More Than Straightening Teeth: The Orthodontist’s Role in Sleep Dentistry

However, certain critical topics remain controversial. Airway constrictions, sleep apnea, and extraction of premolars and its effect on a patient's facial profile are all highly polarizing and debatable subjects among orthodontists, their referring general dentists, and their patients themselves. In this article, the authors will attempt to demystify and clarify the facts behind obstructive sleep apnea (OSA) and the role of the dental professional.

OSA, the most common sleep-related breathing disorder, is a multifactorial disease that is characterized by repeated obstruction of the upper airway during sleep. Among the identified risk factors are obesity (body mass index >30 kg/m²), male gender, increasing age, and menopause.¹ Certain morphological features may also contribute to OSA, such as having a narrow palate, retrognathic and posteriorly rotated mandible, high mandibular plane angle, midface deficiency, dolichofacial vertical pattern (long face syndrome), or a low position of the hyoid bone. These underlying features may be observed clinically in patients who present with tired eyes, a crooked nose, receding chin, narrow face, or forward head posturing. Various genetic disorders that affect the craniofacial complex (eg, Down syndrome, Pierre Robin syndrome, Treacher Collins syndrome, cleidocranial dysostosis) are also known to predispose patients to OSA.²

A major controversy in dentistry is whether orthodontic extractions have any impact on the airway. A non-extraction orthodontic approach may heavily compromise the overall dental health of the patient in cases where there is severe anterior and posterior crowding, a thin periodontal biotype with presence of recessions and thin cortical bone, or bimaxillary protrusion. All of these factors, along with the patient's skeletal and dental classifications, need to be considered when deciding if a patient can be treated without extractions. In an extensive study analyzing the health and dental records of 5,584 patients with a diagnosis of OSA, the authors demonstrated that the absence of premolars is not a significant factor in causing OSA.³

Clinicians have an oppor­tunity to play an important role in identifying OSA pa­tients by asking simple questions pertaining to a patient's quality of sleep, ability to focus, and awareness of any parafunctional habits. Orthodontists' extensive training in craniofacial growth and development, along with their familiarity with the use of oral appliances, positions them to be integral healthcare team members for any patients with suspected OSA, especially in the adolescent population.

Sleep-disordered breathing, including OSA, can have adverse consequences if left untreated. Currently, the "gold standard" of care in the diagnosis of OSA is an in-center overnight sleep study, ie, polysomnography (PSG), which must be confirmed by a sleep medicine physician. The severity of OSA is dictated by the apnea-hypopnea index (AHI) and respiratory disturbance index (RDI) per hour. An AHI or RDI of ≥5 to <15 is considered mild OSA, ≥15 to <30 is moderate, and ≥30 is severe.

The use of CBCT images in orthodontic practice is key for diagnostic purposes relating to hard and soft tissue. However, it is important to appreciate the limitations of this modality pertaining to the actual diagnosis of OSA. A CBCT scan is a static image taken at a certain time in the breathing cycle, and, therefore, it cannot provide information on the neuromuscular tone, potential collapse, or function of the airway. Additionally, there are significant differences regarding a patient's position and ability to function during sleep versus awake states. Dental CBCTs are taken with the patient in a standing or sitting vertical position resulting in the airway being less susceptible to collapsing. In contrast, when patients are sleeping, specifically in the supine position, the pharyngeal muscles are relaxed and the mandible can slide posteriorly, possibly resulting in a more constricted airway.

Home sleep tests are diagnostic tools that also can be used to screen for these conditions. One study compared portable monitoring and autotitration to polysomnography for the diagnosis and treatment of sleep apnea and found that the two methods produced similar results.⁴ Clinical guidelines also support the use of unattended portable monitors for diagnosing OSA in adult patients.⁵

Home sleep tests are designed to be conducted in the comfort of one's own home, and they typically involve wearing a device that monitors breathing, oxygen levels, heart rate, and other parameters while sleeping. This makes them more convenient and less expensive than traditional in-lab sleep studies. However, these tests do have some limitations. For example, they may produce inaccurate results, and they cannot diagnose other sleep disorders.⁵ It is important for patients to receive a thorough medical evaluation and appropriate treatment based on their individual needs. In some cases, orthodontic treatment with mandibular advancement devices may be used to treat mild to moderate OSA and snoring.⁶

In conclusion, the diagnosis of OSA must be made by a sleep medicine physician after a patient undergoes a PSG. CBCT images may be used for treatment considerations in OSA patients but should not be used to establish a diagnosis without the PSG.

Mild cases of OSA can be managed with lifestyle changes such as weight loss, avoiding alcohol and sedatives before going to bed, quitting smoking, and sleeping on the side instead of the back. Collaboration between dental professionals and medical professionals can allow for a comprehensive approach to the treatment of OSA, improving patient outcomes and quality of life.

Continuous positive airway pressure (CPAP) therapy is the most effective and commonly used treatment for moderate to severe OSA. It involves wearing a mask over the nose or mouth during sleep that delivers pressurized air to keep the airway open. Other options include oral appliances, such as mandibular advancement devices, that hold the jaw forward to keep the airway open, surgery to remove excess tissue blocking the airway, and positional therapy that encourages sleeping on the side.

A relatively recent modality, approved by the US Food and Drug Administration in 2014, involves hypoglossal nerve stimulation (HNS) therapy developed by Inspire Medical Systems. The HNS implant is designed for people who cannot tolerate or benefit from CPAP therapy. The small, pacemaker-like device is implanted under the skin in the chest and works by stimulating the hypoglossal nerve to keep the airway open during sleep. The device is activated by a small handheld remote-control unit that the patient uses to turn the device on before going to sleep and off upon waking up. This therapy has been shown to effectively reduce the number of apnea and hypopnea events during sleep and improve sleep quality.⁷ It is an alternative treatment option for moderate to severe OSA that can provide long-term benefits for patients who are unable to use other treatments or have not had success with them. Like any medical procedure, however, there are risks associated with the implantation of the device, and patients should discuss the potential benefits and risks with their doctor before deciding on this treatment option. Any treatment plan for OSA depends on the individual's symptoms, medical history, and severity of the condition.

The field of orthodontics continues to evolve, offering new opportunities for clinicians to enhance their patients' oral health and overall well-being. Clear aligners are increasingly being used to deliver positive results, and technology has progressed to decrease treatment time and increase outcome predictability. Despite the polarizing opinions pertaining to OSA and dentistry, this article aimed to highlight supporting evidence that emphasizes the role of the dentist and orthodontist in identifying patients at risk for this debilitating condition. Dental professionals have a responsibility to improve the quality of life of their OSA patients by ensuring they are accurately identified and referred for further evaluation by sleep medicine physicians. Over the next few years, the way dentists capitalize on this opportunity to establish themselves as experts in recognizing, referring, and treating OSA patients will help fortify the bridge between dentistry and medicine.

Daniel Berant, DMD
Double Board-Certified Specialist in Periodontics and Implant Surgery and Orthodontics and Dentofacial Orthopedics; Private Practice, Manhattan, New York

Diana-Beatrix Velicu, DDS, MSc, MS
Board-Certified Orthodontist; Private Practice,
Plano, Texas