Custom Oral Appliances for Sleep Apnea: A Clinical Guide to Mandibular Advancement Device Therapy

By Dr. Tara M. Griffin, DMD, ABDSM, D.ASBA Co-Founder, Sleep Solution Centers | Diplomate, American Board of Dental Sleep Medicine | Diplomate, American Sleep and Breathing Academy

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Mandibular advancement devices (MADs) have emerged as a frontline alternative to continuous positive airway pressure (CPAP) therapy for the treatment of obstructive sleep apnea (OSA) and chronic snoring. As a practitioner who holds board certification from both the American Board of Dental Sleep Medicine and the American Sleep and Breathing Academy, and who has spent over 15 years fitting, titrating, and managing outcomes with these devices, I have observed firsthand how proper patient selection, diagnostic imaging, and individualized titration protocols can dramatically influence treatment success.

This article provides a clinical overview of mandibular advancement device therapy, including how these appliances work, who they are appropriate for, and what a comprehensive treatment protocol looks like in practice.

How Mandibular Advancement Devices Work

A mandibular advancement device is a custom-fabricated oral appliance worn during sleep that repositions the lower jaw (mandible) in a forward and slightly downward position. This anterior displacement of the mandible pulls the base of the tongue and surrounding soft tissues forward, enlarging the retropalatal and retroglossal airway space and reducing the likelihood of pharyngeal collapse during sleep.

The mechanism is biomechanical. During sleep, the muscles of the upper airway relax. In patients with anatomical predisposition, such as a narrow airway, retrognathic mandible, enlarged tongue base, or excessive soft palate tissue, this relaxation can lead to partial obstruction (hypopnea) or complete obstruction (apnea). By advancing the mandible forward, typically between 5 and 10 millimeters from habitual occlusion, a MAD mechanically increases the cross-sectional area of the oropharyngeal airway and improves airflow.

Research using cephalometric analysis and dynamic MRI imaging has demonstrated that mandibular advancement increases the anteroposterior dimension of the velopharyngeal and oropharyngeal airway by approximately 2 to 5 millimeters, with corresponding reductions in airway collapsibility. These dimensional changes, though modest in absolute terms, can produce clinically meaningful improvements in the apnea-hypopnea index (AHI), oxygen saturation levels, and subjective sleep quality.

Custom Titratable Devices vs. Over-the-Counter Appliances

Not all mandibular advancement devices are equivalent. The 2024 joint clinical practice guideline issued by the American Academy of Sleep Medicine (AASM) and American Academy of Dental Sleep Medicine (AADSM) specifically recommends custom, titratable oral appliances fabricated by a qualified dentist over non-custom, over-the-counter alternatives.

Custom titratable devices offer several clinical advantages. They are fabricated from digital or physical impressions of the patient’s dental arches, ensuring precise retention and comfort. Titration mechanisms, typically bilateral advancement screws, allow incremental protrusion adjustments in 0.25 to 1.0 millimeter increments, enabling the clinician to progressively optimize jaw position based on follow-up sleep testing and symptom response. This precision is critical; research has shown that the therapeutic protrusion distance varies significantly between patients, and under-advancement is a common cause of treatment failure.

Over-the-counter “boil-and-bite” devices, by contrast, offer limited adjustability, poor retention, and inconsistent jaw positioning. A 2019 randomized trial published in Thorax comparing heat-molded devices to custom MADs found that custom appliances achieved statistically superior AHI reduction, and the AASM does not recommend over-the-counter devices for clinical OSA management.

Patient Selection: Who Benefits Most From Oral Appliance Therapy

Appropriate patient selection is one of the most important determinants of treatment success with mandibular advancement devices. Based on current evidence and clinical guidelines, MAD therapy is indicated for:

Primary indications:

• Adults with mild obstructive sleep apnea (AHI 5–14 events per hour) as a first-line therapy
• Adults with moderate obstructive sleep apnea (AHI 15–30 events per hour) as a first-line therapy or alternative to CPAP
• Adults with severe OSA (AHI greater than 30) who are unable to tolerate or refuse CPAP therapy
• Adults with primary snoring who have not responded to conservative measures such as weight loss, positional therapy, and alcohol avoidance

