COVID-19 studies are our top priority. For all other trials, there is a 4-week delay in processing a trial submitted to the ANZCTR and additional delays for updates of registered trials. We appreciate your patience.

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been endorsed by the ANZCTR. Before participating in a study, talk to your health care provider and refer to this information for consumers
Trial registered on ANZCTR

Registration number
Ethics application status
Date submitted
Date registered
Date last updated
Date data sharing statement initially provided
Date results information initially provided
Type of registration
Prospectively registered

Titles & IDs
Public title
Impact on upper airway mechanics of a built in oral appliance airway in patients with obstructive sleep apnoea.
Scientific title
Impact on upper airway mechanics of a built in oral appliance airway in patients with obstructive sleep apnoea.
Secondary ID [1] 289943 0
Oventus OVEN-004
Universal Trial Number (UTN)
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
obstructive sleep apnoea 299927 0
Condition category
Condition code
Respiratory 299824 299824 0 0
Sleep apnoea

Study type
Description of intervention(s) / exposure
Part 1 – Night 1
Assessment of nasal obstruction using rhinomanometry followed by observational level 1 diagnostic sleep study without oral appliance to evaluate relationship between breathing route and Apnoea-Hypopnea Index (AHI), Pharyngeal pressures measured throughout will also be used to evaluate site of upper airway collapse.
Participants with supine AHI <15 and >60 or unable to demonstrate ability to sleep in the supine position or sleep with the required instrumentation, will not go on to participate in Part 2 of the study.

Part 2 – Night 2 and 3
Device - The O2Vent T is a customized oral appliance similar in appearance to a mouth guard. to treat snoring and sleep apnoea. The main structure which forms the breathing port at the front leading to the airways on each side to the rear of the appliance, is made from polished medical grade titanium customized to the maxillary arch. The "landing" area or inserts for the top and lower teeth is customized to the patient's dentition and are made from dual laminate material. The upper insert is fixed to the titanium arch whilst the lower insert is positioned in an advanced position to bring the jaw forward. Further titration is possible with a screw mechanism.

Night 2 – Interventional study with O2Vent T and titration as per titration protocol to optimize level of advancement. Prior to titration, the study dentist will define the limits of advancement for the titration night so that it does not exceed 100%.
1. The titration will commence at the Zero position which will be set at 50% of maximum protrusion
2. The Zero position will be held to the end of the first REM period
3. At the conclusion of the first REM period, titration will commence in 1 mm increments in response to AHI greater than 10 or <50% reduction in the preceding 15 minutes of sleep
4. At least 15 minutes of consistent sleep (not interrupted by periods of wakefulness) should be observed prior to further advancement.
5. Advancement to occur until any of the following conditions are met:
a. limits of advancement as defined by dentist
b. the lower of AHI <10 reached or >50% reduction
c. Limit of device i.e. +7mm reached
6. Advancement to occur in sleep only. No advancement to occur during wakefulness or Stage 1 sleep.

Night 3 – Interventional study with the device airway being opened and closed alternating every 30 minutes. The level of advancement throughout will be the optimal advancement determined on night 2. Pharyngeal pressures measured throughout. Whilst the device airway is closed, breathing is possible through the nose. Whilst the device airway is open, breathing is possible through the nose and the device.

Night 2 will occur approximately 2 months after Night 1 to allow for manufacture of device and acclimatization. Night 3 will occur up to 2 weeks after night Night 2.

Monitoring of adherence is not applicable.
Intervention code [1] 295624 0
Treatment: Devices
Comparator / control treatment
From Night 1 - between subject comparisons of nasal obstruction, breathing route and AHI.
From Night 2 - within subject comparison of breathing route, AHI and Oximterer Dip Rate (ODI) at each level of advancement with minimum data set at 50% and optimal advancement, also compared to Night 1 baseline.
From Night 3 - within subject comparisons of AHI, ODI, Arousal Index, fraction of nasal-oral/device airflow as well as pharyngeal pressures:
- at optimal advancement with O2Vent airway open
- at optimal advancement with O2Vent airway closed
Within subject differences will be compared to the degree of nasal obstruction obtained during awake seated and supine conditions.
Control group

