Is Exercise Bad for Your Teeth?

By GRETCHEN REYNOLDS SEPTEMBER 24, 2014 12:01 AM

Vigorous exercise is good for almost all of the body — except perhaps the teeth, according to a surprising new study of athletes. The study, published in The Scandinavian Journal of Medicine & Science in Sports, found that heavy training may contribute to dental problems in unexpected ways.

There have been hints in the past that athletes could have a heightened risk for cavities and other oral issues. In a studypublished last year in The British Journal of Sports Medicine, dentists who examined 278 athletes at the 2012 Summer Olympics in London reported that a majority displayed “poor oral health,” including high levels of tooth decay, often in conjunction with gum disease and erosion of the tooth enamel. The athletes came from the United States and Europe as well as less-developed parts of the world, and most had access to good-quality dentistry, although many had not visited a dentist in the last year.

The study didn’t examine why the athletes were at such high risk of dental problems, although many of us might assume that sugary sports drinks and bars would be a primary cause. Other studies, however, have found little if any link between consuming sports drinks and developing cavities.

So to better understand what is going on inside the mouths of athletes, researchers with the dental school at University Hospital Heidelberg in Germany and other institutions recruited 35 competitive triathletes and 35 age- and gender-matched healthy adults who were not athletes.

All of the volunteers visited the hospital’s dental lab for a full oral examination, including collection of their saliva after they had been sitting quietly. They also completed questionnaires about their diets, including consumption of sports drinks and other beverages, their normal oral hygiene routines, and their exercise habits, if any.

Fifteen of the athletes also completed an increasingly strenuous run of about 35 minutes on an outdoor track, during which their saliva was collected several times.

Then the researchers compared the groups’ teeth and spit, which turned out to be different in telling ways.

Compared with the control group, the athletes showed significantly greater erosion of their tooth enamel. They also tended to have more cavities, with the risk increasing as an athlete’s training time grew. Over all, the more hours that an athlete spent working out, the more likely he or she was to have cavities.

The researchers found no correlation, however, between consuming sports drinks or any other elements of the athletes’ diets and their oral health.

They also found no differences in the amount or chemical make-up of their volunteers’ saliva after the athletes and the non-athletes had been at rest.

But that situation changed when the athletes worked out. During their experimental runs, the amount of saliva that they produced progressively lessened, meaning that their mouths became drier, regardless of whether they consumed water or other beverages during the workout. The saliva’s chemical composition also shifted, growing more alkaline as the workout continued. Excess alkalinity in saliva is thought to contribute to the development of tartar plaques on teeth and other problems.

The extent of the changes in the athletes’ saliva during a workout were something of a surprise, said Dr. Cornelia Frese, a senior dentist at University Hospital Heidelberg, who led the study.

“We had thought sports drinks and nutrition might have the most detrimental influence on dental decay,” she said, “but we saw no direct link” between them. Instead, it was the changes in saliva during exercise that differentiated the athletes’ mouths from those of the control group. Since saliva “has a very protective function” for teeth, Dr. Frese said, having less of it or a chemically different version during exercise could be problematic.

But, she cautions, this study was small, short-term and in many ways unrepresentative of the oral risks most of us would likely face from exercise. “The athletes participating in our study had a mean weekly training time of nine hours,” she said. They were, in technical parlance, hard-core.

“All we can say” based on the data from this group, she said, “is that prolonged endurance training might be a risk factor for oral health.” Whether less frequent or intense exercise would likewise affect oral health is uncertain but unlikely, Dr. Frese said.

Still there are a few precautions that anyone who exercises and has concerns about their oral health might want to take, she said. Drinking water during workouts could be a start, although the connection between hydration and oral health is not scientifically established, Dr. Frese said. More generally, brush and floss, as you know you should. And if you’re a serious endurance athlete, consider visiting a dentist with a specialty in sports dentistry, she said. The goal is to ensure that your teeth remain in as good shape as the rest of you.

Drs. Oz and Roizen: Improve dental care for healthier teeth and body.

Drs. Oz & Roizen:

September 21, 2014 

A walk down the toothpaste aisle at your local drugstore clearly shows that having whiter, healthier teeth is a 21st-century obsession.

But it turns out that it's always been a challenge: Otzi - a 5,300-year-old mummy retrieved in 1991 from a glacier in the Alps - had cavities and severe gum disease, researchers reported recently. And archeologists have discovered that more than 1.5 million years ago, our very early ancestors (Homo erectus) pried bits of dinner from their teeth with the world's first toothpicks.

Ironically, even though these days you can choose from thousands of products to polish, cleanse and protect your teeth, most of us are not all that much better than Otzi at avoiding decay and periodontal disease. Here are ways to improve dental care.

NINE MONTHS:

How long the average American uses a toothbrush before tossing it.

Dentists recommend replacing your toothbrush every two months. But 91 percent of us wait far longer.

• Tooth tip: Spring for a new brush as soon as bristles start wearing out. New bristles remove at least three times more plaque than older toothbrushes with weak bristles that fail to sweep away plaque at the gumline. And if you use an electric toothbrush, opt for a solid-headed one; new research shows that brushes with hollow heads have up to 3,000 times more bacteria residue than solid ones.

85 PERCENT OF MEN; 65 PERCENT OF WOMEN:

The number of Americans who don't floss daily.

Don't only use dental floss for quick touch-ups before a date, a job interview or your next dental appointment. Daily flossing helps break up colonies of below-the-gumline bacteria before they can cause periodontal disease (gum infection that can lead to tooth and bone loss and is associated with heart disease and Type 2 diabetes).

• Tooth tip: Can't get the hang of winding floss around your fingers and wiggling it down between your teeth? Try one of the floss-holding tools available in the drugstore.

70 PERCENT:

Your increased risk for heart disease if you don't brush twice a day and floss once.

Gum disease boosts levels of body-wide inflammation, which raises your risk for heart disease and diabetes. It's also associated with chronic obstructive pulmonary disease, pneumonia, chronic kidney disease, rheumatoid arthritis, thinking and memory problems, obesity, cancer and even depression.

• Tooth Tip: If you're unsure about the best brushing style (back and forth, around in circles, up and down), you're not alone. A recent survey found that official advice about the best way to brush is all over the map. We say, just make sure you brush for two minutes each time, and reach all your teeth from all sides - front, back and chewing surfaces.

36 PERCENT:

Number of Americans who didn't see a dentist last year.

We know that more than 100 million Americans have no dental insurance. But did you know that keeping up with dentist visits could save you money by helping you avoid serious gum disease that may need extensive treatment and can contribute to a wide range of other health problems? Regular visits to the dentist reduce risk for heart attack, stroke, chest pain and congestive heart failure.

• Tooth tip: Dental schools often offer low-cost care; your local or county health department may have information about other affordable options, too.

30 SECONDS:

Time it takes soda, sports drinks or even juice to damage tooth enamel.

In a recent Australian study, dental experts found that high-acid drinks etch the surface of teeth almost immediately.

• Tooth tip: For stronger teeth, sip water or herbal tea instead of soda or sports drinks. Instead of juice, munch whole fruit. You can cool gum inflammation with a healthy diet, regular exercise and a daily DHA omega-3 supplement (2,000 mg a day for three months). Plus, if approved by your doctor, take a daily 81- to 162-mg aspirin with half a glass of warm water before and after.

