To Örebro University

Introduction: This 10-year prospective cephalometric study evaluates the influence of a mandibular protruding device (MPD) in people with obstructive sleep apnea and snoring.

Methods: A baseline study population of 77 people was followed biennially. After 10 years, 65 people (45 MPD users and 20 stopped-MPD users) were reexamined. At baseline and after 10 years, a lateral cephalogram was taken in the upright position.

Results: MPD users showed significant changes in all cephalometric variables except for maxillary protrusion. The maxillary incisors were retroclined by a mean -4.2 degrees (standard deviation [SD] 3.95; P <0.001), mandibular incisors were proclined by a mean 3.2 degrees (SD, 5.02; P <0.001), and SNB was reduced by a mean -0.6 degrees (SD 1.41; P = 0.01). In those who had stopped MPD use, these initial cephalometric values were retained. Significant changes in decreased overjet and overbite were seen in the MPD group but not in the MPD-stopped group. The length of the mandible (Cd-Pg) increased by a mean of 5.1 mm (SD 6.78; P <0.001) and 6.1 mm (SD 5.99; P <0.001) in MPD and MPD-stopped groups, respectively. The hyoid bone-mandibular plane distance (hy-ML) increased by a mean of 3.3 mm (SD, 2.90; P <0.001) and 3.8 mm (SD 3.67; P = 0.001) in MPD and MPD-stopped groups, respectively.

Conclusions: Long-term nocturnal MPD use causes retroclination of the maxillary incisors and proclination of the mandibular incisors with consequent decreased overjet and overbite. Both MPD and MPD-stopped users obtained increased mandibular length and lower position of the hyoid bone, which can be a normal physiological change with age.