up.\u003c/p\u003e \u003cp\u003eThe sample size was sufficient to give reliability to the results. Statistical significance was achieved, indicating that the treatment effect was large enough to be detected in a limited sample. In addition, although a small sample size, it is substantial because the subjects were evaluated more than ten years post-treatment. Another study conducted similar research showed similar samples.[\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e]\u003c/p\u003e \u003cp\u003eFor ethical reasons, it seems obvious the impossibility of long-term follow-up of untreated Class II individuals. Moreover, most of the growth of airway structures finishes in early childhood, and only a slight continuous increase of about 1 mm was detected between 6 and 17 years of age.[\u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e] Our sample was 18.02 years old (SD 1.78) at the end of treatment, then there was expected to be no increase in the airway dimensions from growth in the follow-up period.\u003c/p\u003e \u003cp\u003eAlthough three-dimensional imaging (3D) using cone-beam computed tomography (CBCT) to evaluate changes in airway dimensions is preferred to a lateral cephalometric radiograph, CBCT is not a standard diagnosis method in Orthodontics and routine use is not recommended for legal and ethical reasons because of radiation exposure.[\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e] Furthermore, the literature shows a significant correlation between sagittal cephalometric measurements of the airway and 3D analysis with CBCT imaging.[\u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e] Therefore, this method for analyzing the airway is still a valid tool as it is inexpensive, has minimal dose radiation, and gives accurate measurements.[\u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e30\u003c/span\u003e]\u003c/p\u003e \u003cp\u003eRegarding the treatment changes in the skeletal components, the sample underwent an improvement in mandibular position, as previously reported for similar appliances, probably due to treatment and normal growth changes[\u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e31\u003c/span\u003e]; mandibular counterclockwise rotation which is in agreement with a previous study[\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e], and improvement in maxillomandibular relationship, as the literature has already shown[\u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e32\u003c/span\u003e], represented mainly by the changes in the mandibular component and growth.[\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e]\u003c/p\u003e \u003cp\u003eThere were no significant changes in the dentoalveolar variables with treatment and it is corroborated by previous studies that found that Herbst CBJ variation causes less mandibular incisor protrusion when compared to other designs of this appliance.[\u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e31\u003c/span\u003e]\u003c/p\u003e \u003cp\u003eConcerning the airway variables, a significant change was observed only in the lower airway space during treatment, increasing. This find is in agreement with previous study that found that the hypopharynx region has the greatest dimensional increase in treatment with the Herbst appliance[\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e], and other studies that reported increase in hypopharynx with Herbst treatment.[\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e, \u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e, \u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e33\u003c/span\u003e] This fact is probably related to the forward shift of the mandible, plus some growth effect.[\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e, \u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e] Some studies that evaluated the effects of the Herbst device on the airways reported an increase in the oropharyngeal region, but this was not found in our study.[\u003cspan additionalcitationids=\"CR15 CR16\" citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e] Dentoalveolar changes by functional orthopedic appliances, especially mandibular incisor protrusion, may be responsible for more anterior tongue position and increase in airways dimensions.[\u003cspan citationid=\"CR34\" class=\"CitationRef\"\u003e34\u003c/span\u003e] In our study the sample did not show significant changes in the dentoalveolar variables, which can explain the insignificant changes in the oropharynx.\u003c/p\u003e \u003cp\u003eMost studies that evaluated the relationship between treatment with Herbst appliance and the maxillary airway did not evaluate the hyoid bone position. Changes in hyoid bone position are related to mandibular position changes.[\u003cspan citationid=\"CR35\" class=\"CitationRef\"\u003e35\u003c/span\u003e] In the present study hyoid bone was moved significantly forward and downward in the treatment period, which corroborates with previous studies that showed anterior displacement of the mandible by the functional appliances improving the horizontal position of the hyoid bone and, consequently, the position of the tongue, increasing upper airway dimensions.