Mehmet Oz, M.D., is host of "The Dr. Oz Show," and Mike Roizen, M.D., is chief medical officer at the Cleveland Clinic Wellness Institute. To live your healthiest, visit sharecare.com. Distributed by King Features Syndicate, Inc.

Read more here: http://www.idahostatesman.com/2014/09/21/3386630_improve-dental-care-for-healthier.html?rh=1#storylink=cpy

Notes from Dr. Norman Blumenstock

SomnoMed provides us four different oral appliances to choose from that can be used for patients with obstructive sleep apnea. Medicare and medical insurance companies generally provide  benefits for oral appliance therapy.

September 24, 2014 02:40 PM Eastern Daylight Time

FRISCO, Texas--(BUSINESS WIRE)--SomnoMed (ASX:SOM) announced this week that it has received Medicare approval for its new SomnoDent® Herbst Advance Classic and Flex oral devices.

The devices, which effectively treat obstructive sleep apnea, have received full CMS/PDAC approval and were allocated the HCPCS Code of E0486 for DME billing, allowing for Medicare reimbursement in the United States. This allows dentists fitting the device to Medicare patients to apply for and be granted specified reimbursement for the device and treatment.

The SomnoDent Herbst Advance devices were officially launched in the U.S. earlier this month through SomnoMed’s network of educated sleep dentists. The products feature an innovative calibration mechanism, which are designed to make fitting and titration easier and more precise for dentists and patients. Reaction from key opinion leaders to the device following its showing at the conventions of the AADSM (American Association of Dental Sleep Medicine) and the AASM (American Association of Sleep Medicine) earlier this summer has been positive and first orders are currently being processed.

Demand for custom made oral appliances as an alternative treatment for treating sleep apnea is expanding both domestically and worldwide. This is due, in part, to elevated awareness of sleep disordered breathing by physicians, dentists and patients. Access to home sleep testing has also increased, creating a higher number of diagnosed patients seeking therapeutic solutions. Additional drivers of OSA treatment include expanded clinical research uncovering the link between sleep apnea and other severe medical conditions, along with patient non-compliance with CPAP devices.

“Medicare approval in the US is a huge step forward for the SomnoDent Herbst Advance devices and for sleep apnea treatment in general,” said Dr. Peter Neustadt, Chairman and CEO of SomnoMed. “Not only does the approval further strengthen SomnoMed’s global leadership position in COAT™ (Continuous Open Airway Therapy) treatment for obstructive sleep apnea, it enables a larger patient population access to the quality of life benefits that come with COAT treatment.”

Dr. Neustadt also noted that the high level of compliance among patients using oral devices is giving COAT a distinct advantage over CPAP for the majority of patients.

About SomnoMed:

SomnoMed is a public company providing diagnostic and treatment solutions for sleep-related breathing disorders including obstructive sleep apnea, snoring and bruxism. SomnoMed was commercialized on the basis of extensive clinical research. Supporting independent clinical research, continuous innovation and instituting medical manufacturing standards has resulted in SomnoDent® becoming the state-of-the-art and clinically proven medical oral appliance therapy for obstructive sleep apnea. The company’s SomnoDent® is a treatment solution that has proven effective for over 175,000 patients in 28 countries.

For additional information, visit SomnoMed at http://www.somnomed.com.

Sleep Apnea Predisposes To Impaired Brain Blood Flow With Physical Activity

Notes from Dr. Norman Blumenstock
Medicalresearch.com interviews Paul Macey, PhD, lead researcher on a study that provides evidence of sleep apnea hurting the brain

Medical Research:  Were any of the findings unexpected?
Dr. Macey:  We did not expect that breathing very hard into a small tube would lead to similar changes in brain blood flow in the sleep apnea and healthy people; we had expected the sleep apnea patients to show problems, as they did during the gripping and cold foot activities.  We now believe the hand and foot activities need to use more higher brain areas, but that these areas are injured in people with sleep apnea, and so the brain processing is weaker.  The breathing into the tube on the other hand works mostly of higher pressure in the chest squeezing the heart and blood vessels, and only uses lower brain areas, which appear to mostly be working in people with sleep apnea.

5 Things You Can Do After Lunch to Improve Sleep Quality

Notes from Dr. Norman Blumenstock
After-lunch strategies can improve sleep quality. If you incorporate these things during the day, it will improve your sleep quality at night.

by Jamie Scott, of Whole9 South Pacific , who lives at 43 degrees south in New Zealand and wakes up to a light alarm.
Last time we looked at the importance of sleep to overall health and touched on three pre-lunch strategies to help your body prepare for the coming night’s sleep.

Today we’ll be talking about after-lunch strategies to improve sleep quality. If you incorporate these things during the day, it will improve your sleep quality at night. First, we have to acknowledge that preparing for sleep several hours prior to going to bed does not come naturally to many people, let alone preparing for bed as soon as you get up. Many people simply cannot think this way, particularly when the strategies they would need to put in place during the day to ensure a good sleep at night put them into conflict with many other aspects of their day – such as work, family, social occasions, and so on. As a general rule, most of us will think and act in the here and now for many of the key decisions in our daily life rather than for something down the track.

Life, however, is full of compromise. So while some of these strategies might be difficult to do if they conflict with other areas of your life, you may need to ask what is more important in the grand scheme of things. Poor sleep, and the negative health consequences that travel with it, are so pervasive and damaging that those sleep-improvement strategies might just be worth it. And nobody ever complained of feeling fully-rested, energised and not chronically feeling under-slept.

Our morning strategies were largely focused on waking the body up properly and using the light and the composition of your breakfast to send all the right wake-up signals to your body, setting the stage for a circadian rhythm that is properly calibrated to the natural light-dark cycle. Doing so has the effect of synchronising your body clock with light and dark cycles so that you get tired and sleepy at the right time of the day (night-time) and that you have the correct precursors there in place to help your body produce enough of the hormone which will induce sleep for you (melatonin).

Having set up these important processes in the morning, the key to the afternoon then, is not to do anything to disturb and disrupt all that good work.

1. Kill the Caffeine

One of caffeine’s effects on our body, and indeed the very reason it helps to wake us up and make us feel alert, is its ability to boost our cortisol levels. In very simple terms, cortisol has a couple of key functions;

1. It is the hormone responsible for waking us up in the morning, mobilizing energy and helping our brain fire on all cylinders.
2. It is one of our key stress hormones.

If anyone knows anything about sleep, you will know that feeling stressed, even at a low level, makes sleep difficult to come by. Caffeine consumed in the morning is generally okay as the cortisol it stimulates is only minor given the amount which is already in circulation as part of our body waking up. But as we hit the afternoon and our natural cortisol levels are starting to drop, the last thing we need to do is to spike them back up with caffeine.

Caffeine has a half-life of approximately 6 hours (though this varies significantly person-to-person), meaning that it takes this long for your body to metabolise half of the amount of caffeine you have consumed down to half the dose. So if you drink a cup of coffee containing 100mg of caffeine, it will take approximately 6 hours to get it down to 50mg in your bloodstream.

If you are constantly drinking coffee all day, particularly late in the day, you will be increasing your caffeine levels (and thus sleep-destroying cortisol) faster than you can get it out of your system. Drink too much caffeine throughout the day and there is a good chance that you will be going to bed with the equivalent of a shot of espresso still in your system.

