Obstructive Sleep Apnea (OSA) is a common sleep disorder where the upper airway repeatedly collapses during sleep, causing breathing to briefly stop or become shallow. This physical obstruction disrupts rest and can lead to serious health issues. While Continuous Positive Airway Pressure (CPAP) remains the standard treatment, many individuals seek less cumbersome alternatives. Oral appliances (OAs), often called mouth guards, offer a non-surgical option for managing OSA. This article evaluates the clinical effectiveness of these devices.
How Oral Appliances Treat Sleep Apnea
Oral appliances work by physically repositioning the jaw and soft tissues to prevent the airway from collapsing during sleep. The most common type is the Mandibular Advancement Device (MAD), which connects to both the upper and lower teeth. A MAD gently pushes the lower jaw (mandible) slightly forward from its normal resting position.
This advancement pulls the attached soft tissues, including the base of the tongue, forward. This action increases the space behind the tongue and soft palate, stabilizing the airway and allowing for unimpeded airflow. The device maintains this position throughout the night, reducing the likelihood of obstruction.
A less common type is the Tongue Stabilizing Device (TSD), which holds the tongue directly in a forward position using suction. The TSD consists of a small bulb placed outside the lips, where the tip of the tongue is held by negative pressure. This mechanism prevents the tongue from falling back into the throat.
Measuring Efficacy and Patient Selection
The effectiveness of OSA treatment is measured using the Apnea-Hypopnea Index (AHI), which counts the average number of breathing cessation or shallow breathing events per hour of sleep. Successful treatment is defined as a significant reduction in the AHI. Studies show that oral appliances achieve clinically meaningful improvements, with success rates for reducing AHI to under 10 events per hour ranging between 30% and 85% of users.
Oral appliances are most consistently effective for individuals diagnosed with mild to moderate OSA (AHI of five to thirty events per hour). For patients in this range, Mandibular Advancement Devices reduce the AHI by an average of 48% to 67%. OAs are also used for patients with more severe OSA who cannot tolerate CPAP therapy. In severe cases, the average reduction in AHI is often less dramatic, but still clinically significant.
Factors such as a lower body mass index (BMI), a smaller neck circumference, and a less severe baseline AHI predict greater treatment success. A sleep specialist or dentist trained in sleep medicine uses these factors to select the most appropriate candidates for this therapy.
Oral Appliances Versus CPAP Therapy
CPAP therapy is the most effective treatment for reducing AHI, especially in moderate to severe OSA. CPAP delivers pressurized air through a mask, creating a pneumatic splint that forces the airway open. Oral appliances rely on mechanical repositioning, which may not completely resolve the obstruction for all patients, particularly those with high levels of airway collapsibility.
A key difference lies in real-world adherence. While CPAP is effective in ideal conditions, many patients struggle with long-term usage due to mask discomfort, noise, and bulkiness. Studies show that CPAP compliance, defined as using the device for at least four hours per night, often hovers around 50% over time.
Oral appliances offer better patient compliance, often reporting usage rates as high as 91% for six hours or more per night. Their small, portable size and silent operation make them easier to use, especially for frequent travelers or those who find the CPAP mask claustrophobic.
Side effects also differ. CPAP users frequently report mask pressure marks, dry mouth, or nasal congestion. Oral appliances can cause short-term side effects such as temporary jaw discomfort, excess salivation, or pain in the teeth and gums during the initial adjustment. Although AHI reduction may be lower with a mouth guard, randomized trials suggest both treatments result in similar improvements in daytime sleepiness, quality of life, and blood pressure.
Types of Devices and Custom Fitting Process
Oral appliances fall into two main categories: custom-made devices and over-the-counter options. Prescription custom-made Mandibular Advancement Devices are the most effective type. They are fabricated from precise impressions of the patient’s teeth and mouth, providing a superior fit that holds the jaw securely in the therapeutically correct position.
Custom Fitting Process
The fitting process involves collaboration between a sleep specialist and a dentist trained in dental sleep medicine. The sleep specialist confirms the OSA diagnosis and prescribes the appliance. The dentist takes physical or digital impressions of the patient’s dental arches. The appliance is then fabricated in a specialized lab to achieve a snug fit and a specific jaw advancement setting.
A feature of custom MADs is their adjustability. This allows the dentist to incrementally increase the degree of lower jaw protrusion over several weeks or months. This gradual titration is necessary to find the maximum comfortable jaw advancement that achieves the greatest reduction in AHI.
Over-the-Counter Devices
Over-the-counter devices are generally less expensive and use a heat-molding process for a rough fit. However, they tend to be bulkier, less comfortable, and non-adjustable. Because they lack the precise fit and incremental adjustment capability of custom devices, they are less effective for treating diagnosed OSA. The American Academy of Sleep Medicine specifically recommends custom-fabricated, titratable devices for OSA treatment.