Q: Is mouth gear safe, considering all that plastic?
A: Now that Health Canada's made it baby-bottle-clear that 91 per cent of us have estrogen-mimicking bisphenol A flowing in our veins, the hunt for hidden sources of chemical contaminants continues.
And all many of us have to do to find some is open up and say "Ahh."
It's been a couple of years since I told you about how bisphenol A is lurking in white dental filling resins, but all you teeth-straighteners should also be aware that clear plastic braces are made of now-notorious polycarbonate plastic. Yep, the same plastic ousted from Canadian baby bottles last year once it was recognized that it leaches hormone-disrupting BPA with wear and tear.
While minimal research has been done on this specific end use, it's safe to assume that chewing, drinking and plain salivating with the plastic in your mouth 24/7 for two years, as clear braces wearers do, will lead to leaching.
One study conducted by Tokyo Medical and Dental University found that polycarbonate braces simply submerged in body-temperature water caused a four-fold increase in BPA over 12 months. Submersion in hot liquid for just a quarter of that time increased leaching more than 12-fold.
By the way, many clear plastic aligners designed as a chic ‘n' subtle substitutes for braces are also made with polycarbonate plastic. At least you remove the aligners when you eat and drink, but you're still wearing them about 20 hours a day. Both ClearCorrect (as of earlier this year) and Invisalign guarantee their devices are BPA-free, but classic stainless steel braces are still the safest (as long as you don't get clear plastic brackets).
What about retainers? Well, it all depends on what they're made of. Acrylic resins are the most popular dental base for everything from retainers to dentures. They're generally polymers made of something called methyl methacrylate (aka PMMA), which is also found in plexiglass, acrylic paint, bone cements and butt implants. (Go figure.)
Now, some consider PMMA safer than similar clear hard plastic goods because it's bisphenol-A-free. Thing is, the MMA in it isn't just a skin irritant and allergen that can trigger asthma and nausea in dental technicians; MMA used in dental appliances can also contain 6 to 8 per cent phthalates (dodgy plastic softeners linked to various health concerns), according to an EU Commission report on plastics in medical devices.
Soft acrylics like denture linings are going to have more phthalates in them than harder ones. In fact, the reason soft acrylics can grow to feel harder in your mouth over time is because those plasticizers leach out, say researchers.
Still, acrylics are generally a hell of a lot better than cheaper vacuum- formed retainers made entirely of PVC, which can have a much higher percentage of hormone-disrupting phthalates. The EU has raised concerns about the leaching of DEHP phthalates into the mouths of those wearing PVC retainers day in, day out - ingesting, by one estimate, 10 mg of DEHP a day.
Ask your dentist for a retainer made of somewhat pricier polypropylene to avoid the whole headache.
Looking for a little extra dental protection on the field/rink/court? Athletes will definitely want to stop sucking on mouthguards made of either PVC or polycarbonate. You'd be better off with one made from safer ethylene-vinyl acetate (EVA) or inert silicone.
You night clenchers will want to make sure you're not grinding down on any dodgy substances, too. Make sure yours is made of polypropylene and/or EVA, like the SleepRight No Boil Dental Guard.
Bottom line is, before you walk out of your dentist's office or pharmacy with a mouthful of plastic, be sure to ask lots of questions and find out exactly what you're in for. You want to be sucking on a sure thing.
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