There is also considerable variation in how efficiently caffeine is metabolised, with some people carrying a specific genetic variant being able to break down caffeine more rapidly. But don’t get all excited – the majority of people are “slow metabolisers” of caffeine, and thus these guidelines are more likely to apply to you than not.

I have had people assure me that they can still fall asleep even after having a coffee late in the day. However, there is a big difference, qualitatively, between being able to fall asleep and going through all the natural deep sleep cycles you need to throughout the night.

This qualitative distinction is also a reason that alcohol is absolutely not your friend if sleep matters to you, since any significant amount of alcohol within a couple hours of sleep negatively affects the type of sleep you get, resulting in abnormal sleep patterns throughout the night. Being asleep is not the same as being in a deep sleep – something caffeine is very good at stopping you from entering, and alcohol is good at stopping you from maintaining. Red Bull and vodka? The worst idea ever.

To minimise the effect caffeine might be having on your sleep, it is a good idea to quit all sources of caffeine about 6-8 hours out prior to bed. In practical terms, this means you might be able to get away with an early afternoon coffee, but make that your last for the day. If you have any sleep or fatigue issues, we also recommend a Caffeine Holiday a couple times a year, too.

2. Blackout the Bluelight

From the Morning Edition, you will recall that I talked about how light is a key stimulus required to wake you up in the morning (hence why it is easier to wake up in the middle of summer compared to the middle of winter). When we talk about natural light being a stimulus to wake you up, what is specifically meant is the blue light spectrum of natural light. Rather inconveniently (but not by chance), all of our new modern techno toys – computer screens, tablets, smartphones, etc., emit light in almost exactly the right wavelength to stimulate the same process.

In other words, the blue light streaming into your eyes from your smartphone that you are holding right up to your face at 9 o’clock at night as you tell the world, via your InstaTwitFace account, that tonight is going to be the night that you finally get a good sleep, is actually sending a signal to your body that the sun is up and it is time to wake up. Research shows us that blue light (even when very dim) has a significant alerting effect – similar to caffeine!

Research in this area has shown that even just a small amount of use of these gadgets at night can delay your melatonin pulse (the hormone which will put you to sleep) by up to 2 hours. So if you are leaving it until 11pm at night to settle into bed, but you have been using your gadgets all night, it could be well after 12-1am before you really fully fall asleep.

Melatonin, in the normal run of things, starts pulsing at around 7pm and really winds up about 9pm. So, ideally, you would want to avoid overdoing the blue light toys around that time. Yeah, right. If you think asking someone to give up sugar is hard, try asking them to give up their iPhone and MySpaceFace account in the evening. It generally ain’t happening for anyone under the age of 30.

Your ‘hack’, should you find it completely impossible to unplug at night, is to wear glasses with orange lenses(similar to what cyclists wear for low light riding), as these glasses filter the sleep-killing blue light.

3. Improve Your Bedroom Environment

Next on our countdown to bedtime, is a check of your sleeping environment. Specifically, we want to look at the bed, the temperature, and the light. You are going to spend at least one-third of your life in bed, so a comfortable bed and pillows are going to be a good investment. For the bed at least, this isn’t perhaps a quick fix if it isn’t the most comfortable of sleepers, but certainly put it on your long list if you just can’t get comfortable.

Of more immediate concern, however, is the temperature of your room. Humans tend to sleep best in a room a bit on the cooler side, but not too cold. Around 16 degrees C (61-62 degrees F) seems to be optimal. This may necessitate cooling the room in summer or heating the room/bed in winter. Being too hot or too cold is a potent disruptor of sleep.

Try to also kill any artificial light sources – all the LEDs from alarm clocks, flashing notification lights on phones, or light from outdoor sources such as the streetlamps. Alarm clocks should be covered or put under the bed, phones and their notification systems should be off (airplane mode works great for this, too). Use the room layout and/or blackout curtains to ensure external light sources like street lamps aren’t seeping in. It’s also a good idea to avoid watching TV or movies in bed. Ideally, your bed is for sleeping and sex, not reading or watching TV or browsing Amazon on your iPad.

If you live in an area where sound pollution is an issue, a white noise machine is a great tool to help reduce how much sound pollution impacts your sleep. There are also mobile phone apps that work well, too.

4. Create a Bedtime Routine

A bedtime routine is a great way to tell your brain that it’s time to start winding down. For those of you with children, you’ll know that a consistent bedtime and routines help with sleep – this is true for adults as well. Dimming the lights, reading a (paper) book, or drinking a cup of herbal tea are good ways to set the tone for slipping easily into Dreamland. Massage, a warm shower or bath, and sex are all great soporifics. (A soporific is the sleep equivalent of aphrodisiac, and I know you know what that means.) Apply accordingly.

Some people find that gentle exercise such as a walk or a restorative yoga class help with sleep, but I will caution you against very intense or prolonged training within a couple hours of bedtime, as the cortisol response from your 10K run near lactate threshold or your 45 minute circuit training class will likely delay the onset of deep sleep.

That being said, evening exercise is better than no exercise at all, so if you are confined to the late evening hours for training, moderating your intensity and allowing more recovery between sets/intervals may help offset the unnatural schedule of modern life.

5. Reduce Emotional Commotion

One of the most potent simulators of the stress response is interpersonal conflict. Schedule all fights with your spouse before noon, and don’t read work-related emails right before bed. Nothing like that note from your boss to get you all wound up. Action movies or psychological thrillers can really get your heart pounding and make it tough to wind down right afterward, too. Episodes of Game of Thrones are hardly a good evening entertainment choice. Even really rousing books (especially engaging works of fiction) can get your cognitive engines whirring, which may or may not be a good thing right before bed.

As you can see, there is a lot involved with getting a good night’s sleep. When someone complains of not being a good sleeper, rarely have they ticked ALL of the boxes outlined in this before lunch and after lunch sleep strategy series and given them a chance to work. There are other sleep disruptors, yes, but these are the basics which everyone should apply first.

Crowdsourcing Campaign Launched for Urine Test to Determine Whether Child Has Sleep Apnea or ADHD

Published on September 17, 2014

For millions of kids, a urine test could mean better, healthier sleep and possibly avoiding a mistaken diagnosis of ADHD.  The East Peezy Pee Test is a new diagnostic test in development at NuSomnea that has been found to be 96.5% accurate in determining if a child has pediatric obstructive sleep apnea (OSA), according to NuSomnea.  This condition is associated with symptoms often mistaken for attention deficit/hyperactivity disorder (ADHD).

This week, NuSomnea launched an Indiegogo fundraising campaign to help complete the development of the urinalysis test and to conduct another validation study in children, to confirm the results found in initial studies.

The Indiegogo campaign offers contributors perks including fun t-shirts and backpacks featuring "The Peezies," the characters from the Easy Peezy video, as well as the Easy Peezy Pee Test when it becomes available.

The test identifies the urinary concentrations of four proteins that are predictive of pediatric OSA. "Diagnosing OSA usually requires an expensive stay at a sleep lab.  It's inconvenient for parents and uncomfortable for kids,"  says Michael Thomas, co-founder of NuSomnea, in a release.  "We're changing that with a simple urine test that's more accessible, more accurate and costs about 75% less."