Primary outcome [1] 299298 0
Obstructive sleep apnoea (OSA) severity as assessed by the Apnoea-Hypopnoea Index (AHI)
Timepoint [1] 299298 0
acquired during all sleep studies on NIght 1, 2 and 3 as part of the protocol
Secondary outcome [1] 326780 0
Route of breathing assessed
a. qualitatively by assigning nasal, oral and oro-nasal breathing epochs
b. qualitatively by calculating fraction of flow through the nasal and oral (device) routes
with data being being acquired during polysomnography including flow through a partitioned mask
Timepoint [1] 326780 0
acquired during all sleep studies on NIght 1, 2 and 3 as part of the protocol
Secondary outcome [2] 326781 0
Site of upper airway collapse assessed by evaluation of pressure at each level of the pharyngeal subdivisions using a multi-transducer manometer placed in the upper airway.
Timepoint [2] 326781 0
acquired during sleep studies on Night 1 and Night 3
Secondary outcome [3] 327770 0
Magnitude of pharyngeal resistance assessed by evaluation of flow and pressures within the pharynx using a multi-transducer manometer placed in the upper airway and assessment of flow through a partitioned mask.
Timepoint [3] 327770 0
acquired during sleep studies on Night 1 and Night 3
Secondary outcome [4] 327771 0
Sleep fragmentation as assessed by evaluation of sleep stages and arousal acquired during overnight polysomnography.
Timepoint [4] 327771 0
acquired during all sleep studies on NIght 1, 2 and 3 as part of the protocol

Key inclusion criteria
1. Age > 18 years old < 75
2. Obstructive sleep apnoea as diagnosed by polysomnography
a. In the last 2 years
b. > 2 years and < 5 years from diagnosis if BMI and general health stable since diagnosis
3. Already using an oral appliance for the treatment of OSA at least 5 nights per week
4. Able to sleep in the supine position
5. Able to provide written informed consent to all study procedures, investigators to access clinical records from treating physician and agrees to adhere to all protocol requirements.

To continue on to Part 2, subjects must demonstrate the following from Part 1
1. Supine AHI >15 and <60
2. Total sleep time > 4 hours
3. Demonstrated tolerance to instrumentation with more than 3 hours of supine sleep time with pharyngeal catheter and partitioned mask.
Minimum age
18 Years
Maximum age
75 Years
Both males and females
Can healthy volunteers participate?
Key exclusion criteria
1. Pregnant or lactating females
2. Participating in another interventional clinical trial
3. Primary snoring
4. Uncontrolled or untreated cardiovascular disease
5. Central Sleep Apnoea events (greater than or equal to 5/hr)
6. Periodic limb disorder
7. Previous Uvulopalatopharyngoplasty (UPPP)
8. Medication usage that could influence respiration or sleep (e.g. regular use of sedatives, heavy alcohol consumption)
9. Severe somatic or psychiatric disorders
10. Periodontal disease, temporomandibular disorder or dental pain that would prevent ongoing suitability for an oral appliance
11. Unable or unwilling to sleep with full face mask
12. Strong gag reflex

Study design
Purpose of the study
Allocation to intervention
Non-randomised trial
Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
Masking / blinding
Blinded (masking used)
Who is / are masked / blinded?
The people receiving the treatment/s

The people analysing the results/data
Intervention assignment
Single group
Other design features
Participants will be unaware of the level of mandibular advancement and the opening and closing of the device airway during sleep. The people analyzing the sleep study data (sleep and respiratory events) will be unaware of the level of advancement and when the airway is open or closed.
Not Applicable
Type of endpoint(s)
Statistical methods / analysis
The sample size is calculated based on AHI obtained from matched pairs of study subjects i.e. subjects act as their own controls with AHI obtained from a) diagnostic and b) optimal level of advancement. Prior data from a pilot study using a similar device, indicate that the difference in the response of matched pairs was 24.7+/-16.8. However, this pilot study did not have an upper limit on the inclusion criteria for AHI so we expect a smaller mean difference in this study. With a true difference in the mean response of matched pairs of 15+/-17, we will need to study 22 subjects to complete Night 1 and 2 of the study to be able to reject the null hypothesis that this response difference is zero with probability (power) 0.9. The Type I error probability associated with this test of this null hypothesis is 0.01.
We expect that up to 25% of subjects completing Night 1 will not go onto Night 2. Therefore, we will need 30 subjects to commence the study.

