Orthodontic management of Obstructive Sleep Apnea : A Systematic Review

Background: Obstructive Sleep Apnea (OSA) is considered a real public health problem, often unrecognized or underdiagnosed, requiring multidisciplinary care, including orthodontics that plays an essential role in the screening and managing ventilation. Objective: Our study aims to explain the vital place of orthodontic therapies, whether orthopedic or surgical, in the multidisciplinary management of OSA and the improvement of nasal breathing through a systematic review Material and methods: The literature search was performed in the following databases: PubMed, Science Direct, and Cochrane Library. The investigation was limited to publications written in English and French from 2010 to January 2022. Results: Based on the keywords, eighty-three references were initially identified. After eliminating duplicates, the number of articles was reduced to seventy-nine. Studying the titles and abstracts made it possible to select fifty articles. After reading the complete text, sixteen publications were included in this systematic review. Eight studies have investigated rapid maxillary expansion (RME), five have evaluated mandibular advancement (MA), and three have investigated the effect of genioplasty in children with OSA. Conclusion: The orthodontic arsenal is well suited and highly beneficial for OSA treatment, whether orthopedic, orthodontic, or surgical correction of jaws.


INTRODUCTION
Obstructive sleep apnea (OSA) is an increasingly common pediatric, chronic disease defined by the American Academy of sleep medicine as a sleep-related breathing disorder characterized by repetitive episodes of complete or partial upper airway obstruction leading to a short-term cessation of ventilation or significant reduction of airflow during sleep. (1,2) The prevalence of OSA among children is defined to be ranging from 1% to 4% (3,4). However, some risk factors include obesity, increasing age, craniofacial morphology, genetics, and syndromes… It may induce a reduction of pharynx size or a rise in airway collapsibility, which leads to a higher prevalence of the pathology (5). The severity of obstructive sleep apnea is classified based on the AHI (Apnea-Hypopnea Index). Categories are mild (AHI between 5 and 15), moderate (AHI between 15 and 30), and severe (AHI superior to 30). (6), (7) Because of its complications and impact on children's quality of life, OSA is considered a real public health problem, often unrecognized or underdiagnosed.
Requiring multidisciplinary care, including orthodontics, plays an essential role in screening the pathology through its craniofacial manifestations, and secondly, helping improve ventilation thanks to a sizeable therapeutic arsenal ranging from orthopedics to orthognathic surgery. Our study aims to explain the important place of orthodontic therapies, whether orthopedic or surgical, in the multidisciplinary management of OSA and the improvement of nasal breathing through a systematic review.

MATERIALS AND METHODS Research strategy:
The systematic search was performed based on an electronic search of several databases (Pub Med, Science Direct, Cochrane Library) covering publications from 2010 to 2021. The search was made with reference to the acronym PICOS and limited to the following keywords in English and French: orthodontics AND obstructive sleep apnea AND children (table1)  (8). The risk of bias in studies was assessed independently by the authors. Any disagreement was resolved by discussion with the examiner. Among the criteria used by these authors, we find sample randomization, comparison between the effects of the intervention, validation of measures, inclusion and exclusion criteria, and statistical analysis.
Regarding the risk of bias for each study analyzed, the documents containing all the points mentioned above (9-13) were rated as "low risk," those for which the number of points in between (6-8) was rated as "medium risk," a high risk "is assigned to studies that meet or less than five criteria.
In studies that investigated rapid maxillary expansion: The risk of bias was considered low in five studies and medium in three studies (Table 2). In studies who investigated mandibular advancement: The risk of bias was considered low in the five studies (table  3).
In studies who investigated genioplasty: The risk of bias was considered low in one study and medium in two others. (Table 4).