In children, common indicators of OSA are behavioral problems, learning disabilities, hyperactivity and attention problems, which may frequently be diagnosed as ADHD or ADD.  Nearly 7 million children between 4 and 17 years old are currently diagnosed with ADHD, but research has reported that up to 50% might actually have pediatric OSA.  Further, a large percentage of kids with ADHD respond to standard treatment for OSA-tonsil and adenoid surgery-reinforcing the conclusion that many have OSA in addition to or instead of ADHD.  If a child has OSA, treating only for ADHD with stimulant drugs may not resolve the issue.

Because the Easy Peezy Pee Test is so convenient to administer, the manufacturer says it has the potential to be used as both a diagnostic tool and a disease management tool to more closely monitor therapy effectiveness and improve patient outcomes.

The Easy Peezy Pee Test by NuSomnea is still in clinical development and should be available to doctors in 2016.

Sleep sensors: waking up to the need to study our night's rest

Notes from Dr. Norman Blumenstock

Many people are turning to fitness trackers to help boost the health benefits of better sleep

Sales of sleep tracking devices are booming as more people become mindful of their health. Big manufacturers are piling in, but do the gadgets work, and, if so – how? Photograph: Vincent Besnault/Getty Images

Every night Jack Hammond straps a small gadget to his wrist. The sensor claims to track his sleep, monitoring every toss and turn so that when he wakes it can tell him how long he slept, how much of it was deep sleep – and how often he was woken up by his unsociable neighbor.

"I can see that I need about four hours' deep sleep to feel refreshed, and I need to be asleep for about eight hours for that to happen," says Hammond, a 36-year-old plumber from Northhampton. "I can also see that when I've had caffeine too late I get less deep sleep."

Hammond's gadget is a fitness tracker – a small bracelet device that by day can measure his activity and calorie burn, the distance he has walked and altitude climbed, and reveal how long he spends at his desk. Part of the "quantified self" movement, more than 3.8m fitness trackers like Hammond's were sold worldwide in 2013, predicted to rise to 14.6m by the end of 2014, according to the analysts CCS Insight.

"Several devices have supported sleep measurement for some time, from smaller companies such as Jawbone, Fitbit and Basis," said Ben Wood, the head of research at CCS Insight. "The big players are now getting in on the action and Sony and Samsung devices support sleep tracking too."

But do the devices work? Does using them do you any good?

Sleep has always been considered scientifically important to all-round physical health. But efficacy of fitness trackers to measure and improve sleep is less established.

Studies have found that people who sleep for less than six hours a night have a risk of high blood pressure three times greater than those who get more than six hours, and that women who sleep less than four hours a night are twice as likely to die from heart disease as those who sleep longer. Other research suggests that a lack of quality sleep is linked to the onset of diabetes, obesity and cancer, not to mention deterioration of mental health and memory. Conversely, sleeping too long has also been shown to cause issues. The recommended amount is between seven and nine hours.

"There's physical restoration component to sleep, including healing, as well as mental restoration component," explains Dr Michael Breus, a US "sleep doctor", based in Scottsdale, Arizona. "During REM [rapid eye movement] sleep in particular there's a cleaning process to get the trash out of there, and a strengthening process that occurs for the more important memories," said Breus.

"Anything that allows you to wake up feeling refreshed in the morning is what you should be aiming for, which is generally between six and nine hours," explained Dr Irshaad Ebrahim from the London Sleep Centre. "But it's not all about time, it's about the quality of the sleep, whether you complete sleep cycles."

As to using motion trackers to measure sleep, he said: "They're not measuring sleep, simply motion – not muscle tone, brain waves, heart rate or eye movement. You cannot infer quality of sleep from motion and tell what is crucial REM [rapid eye movement] sleep and what is not. People can become obsessed about their sleep through these gadgets doing them a disservice, worrying about it and in turn getting less decent sleep and having a negative impact."

Breus is less concerned. "They pique people's curiosity, and it gets them to ask 'how is my sleep'? That's the best thing about them. I wouldn't say they are dangerous, but it's a garbage-in, garbage-out situation, and it's impossible to make recommendations without good data."

For some users, that curiosity can lead them to understand how to sleep better. "My Fitbit told me I slept for more hours than I thought I did," said James Stockton, 29 from Southampton. "It was quite encouraging, and I could see patterns in my sleep when I exercised more or drank alcohol."

If, however, inspired by a sleep gadget, you want to find out general tips for better sleep, you will discover the advice doesn't fit so well with a modern lifestyle. Screens on smartphones, tablets and TVs emit blue light that disrupts the natural process of falling asleep – and is best avoided for an hour before going to bed. Avoiding alcohol and caffeine raises the quality of sleep, as does getting regular exercise.

Motion trackers aren't the only gadgets claiming to track sleep. Products such as the SleepRate, which comes with a chest strap, will track heart rate, which can be used to infer sleep. Although more accurate than motion trackers, they still cannot conclusively monitor all stages of sleep and reveal the crucial quality of a period of sleep.

"I get patients showing me their sleep data on smartphones," said Breus. "But I can't tell them what I don't know. The data isn't good enough to give them a diagnosis. They could be useful for tracking sleep trends over a longer period of time, to see when something changes, though."

Most of the devices currently available to consumers simply track motion to infer sleep. Sleep therapists use much more sophisticated machines that monitor brain waves, muscle tone and eye movement to directly detect the different phases of light and deep sleep.

The next wave of sleep gadgets, expected to hit the market within six months, is likely to include more sophisticated sleep-trackers that can monitor brain wave activity and eventually other biometric indicators, such as heart rate, muscle tone, eye movement and breathing rate.

Brain wave patterns are thought to be the best indicator at present. "We expect this to become a standard feature in most wearable devices , both fitness bands and smart watches, from now on," said Wood.

In the meantime, many sleep-tracking devices are built into tools for tracking more general fitness – and there is evidence that consumers are losing enthusiasm. A third of owners abandon their fitness tracker within six months, according to research from Endeavour Partners.

"I used to track my sleep with my Flex, but I gave up in the end," said Jessica Ross, 22, from Liverpool. "It was boring and didn't really tell me anything to keep me wearing it either at night or through the day. It lasted four months and then went in a drawer."

Top trackers

There are many devices on the market that claim to track your sleep, some better than others.

Here are six of the best available at the moment.

Misfit Shine – £80 A small metal waterproof disc, the Misfit Shine is one of the smallest and most comfortable to wear. It automatically detects deep and light sleep and awake moments via movement. It has a four-month battery life and outputs the data via Bluetooth to an Android or iPhone app.

SleepRate – £60 Combining a chest heart rate monitor with a smartphone app, SleepRate, which uses a heart rate strap, monitors sleep and can craft a bespoke sleep improvement plan. SleepRate claims to be more accurate than motion-based sleep monitors and if serious problems are detected SleepRate will suggest a visit to a sleep doctor.

Jawbone UP24 – £125 This fitness band can monitor light and deep sleep and waking periods using movement while automatically connecting to an iPhone or Android smartphone via Bluetooth. It will also wake up the wearer with a small vibrating alarm at the optimum time for a maximum refreshed feel.

Fitbit One – £80 Fitbit's pedometer-style fitness tracker can also monitor sleep, slipped into a small soft band worn around the wrist. Like the others it detects movement and can wake the user through a small vibrating alarm.

Fitbit Flex – £80 The Flex is essentially the Fitbit One formed into a bracelet, detecting sleep through moment and connecting to the Fitbit iPhone, Android and Windows Phone app via Bluetooth.