Contraindications and limitations:

• Central sleep apnea (MADs address pharyngeal obstruction, not central respiratory drive failure)
• Insufficient dentition to support the appliance (fewer than 8–10 teeth per arch)
• Active temporomandibular joint (TMJ) pathology that may be exacerbated by mandibular protrusion
• Severe periodontal disease
• Patients with a body mass index (BMI) exceeding 35 may have reduced response rates, though BMI alone should not exclude a patient from a trial of therapy

An often-overlooked factor in patient selection is nasal airway patency. In my clinical practice, I have found that evaluating nasal airflow resistance prior to oral appliance fabrication significantly improves outcome prediction. A patient with high nasal resistance due to septal deviation, turbinate hypertrophy, or nasal valve collapse may not respond adequately to mandibular advancement alone, because the primary obstruction occurs upstream of the oropharynx. Rhinomanometry, a functional breathing test that measures transnasal pressure and airflow during respiration, provides objective data on nasal resistance that can inform whether nasal optimization should precede or accompany oral appliance therapy.

The Diagnostic Workup: Beyond the Sleep Study

While polysomnography (PSG) or home sleep apnea testing (HSAT) provides the foundational diagnosis of OSA and establishes the baseline AHI, a thorough diagnostic workup for oral appliance candidacy extends beyond the sleep study alone. In a dental sleep medicine setting, the evaluation typically includes:

Cone-beam computed tomography (CBCT): Three-dimensional imaging of the head and neck allows the clinician to assess airway volume, cross-sectional dimensions at the level of the soft palate and tongue base, hyoid bone position, and craniofacial skeletal relationships. CBCT can identify anatomical risk factors such as mandibular retrognathia, a low-positioned hyoid, or adenotonsillar enlargement that may affect treatment planning.

Rhinomanometry: Four-phase rhinomanometry measures nasal airflow rate and transnasal pressure for each nostril independently, providing an objective assessment of nasal resistance. Elevated nasal resistance, defined as total bilateral resistance exceeding 0.25 Pa/cm³/s at 150 Pascals, has been associated with reduced efficacy of both CPAP and oral appliance therapy. Identifying and addressing nasal obstruction before or during MAD therapy can improve overall treatment response.

Clinical assessment: A comprehensive intraoral and extraoral examination evaluates dental health and stability, periodontal status, TMJ function and range of motion, Mallampati classification, tongue size relative to the oral cavity, and tonsil grading. These findings help determine not only whether the patient is a candidate for a MAD, but also which device design and initial protrusion setting are most appropriate.

This multi-modal diagnostic approach, combining sleep study data, three-dimensional airway imaging, and functional nasal assessment, allows for more precise treatment planning than relying on AHI alone. The goal is to identify the specific anatomical and functional contributors to each patient’s airway obstruction and select the intervention most likely to address them.

Titration and Follow-Up: Optimizing Outcomes

Fabrication and delivery of the device is only the beginning of treatment. Effective oral appliance therapy requires a structured titration protocol in which the degree of mandibular advancement is incrementally increased over several weeks based on symptom response and, ultimately, follow-up objective sleep testing.

In standard clinical practice, the initial protrusion setting is typically 50 to 70 percent of maximum protrusion, allowing the patient to acclimate to the device before further advancement. The patient returns at regular intervals, commonly every 2 to 4 weeks, for adjustment. During these visits, the clinician evaluates symptom improvement (snoring reduction, daytime sleepiness, sleep quality), device comfort, and any emerging side effects such as jaw soreness, tooth tenderness, or bite changes.

Once subjective improvement has been maximized, a follow-up sleep study, either in-lab PSG or home sleep test, is performed with the device in place to objectively verify AHI reduction. The AASM recommends that the follow-up study confirm an AHI below 10, and ideally below 5, events per hour. If the AHI remains elevated, further advancement may be attempted if the patient can tolerate additional protrusion without jaw discomfort or TMJ symptoms.