Preliminary data from Night 3 will be analyzed after 50% of participants have completed the 3-night protocol to determine if there is adequate sample size to reach statistical significance when comparing AHI and pressures between Airway Open and Closed conditions. With 22 subjects, the detectable difference is -6.3 or 6.3 with probability (power) 0.8 and Type I error probability of 0.05 (assuming standard deviation 10). However, there is no preliminary data to indicate the impact of the oral appliance airway on AHI or pharyngeal pressure and therefore preliminary data will be examined. The sponsor shall review the data and decide if a protocol amendment is required to increase total number of participants.

Recruitment status
Date of first participant enrolment
Date of last participant enrolment
Date of last data collection
Sample size
Accrual to date
Recruitment in Australia
Recruitment state(s)
Recruitment postcode(s) [1] 14335 0
6005 - West Perth

Funding & Sponsors
Funding source category [1] 294316 0
Commercial sector/Industry
Name [1] 294316 0
Oventus Pty Ltd
Address [1] 294316 0
1 Swann Road
Indooroopilly QLD 4068
Country [1] 294316 0
Primary sponsor type
Commercial sector/Industry
Oventus Pty Ltd
1 Swann Road
Indooroopilly QLD 4068
Secondary sponsor category [1] 293409 0
Name [1] 293409 0
Address [1] 293409 0
Country [1] 293409 0
Other collaborator category [1] 279162 0
Name [1] 279162 0
Centre for Sleep Science (CSS), University of Western Australia
Address [1] 279162 0
35 Stirling Highway
Country [1] 279162 0
Other collaborator category [2] 279228 0
Name [2] 279228 0
Christopher Pantin
Address [2] 279228 0
Absolute Dental
1/34 Outram St.
West Perth, Western Australia 6005
Country [2] 279228 0

Ethics approval
Ethics application status
Ethics committee name [1] 295742 0
Bellberry Limited
Ethics committee address [1] 295742 0
129 Glen Osmond Road
Eastwood South Australia 5063
Ethics committee country [1] 295742 0
Date submitted for ethics approval [1] 295742 0
Approval date [1] 295742 0
Ethics approval number [1] 295742 0
Application ID 2016-09-707
Ethics committee name [2] 295743 0
University of Western Australia
Ethics committee address [2] 295743 0
35 Stirling Highway
Ethics committee country [2] 295743 0
Date submitted for ethics approval [2] 295743 0
Approval date [2] 295743 0
Ethics approval number [2] 295743 0

Brief summary
The O2Vent T is a mouth splint with an enclosed airway that allows airflow through the device. Like all mouth splints for the treatment of Obstructive Sleep Apnoea (OSA), the lower jaw is brought forward to bring the tongue forward and stabilize the upper airway. However, unlike other devices, patients are able to breathe through the device airway with the jaw position stabilized. At present, there is very little data on the complex relationship between nasal obstruction, route of breathing and the collapsibility of the upper airway during sleep and the impact of the device airway is unknown.

The purpose of this study is to investigate the mechanism of action of an oral appliance with a built in airway in the treatment of obstructive sleep apnoea.
The objectives are to:
1. Determine the relationship between nasal obstruction, Apnoea-Hypopnea Index (AHI) and breathing route in patients with OSA.
2. Evaluate the effect of mandibular advancement on the breathing route and its relationship to the AHI.
3. Evaluate the impact of the oral appliance airway on OSA treatment

Trial website
Trial related presentations / publications
Public notes

Principal investigator
Name 68290 0
Prof Peter Eastwood
Address 68290 0
Centre for Sleep Science
University of Western Australia
35 Stirling Highway
Country 68290 0
Phone 68290 0
+61 8 6457 1706
Fax 68290 0
+61 8 6457 2034
Email 68290 0
Contact person for public queries
Name 68291 0
Ms Robyn Woidtke
Address 68291 0
Oventus Pty Ltd
1 Swann Road
Indooroopilly QLD 4068
Country 68291 0
Phone 68291 0
+61 404921448
Fax 68291 0
Email 68291 0
Contact person for scientific queries
Name 68292 0
Prof Peter Eastwood
Address 68292 0
Centre for Sleep Science
University of Western Australia
35 Stirling Highway
Country 68292 0
Phone 68292 0
+61 8 6457 1706
Fax 68292 0
+61 8 6457 2034
Email 68292 0

Data sharing statement
Will individual participant data (IPD) for this trial be available (including data dictionaries)?
No/undecided IPD sharing reason/comment
under consideration
What supporting documents are/will be available?
No other documents available
Summary results
Have study results been published in a peer-reviewed journal?
Other publications
Have study results been made publicly available in another format?
Results – basic reporting
Results – plain English summary