Withings Pulse O2 – £100 The Pulse will track sleep via movement, giving readings on total sleep and sleep cycles, slipping into a bracelet worn around the wrist. It connects via Bluetooth to an iPhone or Android app to display the data.

CPAP Pressure for Prediction of Oral Appliance Treatment Response in Obstructive Sleep Apnea

Notes from Dr. Norman Blumenstock
In Australian patients, the majority of whom are Caucasian, a higher therapeutic CPAP pressure requirement in conjunction with age and OSA severity characteristics may be useful to indicate likelihood of success with oral appliance (MAS) as an alternative therapy.

Scientific Investigations

CPAP Pressure for Prediction of Oral Appliance Treatment Response in Obstructive Sleep Apnea

http://dx.doi.org/10.5664/jcsm.4020

Kate Sutherland, Ph.D.1,2; Craig L. Phillips, Ph.D.1,2; Amanda Davies, B.Sc.(Hons)1,2; Vasanth K. Srinivasan, M.D.Sc.3; Oyku Dalci, Ph.D.3; Brendon J. Yee, M.D., Ph.D.1,4; M. Ali Darendeliler, Ph.D.3; Ronald R. Grunstein, M.D., Ph.D.1,4; Peter A. Cistulli, M.D., Ph.D.1,2

1NHMRC Centre for Sleep Health (CIRUS), University of Sydney, Australia; 2Centre for Sleep Health and Research, Department of Respiratory Medicine, Royal North Shore Hospital, Sydney, Australia; 3Discipline of Orthodontics, Faculty of Dentistry, University of Sydney, Sydney Dental Hospital, Australia; 4Department of Respiratory and Sleep Medicine, Royal Prince Alfred Hospital, Sydney, Australia

ABSTRACT

Study Objectives

Mandibular advancement splints (MAS) are often preferred to CPAP treatment for OSA but are not always equally efficacious. High therapeutic CPAP pressure has been associated with MAS treatment failure in a Japanese population. We sought to assess the relationship between CPAP pressure and MAS treatment response in an Australian population.

Methods

Therapeutic CPAP pressure and MAS treatment response were obtained from a one-month crossover trial of both treatments. Predictive utility of CPAP pressure to identify MAS treatment response was assessed.

Results

Seventy-eight OSA patients were included (age 49.3 ± 11.1 years, BMI 29.1 ± 5.8 kg/m2) with predominantly moderate-severe OSA (AHI 30.0 ± 12.7/h). CPAP pressure was lower in MAS responders (MAS AHI < 10/h) 9.7 ± 1.6 vs. 11.7 ± 2.4 cm H O, p < 0.01, with area under ROC curve of 0.74 (95% CI 0.63-0.86), p < 0.01. The best cutoff value of 10.5 cm H O useful for discriminating MAS responders and non-responders in the previous Japanese population, was inadequate for prediction in the current population (0.47 negative predictive value [NPV]). However a cutoff of 13 cm H O identified MAS non-responders (1.0 NPV). Multivariate regression identified CPAP pressure (odds ratio [95% confidence interval] 0.53 [0.33-0.87], age (0.93 [0.87-0.99]) and AHI (0.92 [0.86-0.97]) as predictors of MAS treatment response (model r2 = 0.54, p < 0.001).

Conclusions

In Australian patients, the majority of whom are Caucasian, a higher therapeutic CPAP pressure requirement in conjunction with age and OSA severity characteristics may be useful to indicate likelihood of success with MAS as an alternative therapy.

Citation

Sutherland K, Phillips CL, Davies A, Srinivasan VK, Dalci O, Yee BJ, Darendeliler MA, Grunstein RR, Cistulli PA. CPAP pressure for prediction of oral appliance treatment response in obstructive sleep apnea. J Clin Sleep Med 2014;10(9):943-949.

Continuous positive airway pressure (CPAP) is the standard treatment for obstructive sleep apnea (OSA). Although highly efficacious, CPAP is often hindered by poor tolerance and suboptimal adherence,1 limiting its effectiveness in the real world. Mandibular advancement splints (MAS) are an alternative option recommended as a first-line treatment for mild-moderate OSA.2 We have recently found that health outcome improvements, including sleepiness, are similar with MAS and CPAP treatments in patients with moderate-severe OSA.3 Superior patient adherence appears to offset any inferiority of MAS efficacy,3 and MAS may be considered a viable alternative for many patients.

However despite similar health benefits between treatments, approximately one-third of OSA patients will not respond to MAS.4–7 This is of significant concern in terms of resource wastage and treatment delays. Much attention has been given to understanding patient phenotypes which relate to MAS response such as gender, obesity, craniofacial structure, and type and severity of OSA.8 However, none of these factors are universal, and hence there is an unresolved need for reliable indicators of MAS treatment response.

A recent Japanese study has identified pressure requirement in CPAP users as a predictor of MAS response.9 In established CPAP users, a prescribed pressure of above 10.5 cm H2O indicated poor response to subsequent MAS therapy. This prediction method is, of course, restricted to patients who have used CPAP and wish to try MAS. However CPAP pressure would represent a simple predictor, either alone or possibly in combination with other patient characteristics to further improve prediction. This would be clinically useful in patients who have failed or are non-adherent to CPAP and would support implementation of MAS therapy as an alternative in such patients.

In this study, we aimed to firstly confirm a relationship between therapeutic CPAP pressure and MAS treatment response in treatment-naive OSA patients, and secondly to investigate the utility of therapeutic CPAP pressure as an indicator of MAS treatment outcome in an Australian population, predominantly comprised of Caucasians.

METHODS

Patients

OSA patients were participants in a previously published randomized crossover trial of one month of CPAP versus MAS to compare health effects.3 Inclusion criteria for this trial were a new diagnosis of OSA, aged ≥ 20 years, apnea-hypopnea index (AHI) > 10 events/h, ≥ 2 symptoms of OSA, and willingness to use both CPAP and MAS. No limits for body mass index (BMI) were set for inclusion. Exclusion criteria were central sleep apnea, previous OSA treatment, requiring immediate treatment, contraindications to MAS therapy, regular sedative or narcotic use, preexisting lung disease, or psychiatric disease. Self-reported ethnicity data was not collected in this study; however, the majority of patients likely have Caucasian ancestry.

Study Protocol

Patients underwent an acclimatization phase to both CPAP and MAS in a randomized order to optimize both treatments before the study. Subsequently patients were randomized to one month each of CPAP and MAS, with treatment response determined by polysomnography at end of each treatment. The study protocol in Figure 1 illustrates the acquisition of data utilized in this analysis.

BRIEF SUMMARY

Current Knowledge/Study Rationale: CPAP pressure has been shown to predict oral appliance treatment response in Japanese male OSA patients and could be a simple and useful clinical predictor for some OSA patients. We sought to assess the relationship between CPAP pressure and oral appliance treatment response in a predominantly Caucasian population.

Study Impact: We confirm a relationship between lower CPAP pressure and oral appliance treatment response, although not as strong as in the Japanese population and requiring a higher CPAP pressure cutoff value for best predictive utility. CPAP pressure requirement, in conjunction with patient characteristics of age and OSA severity, may be useful in indicating oral appliance treatment response in Caucasian OSA populations.

CPAP

All patients used the same CPAP device (ResMed Autoset S8, ResMed, Bella Vista, Australia). Patients were given the device to use in Autoset mode at home. Therapeutic pressure was determined by the 95th percentile pressure from usage exceeding 4 hours. Therapeutic CPAP pressure was confirmed by overnight polysomnography on CPAP treatment. Only participants who achieved AHI < 5 events/h on this night were included in the analysis as a stringent definition of therapeutic CPAP pressure.

