Clinical impact of two types of mandibular retention devices - A CAD/CAM design and a traditional design - On upper airway volume in obstructive sleep apnea patients.

Objective: This pilot randomized crossover study evaluated the outcomes of two custom-made mandibular retention devices (MRDs), a computer-aided design (CAD)/computer-aided manufacturing (CAM) device (Narval CC™) and a non-CAD/CAM device (Narval™), on oropharyngeal airway volume in patients with obstructive sleep apnoea (OSA).

Methods: 12 OSA patients were recruited from an University Hospital for MRD therapy with either CAD/CAM or non-CAD/CAM first. A cone-beam computed tomography evaluation (CBCT) and polysomnography assessment was performed during baseline assessment and at the end of each study period.

Results: Upper airway volume increased significantly with the CAD/CAM device (7725 +/- 6540 mm, p = 0.008) but not with the non-CAD/CAM device (3805 +/- 7806 mm, p = 0.13). The CAD/CAM device was also associated with a significant decrease in AHI (mean AHI after treatment 9.4±6.7 events/h, p = 0.003) and oxygen desaturation index (mean ODI of ≥ 3%/h 11.9 ± 6.8, p = 0.011). Changes in AHI (14.7 +/- 11.7 events/h, p = 0.083) and ODI (15.5 +/- 19.2, p = 0.074) were not statistically significant with the non-CAD/CAM device. The vertical dimension of occlusion increased significantly following treatment with both MRD devices (both p = 0.003), but was significantly less pronounced with the CAD/CAM device (mean difference: -2.7 +/- 1.7 mm, p = 0.003). Final mandibular protrusion after titration was the same with both devices (85%, p = 0.317).

Conclusion: The CAD/CAM (Narval CC) device was associated with a significant increase in upper airway volume that may be caused by a lower degree of vertical separation between the jaws when compared to the non-CAD/CAM design.