Dr. Jerry Hu and Len Liptak take a close look at OAT device volumes that can affect treatment efficacy, side effects, and comfort.
by Jerry Hu, DDS, D.ABDSM, D.ASBA, D.ACSDD, and Len Liptak, MBA
During an Oral Appliance Therapy (OAT) consultation, many Dental Sleep Medicine practitioners provide patients with the buffet option. The patient is seated in the consultation room, and they are met with an array of different devices in varying colors, shapes, and sizes. Like the people in the buffet line, they don’t always make the choices that are best for them. In this situation, the wrong choice can be costly. It can lead to discontinuation of treatment, poor compliance, and pricey remakes when changing devices. How can dental sleep providers guide patients to select an OAT device that will be comfortable and increase the likelihood of continual, regular use?
Volume is one of the characteristics that dental sleep providers and patients consider when selecting an OAT device. It is widely accepted that OAT device volume is correlated with comfort and adherence. Conversely, device discomfort is routinely cited by physicians as a reason they are reluctant to prescribe OAT. OAT device volume may also impact tongue space and posture, the degree of mandibular protrusion, and the expression of intraoral exostoses, which can impact treatment efficacy and side effects.
Given the importance of OAT device volume, scant objectively recorded data is available to help providers and patients make informed decisions. To the best of the authors’ knowledge, no studies have systematically evaluated and reported on OAT device volume. Many manufacturers advertise device volume. Some claim that their devices are small. Others claim their devices are smaller. Yet others claim they’re the smallest.
Further complicating the challenge is that OAT device samples are made on different sized dental casts. In other words, what the patient sees is not always what the patient gets. There is no standard dental cast baseline for the samples. One manufacturer offers a sample on a pediatric dental cast, for example. Another uses a full-size dental cast with an ABO base. Another manufacturer’s sample omits the terminal molars on their dental casts and devices. Patients are not always aware of these subtle differences, but these differences can be significant in practice.
This leads to the research topic – Are OAT device volumes as advertised?
Multiple sets of five different types of custom OAT devices (n=14) were ordered. Each of these devices utilized the exact same set of digital dental sleep records. The intent of holding the dental records constant was to enable an accurate, objective, comparison of OAT device volumes. The five device types were: Nylon Strap (NS, Panthera n=3), Precision Manufactured (PM, ProSomnus n=3), Reverse Dorsal (RD, Respire n=3), Fulcrum Strap (FS, Somnomed Avant, n=3) and Traditional Dorsal (TD, Somnomed Flex, n=2). All manufacturers were blinded to the intent of the orders.
A classic Archimedes displacement method was used to calculate device volumes. Each OAT device was submerged in water. The amount of water displaced was measured (in ml) to determine the volume for each OAT Device. Three cycles of measurements were made for each OAT device to control for measurement error.
The data revealed a significant range in OAT device volumes, by device type.
The average volume across all devices measured was 2.57 ml +/- 0.79. The PM style devices had the smallest average volume of the devices tested at 1.41 ml +/- 0.17, 55% smaller than the average of all devices measured. The TD style devices had the largest average volume at 3.81 ml +/- 0.17, 149% more volume than the average of all devices measured, and 270% larger than the smallest volume OAT device.
Three of the five devices studied utilize a CAD/CAM manufacturing process. Two of the CAD/CAM devices, the PM and NS devices, are on the smaller end of the volume spectrum. The volume differences are statistically significant. However, the average volume of the third CAD/CAM device, the FS device, is not different than the RD type device in terms of statistical significance.
Importantly, a visual inspection reveals that the variances in volume appear in three areas of the devices evaluated in this study: the lingual aspect, the anterior aspect, and the titration mechanism. The lingual aspect might be clinically significant as it pertains to tongue space. The anterior aspect might be clinically significant as it pertains to lip seal. The titration mechanism might be clinically significant as it could lead to discomfort in the buccal corridor.
This in-vitro study establishes a foundation for additional research. One natural extension of this study would be to evaluate whether these devices, each made from the same dental cast, might result in different OAT device selections in the consult room. Another would be to evaluate whether these differences in OAT volume translate into different treatment results such as adherence, efficacy or side effects.
In conclusion, this study provides an objective measurement of OAT device volumes. Different OAT device types exhibit statistically, and likely clinically, significant differences in volume. Though the smallest volume device utilizes CAD/CAM production, providers should not assume that CAD/CAM devices are smaller volume.
Besides OAT device volumes, Dr. Hu has shared his thoughts about minimizing side effects in oral appliance therapy. Read his article here: https://dentalsleeppractice.com/product-reviews/minimizing-side-effects-a-retrospective-case-series-analysis-of-tooth-movement-in-oral-appliance-therapy-by-dr-jerry-hu/