Airway Management in Restorative Dentistry

Cases like this illustrate that the problem of obstructive sleep apnea (OSA) still looms large in the US—and can be addressed by restorative interventions. According to the American Sleep Apnea Association, 22 million Americans are estimated to be suffering from OSA, leaving them at risk for conditions like cardiovascular problems, obesity, type 2 diabetes, depression, etc. While the continuous positive airway pressure (CPAP) machine is still the gold standard for the medical treatment of apnea, dental interventions are, for now at least, considered the next best thing. In recent years, the fabrication of night guards, splints, and other oral appliances has been seen as a source of financial opportunity for many dentists and laboratories. However, the way dentistry approaches the issue of sleep is evolving, specifically into a field known as airway management.

"Dentistry has this wonderful opportunity to start discovering people with airflow obstructions early," says Jeffrey S. Rouse, DDS, a member of Spear Education's resident faculty, Adjunct Assistant Professor of Prosthodontics at the University of Texas Health Science Center, and in private practice in San Antonio, Texas, and Seattle, Washington. "When we start to see malocclusion, that can indicate a limited ability to breathe through the nose. That is where everything begins. You must be able to breathe through your nose in order to function in a healthy state for your lifetime."

Because dental technicians work so closely with impressions and models and may see the symptoms of OSA on the teeth, they have the opportunity to work with their dentist clients on airway management and/or to help bring them to a wider awareness of these changes. Whether or not your laboratory fabricates oral appliances to treat bruxism or OSA, all dental technicians (and dentists) should be aware of emerging theories, lines of treatment, and even ways to prevent airway obstruction in the mouth.

As the awareness of airflow in dentistry increases, it will become crucial that both dentists and laboratory technicians know how to recognize and address it. "The success of your treatment can depend on the risk factors that patients have," says Tracey Nguyen, DDS, FAGD, AAACD, owner of Lansdowne Dental Care in Leesburg, Virginia. "If you ignore that, your dentistry will fail at some point." Another factor is liability. "In the future, dentists will not be able to do a restorative case without looking at the patient's airway," says Michael Gelb, DDS, MS, owner of The Gelb Center, New York, New York. "Well, they could, but they would risk a lawsuit."

The Causes, Signs, and Symptoms of Airway Obstruction

Many dental professionals interested in airway management agree that the lack of enough intraoral space for the tongue can contribute greatly to a patient's apnea. "It comes down to how massive the tongue is within that space," Nguyen says. "It either will fit comfortably inside your teeth, or it will fall to the back of your throat or outside your mouth. If it doesn't fit comfortably away from the airway, the tongue will push the jaw and everything forward, including teeth Nos. 8 and 9, and can eventually destroy restorations there. I had an apnic patient whose Nos. 8 and 9 implants snapped off at the base, not due to restorative problems, but because of the functional issue caused by not enough intraoral volume," she explains. "I later found out that this patient had severe sleep apnea and was using a CPAP, but his apnea still was not under control. I restored Nos. 8 and 9 again, but now I'm managing his airway with CPAP andoral appliance therapy."

How occlusion problems develop in humans is a topic of debate in the medical/dental community—specifically centering on genetics versus environment. "When I started, dentists assumed we were working against genetics all the time," Rouse says. More recently, scientists have noted how perfect human teeth were centuries and millennia ago; the theories as to why malocclusion has developed run the gamut from how the advent of agriculture changed our diet to the decline in breastfeeding to resting oral posture.^1-3 It could very well be a combination of such factors playing on our genes. "Over time, we're recognizing that the environment can alter the genetic pathway pretty significantly," Rouse says. "The less we find the cause is in genetics, the greater opportunity we have to improve people's condition dramatically for quite some time."

Both the American Dental Association and American College of Prosthodontics have urged dentists to learn more about their patients' medical histories and any current health issues or symptoms, especially as they may relate to OSA.^4,5 That is the first step. However, early characterizations of the typical OSA patient as a middle-aged, obese man have contributed to a degree of tunnel vision by medical doctors and dentists alike.

"That's really the low-hanging fruit," Rouse says. "The real issue is, ‘Where did that person come from? How did they get to that point?' In most people, slow evolution of airflow-limited breathing events over time break the system down. The symptoms will vary depending on where the patient is in their evolution."

Upper airway resistance (UAR) is perhaps one stage of that progression. While an OSA diagnosis requires at least five recorded events during which a patient stops breathing for 10 seconds each, a person with UAR may stop breathing for only 3 or 5 seconds at a time but do it many, many times each night. "New studies document how destructive multiple minor sleep fragmentations can be," Nguyen says. "Upper airway restriction may be triggering sympathetic activity like bruxing, TMD, chronic fatigue, or even fibromyalgia. By dismissing these issues in our young, ‘healthy-looking' patients because they don't fit the OSA patient stereotype, we're keeping ourselves from seeing the big picture and helping more people."

