By Shalini Paruthi, MD; Umesh Goswami, MD; Jennifer So, MD; Pahnwat Taweesedt, MD; Navin Verma, MD; and Steven Holfinger, MD, MS, on behalf of the AASM Emerging Technology Committee
Mechanisms of mandibular advancement
MADs function by repositioning the lower jaw to increase the airway space in the oropharynx, thereby improving airflow. Although each device has unique features, most use dental molds combined with adjustable mechanisms to gradually advance the lower jaw forward or increase vertical space, or both. Certain devices, such as the Complete Airway Repositioning and/or Expansion (C.A.R.E.) appliances from Vivos Therapeutics, Inc., also incorporate midfacial repositioning and palatal expansion to further enhance airway opening.
Various mechanical designs are employed in MADs, including:
- Laterally placed elastic straps — e.g., Elastic Mandibular Advancement (EMA)
- Telescope-style hinges — e.g., Silent Nite Sleep Appliance with Glidewell Hinge
- Herbst-style dual arms — e.g., ProSomnus EVO [PH]
- Adjustable hinge-flanges — e.g., mmRNA and mRNA devices (Vivos Therapeutics, Inc.)
The degree of mandibular advancement is tailored to the patient’s needs.
Customization and fabrication
The AASM clinical guideline recommends that MADs are custom-made for each patient. Traditionally, manual dental impressions were taken in the sleep dentist’s office and sent to a manufacturing facility for fabrication. However, advances in digital technology have increasingly replaced this process. Digital imaging allows for computer-aided design of devices, offering several benefits. Digital imprints can be electronically sent for fabrication, shortening manufacturing times, and the design may be modified based on a dentist’s preferences or predictive algorithms. Digital imprints can also be re-used if needed. Turnaround times for production vary depending on the method and manufacturer — from on-site 3D printing (such as LuxCreo EMA 3D) to specialized labs requiring a minimum of three days for production (such as Silent Nite).
Materials
The materials used in these devices vary widely, including acrylic resins, thermoplastic polymers, silicone elastomers, and dual-laminate materials. Some devices, like the EVO, boast a smaller physical footprint by utilizing proprietary materials such as “MG6.” Patients with bruxism are likely to benefit from thicker acrylic devices that tolerate higher force, with some devices FDA cleared for mild-moderate OSA and bruxism (Slow Wave DS8, Slow Wave Inc.). Slimmer devices are also now more readily available for patients who have a greater emphasis on comfort, small oral cavities, or more sensitive gag reflexes.
Real-time adjustments
The MATRx device, created by Zephyr Sleep Technologies, launched in 2012 and allowed for real-time advancement of the MAD during sleep to evaluate protrusion effects on the resolution of apneas and hypopneas overnight during a sleep study. However, this is no longer available, as Zephyr Sleep Technologies ceased operations in 2021. In-office MAD titration can instead be attempted for the awake patient using chairside imaging. One example is the Eccovision Acoustic Diagnostic Pharyngometer and Rhinometer (Sleep Group Solutions). This assesses nasal and oral airway volume when making lateral or horizontal adjustments to the MAD while the patient is awake.
Assessing the efficacy of oral appliances
Sleep dentists play a crucial role as part of a collaborative care model. When working closely with sleep physicians, they help ensure the MAD is properly fitted, make adjustments over time, and monitor for dental complications. Sleep dentists often determine titration endpoints based on oral exam findings, clinical symptoms, and sometimes overnight assessments.
In current clinical practice, physicians assess the effectiveness of oral appliance therapy using both patient feedback and objective data. Many patients report improvements such as less snoring, better sleep quality, and reduced daytime fatigue. However, when sleep apnea is moderate or severe, or indicated based on clinical findings, confirming therapeutic success is important. This typically involves a repeat sleep study, either in-lab polysomnogram or home sleep apnea test.
However, a limitation of this traditional model is the lack of adherence and therapeutic monitoring. While their advantages in size and comfort over CPAP may increase adherence (longer use overnight), MADs do not maintain significantly better adherence rates at one year from the time of prescription. Studies have shown that adherence with the therapy improves if the users are aware that their adherence is being monitored. Implanted, modular, micro-recorders (e.g., DentiTrac, Braebon Medical Corp.) may be attached to the buccal surface of any oral appliance. This recorder objectively tracks device adherence using embedded sensors, including intraoral temperature, and a proprietary algorithm to overcome thermostatic water bath deception. Additional measures such as head position (supine vs. non-supine) are also recorded and provided in the nightly report. While the device battery lasts two years, internal memory storage limitations require downloads at six-month intervals. Rest Assure (Somnomed, Ltd) provides similar long-term data.
Monitoring the efficacy of MADs with continuous overnight pulse oximetry may provide some useful insight into trends in oxygen saturation or help detect persistent desaturations. However, respiratory events related to arousals are likely to be missed. New sensors directly integrated into MADs are under development, but not yet available (see table). Despite the obvious benefits, the widespread use of objective adherence or therapeutic tracking devices remains limited by cost, insurance coverage and availability.
Conclusion
Technological advances have expanded treatment options for patients who have OSA. Notably, materials used in MADs today are thinner, lighter and better tolerated. Embedded sensors provide much needed research data and meaningful feedback for patients. A collaborative approach promotes safe, effective and personalized treatment — and ultimately leads to better outcomes for patients.
Mandibular advancement devices at a glance
| Features | Examples |
|---|---|
| Recent devices | AIO Breathe (AIOMEGA, LLC), Narval CC (ResMed SAS), and O2Vent Optima (Oventus Medical) FDA indication severe OSA* – C.A.R.E. appliances (Vivos Therapeutics, Inc.) Additionally targets velo-pharynx – EVO Guided (ProSomnus) |
| 3D-printed materials | Hushd Pro Avera (Good Sleep Co Pte Ltd.), Silent Nite 3D Sleep Appliance (Glidewell), and Panthera Classic/X3 (Panthera Dental) In-office 3D printing – EMA 3D (LuxCreo Inc., EMA-Sleep Inc.) Treatment of bruxism and OSA – Slow Wave DS8 (Slow Wave Inc.) |
| Diagnostic use | Airway Imaging – Eccovision Acoustic (Sleep Group Solutions) MAD Titration – MATRx Plus (DISCONTINUED; Zephyr Sleep Technologies) |
| Data tracking | Adherence – Dentitrac (Braebon Inc.) Adherence and therapy – Rest Assure (SomnoMed Ltd.) and t.e.s.a. (IN DEVELOPMENT, Dianyx Innovations LLC) SpO2 tracking – ProSomnus HWO2 (IN DEVELOPMENT, ProSomnus) |
*In general, devices with FDA-510(k) clearance have mild/moderate OSA and snoring indications; they are used as an alternative to CPAP for severe OSA. The FDA-510(k) clearance for the C.A.R.E. appliances includes severe OSA along with the use of PAP and/or myofunctional therapy as needed.
