The only UK retainer tested for microplastic release — results published in full.
You wear it eight hours a night, for years — and every other UK retainer is untested thermoplastic. Ours is tested lot by lot, results published in full. New to this? Read our guide to BPA-free retainers in the UK.
The only UK retainer independently tested for microplastic release — every result published by lot. A published result, not a marketing claim.
Every bio. retainer is independently tested for:
| Test | Method | Standard | Result |
|---|---|---|---|
| Microplastic particle release | Simulated wear (saliva simulant, 37°C, 14 days) | ISO 10993-12 extraction | Below detection limit |
| BPA, BPS, BPF leachate | LC-MS/MS analysis of eluate | EU Reg. (EC) No 10/2011 | Not detected |
| Phthalates | GC-MS extraction analysis | REACH Annex XVII | Not detected |
| Heavy metals | ICP-MS (oral simulant) | ISO 10993-13 | Below limits |
| Biocompatibility | Cytotoxicity assay | ISO 10993-5 | Biocompatible |
| Polymer composition | FTIR spectroscopy | In-house disclosure | Published |
Full reports by lot number published on The bio. Standard. Re-tested on every new production batch.
What bio. is made of.
Most brands never disclose their materials. We do the opposite — every substance disclosed, every claim tested, every result published.
100% microplastic-free
No unstable plastics that fragment and leach over time. Independently tested for microplastic particle release under simulated wear — confirmed below detection limits.
Confirmed by ISO 17025 labAdvanced organic polymers
Formulated from biocompatible, plant-derived organic polymers. Extreme durability, long-term safety. Full composition disclosed by FTIR spectroscopy.
Plant-derived · BPA-free · Phthalate-freeIndependently tested
Every production batch tested by an ISO 17025-accredited laboratory. Results for BPA, BPS, BPF, phthalates, heavy metals and microplastic release published by lot number.
Re-tested every batch
Worn while you sleep. Nothing more asked.
Cool water, before and after. Never hot — heat is what warps and degrades a retainer, ours included.
Through the night, every night. Teeth drift for decades after braces; the retainer is what holds the line.
Dry, in its case, out of the sun. A year of nights is what it is built for — then it is replaced, fresh and tested.
What you are actually wearing.
Choose your impression method.
Impression kit
No scan, no problem. Your kit arrives next day with step-by-step instructions and a video walkthrough. Take your own impressions in about 10 minutes, then post them back in the pre-paid packaging.
Next-day kit · 5 working days returnUpload a digital scan
If your dentist has an intraoral scan, upload the files directly — we accept STL and PLY. We check them, confirm they're usable, and go straight to manufacture.
STL / PLY · Fastest turnaroundSend physical models
Already have study models from a previous clinician? Post them to us and we'll digitise them to build your retainer. We return your originals with your finished set.
Casts & models · Originals returnedSimple pricing.
Your retainer is custom-made to your teeth. The subscription keeps your set fresh year on year — teeth shift, materials age. An annual replacement is the standard of care.
bio.retainers
- Upper, lower, or both arches
- Bio-derived plant polymer
- ISO 17025 tested, results published
- Impression kit available (+£30)
- Delivered in 5 working days
bio.retainers
- New custom retainers every 12 months
- Automatic renewal, no re-ordering
- Same material, same published testing
- Cancel by email anytime
Choose your arches and add an impression kit at the next step. Secure checkout with Stripe — card details are never stored by bio.
How do home impressions work?
Your kit arrives with putty, trays and clear step-by-step instructions. You take your impressions at home in a few minutes, post them back to us, and your retainers are made from your own moulds.
Upper, lower — or both?
Whichever arch had braces is the one that needs holding. If both did, both. If you are unsure, email us a photo of your old retainer and we will tell you honestly.
Why replace it yearly?
Retainers wear — surfaces roughen, and older devices shed more. The subscription keeps you on the fresh end of the wear curve, with each replacement tested and published like the first. Read the research →
Tested lot by lot. Published in full.
From £100 per arch. From £140/year subscription. Delivered to your door.
Order bio.retainers