We explain advantages, limitations, and other considerations of common materials used in dental devices for obstructive sleep apnea.
Information source: Janice Gruber, laboratory customer service manager, Great Lakes Orthodontics; Gary Bailey, DDS, director of clinical support, Airway Management Inc
Advantages: A common material for a variety of oral appliances, hard acrylics can be adjusted or repaired easily chairside, are easy to insert and remove, and boast snap fit. If the patient has minor dental changes, hard acrylic appliances can sometimes be modified without the need for an entirely new appliance. They complement most dentitions.
Limitations: Patients with sensitivity may feel hard acrylic appliances are “too tight” or are “pinching their teeth.” Solutions can sometimes be found that will allow the sensitive patient to stay in a hard acrylic appliance or softer materials can be considered.
Other considerations: General dentists are typically familiar with this material because it is commonly used to make TMJ appliances and dentures. These appliances are good for bruxers. Hard acrylic appliances are most retentive when the shape of the clinical crown has good undercuts. Clasps can be added for additional retention.
Also known as: Suck Down Material, Polymer and Monomer, Cold Cure, Cold Pack. Trademarked names include Biocryl.
Information source: Gary Bailey, DDS, director of clinical support, Airway Management Inc; Janice Gruber, laboratory customer service manager, Great Lakes Orthodontics
Advantages: Soft and pliable at warm temperatures, thermal acrylics allow for comfort and easy seating. They provide better retention with crowded dentition (these have to be relieved to allow for insertion) because the material can be left longer and/or clasps can be added for further retention. Edentulous patients with a good boney ridge can wear thermal acrylic oral appliances.
Limitations: More frequent replacement may be needed than for hard acrylic appliances. These may need to be replaced especially frequently for clenchers or bruxers.
Other considerations: The pliability of thermal acrylics allows them to flex over crowns and bridges, making them a good choice for patients with restorations. Thermal acrylic appliances are also good for patients with sensitive teeth. A related material is irradiated thermal acrylic; the irradiation process makes the thermal acrylic more rigid, giving it increased durability while maintaining the advantages of other thermal acrylics.
Also known as: Trademarked names include Veriflex, Astron, Talon, True Clear, ThermAcryl.
Information source: Janice Gruber, laboratory customer service manager, Great Lakes Orthodontics
Advantages: An extremely soft option compared to the others listed here, ethylene-vinyl acetate-made appliances are comfortable for patients with sensitive teeth and veneers. They are easy to insert and remove.
Limitations: More frequent replacement may be needed than for appliances made of any other material. These are not a good choice for clenchers or bruxers.
Other considerations: These appliances may be a good choice for the elderly or those with poor manual dexterity. They will work with edentulous patients with a good boney ridge.
Also known as: EVA, Mouthguard Material, Athletic Guard Material, Soft Material.
Information sources: Mayoor Patel, DDS, MS, and Hector Rico, co-owners, MAP Lab; Gary Bailey, DDS, director of clinical support, Airway Management Inc; Janice Gruber, laboratory customer service manager, Great Lakes Orthodontics
Advantages: Soft on the inside and hard on the outside, laminated appliances combine the rigidity of hard acrylic with a liner of soft material that is more comfortable in the mouth. In several respects, they combine the advantages of hard acrylic with the advantages of soft materials.
Limitations: Laminated appliances are not as durable as hard acrylic appliances. The soft side absorbs moisture and yellows, which means more frequent replacement. Clasps cannot be added for further retention.
Other considerations: If anything changes in the patient’s mouth (for example, the addition of a crown), a completely new appliance must be created—realignment can’t be done. (On a hard acrylic appliance, the appliance can sometimes be ground to re-fit.) If not bonded strongly, the materials can separate from each other or peel off. Patients with sensitive teeth are good candidates for laminated appliances.
Also known as: Hard-Soft Material, Dual Laminates (one layer of hard and one layer of soft), Triple Laminates (two layers of one material, generally hard acrylic, with one layer of another, generally soft, material). Trademarked names include DuraSoft.
Information source: Annie McBride, senior product manager, Narval, ResMed
Advantages: Biocompatible polymer appliances are lightweight while extremely durable, can be adjusted chairside in seconds, and are easy to insert and remove for a snap-and-go fit. Biocompatible polymer was originally used in joint replacement, so it boasts proven resilience and strength. Biocompatible polymer has not been proven to cause any allergic reactions, eliminating concerns for patients with allergies or sensitivities to acrylic or metal and associated patient discomfort from resulting plastic or metallic aftertaste.
Limitations: Patients with short clinical crowns or lack of buccal or lingual undercuts may not be candidates. However, adjustments can be made to maximize retention.
Other considerations: The biocompatibility, BPA, and phthalate-free material eliminate the concern for patients with allergies or sensitivities to acrylic or metal.
Also known as: Nylon Polymer, Synthetic Polymer, Polyamide 12, PA 12, Medical-Grade Nylon.
Information source: Thomas Meade, DDS, inventor of Quali-Som’s TheraSom Cast
Advantages: Virtually indestructible, devices made of this alloy have a lifespan much longer than that of other dental devices. Being nonporous, it won’t stain or take on odors. Patients with allergies do better with specific compositions of this alloy because certain triggers—like iron or steel—can be avoided. Specific oral appliance designs made from this alloy allow for a slim fit that avoids using tongue space on the lingual of the mandibular teeth, which allows for less required jaw protrusion and thus less chance of TMJ concerns.
Limitations: While the alloy itself is inexpensive, casting it is expensive—so expect to pay more for devices made of this material.
Other considerations: The extreme durability makes it an ideal choice for bruxers. Some devices are made entirely of an alloy while others use the alloy as the framework, then coat with acrylic—which introduces other advantages and limitations.
Also known as: Cobalt-Chrome Alloys, Co-Cr Alloys. Trademarked names include Vitallium (65% cobalt, 30% chromium, 5% molybdenum, and other substances).
[sidebar width=”240” float=”right”]Hardware Considerations
• Different devices have different hardware, ranging from screws to tubes to clasps to hooks to hinges.
• Be aware of patients’ allergies and sensitivities as hardware can include nickel and other materials that can trigger a response.
• Take into account how severely patients manifest bruxism and their lateral thrust habits, as these can affect your hardware choices.
• Many dentists learn more about hardware options as patient-specific needs become apparent.[/sidebar]
[sidebar width=”240” float=”right”]Elastics Considerations
• Elastics are used with some appliances to keep the mandible engaged, which keeps the airway open. (Generally, the addition is to appliances that have separate upper and lower components.) Patients with open mouth breathing habits can benefit from adding elastics to their appliance of choice so the mandible doesn’t drop open.
• Choose an appropriate weight and length, so the elastics are holding in place only, not applying force.
• Understand your patients’ allergies, as elastics are available in latex and non-latex options.[/sidebar]
Sree Roy is editor of Sleep Review. CONTACT email@example.com.