Narval CC clinical research

ORCADES was designed to evaluate the efficacy and compliance of the Narval CC mandibular repositioning device (MRD)*. This large, multicentre study followed 369 patients with obstructive sleep apnoea-hypopnoea syndrome (OSAHS) who were being treated with a custom-made MRD over a period of 5 years.1 158 patients – 43% of the study participants – had severe OSAHS (apnoea hypopnoea index (AHI)>30).

The aim of the ORCADES study is to provide solid clinical proof of the benefits of Narval CC in the treatment of snoring and OSAHS in routine practice. The 3-6 month follow-up results of the ORCADES study were published in the Sleep Medicine Journal in 2015; the 2-year follow-up results were presented at the ERS Congress in September 2016.

In the 3-month analysis2, ORCADES looked at the difference in manufacturing process for Narval CC: out of the total sample, 312 patients were treated with a Narval CC produced with a computer-aided design and computer-aided manufacturing process (CAD/CAM), while 57 patients were treated with a Narval CC that used a “traditional” process (non-CAD/CAM). This allowed for sub-group analysis.

Efficacy in the reduction of AHI and symptoms1,3

AHI efficacy:1-3

A Narval CC produced using the CAD/CAM process is more effective in reducing AHI than a non-CAD/CAM MRD, regardless of the initial OSAHS severity.

  • Success rate (reduction of initial AHI ≥50%) of the Narval CC CAD/CAM MRD: 79% (CI 95%: 74-83%) regardless of the initial severity of initial OSAHS; for the non-CAD/CAM MRD: 61% (CI 95%: 47-72%); p=0.0031
  • Complete response (AHI<10): CAD/CAM Narval CC: 66% (CI 95%: 61-72%) vs non-CAD/CAM: 49% (CI 95%: 36–62%); p=0.017
  • The Narval CC CAD/CAM MRD had three times the probability of success compared to the non-CAD/CAM MRD (OR=3.0, p=0.0035)


After 2 years, Narval CC efficacy on AHI remained positive in a majority of cases.3

  • Complete response (AHI<10) = 56% of OSAHS patients
  • Reduction of AHI<15 (cardiovascular risks protection)

– 84% of moderate OSAHS patients (patients who presented an AHI between 15 and 30 at the 1st inclusion visit);

– 53% of severe OSAHS patients (patients who presented an AHI>30 at the 1st inclusion visit);

– 70% of patients maintain or improve their AHI reached at 3-6 months.

Efficacy in sub-groups:

  • In severe OSAHS patients (AHI>30 at inclusion): 61% obtained an AHI<15 at the 3-month follow-up1 and 53% of the patients still had an AHI<153 after 2 years of therapy.
  • In women: Whatever the baseline severity of OSA, efficacy at the 3-month follow-up is higher compared to men.4


Symptom efficacy:1,3

  • Significant efficacy on snoring
    • Patient self-reported data show the disappearance of bothersome snoring in more than 80% of patients after 3 months, with results maintained after 2 years (p<0.0001)



    • Objective snoring data measured by PSG after 2 years show a reduction of 75% (p<0.0001).
  • Sleepiness reduction: also improving over time. 3.4 points of reduction in the Epworth score (p<0.0001). 62% of patients with an initial Epworth score > 10 were no longer sleepy at 2-year follow-up.



  • Significant improvement in quality of life: +24% increase in the Quebec sleep questionnaire (p<0.0001) after 3 months, which continues to improve after 2 years: +29% increase in the Quebec questionnaire after 2 years (p<0.0001).


* QSQ = Quebec Sleep Questionnaire

Excellent compliance and tolerance
maintained over time1,2,3

  • 85% of patients wore the device every night even after 2 years.
  • After 2 years, compliance was 6.7 hours/night and 6.7 nights/week (average sleep duration of 7 hours in the study).
  • Only 8% of treatment withdrawal for adverse events and/or intolerance after 3 months1. This results remains stable after 2 years as the majority of side effects appears during the first weeks of treatment3.

The most frequent adverse events were minor and temporary.

MRD clinical research

A growing body of clinical research demonstrates the efficacy and compliance of mandibular repositioning devices (MRDs) in treating obstructive sleep apnoea and snoring. MRDs improve patient compliance and quality of life, and reduce both snoring and apnoea-hypopnoea index (AHI).

Support for investigator initiated research

ResMed believes in the need to support ethical, independent clinical research, conducted by qualified third-party investigators.


*Please note the Narval CC mandibular advancement device is not available in England, Scotland or Wales.

Narval CC is indicated to treat adults with snoring or mild to moderate obstructive sleep apnoea (OSA). In cases of severe OSA, it is indicated after continuous positive airway pressure (CPAP) therapy failure, non-compliance or refusal.

This content is intended for health professionals only. Please refer to the instructions for use for relevant information related to any warnings and precautions to be considered before and during use of the product.


  1. Vecchierini MF & al. A custom-made mandibular repositioning device for obstructive sleep apnoea-hypopnoea syndrome: the ORCADES study. Sleep Med. 2016 Mar;19:131-40. doi: 10.1016.
  2. Vecchierini MF & al. Impact of a custom-made mandibular repositioning device on blood pressure in obstructive sleep apnea patients noncompliant with continuous positive airway pressure. Abstract supplement. Sleep, 2015;(38).
  3. Attali V & al (for Orcades Study Investigators). Two year follow-up results of ORCADES study: Long-term mandibular repositioning device (MRD) therapy in patients treated for obstructive sleep apnea (OSA) – European Respiratory Journal 01 September 2016; Volume 48, issue suppl 60.
  4. Vecchierini MF & al (for Orcades Study investigators). Gender-specific efficacy of Mandibular Repositioning Device (MRD) therapy in obstructive sleep apnea (OSA) patients. Subgroup analysis of ORCADES study data. 2016 JSR 25 (Suppl. 1),5–377.