In the dental office, occupational hazards are everywhere. You wear masks and gloves to protect yourself from the dangers of infection from close contact with patients’ saliva and blood. You give attention to your posture to minimize the risk of musculoskeletal disease. And you wear nitrile gloves, sometimes two pair, when working with acrylates.
Or perhaps not. A search of some popular dental journals online yielded zero articles on the hazards of what the American Contact Dermatitis Society named the 2012 Allergen of the Year – Acrylates.
Acrylates – What Are They?
Though they get little mention, acrylates are everywhere. The salts of acrylic or methacrylic acid can be polymerized to form solid plastics. Polymerized methacrylate was first used in the 1930s, when mass production of Plexiglas began. It is now used in windowpanes, car lights and windshields, and streetlamps. Over time, other acrylates have been synthesized and are now found in paints, adhesives, printing inks and medical devices. Fully polymerized acrylic plastics are inert and harmless. However, the building blocks – acrylates and methacrylates – are strong irritants and notorious allergens.
But what does this have to do with safety in the dental office?
Acrylates in the Dental Office
These days, many methacrylates are used in dental bonding materials. These dental materials seem to be a major cause of contact dermatitis in dental personnel. The polymerization (curing process) of these adhesives and materials occurs with exposure to UV light and with the help of a priming photoinitiator, or when two components are mixed causing a chemical reaction. In both cases, unreacted monomers are released. These “free monomers” can cause irritation to skin and eyes, asthma, and allergic dermatitis.
“Dental surgeons, assistants, and technicians are also at risk of allergic sensitization from monofunctional and polyfunctional (meth)acrylates and from the epoxy acrylate prepolymers.” – American Contact Dermatitis Society
Widely used dentin primers and dentin bonding agents and cements that contain 2-HEMA (hydroxyethyl methacrylate) have been studied. The authors concluded that the free monomers released from HEMA can affect dental personnel as well as patients in the immediate vicinity.
There are numerous reports of acrylate associated allergy in dental personnel, including fingertip paraesthesia and occupational allergic contact dermatitis caused by a restorative dental material with polymethylmethacrylate.
Testing and Protection
Testing for allergic sensitization to acrylates is difficult. The allergens have to be kept frozen or refrigerated, delayed positive results are common, and patch testing can cause severe allergic reaction.
Methacrylate monomers penetrate vinyl and latex gloves within minutes. For this reason, the American Contact Dermatitis Society recommends double gloving with nitrile gloves, or polyethylene gloves under nitrile gloves. This should afford adequate protection for tasks that do not exceed 30 to 60 minutes.
Dental products such as acrylics, resins and polymer materials represent significant advances in dentistry and are here to stay. Your best option to minimize the risk of developing an acrylate allergy is to stay informed about the signs and symptoms of allergic reactions, keep records of dental materials being used, and put in place whatever precautions are available to limit your exposure.
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