The Short Answer
CPAP and oral appliances both treat obstructive sleep apnea (OSA), and neither is better for everyone. CPAP is usually stronger at stopping breathing pauses. Oral appliances are often easier to wear, and some people use them more. Which one is right for you depends on how severe your OSA is, what your sleep physician recommends, and what you will actually use night after night.
This guide compares the two on the points that matter most: how well they work, how much people use them, side effects, cost, travel, and which severity of sleep apnea each one fits. It draws on clinical guidelines and head-to-head studies. A sleep physician diagnoses OSA with a sleep test and should help you make the choice. This page is general education, not medical advice.
What Each Treatment Does
CPAP (continuous positive airway pressure) uses a machine, a hose, and a mask to blow air into your airway so it stays open. It is the most common first treatment for OSA. The AASM guideline on positive airway pressure says treatment should be based on a diagnosis from objective sleep testing and should include follow-up that troubleshoots problems and checks usage and effectiveness data. [2]
An oral appliance is a custom mouthpiece, most often a mandibular advancement device, that holds your lower jaw slightly forward during sleep so the airway is less likely to collapse. A dentist who provides oral appliance therapy makes and adjusts it on a physician's prescription. See our guide to dental treatment for sleep apnea for how the fitting process works.
What the Guidelines Say
The joint guideline from the AASM and the American Academy of Dental Sleep Medicine covers oral appliance therapy. It recommends that sleep physicians consider oral appliances, rather than no treatment, for adults with OSA who are intolerant of CPAP or prefer another therapy. [1] It suggests that a qualified dentist use a custom, adjustable appliance rather than a non-custom device. [1] It also suggests dental follow-up to look for side effects and bite changes, and follow-up sleep testing to check that the device works. [1]
In other words, oral appliances are recommended as an option, especially when CPAP does not work out, and the guideline expects a physician and a dentist to share the follow-up. The National Heart, Lung, and Blood Institute lists both CPAP and custom-fitted oral appliances among treatments for sleep apnea. [8]
Effectiveness: How Much Do They Lower the AHI?
The apnea-hypopnea index (AHI) counts breathing pauses and shallow breaths per hour of sleep. A lower number means fewer events.
Moderate to severe OSA (randomized crossover trial)
In a randomized crossover trial of 126 adults with moderate to severe OSA (average starting AHI 25.6), each person used CPAP for one month and an oral appliance for one month. CPAP was more effective at lowering the AHI: 4.5 events per hour on CPAP versus 11.1 on the appliance. [3]
Severe OSA (randomized trial)
A randomized trial of 144 adults with severe OSA compared an oral appliance with CPAP for 12 months. At 6 months, the median AHI fell from 44.0 to 20.9 on the appliance and from 50.7 to 2.1 on CPAP. [4] So CPAP lowered the AHI far more. An AHI of 20.9 is still in the moderate range, which is one reason a follow-up sleep test matters for anyone with severe OSA who uses an oral appliance.
What to take from this
CPAP is stronger at reducing AHI, and the gap is larger in severe disease. The American Sleep Apnea Association says the same: CPAP lowers AHI scores more than a mandibular advancement device. [7] But the AHI is not the whole story, as the next section shows.
Real-World Use: What People Actually Wear
A treatment only works if you use it. Research on CPAP shows a persistent problem. A review in the Proceedings of the American Thoracic Society found that when adherence was defined as more than 4 hours a night, 46% to 83% of patients with OSA were reported as nonadherent. [6] A systematic review of 82 papers covering 20 years of data found a non-adherence rate of about 34% and no meaningful improvement over time. [5]
Studies comparing the two treatments find that oral appliances are often worn more. In the crossover trial, reported use was 6.5 hours a night with the appliance versus 5.2 hours with CPAP. [3] In the severe OSA trial, median nightly use was 5.4 hours with the appliance and 4.9 with CPAP. Use of 6 hours or more a night was 56.1% with the appliance and 28.3% with CPAP. [4] Note that the crossover trial's use figures were self-reported.
