Braces, mouth expander, retainers, headgear and eventually dentures are appliances that are custom-fit by the orthodontist to individual’s mouths. Even with sterilization, reuse is not recommended and neither is it practical. Dentures and retainers are made from acrylic or nylon resin and metal and separating the materials from the appliance can be quite difficult. A small amount of metal cannot justify the expense.
Many dental appliances like mouth expander and braces are made partly or fully from metal which is recyclable. Some orthodontists use professionally sterilized and remanufactured metal brackets that only cost half the price of the new ones. EPA requires dental offices to install and regularly maintain an amalgam separator on their drains so that mercury and other pollutants will not flow to the water system.
There are hazardous metals like mercury that is used for fillings and lead from x-ray aprons. The safest way to dispose of these hazardous metals is through recycling. When gold is used in fillings, recycling will be profitable.
Dentures and other appliances accumulate lots of oral bacteria. When steam is used for sterilization, it consumes a lot of water and electricity. Older methods of sterilization make use of chemicals like glutaraldehyde, formaldehyde and alcohol. Some clinics may steam sterilize discarded appliances but since they are not reusable, there are dental clinics that simply dispose contaminated medical waste like used gloves and items that came into contact with body fluids.
Molded plastic retainers are usually made from various brands of plastic polymers and it is often impossible to determine their exact composition. Even in municipalities where medical waste is accepted, plastics cannot be recycled when nothing is known about their composition.
Since dental appliances are mostly waste, dental and orthodontic practices are starting to eliminate the disposables. Plastic mold trays are being replaced with metal alternatives while washable face shields are taking the place of disposable masks.
If you are curious about the mouth expander, it is an appliance that is placed inside the mouth to create more space and allow permanent teeth to grow straighter and more comfortably. It may sound terrifying but it prevents crossbite, overcrowding and impacted teeth.