Design: Single-centre, randomised two-period crossover trial
Population: 16 adults with moderate OSA (AHI 15–30)
Primary outcome: Change in apnoea-hypopnoea index with each appliance
Effect: Median AHI 17.6 to 3.1 and 2.3; difference 0.16 events/h (−2.56 to 2.87)

A small crossover trial in Belgium, published in Sleep and Breathing on 28 October, gave 16 adults with moderate obstructive sleep apnoea two different custom-made bi-block mandibular advancement devices, three months each.

Median apnoea-hypopnoea index fell from 17.6 to 3.1 with one device and 2.3 with the other. The trial found no difference between them, but it was not designed to show equivalence, and a change from home polygraphy to laboratory polysomnography between periods confounded the comparison. Twelve and ten of 16 reached an index below 5.

The practical message is the established one: a custom-made, titrated oral appliance is an effective option for moderate OSA in people who cannot tolerate CPAP. The choice between designs can rest on fit, comfort and cost.

Offer a custom mandibular advancement device for moderate OSA when CPAP is not tolerated.
Refer to a dentist experienced in sleep appliances for fitting and titration.
Repeat a sleep study on the device to confirm response.
Choose the design on comfort and cost; this trial showed no difference between two.

Why it matters

Many patients abandon CPAP, and oral appliances are an underused alternative.

The statistics, in plain English

The between-device difference of 0.16 events per hour (95% CI −2.56 to 2.87) is small, but with 16 patients the trial cannot prove the devices are equivalent.