[\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e, \u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e] The downward displacement of the hyoid bone after Class II functional treatment was also reported in the literature previously.[\u003cspan citationid=\"CR36\" class=\"CitationRef\"\u003e36\u003c/span\u003e, \u003cspan citationid=\"CR37\" class=\"CitationRef\"\u003e37\u003c/span\u003e] Change in the hyoid bone position in a superior direction was reported after functional advancement of the mandible, however, in the long term, it resumed its original position as a compensatory action.[\u003cspan citationid=\"CR38\" class=\"CitationRef\"\u003e38\u003c/span\u003e]\u003c/p\u003e \u003cp\u003eMore information about the long-term effects of fixed functional appliances in the airway dimension is needed. To the best of our knowledge, only one study has evaluated the long-term effects of fixed functional appliances on upper airway[\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e], and they did not analyze the changes in the hypopharynx dimension and hyoid bone position, and included patients treated with extraction in their sample. Tooth extraction can interfere with airway dimensions, although in different ways in different malocclusions. In Class II patients, after extraction of maxillary premolars, there was a reduction in the dimensions of the velopharynx.[\u003cspan citationid=\"CR39\" class=\"CitationRef\"\u003e39\u003c/span\u003e] In contrast, mesial movements of molars in Class I patients increased the posterior space of the tongue, consequently increasing the dimensions of the airway.[\u003cspan citationid=\"CR39\" class=\"CitationRef\"\u003e39\u003c/span\u003e] Some authors have researched the long-term effects of removable functional appliances in the upper airway[\u003cspan citationid=\"CR37\" class=\"CitationRef\"\u003e37\u003c/span\u003e, \u003cspan citationid=\"CR40\" class=\"CitationRef\"\u003e40\u003c/span\u003e], however it is important to note that different functional appliances may affect the dentoalveolar and skeletal structures[\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e], as well in the upper airway and hyoid bone position.[\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e, \u003cspan citationid=\"CR41\" class=\"CitationRef\"\u003e41\u003c/span\u003e]\u003c/p\u003e \u003cp\u003eIn the present study, only the horizontal position of the hyoid bone changed significantly in the long-term posttreatment period, moving forward, which agrees with the study by Ulusoy.[\u003cspan citationid=\"CR37\" class=\"CitationRef\"\u003e37\u003c/span\u003e] All other variables remained stable during this period, converging with results from previous long-term follow-up studies with functional appliances.[\u003cspan citationid=\"CR37\" class=\"CitationRef\"\u003e37\u003c/span\u003e, \u003cspan citationid=\"CR40\" class=\"CitationRef\"\u003e40\u003c/span\u003e]\u003c/p\u003e \u003cp\u003eOur results have a relevant clinical impact, considering that Orthodontists can ensure that the outcomes of Herbst functional appliance in pharyngeal dimensions and hyoid bone position are stable over the years.\u003c/p\u003e \u003cp\u003eAs this is a retrospective study, we do not know if special instruction was given to the patient about the tongue and head position in the lateral cephalogram records, affecting our findings. Another limitation of this study was that a retrospective study design could not include body mass index (BMI). Body mass index has been shown to impact the airway dimensions in children[\u003cspan citationid=\"CR42\" class=\"CitationRef\"\u003e42\u003c/span\u003e] and adults[\u003cspan citationid=\"CR43\" class=\"CitationRef\"\u003e43\u003c/span\u003e] and may have influenced the airway measurements.\u003c/p\u003e \u003cp\u003eFuture studies should be conducted to correlate dimensional changes in the airways and the impact on respiratory problems and sleep disorders.\u003c/p\u003e"},{"header":"CONCLUSION","content":"\u003cp\u003eDuring treatment, the sample showed a significant increase in the hypopharynx, which may be related to the forward shift of the mandible, plus some growth effect. The hyoid bone was moved forward and downward as a treatment effect. All studied variables remained stable in long-term follow-up, except for the horizontal position of the hyoid bone which changed significantly, moving forward.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e \u003ch2\u003eConflicts of interest:\u003c/h2\u003e \u003cp\u003eAll authors of this study declare no conflicts of interest or other relationships/conditions/circumstances that present a potential relationship of conflict of interest.\u003c/p\u003e \u003c/p\u003e\u003ch2\u003eFunding:\u003c/h2\u003e \u003cp\u003eThis work was supported by the Coordination for the Improvement of Higher Education Personnel (CAPES) [finance code 001].\u003c/p\u003e\u003ch2\u003eAuthor Contribution\u003c/h2\u003e\u003cp\u003eThagid Yasmin Leal Almeida: Study concept and design, data acquisition and analysis, validation, manuscript draft, manuscript review \u0026amp; editing.Tiago Fialho: Study concept and design, manuscript draft, manuscript review \u0026amp; editing.Karina Maria Salvatore Freitas: Data acquisition and analysis, manuscript draft, data curation, English revision.Jos\u0026eacute; Fernando Castanha Henriques: Study concept and design, data acquisition and analysis, scientific revision.Marcos Roberto de Freitas: Study concept and design, statistical analysis, validation, visualization, manuscript review\u0026amp; editing, project administration, scientific revision.