Do No Harm: How to Avoid Impeding the Airway

"Dentistry as a whole can have an impact on the airway, either positive or negative," Rouse says. Both dentists and technicians need to be aware of the consequences of what they put into or remove from patients' mouths. Creating conditions that lead to a restricted airway is just as easy as further restricting the airway of a patient who already suffers from OSA.

First and foremost, considering the airway as the primary concern when treatment planning is critical. "Today, every treatment planning decision should start with the question: Does this patient have an airway issue?" Rouse says. Gelb agrees: "Airway-first treatment planning trumps everything." Having that critical piece of knowledge will help inform the entire treatment plan and approach of the dentist and restorative team. Many dentists are adding questions about sleep apnea or snoring in their patient questionnaires to address this.

While there has been little study of such treatments on a large scale, all dental professionals concerned with airway issues can agree that the size of the intraoral space matters. "Narrowing the arch or constricting the arch is a major flaw," says Paul Federico, MDT, owner of Federico Dental Lab in Staten Island, New York. This is especially important in fabricating prosthetics and to avoid overcontouring.

"In the past, I had patients complain that their dentures were too big or they felt like they were choking them," Rouse says. "What they were really saying was that the way the denture was designed was really impinging on their airway. Now we need to consider the vertical dimension, the intraoral volume, and how adding acrylic or other material could impinge on this volume."

Loss of intraoral space happens in other ways as well. One dental practice coming under scrutiny is the routine extraction of bicuspids and orthodontic retraction of the arches, which definitely narrows the upper archway. Some dentists are quite vocal about the damage that such a practice has in restricting intraoral volume and thereby impinging on the airway. Orthodontist William Hang, DDS, MSD, owner of Face Focused, a private practice in Agoura Hills, California, is one such practitioner. For more than 20 years, he has specialized in correcting what he calls the Extraction Retraction Regret Syndrome by reopening spaces where permanent teeth had been removed for orthodontics and restoring those spaces with implants. This approach, he says, is a way to provide facial balance and treat sympathetic conditions like TMD, restricted airway, OSA, chronic pain, etc.⁶

Like Hang, Victor Avis, DDS, owner of The Avis Alternative in Staten Island, New York, takes this approach—reopening extraction spaces to create tongue space, improve airway, and relieve constricted bites—for some of his own patients.

"There aren't many of us doing this—dozens rather than hundreds," he says. "However, we see how reopening those spaces is having a tremendous impact on patients' quality of life and airway. Widening the arches 16 mm to create tongue space and overjet can make such a difference in pain patterns."

While the dental establishment may largely still be committed to extraction-retraction-based orthodontics, it is possible that such practices may wane on their own due to newer methods and technologies. "Tray-based orthodontics like Invisalign actually do a fairly good job of expanding the arches," explains Sousa, a dentist and dental technologist, and owner of East Hills Dental Associates in Roslyn Heights, New York. "In traditional orthodontics, using wires and rubber bands makes it easier to constrict the arch, which can result in less space for the tongue. Now, tray-based orthodontics can expand the arches more easily and help maintain or improve the airway. I see orthodontics rapidly moving in that direction." If this occurs, and if restrictive orthodontics is at least a factor, it's possible that the prevalence of OSA and airway issues may prove to be a generational problem—mainly affecting the age group that had retractive orthodontics—that will fade as orthodontic approaches change.

Both Avis and Hang are proponents of the theories and practices of orthotropics, developed by John Mew, BDS Lond (LDS RCS End, MFGDP [UK], M Orth RCS Edin). Mew's approach—which posits that poor resting oral posture is a major cause of malocclusion—has been a controversial topic in dentistry for more than 35 years. Correct resting oral posture is to breathe through the nose (mouth closed and tongue on the roof of the mouth) with teeth touching. The essence of the argument is that the impact of the musculature and soft tissue on oral and facial development, airway, and restorations cannot be overemphasized.

Avis has no doubt. "A full-mouth reconstruction can go into the mouth perfectly, but it does not remain pristine because it has forces working on it," he says. "Restorations break down and fail because they exist in a dynamic environment. Dysfunctional muscle activity affects teeth and restorations on a chronic basis. Therefore, it is critically important to understand the root cause of muscle dysfunction and incorrect oral posture and retrain both if we are to optimally manage the forces on our teeth, implants, and dental restorations."

It is no surprise that Avis employs a full-time myofunctional therapist at his practice. "There needs to be more consideration of the soft tissues, anatomy, and airway and their influence on occlusion, contacts, parafunctional habits, caries, and attrition," Avis says. He recommends that dentists and even dental technicians, who work more with the hard surfaces in the mouth, educate themselves on facial musculature. The same, he says, goes for myofunctional therapists to learn more about teeth and skeletal issues. "We all work in the same dynamic environment: the mouth," he says. "We need to learn more about each other's specialties to understand the big picture of what we're doing in the mouth and how we can best help our patients."

