Dr. Emil Herbst (1872–1940), who invented his eponymous appliance to correct Class II malocclusion, made many contributions to the field of dentistry; his most famous design appears in the literature in 1909 for the Fifth International Dental Congress in Berlin. To remove patient compliance as an obstacle to treatment, the Herbst appliance was designed as a fixed device that acts as a hinge between the maxilla and the mandible. The hinge was made of silver or gold tubes with corresponding rods that forced the mandible forward, but allowed speech, chewing and swallowing.

The device functionality improved with a change to a barrel screw advancement mechanism so that jaw position could be micro-adjusted in increments less than 1 mm, allowing for easier and more precise protrusion. Clinicians commonly report that while barrel screw adjustments are easier than changing the rods, it is easy to lose count of the turns and advance asymmetrically, which is uncomfortable for some patients.

In 1970, Dr. William Dement opened the first sleep diagnostic lab at Stanford University, leading to a boom in sleep apnea diagnoses and patients requiring treatment. Medical doctors from Germany and dentists from the U.S. realized that holding the jaw forward could open the airway in these patients, and soon afterward they began using removable Herbst-style functional appliances for this purpose. The timing of resurged interest in Herbst appliances led by Dr. Pancherz could not have been better.

As the problems of sleep apnea became better known, demand for diagnosis and treatment grew, with dentists increasingly becoming vital members of an airway-centered healthcare team. Inventive, forward-thinking providers and manufacturers have developed dozens of new mechanisms to hold the jaw forward — Dr. Herbst’s hinge remains, but improved.

With more practitioners experienced in treating snoring and sleep apnea in a clinical setting, demands on the appliances have changed. Key to the treatment of the sleeping airway with an oral appliance is finding the correct jaw position — something no available technology provides today.

Research has shown that the effective treatment position varies widely, from almost no protrusion to a maximum-forward posture that patients cannot achieve from their first night of appliance use. Like every adaptive process, progression — from a little to a lot, from inflexible to limber — takes a variable amount of time depending on the patient. Shortcutting the process is more likely to result in abandonment of effort than a quicker route to maximum protrusion. Hence, adjustable mandibular advancement devices are the norm in dental practice. The OASYS Hinge Appliance™, a recent iteration of the Herbst-style design, has a 10-mm range. The dentist specifies a start position; typically, the device can be backed off a millimeter in case even the gently forward original position is more than comfort allows.

No device is perfect, however. There is simply too much human variation in our patient population. Metal-allergic or metal-averse patients may never accept the metal hinge tubes near their cheek tissue.

To treat snoring and sleep apnea, what is required is a jaw position that is advanced enough to maintain an open airway yet comfortable enough for the patient to fall asleep and stay asleep for the whole night. Many patients adapt easily to the Herbst-style device, as it provides maximum room for the tongue and allows the mandible to move freely in all directions except toward the pharyngeal space.

The design of the traditional Herbst appliance has changed a little to accommodate the needs of snoring and sleep apnea patients. However, the basic function of the device has remained the same.

We believe Dr. Herbst would be stunned by the impact that his jaw advancement device has had in the world of sleep dentistry. Oral appliance therapy (OAT) is now recognized as the first line of treatment for snoring and sleep apnea. There have been many rigorous controlled studies that have shown that, while OAT is not as adept in the treatment reduction of AHI (apnea-hypopnea index) as CPAP (continuous positive airway pressure) therapy, OAT patients are much more adherent to therapy than CPAP patients, resulting in better treatment outcomes.

The popularity of the latest generation of Herbst-style appliances like the OASYS Hinge Appliance continues to grow, largely due to Medicare and Medicaid restricting reimbursement to a small number of designs. The Herbst design was the first on this approval list, called PDAC (Pricing, Data Analysis and Coding). As more patients with this coverage are diagnosed, and as more privately funded insurances choose to follow PDAC restrictions, every dentist providing oral appliances to treat snoring and sleep apnea must be familiar with Herbst-style devices.

Thankfully, PDAC does approve other designs with their own unique characteristics, such as TAP® devices (dreamTAP™, TAP 3 TL, TAP) that keep the mouth closed with a different advancement mechanism from that of the Herbst design. To address each patient’s specific clinical needs, the astute clinician must become familiar with several appliance types, material choices, and other features and benefits.

What matters is opening the airway so patients can take every breath easily during sleep. Herbst-style devices, including OASYS Hinge Appliances, are typically easy for patients to accept, and clinicians to deliver and support — and they are approved for reimbursement. This excellent combination allows clinicians to address the community health crisis of sleep-related breathing disorders.

To discover the simple, three-step process to screen and treat patients for snoring and sleep apnea, visit glidewell.com/pmad.