\u003c/p\u003e\u003ch2\u003eData availability:\u003c/h2\u003e \u003cp\u003eThe data underlying this article will be shared on reasonable request to the corresponding author.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eProffit WR, Fields HW Jr., Moray LJ (1998) Prevalence of malocclusion and orthodontic treatment need in the United States: estimates from the NHANES III survey. 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Aust Orthod J 16:157\u0026ndash;166\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMortezai O, Shalli Z, Tofangchiha M, Alizadeh A, Pagnoni F, Reda R, Testarelli L (2023) Effect of premolar extraction and anchorage type for orthodontic space closure on upper airway dimensions and position of hyoid bone in adults: a retrospective cephalometric assessment. PeerJ 11:e15960\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eHan S, Choi YJ, Chung CJ, Kim JY, Kim KH (2014) Long-term pharyngeal airway changes after bionator treatment in adolescents with skeletal Class II malocclusions. Korean J Orthod 44:13\u0026ndash;19\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eJena AK, Singh SP, Utreja AK (2013) Effectiveness of twin-block and Mandibular Protraction Appliance-IV in the improvement of pharyngeal airway passage dimensions in Class II malocclusion subjects with a retrognathic mandible. Angle Orthod 83:728\u0026ndash;734\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eEkstr\u0026ouml;m S, Hallberg J, Kull I, Protudjer JLP, Thunqvist P, Bottai M, Gustafsson PM, Bergstr\u0026ouml;m A, Mel\u0026eacute;n E (2018) Body mass index status and peripheral airway obstruction in school-age children: a population-based cohort study. Thorax 73:538\u0026ndash;545\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMayer P, P\u0026eacute;pin JL, Bettega G, Veale D, Ferretti G, Deschaux C, L\u0026eacute;vy P (1996) Relationship between body mass index, age and upper airway measurements in snorers and sleep apnoea patients. Eur Respir J 9:1801\u0026ndash;1809\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"Malocclusion, Angle Class II. Orthodontic Appliances, Functional. Pharyngeal Airway. Hyoid Bone. Effects, Long-Term","lastPublishedDoi":"10.21203/rs.3.rs-4536044/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-4536044/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003e\u003cstrong\u003eObjective: \u003c/strong\u003eThis study aimed to evaluate the long-term changes in the pharyngeal dimensions and hyoid bone position in Class II malocclusion patients treated with Herbst functional appliance.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eDesign: \u003c/strong\u003eRetrospective cohort study.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eSetting:\u003c/strong\u003e Department of Orthodontics, Bauru Dental School, University of São Paulo – Brazil.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eMethods:\u003c/strong\u003e The sample comprised 15 skeletal Class II malocclusion patients (13.00 years old ± 1.21) treated with Herbst functional appliance and followed for a mean period of 10 years (10.73 years ± 3.67). Lateral headfilms were used to evaluate the pharyngeal dimensions and hyoid bone position, and the measurements were performed with Dolphin® Imaging 11.9. Intragroup comparison between the evaluation stages was performed with repeated measures ANOVA, followed by Tukey tests if necessary. Results were considered statistically significant at p\u0026lt;0.05.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eResults: \u003c/strong\u003eRegarding the pharyngeal cephalometric variables, only the lower airway space increased significantly in the treatment period, and all of them remained stable remained stable during follow-up period. The hyoid bone moved significantly forward and downward during the treatment period and even further forward during the long-term posttreatment period.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConclusion: \u003c/strong\u003eThe outcomes of Herbst functional appliance in pharyngeal dimensions and hyoid bone position are stable over the years.\u003c/p\u003e","manuscriptTitle":"Long-term Evaluation (10 Years) of the Outcomes of Herbst Functional Appliance in Pharyngeal Dimensions and Hyoid Bone Position in the Treatment of Class II Patients","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2024-07-08 16:58:38","doi":"10.21203/rs.3.rs-4536044/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"1c2fc247-0276-4fcf-8e77-8719888cdc7e","owner":[],"postedDate":"July 8th, 2024","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2024-07-17T05:21:14+00:00","versionOfRecord":[],"versionCreatedAt":"2024-07-08 16:58:38","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-4536044","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-4536044","identity":"rs-4536044","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}