RESULTS
-Based on the keywords, 83 bibliographical references were initially identified. After eliminating duplicate references, the number of articles was reduced to 79. Studying the titles and abstracts made it possible to select 50 articles. After reading the complete text, 16 articles were included in this systematic review.
-Eight studies have investigated rapid maxillary expansion (Table 5), five studies have evaluated the effect of mandibular advancement (Table 6), and three studies have investigated the impact of genioplasty in children with OSA (Table 7).       Thus, orthodontists should be aware of craniofacial manifestations of this disorder and competent enough to recognize its signs and symptoms. Furthermore, orthodontic arsenal, whether orthopedic or surgical correction of jaws, is well suited and highly beneficial for OSA treatment, thanks to their expertise and knowledge regarding the growth and development of orofacial and dentofacial structures. Our study aims to explain the critical place of orthodontic therapies, including rapid maxillary expansion, mandible advancement, and genioplasty, in the multidisciplinary management of OSA and the improvement of nasal breathing through a systematic review.
-Rapid maxillary expansion Rapid maxillary expansion is an effective orthopedicorthodontic therapy for skeletal transversal maxillary constriction in young patients, aiming to increase maxillary width by opening the mid-palatal suture and lateral displacing the maxillary bones. Besides its effects on the maxillary bone, the rapid maxillary expansion also affects the surrounding front maxillary, zygomaticomaxillary, zygomaticotemporal, and pterygopalatine sutures. An increase in nasal cavity width is observed, and a decreased nasal resistance and improved airflow. (25,26) The relationship between rapid maxillary expansion and the decrease of IAH remains unclear because only limited studies have evaluated this treatment for its efficacy in ameliorating OSAS symptoms. Caprioglio et al. in 2014 (13), through their threedimensional investigation of the upper airway, found that RME treatment was effective in increasing pharyngeal airway and MSV in patients with bilateral maxillary deficiency the same for Erdur and Al (27) in 2020, Almuzian and Al en 2015 (28). Lin and AL in 2020 (29) carried out a meta-analysis including 14 studies since 2018 to compare the effectiveness of all interventions in pediatric OSA's resolution. They reported that rapid maxillary is helpful in the improvement of breathing and hypoxemia. Pirelli and Al (9) in 2015 have investigated the effect of rapid maxillary expansion in 31 children with OSA involving a narrow maxilla, and they reported after 12 months follow-up that into adulthood present they still present stable, long-term results post RME treatment for pediatric OSA in accordance with Villa and al in 2015 (10), and Fatsuca and al. 2015 (11) Figure 2 : Headfilms before and ongoing orthodontic treatment following rapid maxillary expansion -Mandibular advancement: Obstructive sleep apnea is often associated with a retrognathic mandible responsible for narrowing the upper airway. Therefore, functional appliances used to treat children with skeletal cl II due to mandibular retrognathism can also benefit OSA management. They put the mandible in a forward position. These functional appliances are removable intra-oral devices that alter the muscular forces against the teeth and respective basal bones. This altered neuro-muscular action affects bony growth and occlusal development. It's considered mandibular advancement devices frequently used to treat adult OSA to prevent the collapse between the oropharynx and tongue during sleep. Functional appliances may lead to variable effects on the dentoalveolar and skeletal structures. However, The Herbst appliance is the most commonly used for stimulating mandibular growth. When the mandible grows forward, the tongue is displaced anteriorly either directly by the forward movement of the muscle or indirectly by advancing the mandible and moves away from the soft palate, which undergoes dimensional and angular changes such as the increase in the oropharyngeal depth and thickness increasing the airway space and to facilitate the superior respiratory system, reduced snoring and im¬proved airflow (30,31,32) Through the years, numerous studies have aimed to investigate the effectiveness of skeletal class II functional  (38) who carried out a meta-analysis which agreed with the results of the previous studies and showed supportive evidence for MAA treatment in pediatric mild to severe OSA.

Figure 3
: Headfilms before and ongoing orthodontic treatment following mandibular advancement -Genioplasty : In moderate forms of OSA early ENT, physiologic and orthopedic management can offer a favorable prognosis and effective results. However, when the disease is more severe and more challenging, with a very pronounced vertical pattern and complex lip seal without labial and chin muscle hyperactivity, genioplasty can provide an adjunct to orthodontic treatment for the correction of mandibular vertical excess. Early genioplasty performed during growth can improve esthetic and functional results and provide stability as it encourages spontaneous lip closure without excessive demands on the peri-oral muscles, particularly the mentalis. (24) It also helps the switch from mouth breathing to nasal breathing if tongue posture, both at rest and functionally, is normal and if ENT problems are eliminated. It is also important to link early genioplasty with maxillofacial rehabilitation to improve the tone and elevation of the genioglossus muscle. (39). Nevertheless, two factors seem to be particularly important to study when deciding to implement genioplasty: Direction of the osteotomised fragment shifting and the amount of advancement (40) According to several studies, genioplasty significantly reduces the apnea-hypopnea index in adults suffering from mild to moderate OSA. However, the role of genioplasty in improving children's breathing is limited. It derives only from a few assessments such as Bedoucha and Al in 2015 (41), who state that early genioplasty performed during growth can help correct nasal breathing by the recalibration of the upper airway at the oropharyngeal level. This is consistent with Frapier et al. 2011 (23) and Chamberland et al.2015(42). Frapier and Al in 2010 (24) and 2011 (23), reported that genioplasty performed during the growth promotes change in the direction of mandibular growth towards anterior rotation with a sagittal gain, which is beneficial for increasing pharyngeal dimension and improvement of ventilation, Chamberland and al. reported same results in 2015 (42).

CONCLUSION
OSA is a real public health problem, often unrecognized or underdiagnosed, requiring multidisciplinary care, including orthodontic treatment that plays an essential role in breathing improvement. In fact, studies agreed that either rapid maxillary expansion, mandibular advancement, or early genioplasty induce in several ways the management of OSA and improvement of nasal breathing. However, more investigations are needed to support those results.

AUTHORS' CONTRIBUTIONS
The participation of each author corresponds to the criteria of authorship and contributorship emphasized in the Recommendations for the Conduct, Reporting, Editing, and Publication of Scholarly work in Medical Journals of the International Committee of Medical Journal Editors. Indeed, all the authors have actively participated in the redaction, the revision of the manuscript, and provided approval for this final revised version.