CATEGORY: SLEEP & RECOVERY
Adults with obstructive sleep apnea and high blood pressure who wore a custom-fitted, jaw-advancing mouthguard at night saw their average around-the-clock blood pressure fall by 2.5 mm Hg over six months—enough to meet the trial’s preset bar for keeping pace with CPAP, the standard treatment, whose own group’s change was not statistically significant. The randomized trial, called CRESCENT, followed 220 patients and was published in the Journal of the American College of Cardiology.1
Two Ways to Hold a Floppy Airway Open
Obstructive sleep apnea is a condition in which the throat repeatedly narrows or collapses during sleep, choking off airflow dozens of times an hour; each episode jolts the nervous system and, over years, pushes blood pressure upward. The standard fix is CPAP—a bedside machine that blows gently pressurized air through a mask to splint the airway open. The challenger in this trial was a mandibular advancement device, a dentist-fitted appliance that looks like a two-piece sports mouthguard and works by nudging the lower jaw forward a few millimeters—much like propping a soft drinking straw so it cannot pinch shut. Many people find masks and hoses hard to live with, which is why a quieter, cordless alternative matters.
Six Months, Measured Around the Clock
Researchers at three hospitals in Singapore enrolled 220 adults—most in their late fifties and early sixties—who had both high blood pressure and moderate-to-severe sleep apnea, and assigned each by chance to one device or the other, the design that lets any difference be credited to the treatment itself. The headline measurement was 24-hour blood pressure, taken by a wearable cuff that inflates at intervals through an entire day and night at the start of the study and again six months later. The trial was built as a noninferiority comparison: the mouthguard would pass only if its blood-pressure result stayed within a preset margin of CPAP’s.
A Two-and-a-Half-Point Drop, and Longer Nightly Wear
The mouthguard passed. Its wearers’ 24-hour average blood pressure fell 2.5 mm Hg from baseline, while the CPAP group’s change was not statistically significant; the between-group difference of 1.6 mm Hg in the mouthguard’s favor stayed well within the preset margin, and the mouthguard showed larger reductions on the secondary blood-pressure measures, especially overnight. The researchers had designed the study expecting the mouthguard simply to prove no worse, and part of the explanation for its showing turned out to be wear time: a sensor embedded in each device recorded that 56.5% of mouthguard users wore it six or more hours a night, versus 23.2% of CPAP users. Daytime sleepiness improved similarly in both groups. One caution the investigators noted: all participants were Asian and most were men, in a single country, so the result may travel imperfectly to other groups.1
Fourteen Trials Point the Same Way
A 2026 pooled analysis of 14 randomized trials covering 1,141 patients—CRESCENT among them—landed on the same bottom line: no meaningful difference between the two treatments in 24-hour or nighttime blood pressure, a small daytime edge for the mouthguard of about 2 mm Hg, and roughly 43 more minutes of nightly use.2 The same analysis carries the important qualifier: CPAP remains clearly better at suppressing the breathing interruptions themselves, preventing about eight more per hour. The mouthguard’s blood-pressure showing reflects a weaker therapy worn long enough to do its work—not a stronger one.
Key Takeaways
- In a six-month randomized trial of 220 adults with high blood pressure and moderate-to-severe sleep apnea, a custom jaw-advancing mouthguard lowered 24-hour blood pressure by 2.5 mm Hg and met the preset standard for keeping pace with CPAP.
- Mouthguard users wore their device far longer each night than CPAP users did—56.5% versus 23.2% managed six or more hours—which the researchers pointed to in explaining the result.
- CPAP is still the more powerful treatment for stopping apnea episodes themselves; a pooled analysis of 14 trials found it prevents several more breathing interruptions per hour than the mouthguard.
- The finding speaks mainly to people who cannot tolerate CPAP: a fitted oral device delivered comparable blood-pressure results in this trial rather than no treatment at all.
References
- Ou YH, Colpani JT, Cheong CS, et al. Mandibular Advancement vs CPAP for Blood Pressure Reduction in Patients With Obstructive Sleep Apnea: The CRESCENT Trial. Journal of the American College of Cardiology. 2024;83(18):1760–1772. link
- Cheng T, Wang Q, Wei W. Effects of mandibular advancement devices vs. CPAP on blood pressure in obstructive sleep apnea: a systematic review and meta-analysis of randomized controlled trials. Frontiers in Neurology. 2026;17:1846726. link