Long-term management is equally important. Patients using mandibular advancement devices require ongoing monitoring, typically every 6 to 12 months, to assess device integrity, dental occlusion changes, TMJ status, and continued therapeutic efficacy. Bite changes, including anterior open bite and reduction of overbite, have been documented in long-term MAD users, occurring gradually over months to years. Early detection allows for intervention through morning occlusal exercises or repositioning protocols to mitigate permanent dental shift.

CPAP Non-Adherence: The Clinical Reality Driving Oral Appliance Adoption

The growth of oral appliance therapy as a treatment for OSA is directly linked to the persistent challenge of CPAP non-adherence. CPAP remains the gold standard therapy for moderate-to-severe OSA, and its efficacy in reducing AHI to near-normal levels is well established. However, real-world adherence data consistently shows that a substantial proportion of patients prescribed CPAP do not use it consistently.

Studies examining CPAP compliance, defined by the Centers for Medicare and Medicaid Services as usage of at least 4 hours per night on at least 70 percent of nights, have reported non-adherence rates ranging from 46 to 83 percent, depending on the population studied and the follow-up interval. The most commonly cited barriers include mask discomfort, claustrophobia, nasal congestion, aerophagia, and social or travel inconvenience.

This compliance gap has significant clinical implications. An OSA treatment is only effective when it is used. While CPAP produces greater AHI reduction per hour of use compared to oral appliances, the higher nightly usage rates observed with MADs, often exceeding 6 hours per night in compliant patients, can result in comparable or even superior overall health outcomes. A concept described in the literature as “mean disease alleviation” accounts for both efficacy and adherence to estimate the true clinical impact of a therapy across all hours of sleep.

The practical implication for clinicians is that oral appliance therapy should not be viewed merely as a second-line option for patients who have “failed” CPAP, but as a clinically valid first-line treatment for appropriately selected patients, particularly those with mild-to-moderate OSA who express a preference for a non-mechanical intervention.

The Role of Adjunctive Therapies

In clinical practice, mandibular advancement device therapy is frequently combined with adjunctive interventions to optimize outcomes. These may include:

Positional therapy: For patients with position-dependent OSA, where the AHI is significantly higher in the supine position, combining a MAD with positional training or a positional therapy device can address both pharyngeal collapse and gravitational effects on airway patency.

Nasal optimization: Addressing nasal obstruction through medical management (nasal corticosteroids, antihistamines), mechanical aids (nasal dilator strips or internal dilators), or surgical intervention (septoplasty, turbinate reduction, nasal valve repair) can improve airflow through the nasal passage and enhance the effectiveness of oral appliance therapy.

Myofunctional therapy: Orofacial myofunctional therapy, a program of exercises targeting the tongue, soft palate, and pharyngeal musculature, has been shown in meta-analyses to reduce AHI by approximately 50 percent in adults and 62 percent in children with OSA. When combined with oral appliance therapy, myofunctional exercises may strengthen the neuromuscular tone of the upper airway and improve long-term treatment response.

Weight management: Obesity is the single strongest modifiable risk factor for OSA. Research has demonstrated that a 10 percent reduction in body weight is associated with an approximately 26 percent reduction in AHI. Weight management counseling is a standard component of comprehensive OSA care.

These adjunctive approaches reflect a broader principle in dental sleep medicine: effective treatment of sleep-disordered breathing often requires a multi-modal strategy tailored to the individual patient’s anatomy, physiology, and behavioral patterns.

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About the Author

Dr. Tara M. Griffin is a board-certified dental sleep medicine practitioner and Co-Founder of Sleep Solution Centers in Orlando, Florida. She holds a Double Diplomate from the American Board of Dental Sleep Medicine (ABDSM) and the American Sleep and Breathing Academy (ASBA), and is one of ten doctors internationally certified to train physicians in DNA, mRNA, and VIVOS oral appliance systems for the treatment of obstructive sleep apnea and TMJ disorders. In 2016, she was invited to speak as an expert in dental sleep medicine at the Harvard Faculty Club. In 2018, she received the Pioneer Award from Vivos Therapeutics at their inaugural Breathing Wellness Conference. Dr. Griffin has published medical abstracts in national sleep journals and serves on the Clinical Advisory Board of Vivos Therapeutics, Inc. (NASDAQ: VVOS).

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