MAS

The MAS used was a titratable two-piece customized device (SomnoDent, SomnoMed Ltd, Australia) with previously established clinical efficacy.4,10 Patients underwent a 6-week acclimatization period to incrementally advance the device until maximal comfortable jaw protrusion was reached and confirmed by the treating orthodontist.

Treatment Response Definitions

In order to assess generalizability, we used 3 definitions of treatment outcome that are used variably in clinical practice and to allow comparison with previous findings.9 MAS treatment response was most stringently defined as complete resolution of OSA defined by a treatment AHI < 5 events/h (definition 1). As baseline AHI was > 10/h in this sample, this also reflects a > 50% decrease in all patients. Secondly, treatment response was defined as a MAS treatment AHI < 10 events/h and > 50% reduction in AHI from baseline (definition 2). Thirdly, a more liberal definition of response was defined as ≥ 50% reduction in AHI from baseline regardless of the final AHI achieved (definition 3). These 3 alternate definitions of MAS treatment response are summarized in Table 1.

Statistical Analysis

Statistical analyses were performed using statistical software (SPSS version 21.0 for Windows; SPSS, Inc., IL, USA). Continuous variables (optimal CPAP pressure and other baseline characteristics) were compared between MAS treatment response groups using independent t-test and categorical variables with χ2 test. Univariate logistic regression was used to assess the predictive value of CPAP pressure for MAS response. Multivariate logistic regression analysis was used to identify the best prediction model from patient variables and therapeutic CPAP pressure. Predicted values of the models were assessed by receiver operating characteristic (ROC) curve analysis using the area under curve (AUC).

RESULTS

Patient Characteristics

Seventy-eight patients who completed both MAS and CPAP treatment arms were confirmed to have AHI < 5/h on CPAP and were therefore included in the analysis. Excluded patients (CPAP AHI > 5/h) did not differ in age, BMI, neck or waist circumference, AHI, MAS response, or CPAP pressure requirement compared to those included in the analysis. Eight patients had mild OSA (AHI 10-14.9/h), 33 moderate (AHI 15-29.9/h), and 37 had severe OSA (AHI > 30/h). Patients were predominantly Caucasian, mostly male (81%), middle-aged, and over-weight; 52.6 percent of patients had a complete response to MAS treatment (AHI < 5/h, definition 1). Baseline characteristics are shown in Table 2. MAS treatment responders were significantly younger and less obese with a tendency towards a lower baseline AHI than non-responders. However gender proportions and supine-predominant OSA frequency did not differ between responders and non-responders in this sample.

Therapeutic CPAP Pressure and MAS Treatment Response

Mean CPAP pressure was 10.4 ± 2.1 (± SD), with a range of 4-18 cm H2O. CPAP pressure did not significantly differ between responders and non-responders by definition 1 (10.0 ± 1.4 vs. 10.8 ± 2.6 cm H2O, p = 0.09). By definition 2, responders (AHI < 10/h on MAS) had a lower CPAP pressure requirement than non-responders (9.7 ± 1.6 vs. 11.7 ± 2.4 cm H2O, p < 0.01). Responders defined by ≥ 50% reduction in AHI (definition 3) also had a lower CPAP pressure (10.0 ± 2.0 vs. 11.6 ± 2.3 cm H2O, p < 0.05). CPAP pressures for responders and non-responders, by all 3 definitions, are shown in Figure 2. In univariate analysis CPAP pressure had predictive value in discriminating MAS treatment responders and non-responders by definitions 2 (AUC [95% CI] 0.74 [0.63-0.86], p < 0.01) and 3 (0.70 [0.55-0.84], p < 0.05) (Table 3). As post-treatment AHI < 10/h (definition 2) is probably the most clinically useful, we explored CPAP pressure cutoff values to correctly classify patients using this model (Table 4). A pressure cutoff value of 13 cm H2O most accurately identified non-responders to MAS therapy (negative predictive value = 1). However, patients requiring pressures ≥ 13 cm H2O represented < 10% of this patient sample. This cutoff value correctly classified 69.2% of patients as MAS responders or non-responders. Below 13 cm H2O there was much overlap in pressures between responders and non-responders making CPAP pressure alone inadequate to discriminate between these patients.

Prediction of MAS Treatment Response

Multivariate logistic regression was performed to assess the utility of baseline characteristics (age, gender, BMI, neck circumference, baseline AHI, in combination with CPAP pressure) in the prediction of MAS treatment response (Table 5). In the model for MAS response by definition 1 (MAS AHI < 5/h) only baseline AHI and age were significant predictors. In predicting MAS response by definition 2 (MAS AHI < 10/h), the combination of baseline AHI, age, and CPAP pressure were significant, with 54% of the variance in MAS response explained by the model. This multivariate model correctly classified more patients than the prediction model based on CPAP pressure alone (AUC [95%CI] 0.84[0.75-0.93], p < 0.001). By definition 3 of MAS response (≥ 50% AHI reduction), only age and neck circumference, but not CPAP pressure, had predictive value.

DISCUSSION

This is the largest study to assess the relationship between therapeutic CPAP pressure and MAS treatment response and the first study in a treatment-naive and a non-Japanese population. Our findings lend support to the previously reported relationship between CPAP pressure and MAS treatment response,9 and extend these findings by identifying a much higher CPAP pressure cutoff for negative prediction of MAS response in this population. The implication is that there may be population-specific characteristics that influence the cutoff pressure values for which CPAP is best predictive of MAS response. This could be attributed to differences in obesity and craniofacial phenotypes between Japanese and Australian populations.

Our data support the notion that there is some relationship between MAS treatment response and CPAP pressure requirement with MAS non-responders requiring higher pressures. However this relationship seems not to be as pronounced as in the previous Japanese study, with higher pressures only observed in nonresponders by definitions 2 and 3 (MAS AHI < 10/h and > 50% AHI reduction). The median difference in pressures between responders and non-responders was also much narrower in the current study at 1 cm H2O, compared to ≥ 4 cm H2O in the previous study. In the Japanese study, a CPAP pressure cutoff value of 10.5 cm H2O most reliably classified patients in terms of MAS response, with pressures higher than this generally indicating a negative response to MAS.9 This value was inadequate for use in our patient sample and correctly classified only 47% of patients as non-responders, due to a large overlap of MAS treatment responders and non-responders with therapeutic CPAP pressures in the < 12 cm H2O range. Our results indicate that application of this method of prediction to an Australian population requires a higher cutoff value of 13 cm H2O for best discrimination, with 100% of patients above this level correctly classified as non-responders and 75% of the patients below this level as responders. This substantial difference in CPAP cutoff values to best classify MAS responders and nonresponders between these two populations suggests that there may be an influence of ethnicity factors on the relationship between CPAP pressure and MAS treatment response.

