Oral Appliances and Cardiovascular Evidence

Treating obstructive sleep apnea — with either an oral appliance or CPAP — has been associated in studies with small average reductions in blood pressure. For oral appliances specifically, a 2015 network meta-analysis published in JAMA pooled 51 randomized trials (4,888 patients) and found mandibular advancement devices were associated with an average systolic reduction of about 2.1 mm Hg and diastolic reduction of about 1.9 mm Hg versus inactive control — with no statistically significant difference from CPAP’s associations. Averages of this size are meaningful at a population level; whether any individual’s blood pressure changes, and by how much, cannot be predicted.

No published evidence demonstrates that oral appliance therapy prevents heart attacks, strokes, cardiovascular disease, or cardiovascular death. The trials conducted so far have measured blood pressure and related markers over months, not cardiovascular events over years. Distinguishing these two categories — a measured change in a risk factor versus prevention of events — is the single most important skill for reading this literature, and the reason this page is deliberately conservative. The trial designs behind these claims are explained in our research literacy guide.

Untreated obstructive sleep apnea is associated — in observational research — with higher blood pressure and with increased cardiovascular risk. Repeated breathing pauses during sleep strain the cardiovascular system through oxygen dips, sleep fragmentation, and stress responses. That association is the reason researchers have asked whether treating OSA improves measurable cardiovascular markers such as blood pressure.

An association, however, is not a guarantee of reversal. Observational links between OSA and cardiovascular disease cannot tell us by themselves that treating OSA prevents events — a limitation the research community itself emphasizes. Studies like CRESCENT are how the question is properly tested: a defined population, randomization, a prespecified endpoint, and a prespecified margin. The next section examines that trial closely.

CRESCENT (the Cardiosleep Research Program on OSA, Blood Pressure Control and Maladaptive Myocardial Remodeling — Non-inferiority Trial) recruited 321 adults aged 40 or older with hypertension and increased cardiovascular risk at three public hospitals; of these, 220 with moderate-to-severe OSA (an apnea-hypopnea index of 15 or more events per hour) were randomized. This population definition matters: the trial’s findings speak to adults with hypertension, elevated cardiovascular risk, and at least moderate OSA.

Participants were randomized one-to-one to a mandibular advancement device or CPAP. The primary outcome was the change in 24-hour mean arterial blood pressure from baseline to six months. The trial was designed as a noninferiority comparison with a prespecified margin of 1.5 mm Hg — meaning the oral appliance would be declared "not meaningfully worse" than CPAP for blood pressure if the difference between groups stayed within that margin. Noninferiority designs are explained in plain language in how to read oral appliance research.

In the oral appliance group, 24-hour mean arterial blood pressure fell by about 2.5 mm Hg at six months, a statistically significant change, while no significant change was observed in the CPAP group. The between-group difference stayed within the predefined margin, meeting the noninferiority criterion. Reductions in secondary ambulatory blood-pressure measures were larger in the oral appliance group, most pronounced for asleep blood pressure. Both groups improved daytime sleepiness by similar amounts, and there were no significant between-group differences in cardiovascular biomarkers.

A noninferiority result says the oral appliance was, within the margin defined in advance, acceptable for blood pressure relative to CPAP in this population. It does not say the oral appliance was better than CPAP, equal to CPAP for every outcome, or appropriate for every patient — and it measured blood pressure, not heart attacks or strokes. One well-conducted trial is evidence; it is not the final word on a field.

Pooling many trials gives a steadier view than any single study. The 2015 JAMA network meta-analysis referenced above combined 51 randomized trials and 4,888 patients: compared with inactive control, CPAP was associated with average reductions of roughly 2.5 mm Hg systolic and 2.0 mm Hg diastolic, and mandibular advancement devices with roughly 2.1 and 1.9 mm Hg respectively — and the difference between the two therapies was not statistically significant. The practical reading: both therapies are associated with modest average blood-pressure effects; neither is a blood-pressure treatment; and the similarities matter more than the small differences.

Where the science stands overall: the long-term cardiovascular benefit of treating OSA remains an area of active research and expert discussion — a 2024 American Thoracic Society workshop report was organized around precisely this unresolved question. Patients deserve that honest framing rather than promotional certainty.

If you have hypertension or cardiovascular concerns, the right home for those is your physician’s office. Oral appliance therapy treats sleep-disordered breathing; it is not a blood-pressure therapy, and research about average blood-pressure effects is not a reason to start, stop, or change any medication. If you use an oral appliance, keep every member of your care team — sleep physician, dentist, and the physician who manages your cardiovascular health — informed about your treatment.

This page exists so that when you encounter a headline claiming an oral appliance "protects the heart," you can ask: what endpoint was measured, in whom, for how long? The honest current answer to whether oral appliances prevent cardiovascular disease is that the question is not settled — and anyone who tells you otherwise is ahead of the evidence. For how to evaluate such claims yourself, see how to read oral appliance research.

Ou YH, Colpani JT, et al. — Mandibular advancement vs CPAP for blood pressure reduction in patients with obstructive sleep apnea: the CRESCENT randomized noninferiority trial (Journal of the American College of Cardiology, 2024).

Bratton DJ, Gaisl T, Wons AM, Kohler M. — CPAP vs mandibular advancement devices and blood pressure in patients with obstructive sleep apnea: a systematic review and network meta-analysis (JAMA, 2015).

American Thoracic Society workshop report on the cardiovascular benefit of OSA treatment — expert consensus on an unresolved scientific question (2024).

American Academy of Sleep Medicine and American Academy of Dental Sleep Medicine — joint clinical practice guideline (Journal of Clinical Sleep Medicine, 2015), for treatment context.

For how this site selects and applies its sources, see Evidence & Sources and the Medical Content Policy.