A dental sleep medicine practitioner shares how he determines if OAT will work prior to ordering a custom appliance. He also employs the system to create a temporary appliance in the interim.

The MATRx is one of several devices that can be used to predict oral appliance efficacy. If you use a different predictive device and want to share your experience, we want to hear from you. E-mail sroy[at]allied360.com to be considered for a future article.—SR


The concern that oral appliance therapy (OAT) may not be efficacious on a given patient is a real obstacle to patients proceeding with OAT and to physicians referring obstructive sleep apnea (OSA) patients to dentists. I have overcome this obstacle in my London, Ontario, Canada, dental practice via a predictive device called the “MATRx.” I have been employing MATRx (developed by Calgary, Alberta, Canada-based Zephyr Sleep Technologies) for about two years and have found it a valuable way to predict OAT success, provide patients with an interim oral appliance while their custom oral appliance is being manufactured, and develop bidirectional referrals with sleep labs. I do not have any financial stake in Zephyr, nor am I being compensated by Zephyr to write this article. I want to share what has worked for me to benefit more patients and the field of dental sleep medicine.

MATRx Overview


The dentist asks the patient to move the lower jaw forward to maximum protrusion and records this position as well as the patient’s comfortable bite position using the MATRx temporary tray scale.

The MATRx procedure starts in the dental office where the dentist adds impression material (polyvinyl siloxane) to two disposable trays that fit the patient’s teeth. The dentist then asks the patient to move his/her lower jaw forward to maximum protrusion (approximately 10-12 mm, typically) and records this position as well as the patient’s comfortable bite position using the temporary tray scale. The measurements are recorded and put on a prescription for the patient. The patient takes the prescription and the temporary upper and lower trays to the sleep lab, where he or she goes for polysomnography (PSG).

At the sleep lab, the upper and lower trays are placed in the patient’s mouth and are attached to a remote-controlled mandibular positioner. This is so the mandible can be progressively protruded under PSG observation without disturbing the patient’s sleep.1-3 Similar to a split-night PAP titration in which the patient is both diagnosed and titrated for therapy in the same night, the MATRx titration can be performed following the diagnostic PSG to identify whether the OSA patient is a responder to OAT and determine the effective target protrusive position (ETPP) for their therapeutic appliance.

This remote-controlled device allows small, precise movements in the anteroposterior dimension. The purpose is to determine an effective target position for the oral appliance. While the mandible is being slowly titrated forward without waking up the patient, the PSG will reveal whether the OSA is being treated successfully. An article published in SLEEP 2013 entitled “Remotely Controlled Mandibular Protrusion During Sleep Predicts Therapeutic Success with Oral Appliances in Patients with Obstructive Sleep Apnea” reviews the results of the MATRx clinical trial and reports the predicted ETPP provided an efficacious protrusive position in 93% of the patients correctly predicted to be therapeutically successful with OAT. The therapeutic success criteria were an apnea-hypopnea index (AHI) less than 10 and a 50% reduction in baseline AHI. The oral appliance used in the trial was the SomnoDent appliance.3

As the dentist, I do not attend the MATRx PSG study. I receive a report from the sleep lab after the study that tells me whether the patient’s OSA was successfully treated and, if so, how far to advance the mandible. Dentists who want to locate a local sleep lab that has a MATRx testing program can visit the “For Dentists” section of Zephyr’s website or call its customer support center at 877-341-8814. Sleep labs who want to add this service and dentists who would like to start working with a MATRx lab in their area can contact Zephyr by phone, e-mail, or through its website.


The sleep study is an essential part of the income for sleep specialists. The addition of the MATRx system can increase the number of attended sleep studies performed by the sleep lab.

Another advantage is that the patient’s MATRx titration trays can serve as a temporary appliance after their MATRx study, while a custom appliance is being made, using the MATRx TD Clip. In my opinion, it is important that temporary appliances be placed to maintain a patent airway anytime a patient’s oral appliance is being made or repaired. (Note: This TD Clip accessory for the MATRx titration trays is not yet cleared for sale in the United States.)

