Clinial Study of Treatment With Mandibular Advancement Device in Patients With Obstructive Sleep Apnea Across 6 General Hospitals

Study Objectives: To retrospectively study mandibular advancement treatment efficacy using apnea-hypopnea index (AHI) and oxygen desaturation index (ODI), in a large cohort of patients, in 'real world' settings across 6 general hospitals.

Methods: Diagnosis at 6 Belgian recognised OSA sleepcenters with type-1 polysomnography. After drug-induced sleep endoscopy by Ear-Nose-Troat-specialist, patients with positive effect of mandibular protrusion on reopening the upper airway were referred. The mandibular advancement device (MAD) was fitted in 'maximal comfortable protrusion' minus 2mm. A type-3 home polygraphy with MAD followed titration.

Methods Patients were diagnosed at conventionalized Belgian OSA sleep centers, in alphabetical order: AZ Monica (Antwerpen), AZ Sint-Maarten (Mechelen), AZ Voorkempen (Malle), Heilig Hart Ziekenhuis (Lier), Imelda Ziekenhuis (Bonheiden), and VITAZ (Sint-Niklaas), with a type 1 polysomnography. The apnea-hypopnea index (AHI; number of events/h sleep), oxygen desaturation index (ODI; number of desaturations/h sleep) and body mass index (BMI; kg/m2) were calculated.

The Ear-Nose-Troat-specialist at the OSA sleep center performed an awake examination of the upper airway, followed by a drug-induced sleep endoscopy (DISE). Patients with positive effect of mandibular protrusion on reopening of the upper airway were referred to the dental sleep professional (DSP) for dental clinical and/or radiological examination. The DSP registered the mandibular protrusive trajectory with a bite registration device (The BiteFix, Scheu-Dental, Iserlohn, Germany) and a hard bite registration paste (Futar Fast, Kettenbach, Germany), as to achieve a stable fit on both tooth arcs. Next, the 'maximal comfortable protrusion' (MCP, mm) of the mandible was determined, being the most forward mandibular protrusion still tolerated by the patient and tested during DISE.

At the time of fitting, the patients received full explanation on the MAD titration schedule and were instructed to titrate after fitting of the MAD till resolution of the snoring symptoms or upon reaching physiological limits. A 1-month follow-up was performed by telephone. Next, a type 3 home polygraphy with the MAD was organized between 3 to 5 months after treatment start, recording identical parameters as at baseline, making each patient to serve as the own control.

Inclusion In Belgium, the reimbursement criterion for MADt leaves out central apneas in the calculation of AHI and requires this 'obstructive AHI' (OAHI) to be ≥ 15 events/h. In the absence of any central event, the OAHI = AHI, whereas in the presence of central events OAHI \< AHI. Patients with OAHI ≥ 15 events/h and therefore AHI ≥ 15 events/h were included on the condition that the full clinical pathway as described before was followed and that the MAD was self-reportedly used at least 4 hours per night. Further reporting is done on AHI, for reasons of comparison with other studies.

Parameters Age (years) and gender (Male/Female, M/F) were noted. Questionnaires were used at baseline and controls for the quantification of snoring using a visual analogue score on loudness (VAS-snore) with a Likert-scale from 0 (no snoring) up to 10 (partner sleeps in other room). A VAS-snore \> 3/10 represents socially disturbing snoring. The Epworth sleepiness score (ESS) quantifies daytime sleepiness with ESS ≥ 11/24 representing increased propensity to fall asleep during daytime.

Mandibular advancement device The starting position of the MADt was set at MCP minus 2mm (MCP-2, mm). Digital imprints of both tooth arcs were taken (Trios, 3Shape, Copenhagen, Denmark) as well of the bite-registration in the MCP-2 position. The selected MAD (EVO, ProSomnus Sleep Technologies, Pleasanton, CA, USA) uses a Class IV resin (United States Pharmacopeia and National Formulary) which is the highest grade of material currently available. Its design is characterized by perpendicular rectangular posts to protrude the mandible. Such design could preserve mandibular advancement even during limited mouth opening while asleep. The fully digital manufacturing pathway, starting from the digital intra-oral scans up to the 3D milling, favors accuracy-of-fit on the dental arcs.

Eligibility Criteria:
Inclusion Criteria:

* obstructive apnea-hypopnea index ≥ 15 events/h sleep
* complete clinical pathway

Exclusion Criteria:

* obstructive apnea-hypopnea index \< 15 events/h sleep
* not dental fit