There are recognized differences between ethnicities in craniofacial and obesity risk factors associated with OSA. For the same level of OSA severity, Caucasians have been shown to have more obesity compared to Asians with OSA, whereas Asians show a greater restriction in craniofacial skeletal measurements associated with OSA, such as restricted maxillary and dimensions and retro-positioning, compared to Caucasians.11–14 Therefore both populations appear to have an anatomical imbalance contributing to upper airway collapsibility,15,16 but this is primarily driven by excess soft tissues in Caucasians and bony restriction in Asians. Differences in the relationship between CPAP pressure and MAS response may relate to these different hard and soft tissue proportions. BMI was lower in MAS responders in our study and was a predictor of response in univariate analyses (data not shown); however, no such relationship was evident in the Japanese study,9 suggesting obesity was less of a factor in MAS treatment response. BMI and neck circumference also relate to CPAP pressure in Caucasian populations.17,18 Craniofacial measurements have additionally contributed to CPAP pressure determination in a Japanese study, whereas only soft palate length had any association with CPAP pressure in a French study.19,20 Therefore craniofacial/obesity factors may have also differentially contributed to MAS response and/or CPAP pressure requirements between the two populations, although craniofacial factors were not assessed in either study.

Differences in the relationship between CPAP pressure and MAS treatment response between these two studies may additionally relate to other factors. There was also a difference in gender between the two studies, with the study of Tsuiki and colleagues including only males. Nineteen percent of subjects in the current study population were female. However there was still not adequate numbers to determine if gender has an influence on the MAS response/CPAP pressure relationship, although there was no difference in pressure requirement between genders (data not shown). Treatment success rates were much higher in the current study, with a greater proportion of patients achieving AHI < 5/h with MAS (47.6% vs. 29%), which may relate to differences in MAS devices. In the current study a titratable, two-piece appliance was used which allows the jaw to be advanced incrementally over time to maximize efficacy.21,22 Our treatments were implemented as part of a one-month crossover trial of optimal forms of both MAS and CPAP treatment with a 2-week treatment washout period in between. This differs to the previous Japanese study in which long-term compliant CPAP users were invited to participate and try MAS therapy.9 Previous and consistent use of CPAP may have some effect on the subsequent relationship with MAS treatment outcome, as it is possible that long-term CPAP use may influence the efficacy of MAS therapy through changes in upper airway and soft tissues and craniofacial skeletal structure.23,24

Our study found CPAP pressure combined with patient age and OSA severity (AHI) in a multivariate model provided the best discrimination of MAS treatment responders and nonresponders in this OSA population. Patient factors such as younger age, less obesity, female gender, and supine-dependent OSA have variously been associated with MAS treatment success.6,25–28 A significant limitation of MAS therapy is the inability to pre-identify patients with a good treatment response. Overall it seems unlikely that MAS response can be determined by single patient characteristics alone. MAS response is influenced by multiple factors relating to both structural and functional aspects of the upper airway.29 Objectively validated tests of MAS treatment function may ultimately be required to accurately predict treatment response.10,30–33 For example a single-night titration study of mandibular advancement using an available commercial remotely controlled titration device or assessment of upper airway response to mandibular advancement via nasendoscopy to observe the airway response during drug-induced sleep or even wakefulness.34–36However in CPAP failure patients with known therapeutic pressure, this information in conjunction with age and OSA severity characteristics, may be useful to give an indication of the likelihood of success with MAS as an alternative therapy.

This study has extended investigation of a relationship between therapeutic CPAP pressure and MAS treatment response in a large sample of Australian OSA patients. However, potential study limitations include that although there was a range of pressures in the sample (4-18 cm H2O), only a minority of the sample (10%) required pressures higher than 13 cm H2O. Therefore we cannot confirm whether our negative predictive value would remain as high with the inclusion of more patients in the higher range. However, these pressures were confirmed to be therapeutic by polysomnography and they are within the range of commonly prescribed pressures. Furthermore, we were able to adequately demonstrate that the lower pressure cutoff value of 10.5 cm H2O is unsuitable for the studied population. Craniofacial factors are also implicated in MAS treatment response, but craniofacial assessment was not included in this analysis; however, a comprehensive cephalometric study in a similar OSA population suggests that craniofacial factors alone are not highly predictive of MAS response,37 and these can be difficult to assess in routine clinical practice. Finally, although our sample population likely included mostly patients with Caucasian ancestry, no ethnicity data was collected in this study.

In conclusion, therapeutic CPAP pressure was higher in MAS treatment non-responders compared to responders (depending on the definition of response used). CPAP pressure did have predictive utility in discriminating MAS treatment responders and non-responders in this sample of Australian OSA patients. However, the previously determined CPAP pressure threshold to identify MAS non-responders in a Japanese population was found to be inadequate for reliable prediction. Our results suggest CPAP pressures above 13 cm H2O are likely to indicate non-responsiveness to MAS treatment in the studied population. However prospective validation of CPAP pressure as a predictor of MAS response is still required. A combination of age, OSA severity, and CPAP pressure provided the best estimation of MAS treatment response, illustrating that one single patient variable is unlikely to provide a definitive indication in all patients. This study highlights the need to test reported prediction methods in different OSA populations in which relevant factors such as obesity and craniofacial phenotypes are likely to differ.

DISCLOSURE STATEMENT

ResMed Inc donated all continuous positive airway pressure equipment for the trial. SomnoMed Ltd. donated all oral appliances for the trial. Dr. Cistulli is a chief investigator on sponsored clinical trials in obstructive sleep apnea for ResMed Inc and Exploramed Inc. His department receives equipment support for oral appliance research from SomnoMed Ltd, and he has a pecuniary interest in the company from previous involvement in product development. He is a medical advisor to Exploramed Inc (a US medical device incubator) and Zephyr Sleep Technologies. He has received speaker fees/travel support from ResMed Inc Fisher & Paykel Healthcare. The other authors have indicated no financial conflicts of interest.

