Question from Rosie
I came across your wonderful website while researching TPU. I’ve been using SmileDirectClub aligners in lieu of braces for over a year and a half to straighten out my teeth . The aligners are in my mouth for about 22 hours a day. I found out from the company that they are made of a “BPA-free thermoplastic polyurethane material, as opposed to SLA (Stereolithography).” Do you think there is a health risk in having these aligners in my mouth for so long? Are there other questions I should be asking the company? Thank you!
Lisa’s Answer
I have looked into braces, aligners and retainers and unfortunately, there are no perfect answers. Fortunately, TPU is a plastic with fairly low toxicity. You can ask for a Safety Data Sheet (SDS) that may give you a little more information into the ingredients and health effects.
Thank you, Lisa!
I wrote back to the company and they provided the following:
“SmileDirectClub’s custom-made, BPA-free invisible aligners are made of Polyethylene Terephthalate “Pet-G” and Duran Material. They are free of xenoestrogen.
Phthalates are a group of chemicals used to soften and increase the flexibility of plastic and vinyl. Polyvinyl chloride is made softer and more flexible by the addition of phthalates. Phthalates are used in hundreds of consumer products.”
Does that change anything? Thank you!
This is confusing! Polyethylene terephthalate does not contain phthalates. Orthophthalates, not terephthalates are what is used to soften plastics. This also seems to imply that the product contains polyvinyl chloride (PVC) which is surprising. I would check back and verify if it contains PVC and phthalate plasticizers. If so, I would not use it. If not, and it is made of polyethylene terephthalate, it is a safer plastic. You can read more about it here. Obviously, not having plastic in your mouth for long period of times is best.