Leading plastic heads vs PRIMALS.
See which one won.
We tested both electric toothbrush replacement heads for plastic, mold and what is actually inside. 2.3 million microplastics a year. Glue wells you cannot see. Mold in a cavity you cannot reach.
a year
degradation
hand-woven
Two electric toothbrush heads, two materials. Only one sheds plastic into your body.
And the bristle is the only part that touches you. Three tabs: how much comes off, where it goes, and what it does once it gets there.
Around 3,000 particles every session, roughly 2.3 million a year, and a sonic motor grinds them loose faster than a manual brush does. You replace the head every few months anyway. The next one does not have to be plastic.
Where the particle numbers come from
Ecotoxicology and Environmental Safety, 2025 (PMID 40680448), which measured roughly 3,000 microplastic particles released per brushing session. The annual figure is arithmetic from that at two sessions a day. The study examined manual brushes; a fast motor puts more stress on the bristle, not less.
This is the part people miss. It is not that plastic ends up in your mouth. It is that your mouth is the doorway. Swallowing it would be better; your gut passes most of it. Gum tissue does not.
What this study does and does not show
New England Journal of Medicine, 2024. Researchers examined carotid plaque removed from patients during surgery and followed them for around 34 months. Those with polyethylene or PVC detected in the plaque had a 4.5x higher rate of heart attack, stroke or death from any cause, and their plaque showed raised inflammatory markers. An association was observed. The study does not establish that microplastics caused those events, and it did not study toothbrushes.
Ninety days, side by side
One replacement cycle. Scrub the timeline and watch what happens to each bristle, and to the head it sits in.
What is actually inside your replacement head
Nobody reads a brush head like an ingredients label. Two tabs: what is growing inside the plastic one, and how the natural one is built.
PRIMALS heads are heat-carbonized bamboo. No hollow cavity, no trapped water, no mold trap. The bamboo dries between brushes, and both boar and horse bristle are naturally antimicrobial.
Most brands staple nylon tufts into wells of synthetic glue, then seal it inside a housing that soaks in water twice a day. PRIMALS heads are woven by hand, so there is no glue and no cavity for bacteria to hide in.
Where the construction findings come from
Wetzel 2005, cited in the Journal of Dental Hygiene (JDH 88/4/237), found that how bristles are anchored into a brush head changes how much bacteria survives on it. Stapled-and-glued tufts trap contamination inside the wells, while hand-woven construction eliminates those cavities entirely.
Three parts, one winner
Same test, applied to the part you actually replace.
You do not need a new toothbrush. PRIMALS heads click straight onto your Philips Sonicare handle. No adapter, no new device. You were going to buy a new head anyway. This one just is not made of plastic.
Tested. Compared. PRIMALS wins.
Clinicians who have shared PRIMALS
Verified clinicians who have looked at the research behind PRIMALS bristles and shared it in their own words.
“I love the Boar Bristle & Bamboo Toothbrush because the bristles are composed entirely of animal fibers. That means they are made without plastic like many toothbrushes you would find at the store. Research in Environmental Pollution found that standard plastic toothbrushes can and often do shed microscopic particles or ‘microplastics.’ There is a lot that I like about this product, and I would happily recommend it as part of an oral care routine.”
Dr. Preeti Kallu, MDInternal Medicine · 26 years in practice“I like this as an alternative to regular toothbrushes, some of which may expose patients to chemicals called endocrine disruptors. Found in nylon and plastic, these chemicals may mimic the body's own hormones and may send false signals to cells with potentially damaging downstream effects. Since we brush our teeth every day, the mouth can become a recurring entry point for these chemicals. That’s why I am such a fan of the Boar Bristle Toothbrush. It uses natural boar hair bristles and a bamboo handle that is designed without synthetic polymers like plastic. For plastic-conscious patients, switching to an all-natural toothbrush like this one may reduce exposure to certain chemicals and help maintain a safe dental routine.”
Cretude Dorcius, NPPrimary Care · 4 years in practice“Conventional nylon bristles can shed tiny plastic fragments with every use. This bamboo toothbrush from PRIMALS uses natural horse hair bristles instead, which may appeal to patients wanting to reduce their exposure to microplastics. Horse hair is made of keratin, the same protein found in human hair and nails. As part of a more plastic-conscious lifestyle, I think switching to a toothbrush like this one from PRIMALS is an easy choice to make.”
Dr. Matthew Finnegan, MDPrimary Care · 38 years in practice“I think anyone looking to preserve the integrity of their teeth should try this PRIMALS bamboo toothbrush. I like that the horsehair bristles of this toothbrush are naturally fine and flexible, so gentleness is built into the material rather than engineered through different grades of nylon. The bristles are also anchored without glue or synthetic binders, which tells me there are fewer potential irritants to contact sensitive gum tissue.”
Arpita Patel, NPFamily Medicine · 7 years in practiceShared via FrontrowMD. Clinicians are compensated for their time reviewing product materials and research. Statements reflect individual professional opinion, not medical advice.
What it looks like in use
Both bristle types, photographed in ordinary homes rather than a studio.
Which bristle do you prefer?
Both heads click onto the same handle. Both are natural, plastic-free and glue-free. Only the bristle changes.
Boar Bristle Replacement Heads (4 Pack)
If you prefer firm bristlesFirm natural bristle that digs into plaque and buildup. Hand-woven into bamboo, glue-free.
Best for: deep cleaning, plaque and stain buildup
Shop Boar Bristle Heads
Horse Bristle Replacement Heads (4 Pack)
If you prefer soft bristlesThe softest natural bristle. Flexes along the gumline instead of scraping at it.
Best for: sensitive gums, receding gumlines, kids 6+
Shop Horse Bristle HeadsBuilt for the PRIMALS Electric Toothbrush · Fits all Philips Sonicare click-on handles · 60-day satisfaction guarantee
Questions this raises
They are built for the PRIMALS Electric Toothbrush and also fit all Philips Sonicare click-on handles, including Protective Clean, Expert Clean, Diamond Clean, 9900 Prestige, Healthy White and Flex Care. If your current head clicks straight onto the metal drive shaft without twisting, it fits. Not compatible with Philips One, screw-on handles, or any handle where the head twists or locks into place. PRIMALS is not affiliated with or endorsed by Philips. Compatibility is based on handle design only.
Two things. The nylon bristles shed microplastics, up to 3,000 per use, that absorb through your gums into your bloodstream. And the plastic housing traps mold and bacteria in a sealed cavity you cannot clean, while leaching BPA, phthalates and PFAS into your mouth.
Boar bristle is firm, but it is not harsh like plastic. It is naturally tapered, so it flexes and spreads pressure instead of scraping like stiff nylon. If you want softer, our horse bristle heads are the softest natural bristle available and fit the same handle.
The opposite in practice. Boar bristle is naturally antimicrobial, and heat-treated bamboo dries between brushes instead of trapping moisture. Replace every 1 to 3 months, the same as any head.
Yes. A few bristles may come loose in the first week or two while the bamboo adjusts to your bathroom's humidity, and it settles down. Leave a 0.5 to 1mm gap between the head and handle for proper vibration transfer, and stand the brush upright to dry.
Every 1 to 3 months, or sooner if the bristles fray, flatten or split. Each pack comes with 4 heads, and you can subscribe for automatic delivery so you never run out.