REFERENCES

1	Kribbs NB, Pack AI, Kline LR, et al., authors. Objective measurement of patterns of nasal CPAP use by patients with obstructive sleep apnea. Am Rev Respir Dis. 1993;147:887–95. [PubMed]
2	Kushida CA, Morgenthaler TI, Littner MR, et al., authors. Practice parameters for the treatment of snoring and obstructive sleep apnea with oral appliances: an update for 2005. Sleep. 2006;29:240–3. [PubMed]
3	Phillips CL, Grunstein RR, Darendeliler MA, et al., authors. Health outcomes of continuous positive airway pressure versus oral appliance treatment for obstructive sleep apnea: a randomized controlled trial. Am J Respir Crit Care Med. 2013;187:879–87. [PubMed]
4	Chan AS, Sutherland K, Schwab RJ, et al., authors. The effect of mandibular advancement on upper airway structure in obstructive sleep apnoea. Thorax. 2010;65:726–32. [PubMed]
5	Gotsopoulos H, Kelly JJ, Cistulli PA, authors. Oral appliance therapy reduces blood pressure in obstructive sleep apnea: a randomized, controlled trial. Sleep. 2004;27:934–41. [PubMed]
6	Mehta A, Qian J, Petocz P, Darendeliler MA, Cistulli PA, authors. A randomized, controlled study of a mandibular advancement splint for obstructive sleep apnea. Am J Respir Crit Care Med. 2001;163:1457–61. [PubMed]
7	Pitsis AJ, Darendeliler MA, Gotsopoulos H, Petocz P, Cistulli PA, authors. Effect of vertical dimension on efficacy of oral appliance therapy in obstructive sleep apnea. Am J Respir Crit Care Med. 2002;166:860–4. [PubMed]
8	Sutherland K, Cistulli P, authors. Mandibular advancement splints for the treatment of sleep apnea syndrome. Swiss Med Wkly. 2011;141:w13276. [PubMed]
9	Tsuiki S, Kobayashi M, Namba K, et al., authors. Optimal positive airway pressure predicts oral appliance response to sleep apnoea. Eur Respir J. 2010;35:1098–105. [PubMed]
10	Zeng B, Ng AT, Qian J, Petocz P, Darendeliler MA, Cistulli PA, authors. Influence of nasal resistance on oral appliance treatment outcome in obstructive sleep apnea. Sleep. 2008;31:543–7. [PubMed Central][PubMed]
11	Lee RW, Vasudavan S, Hui DS, et al., authors. Differences in craniofacial structures and obesity in Caucasian and Chinese patients with obstructive sleep apnea. Sleep. 2010;33:1075–80. [PubMed Central][PubMed]
12	Li KK, Kushida C, Powell NB, Riley RW, Guilleminault C, authors. Obstructive sleep apnea syndrome: a comparison between Far-East Asian and white men. Laryngoscope. 2000;110:1689–93. [PubMed]
13	Liu Y, Lowe AA, Zeng X, Fu M, Fleetham JA, authors. Cephalometric comparisons between Chinese and Caucasian patients with obstructive sleep apnea. Am J Orthod Dentofacial Orthop. 2000;117:479–85. [PubMed]
14	Sutherland K, Lee RW, Cistulli PA, authors. Obesity and craniofacial structure as risk factors for obstructive sleep apnoea: impact of ethnicity. Respirology. 2012;17:213–22. [PubMed]
15	Watanabe T, Isono S, Tanaka A, Tanzawa H, Nishino T, authors. Contribution of body habitus and craniofacial characteristics to segmental closing pressures of the passive pharynx in patients with sleep-disordered breathing. Am J Respir Crit Care Med. 2002;165:260–5. [PubMed]
16	Tsuiki S, Isono S, Ishikawa T, Yamashiro Y, Tatsumi K, Nishino T, authors. Anatomical balance of the upper airway and obstructive sleep apnea. Anesthesiology. 2008;108:1009–15. [PubMed]
17	Hoffstein V, Mateika S, authors. Predicting nasal continuous positive airway pressure. Am J Respir Crit Care Med. 1994;150:486–8. [PubMed]
18	Loredo JS, Berry C, Nelesen RA, Dimsdale JE, authors. Prediction of continuous positive airway pressure in obstructive sleep apnea. Sleep Breath. 2007;11:45–51. [PubMed]
19	Akashiba T, Kosaka N, Yamamoto H, Ito D, Saito O, Horie T, authors. Optimal continuous positive airway pressure in patients with obstructive sleep apnoea: role of craniofacial structure. Respir Med. 2001;95:393–7. [PubMed]
20	Sforza E, Krieger J, Bacon W, Petiau C, Zamagni M, Boudewijns A, authors. Determinants of effective continuous positive airway pressure in obstructive sleep apnea. Role of respiratory effort. Am J Respir Crit Care Med. 1995;151:1852–6. [PubMed]
21	Aarab G, Lobbezoo F, Hamburger HL, Naeije M, authors. Effects of an oral appliance with different mandibular protrusion positions at a constant vertical dimension on obstructive sleep apnea. Clin Oral Investig. 2010;14:339–45. [PubMed]
22	Walker-Engstrom ML, Ringqvist I, Vestling O, Wilhelmsson B, Tegelberg A, authors. A prospective randomized study comparing two different degrees of mandibular advancement with a dental appliance in treatment of severe obstructive sleep apnea. Sleep Breath. 2003;7:119–30. [PubMed]
23	Ryan CF, Lowe AA, Li D, Fleetham JA, authors. Magnetic resonance imaging of the upper airway in obstructive sleep apnea before and after chronic nasal continuous positive airway pressure therapy. Am Rev Respir Dis. 1991;144:939–44. [PubMed]
24	Tsuda H, Almeida FR, Tsuda T, Moritsuchi Y, Lowe AA, authors. Craniofacial changes after 2 years of nasal continuous positive airway pressure use in patients with obstructive sleep apnea. Chest. 2010;138:870–4. [PubMed]
25	Chung JW, Enciso R, Levendowski DJ, Morgan TD, Westbrook PR, Clark GT, authors. Treatment outcomes of mandibular advancement devices in positional and nonpositional OSA patients. Oral Surg Oral Med Oral Pathol Oral Radiol Endod. 2010;109:724–31. [PubMed]
26	Hoekema A, Doff MH, de Bont LG, et al., authors. Predictors of obstructive sleep apneahypopnea treatment outcome. J Dent Res. 2007;86:1181–6. [PubMed]
27	Liu Y, Lowe AA, Fleetham JA, Park YC, authors. Cephalometric and physiologic predictors of the efficacy of an adjustable oral appliance for treating obstructive sleep apnea. Am J Orthod Dentofacial Orthop. 2001;120:639–47. [PubMed]
28	Marklund M, Stenlund H, Franklin KA, authors. Mandibular advancement devices in 630 men and women with obstructive sleep apnea and snoring: tolerability and predictors of treatment success. Chest. 2004;125:1270–8. [PubMed]
29	Chan AS, Lee RW, Srinivasan VK, Darendeliler MA, Cistulli PA, authors. Use of flow-volume curves to predict oral appliance treatment outcome in obstructive sleep apnea: a prospective validation study. Sleep Breath. 2011;15:157–62. [PubMed]
30	Bosshard V, Masse JF, Series F, authors. Prediction of oral appliance efficiency in patients with apnoea using phrenic nerve stimulation while awake. Thorax. 2011;66:220–5. [PubMed]
31	De Backer JW, Vanderveken OM, Vos WG, et al., authors. Functional imaging using computational fluid dynamics to predict treatment success of mandibular advancement devices in sleep-disordered breathing. J Biomech. 2007;40:3708–14. [PubMed]
32	Zeng B, Ng AT, Darendeliler MA, Petocz P, Cistulli PA, authors. Use of flow-volume curves to predict oral appliance treatment outcome in obstructive sleep apnea. Am J Respir Crit Care Med. 2007;175:726–30. [PubMed]
33	Zhao M, Barber T, Cistulli P, Sutherland K, Rosengarten G, authors. Computational fluid dynamics for the assessment of upper airway response to oral appliance treatment in obstructive sleep apnea. J Biomech. 2013;46:142–50. [PubMed]
34	Remmers JE, Charkhandeh S, Grosse J, et al., authors. Remotely controlled mandibular protrusion during sleep predicts therapeutic success with oral appliances in patients with obstructive sleep apnea. Sleep. 2013;36:1517–25. [PubMed Central][PubMed]
35	Vroegop AV, Vanderveken OM, Dieltjens M, et al., authors. Sleep endoscopy with simulation bite for prediction of oral appliance treatment outcome. J Sleep Res. 2013;22:348–55. [PubMed]
36	Chan AS, Lee RW, Srinivasan VK, Darendeliler MA, Grunstein RR, Cistulli PA, authors. Nasopharyngoscopic evaluation of oral appliance therapy for obstructive sleep apnoea. Eur Respir J. 2010;35:836–42. [PubMed]
37	Ng AT, Darendeliler MA, Petocz P, Cistulli PA, authors. Cephalometry and prediction of oral appliance treatment outcome. Sleep Breath. 2012;16:47–58. [PubMed]