Modalities for Management of Existing Airway Issues

According to both the medical and dental communities, CPAP is always the first approach to treating OSA, as its efficacy is well documented.^5,7 Nonetheless, many patients cannot tolerate using a CPAP, and this treatment is notorious for its lack of compliance. Dentistry offers an alternative method that treats OSA more directly, since this problem may very well start in the mouth.

The use of oral appliances, or splints, to help treat OSA has experienced a boom over the last decade, as documented in an article by IDT Executive Editor Daniel Alter, MSc, MDT, CDT (insidedentaltech.com/idt1083). Recently taking the lead as the most recommended dental approach, titrating appliances focus on opening the airway by repositioning the mandible. There are five major types of splints that offer a variety of protrusion, vertical dimension, and guidance. Oral appliance therapies for sleep disordered breathing were explained in a four-part series by Gregory K. Essick, DDS, PhD, et al (insidedentaltech.com/idt1084). Selecting which appliance works for which type of patient is less precise, with dentists often guessing what might improve air flow. "Studies indicate that 50% of night guards are shown to close the airway and worsen snoring and apnea," Gelb says. Nguyen adds: "There are so many kinds of appliances, and each one has a different effect on where the joints are and where the airway is. Some people with a high-angle mandible cannot tolerate an open vertical because we are actually closing that angle and the airway."

Other dentists recognize this problem as well. "Opening someone's vertical dimension absolutely impacts their airway, so it would be nice to know if that impact is negative or positive before we begin restoration," Rouse says. With that in mind, Rouse worked with Frank Spear, DDS, MSD, and Greggory Kinzer, DDS, MSD, to develop a process they call the Seattle Protocol. "Scientific support exists for each type of splint," Rouse says, "but not everyone can use the same kind." By utilizing provisional splints with different variations of vertical dimension and protrusion, this process reduces the amount of time, money, and work invested in finding the ideal treatment approach for each person.

While the Protocol focuses on finding the correct kind of splint, for Rouse that is not the end of the road. "Ultimately, a splint is a bandage. We never leave the patient in a splint," he says. Rather, the patient's choice of splint helps the dental team consider what kind of further treatment could help the patient get the benefits of the splint permanently. The Seattle Protocol is not a means to fabricating the perfect "bandage"; it is rather a diagnostic tool that ideally will help the dentist develop ways to resolve the patient's problem rather than continue to manage it. "We provide a resolution strategy to the patient afterward," Rouse says, "which may include elements such as myofunctional therapy, orthodontic arch widening, ENT surgery, restorative dentistry, weight loss, diet change, etc."

Airway's Impact on Dental Technology

In some ways, dental technicians are uniquely positioned to see such evidence of airway issues early in the process. By looking at the casts and waxing up the teeth, they can see evidence of symptoms such as teeth being ground down by bruxism or acid erosion from GERD, as well as limited intraoral volume, any of which could indicate a restricted airway.

"Technicians will see signs of breakdown in teeth that cannot be explained by occlusion alone," Federico explains. "The problem with the bite itself can be the result of an airway problem. It is important to look for evidence of symptoms such as the movement or migration of teeth, the tongue thrusting the teeth out of the way, or a jaw position relationship that has changed. From a cast, I can see if the maxillary palate is the proper width. The palate may need to be expanded and the teeth moved orthodontically into a better position for the airway."

While laboratories may not be afforded the luxury of seeing casts or photos of their patients from 5, 10, or 15 years ago for comparison, dentists have that advantage. Technicians have the opportunity to ask their dentists questions: Has the patient always had an open bite? Have you noticed any changes in their dentition in the last 3 to 5 years? Has the patient developed any new problems like OSA or TMD? Getting this kind of information through the dentist is critical, once again emphasizing the importance of a close partnership between the dentist and the laboratory to offer the best care for patients.

"I ask the questions that the dentist cannot answer," Federico says. "I like to get the dentist excited about looking at these problems from new perspectives and interested in working on new solutions."

Some dentists really welcome this level of engagement with their laboratories. "We want technicians asking better questions of the dentists and holding the dental community to a higher diagnostic norm," Avis says. Rouse adds: "The more we question and communicate with each other, the more strength we have as partners for our restorative teams."

This inquiry will need to occur in the diagnostic and treatment planning stages. Technicians should broach these issues early so the team can formulate the best plan before fabrication and the correct restorations can be made.

"Dentists must perform full diagnostics and ensure that everyone on the restorative team knows the issues with the case," Sousa says. "They must actually solve the problem together before preparing the teeth. A dentist can only do that when they have a solid working relationship with the laboratory. If a dentist just ships out cases with a minimal prescription and doesn't communicate with the laboratory, they will not get the same quality of results as they would have with mutual understanding."

One thing that can be assured is that airway management in dentistry is not going away, and will likely play a bigger and bigger role in the future.

"This is not a fad," Rouse asserts. "I started looking at this issue years ago, and it continues to become apparent through research that what we're saying is right. It has almost become incontrovertible: This is a real problem and we can do something about it. Some people want it to go away; they want to continue practicing ‘comfortable' dentistry, and this new approach makes them uncomfortable. But this is not going away."