Braces, expanders, headgear, retainers, and eventually, dentures. Over a lifetime, that’s lots of metal, plastic, and even precious metals and hazardous materials in our mouths. Except for the occasional broken retainer, most of our dental appliances are removed at the clinic. Where do they all go?
Unfortunately, most of what lives in our mouths is worse than garbage — it’s hazardous waste. Dentures and other such appliances naturally pick up a lot of oral bacteria. Steam sterilization uses a lot of water and electricity, while older sterilization methods can use chemicals like glutaraldehyde, formaldehyde, and alcohol. Some clinics may steam sterilize discarded appliances, but since many dental appliances are not reusable or recyclable anyway, most dentists and orthodontists dispose of them with contaminated medical waste like used gloves and other items that contact body fluids.
While disposed dental appliances are no more likely to be noticed in your garbage can than old toothbrushes, they are technically categorized as medical waste, which is banned from residential garbage service in many communities.
Aside from the ick factor in second-hand teeth, nearly all dental appliances are custom made to fit an individual’s mouth, so even with sterilization, reuse is not practical. Dentures and many retainers are generally made of acrylic or nylon resin and metal. Separating the multiple materials used in a single appliance would be difficult, and the amount of recyclable material recovered would not justify the cost. Most of the plastics used in appliances are not recyclable.
Molded plastic retainers are made from a variety of brand-proprietary plastic polymers, so it’s impossible to know the exact composition. Even if municipal programs accepted medical waste, they cannot recycle plastic when the exact composition of the material is unknown.