Moderate sleep apnea: two oral appliances compared, with no equivalence demonstrated

Each participant wore both appliances

This randomized trial, conducted at a single center in Genk, Belgium, compared the SomnoDentFlex and OrthoApnea NOA devices. Participants wore each appliance for three months, in a randomly assigned order, with a two-week break between periods.

All 16 adults had moderate obstructive sleep apnea. Participants and clinicians knew which device was being used, but those scoring the examination results did not. The trial was registered before enrollment began.

Less frequent respiratory events with both devices

The apnea-hypopnea index, or AHI, measures the number of apneas and hypopneas per hour. Its median value fell from 17.6 events per hour before treatment to 3.1 with SomnoDentFlex and 2.3 with NOA. These reductions were statistically significant compared with baseline.

In a post hoc analysis, an AHI below 5 events per hour was observed in 12 out of 16 participants with SomnoDentFlex and 10 out of 16 with NOA. These results describe this small group and do not guarantee an individual response.

The estimated difference between the devices was 0.16 events per hour, with a 95% confidence interval ranging from −2.56 to +2.87. No statistically significant difference was detected. This does not demonstrate that the appliances are identical or interchangeable.

A comparison weakened by the measurements

The main comparative analysis between the appliances was not initially planned. More importantly, the assessment method changed between periods, from home respiratory polygraphy to laboratory polysomnography. The authors report a period effect that cannot be separated from this change in method.

Information on actual appliance use and adjustments was also insufficient. No participant discontinued because of an adverse event, but these events were not collected systematically: the absence of discontinuations is therefore not enough to establish good tolerability.

The useful finding remains limited: both appliances were associated with a reduction in AHI in this trial, with no established comparative advantage. These data are not enough to choose one over the other.

What we can take away

Both appliances were associated with a reduction in respiratory events, but this trial demonstrates neither the superiority of either appliance nor their equivalence.