This is the idea of effective adherence. A treatment that is a little less powerful but used more can produce similar real-world results. The crossover trial's authors suggested this may explain why important health outcomes were similar after one month: sleepiness, driving simulator performance, and disease-specific quality of life improved by similar amounts on both treatments. Neither treatment improved 24-hour blood pressure in that short trial. [3]
In the 12-month severe OSA trial, both treatments improved sleep-related quality of life. CPAP had a slightly greater effect on the Epworth Sleepiness Scale. Nighttime blood pressure dropped with the appliance but showed no significant change with CPAP. The paper reports this as a substudy, so read it as one data point. [4]
Side Effects
Both treatments have downsides. They are just different.
CPAP
The National Heart, Lung, and Blood Institute lists congestion, dry eyes or mouth, nosebleeds, and a runny nose as possible effects. [8] In the severe OSA trial, dry mouth was reported by 50.8% of CPAP users and nasal congestion by 23.0%. [4]
Oral appliance
In the same trial, jaw pain was reported by 14.8% of appliance users and tooth discomfort by 8.2%. [4] The American Sleep Apnea Association lists early effects such as tooth soreness, jaw pain, dry mouth or extra drooling, and irritated gums, and long-term concerns such as a slight underbite and, rarely, loosened teeth. [7] This is why the guideline suggests dental follow-up to watch for bite changes. [1]
Cost
CPAP machines and oral appliances are both usually handled through medical insurance rather than dental insurance, though coverage rules differ by plan. Some dental offices are not set up to bill medical insurance for oral appliances, and the upfront cost of a custom device can be in the thousands. The American Sleep Apnea Association says custom devices "can cost thousands of dollars" and that insurance may cover some of the cost. [7]
Costs over time differ. A CPAP machine needs replacement masks, tubing, and filters. An oral appliance is a single custom device. Medicare lists a 5-year reasonable useful lifetime for it, with dental follow-up along the way. [9] Your out-of-pocket cost depends on your plan. Read our full guide to oral appliance cost and insurance, including Medicare criteria.
Travel and Daily Life
This part is about convenience rather than evidence, but for many people it decides the question. A CPAP setup needs power, a machine, a hose, a mask, and a humidifier with water. Travel CPAP units exist, but you still carry and clean equipment. An oral appliance is a small case that fits in a pocket and needs no electricity, which makes trips, camping, and power outages simpler. Some people find a mouthpiece easier to sleep with. Others do not like the feeling of a device in the mouth. Both choices are fine if you use them.
Severity and Who Each Fits
Severity guides the choice. The AASM and AADSM guideline recommends considering an oral appliance for adults who cannot tolerate CPAP or prefer another option. [1] Most guidance treats CPAP as the first choice for severe OSA, because it lowers the AHI the most. [4] [7]
- Mild to moderate OSA: Both are reasonable. Many people pick the one they will use more consistently. [1] [3]
- Severe OSA: CPAP is generally the stronger choice. An oral appliance can be considered if you cannot use CPAP or prefer it, with follow-up sleep testing to confirm that it works. [1] [4]
- You have tried CPAP and cannot stay on it: An oral appliance is a guideline-supported option to discuss. [1]
- You have few teeth, loose teeth, gum disease, or jaw joint problems: A dentist will need to check that an appliance is safe for you, and it may not be a good fit. Your dentist will advise.
What If Neither Works?
You have other options, including positional therapy, weight-loss treatment, nerve stimulation, and surgery. See our guide to CPAP alternatives. Some people also use more than one treatment together, which you can discuss with your physician.
How to Choose
Bring your sleep study results to your sleep physician and ask these questions:
- How severe is my sleep apnea, and what does that mean for my choices?
- Have I given CPAP a fair try? What could still be fixed, such as mask fit or dryness?
- Am I a candidate for an oral appliance, and what follow-up sleep test will you order?
- If I choose an appliance, who will manage my dental follow-up?
- What would make us switch treatments?
Find a Dentist Who Provides Oral Appliance Therapy
Start with a diagnosis. A physician must confirm sleep apnea with a sleep test before any treatment, including an oral appliance. [1] Dental sleep medicine is not a recognized dental specialty, so look for a dentist with training in it and a plan to coordinate with your physician.
When you are ready, search our provider directory for dentists in your area. A prosthodontist may offer oral appliance therapy, and some general dentists do as well. Ask about their training, how they adjust the device, and how they handle follow-up testing. Browse our list of dentists who provide oral appliance therapy, grouped by state.
