Inclusion Criteria:
* • Provision of signed and dated informed consent form
* Unable to tolerate or decline positive airway pressure therapy
* Absence of markedly enlarged tonsils, defined as 3+ or 4+ according to the Brodsky classification
* Able to protrude tongue ≥20mm beyond maxillary incisors
* No uncontrolled nasal obstruction (must be able to breathe through nose)
* Stable medication regimen for ≥1 month
* Stated willingness to comply with all study procedures and availability for the duration of the study
* Male or female, of any race, aged 18-70 years (inclusive)
* If diagnosed with uncomplicated Mild to moderate, moderate to severe OSA (i.e., AHI \>5, \<30 h-1); where uncomplicated is defined by the absence of:
* Conditions that place the patient at increased risk of non-obstructive sleep-disordered breathing (e.g., central sleep apnea, hypoventilation, and sleep-related hypoxemia). Examples of such conditions include significant cardiopulmonary disease, potential respiratory muscles weakness due to neuromuscular conditions, history of stroke, and chronic opiate medication use.
* Concern for significant non-respiratory sleep disorder(s) that require evaluation (e.g., disorders of central hypersomnolence, parasomnias, sleep-related movement disorders) or interfere with accuracy of HSAT (e.g., severe insomnia).
* Environmental or personal factors that preclude the adequate acquisition and interpretation of data from HSAT.
* Body mass index (BMI) \< 35 kg/m2
* Neck circumference \< 45 cm
* Absence of severe oxyhemoglobin desaturation during sleep, indicated by mean nocturnal SpO2 \> 82%
* Mandibular range of motion \> 5 mm in protrusive direction
* Adequate dentition, as determined by the site dentist
* Must have a smart phone able to download 02 ring app
Exclusion Criteria:
* • Inability to breathe through the nose comfortably
* Presence of \> 25% Central Sleep Apnea (CSA)
* Severe OSA above AHI \>40
* Uncontrolled sleep disorder such as narcolepsy, chronic insomnia, restless legs syndrome, or REM behavior disorder
* Presence of positional obstructive sleep apnea per Cartwright's definition (Ratio of respiratory events in the supine to nonsupine position greater than 2:1)
* History of surgery intended to alter anatomy for the correction of OSA, such as uvulopalatopharyngoplasty (UPPP), maxillomandibular advancement (MMA), or tongue/hyoid suspension.
* History of surgery intended to restore normal anatomy, such as tonsillectomy, adenoidectomy, septoplasty, or polypectomy within the previous 6 months
* Presence of hypoglossal nerve stimulation device
* Use of CPAP or OAT within the two weeks prior to the screening HSAT
* Anticipated change in medical therapy during the study protocol that could alter OSA severity (e.g., weight loss surgeries; UPPP, MMA, tongue/hyoid suspension)
* Loose teeth or advanced periodontal disease
* Teeth extractions/Presence of a dental post implanted less than 12 months
* Removable dentures
* History of temporomandibular joint disorder (TMJ)
* Resistant hypertension, defined as inadequately controlled blood pressure despite therapy with ≥ 3 oral hypertensive agents
* Presence of congestive heart failure (NYHA Class IV), persistent/permanent atrial fibrillation, or acute coronary artery disease (STEMI/NSTEMI/USA) in the past 30 days.
* Presence of neuromuscular diseases e.g. myasthenia gravis, amyotrophic lateral sclerosis, Guillain-Barré syndrome and muscular dystrophy, or hypoventilation disorders which results in shallow breathing during sleep and/or cyanosis of the fingers/toes.
* Presence of pulmonary disease resulting in significant desaturation, e.g., severe chronic obstructive pulmonary disease, interstitial lung disease (SaO2 nadir of 87%), or pulmonary hypertension
* History of cerebrovascular incident within the last 12 months
* Use of pacemaker or other life supporting device
* Anticipated change in body weight \> 5% during the study period
* Participation in other studies that could interfere with the study protocol
