Researchers have identified in a new study that mandibular advancement devices (MADs) are a valuable and acceptable treatment for patients with severe obstructive sleep apnea (OSA) and hypertension, offering significant improvements in sleep-related quality of life and blood pressure. Although continuous positive airway pressure (CPAP) is currently the gold standard treatment, this study demonstrates that MADs have cardiovascular benefits and improved patient compliance, and they can be an alternative in clinical practice. The study was published in theJournal of Dental Researchby J. T. Colpani and fellow researchers. This randomized trial substudy comprised 144 patients with severe OSA, who were assigned to MAD (n=73) or CPAP (n=71) treatment for 12 months. Measured outcomes were ambulatory BP, apnea-hypopnea index (AHI), quality of life related to sleep, cardiac MRI indexes, heart rhythm, biomarkers, and adverse events. Median nightly use was 5.4 hours (2.9–6.5) for MAD and 4.9 hours (4.0–6.0) for CPAP, with 56.1% of MAD users and 28.3% of CPAP users having ≥6 hours/night adherence. The AHI at baseline was 44.0 events/h in the MAD group and 50.7 events/h in the CPAP group. At 6 months, AHI reduced to 20.9 events/h with MAD and 2.1 events/h with CPAP. MAD treatment reduced significantly: Asleep mean BP: −4.7 mm Hg (95% CI: −8.3 to −4.0; P = 0.015) Asleep systolic BP: −2.0 mm Hg (95% CI: −10.0 to −4.0; P = 0.047) Asleep diastolic BP: −4.0 mm Hg (95% CI: −9.0 to −3.0; P = 0.007) Between-group differences benefited MAD compared with CPAP for: Asleep mean BP: −3.70 mm Hg (95% CI: −7.40 to 0.00; P = 0.050) Asleep systolic BP: −4.78 mm Hg (95% CI: −9.51 to 0.04; P = 0.048) Both therapies enhanced quality of life related to sleep, but CPAP had a slightly greater effect on the Epworth Sleepiness Scale (Δ1.63; 95% CI: 0.45 to 2.81; P = 0.007). There were no significant alterations in cardiac MRI parameters, ambulatory heart rhythm, or biomarkers for either group. Adverse effects varied: MAD users: jaw pain (14.8%), discomfort of teeth (8.2%) CPAP users: dry mouth (50.8%), nasal congestion (23.0%), air leakage (29.5%) This randomized study proved MADs to be an effective and acceptable substitute for CPAP in the case of patients with severe OSA and hypertension, especially for nocturnal blood pressure improvement and compliance. Although CPAP is still better at the suppression of apnea events, MADs can have larger cardiovascular benefits and are a valuable treatment strategy in the practice setting. Colpani, J. T., Ou, Y.-H., Kosasih, A. M., Lee, F. K. F., Chan, S.-P., Tan, H. H., Wong, R. C. W., Chin, C. W., Cistulli, P. A., & Lee, C.-H. (2025). Mandibular advancement device versus CPAP in severe obstructive sleep apnea. Journal of Dental Research, 00220345251361796.https://doi.org/10.1177/00220345251361796