Obstructive sleep apnea (OSA) is a sleep-related breathing disorder characterized by repeated narrowing or collapse of the upper airway during sleep. A 2026 overview of systematic reviews compared the two primary treatment approaches — continuous positive airway pressure (CPAP) and oral appliance therapy using a mandibular advancement device (MAD) — to characterize their relative effectiveness and adherence patterns ([PMID 42625095]).
Key Points
- Continuous positive airway pressure (CPAP) reduces breathing pauses more effectively than mandibular advancement devices (MADs), based on objective sleep study measurements ([PMID 42625095]).
- MADs performed comparably to CPAP on daytime sleepiness and were linked to better nightly adherence and quality-of-life outcomes in some reviews ([PMID 42625095]).
- No systematic review included in this overview met high methodological quality standards, so both the reported CPAP advantage in AHI reduction and the long-term MAD outcome data should be interpreted cautiously ([PMID 42625095]).
- Real-world effectiveness depends heavily on whether a patient actually uses the device every night — not just which device produces a larger effect on objective testing.
- The American Academy of Sleep Medicine (AASM) recommends MADs for mild-to-moderate OSA, or for moderate-to-severe OSA when a patient cannot tolerate or declines CPAP, per current AASM clinical practice guidelines.
What is obstructive sleep apnea, and why does treatment choice matter?
During sleep, the muscles of the throat and tongue relax, allowing the upper airway to narrow. In OSA, this relaxation combines with contributing anatomical and physiological factors — which may include obesity, soft palate or tongue base position, reduced upper airway neuromuscular tone, and craniofacial variation such as mandibular retrognathism (a lower jaw positioned further back than average) — to produce repeated narrowing or closure of the airway, interrupting breathing. OSA is considered a multifactorial disorder, and no single anatomical feature is established as its sole structural driver. Each breathing pause can briefly lower blood oxygen and fragment sleep.
Over time, untreated OSA has been associated with cardiovascular and metabolic conditions, including resistant hypertension, atrial fibrillation, and heart failure. Professional society statements addressing these associations characterize a number of related clinical recommendations — such as OSA screening in certain cardiovascular populations — as reasonable practice within areas of clinical equipoise, rather than as reflecting causal relationships established by high-certainty evidence.
Severity is measured using the apnea-hypopnea index (AHI) — the number of apneas and hypopneas per hour of sleep. Standard diagnostic thresholds are:
- Mild: 5.0–14.9 events/hour
- Moderate: 15–29.9 events/hour
- Severe: ≥30 events/hour
AHI values are sensitive to the hypopnea scoring criteria applied (for example, a 3% versus 4% oxygen desaturation or arousal requirement), which can affect the comparability of AHI reduction figures pooled across different studies, including across the 14 systematic reviews summarized below.
Because CPAP and MADs work through different mechanisms — CPAP holds the airway open with pressurized air, while a MAD repositions the lower jaw and tongue base forward — the two therapies have different strengths, and a 2026 overview of 14 systematic reviews set out to compare them directly ([PMID 42625095]).
How is it diagnosed?
A diagnosis of OSA requires an overnight sleep study, either in a laboratory (polysomnography) or through a validated home sleep apnea test. The study measures the AHI along with oxygen desaturation events, and results are interpreted alongside symptoms such as daytime sleepiness, witnessed pauses in breathing, or morning headaches. A dental sleep medicine evaluation — assessing jaw position, airway anatomy, and dental/periodontal suitability for an oral appliance — is a separate step that follows the sleep study, not a replacement for it.
Which treatment is right for me?
This is the central question the new overview addresses. The findings point to a trade-off rather than a single “better” therapy:
| Factor | CPAP | Mandibular advancement device (MAD) |
|---|---|---|
| Reduction in AHI / oxygen desaturation | Greater reduction, based on objective measurements ([PMID 42625095]) | Smaller reduction than CPAP, based on objective measurements ([PMID 42625095]) |
| Daytime sleepiness | Effective | Comparable effect to CPAP in several reviews ([PMID 42625095]) |
| Nightly adherence | Often limited by mask discomfort, air pressure intolerance | Better adherence reported in some reviews and long-term studies ([PMID 42625095]) |
| Quality of life | Effective when used consistently | Comparable or favorable in some reviews ([PMID 42625095]) |
| AASM guidance | First-line for moderate-to-severe OSA | Recommended for mild-to-moderate OSA, or moderate-to-severe when CPAP is not tolerated |
| Evidence certainty | No included review met high AMSTAR-2 methodological quality; the reported CPAP advantage in AHI reduction is drawn from the same lower-quality review base ([PMID 42625095]) | No included review met high methodological quality; long-term MAD efficacy data are particularly limited ([PMID 42625095]) |
The cited overview documents an apparent contradiction: CPAP achieves greater AHI/ODI reduction on objective sleep study measurements, while MADs performed comparably on daytime sleepiness and quality-of-life measures in several of the included reviews ([PMID 42625095]). One plausible explanation — though not one stated by the overview’s authors — is that differences in nightly adherence between the two therapies may narrow the real-world gap in outcomes despite CPAP’s larger per-night physiological effect. This remains a hypothesis rather than an established mechanism and would require direct confirmation in comparative studies designed to test it.
None of this means either device is interchangeable for every patient. Severity, anatomy, nasal or claustrophobic issues with a mask, dental and jaw joint health, and personal tolerance all factor into selection. This is an individualized decision made with a sleep physician and dentist together, not a one-size-fits-all recommendation.
When should I see a specialist?
Consider a referral to a sleep physician for loud snoring with witnessed breathing pauses, unexplained daytime sleepiness, or risk factors such as resistant hypertension or arrhythmia. If OSA is diagnosed and CPAP has already been tried and not tolerated — or if the diagnosis is mild-to-moderate — a consultation with a dentist trained in dental sleep medicine is the next step to evaluate candidacy for a MAD, including a dental and airway exam and, where available, mandibular titration testing to help estimate likely response before full appliance fabrication.
For referring providers
The 2026 overview ([PMID 42625095]) synthesized 14 systematic reviews using AMSTAR-2 quality appraisal and found that no included review met high methodological quality criteria, and substantial overlap of primary studies existed across reviews — factors that limit the certainty of pooled conclusions on both sides of the comparison, including the reported CPAP advantage in AHI reduction and long-term MAD durability. Clinically, this supports continuing to position CPAP as first-line therapy for moderate-to-severe OSA per AASM guidance, while considering MAD referral for CPAP-intolerant or CPAP-refusing patients, or for mild-to-moderate disease, with conservative interpretation of the magnitude of comparative benefit in either direction.
Objective adherence monitoring — increasingly available for oral appliances as well as CPAP — is a useful adjunct when comparing real-world effectiveness in an individual patient; this is a general clinical consideration separate from the findings of the cited overview. Patient selection for MAD response remains an area of active development, including single-night remote-controlled mandibular titration protocols, which have been reported to have good positive predictive value in initial testing; this line of evidence also falls outside the cited overview and warrants confirmation in larger, independent studies before broader clinical application.
References
- Comparative effects of CPAP and mandibular advancement devices in obstructive sleep apnea: an overview of systematic reviews. Sleep & Breathing = Schlaf & Atmung. 2026. PMID 42625095.