Oral Appliance Billing

In Canada, the vast majority of patients have to pay out-of-pocket for their oral appliances. Patients do not know what to expect regarding the fee. On TV and the Internet, patients see advertisements for over-the-counter oral appliances for $79 (and for which the patient must declare they do not have TMJ problems or OSA, despite the fact that most people with OSA don’t know they have the disorder) so they are obviously shocked when they learn the cost of a custom oral appliance could be thousands of dollars. I have found, however, that patients who are referred for a MATRx study are typically agreeable to spending a small out-of-pocket fee to know in advance if an oral appliance will be effective in treating their OSA. I charge $250 to examine the patient, prepare their MATRx tray impressions, and determine the maximum protrusive position to ensure the titration is performed comfortably within the patient’s mandibular range of motion.

Bidirectional Sleep Lab Referrals

After the custom appliance arrives, I also send the patient back to the sleep lab for an efficacy study.

With increasing awareness of MATRx, hopefully more sleep specialists will recommend this patient selection tool for determining in advance the efficacy of oral appliances. Most sleep specialists and medical doctors prefer to recommend CPAP therapy over OAT. While extremely effective, particularly in the treatment of severe OSA, adherence to treatment with CPAP is reported to be low, increasing the need for alternative treatments.4,5 Previously, OAT was recommended as a CPAP alternative for mild or moderate OSA;6,7 however, these guidelines have recently been updated to expand the role of oral appliances in the treatment of OSA. It is now recommended that sleep physicians consider an oral appliance prescription, rather than no treatment, for OSA patients who are intolerant of CPAP therapy or prefer alternate therapy.8

I also find that MATRx builds bidirectional relationships between dentists and sleep labs. Most recently, my referrals from sleep labs and sleep physicians have increased. They appreciate that I refer patients to the sleep lab for both the initial split-night study and for the OAT efficacy study after the custom oral appliance is ready. I also ensure I keep the physician abreast of the patient’s progress via thorough reports.


BrockRondeau, DDS

Perhaps the ideal situation might be for the medical doctors, sleep specialists, or dentists to ask the patient what treatment he or she would prefer. If they prefer CPAP, if they have comorbid health problems, or they are obese, then encourage the patient in that direction. If the patient prefers OAT, then have the sleep lab contact a dentist who is familiar with the MATRx technique.

Regardless, patients, dentists, and sleep specialists should be pleased with this new technology that will demonstrate prior to the fabrication of the oral appliance that patients will be positive responders to treatment. I am glad to see Zephyr’s John E. Remmers, MD, and Shouresh Charkhandeh, DDS, winning well-deserved accolades (such as the AADSM Clinical Research Award, awarded to Remmers in 2016, and the AADSM Clinical Excellence Award, awarded to Charkhandeh in 2015) for this invention. The technique for determining what pressure must be attained during the PSG in order to reduce the AHI and eliminate the OSA is used routinely prior to the treatment with CPAP. Using a sleep study to determine what degree of mandibular advancement will reduce the AHI and eliminate OSA seems to be a similar concept and one that should be utilized by more sleep labs and patients.

Brock Rondeau, DDS, IBO, DABCP, DACSDD, DABDSM, DABCDSM, is a diplomate of the American Board of Dental Sleep Medicine. He is the owner of Rondeau Seminars, which provides dental continuing education in orthodontics, TMD, and sleep dentistry. View the class schedule at www.rondeauseminars.com.

1. Dort LC, Hadjuk E, Remmers JE. Mandibular advancement and obstructive sleep apnoea: a method for determining effective mandibular protrusion. Eur Respir J 2006; 27:1003-9.
2. Tsai WH, Vazquez JC, Oshima T, et al. Remotely controlled mandibular positioner predicts efficacy of oral appliances in sleep apnea. Am J Respir Crit Care Med 2004; 170:366-70.
3 Remmers JE, Charkhandeh S, Grosse J, Topor Z, Brant R, Santosham P, Bruehlmann S. Remotely controlled mandibular protrusion during sleep predicts therapeutic success with oral appliances in patients with obstructive sleep apnea. SLEEP 2013; 36(10):1517-1525.
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8. Ramar K, Dort LC, Katz SG, Lettieri CJ, Harrod CG, Thomas SM, Chervin RD. Clinical practice guideline for the treatment of obstructive sleep apnea and snoring with oral appliance therapy: an update for 2015. J Clin Sleep Med 2015;11(7):773–827.