Filling the Gap: The Truth About Amalgam

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Let’s start with a little glittering truth wedged between your molars: that silvery filling, the one you’ve had since you were twelve, is made of mercury. 

Yes, mercury. The same toxic metal that once sent hat-makers barmy and poisoned Victorian children in their rattles. And yet, here we are in the 21st century, still screwing it into our heads and calling it “safe”. After a decade of intensive campaigning from groups such as the Campaign For Mercury-Free Dentistry, mercury was banned within the EU from 1 January 2025.

Why the UK still valiantly defends the use of a classified neurotoxin, can only be explained by the ‘follow-the-money’ argument.

Dentists will tell you it’s perfectly fine. “Clinically proven,” they say, as they lower the drill and hum to the radio. 

And we, the trusting, fluoride-fresh public, nod back. Because if the man in the mask says it’s acceptable, then it must be socially acceptable too.

But let’s put aside the polite white lie and ask – is it actually healthy?

The short answer is: not particularly. Which is why increasing numbers of dentists now look at amalgam with the same embarrassment one reserves for a photo of themselves in the 1980s wearing shoulder pads and smoking indoors.

The Rise of the White Stuff

Enter the composite, the “white filling,” dentistry’s clean, modern face. The name itself sounds reassuringly pure, doesn’t it? Like a toothpaste advert set in a Scandinavian mountain range.

“Composite” comes from the Latin compositum, meaning “put together.” Which is apt, because these things are indeed cobbled together, a Frankenstein of plastics, quartz, glass, and chemical ambition. 

The scientific explanation reads like the ingredients list of a laboratory mishap: an organic plastic matrix cuddling up to inorganic fillers, all bound together by something called silane, because, it seems, we ran out of vowels.

The plastic in question is a charming little compound called Bisphenol A glycidyl methacrylate, Bis-GMA for short, which sounds like a rapper but is, in fact, a xenoestrogen. 

That means it behaves like estrogen’s evil twin: pretending to be a hormone while quietly mucking up your reproductive system.

In animal studies, Bisphenol A (BPA) has been shown to interfere with sexual and brain development, cause infertility, cancer, and behavioural disorders. In humans, it’s been politely “associated” with obesity, the sort of association that would have it unfriended on social media.

When your mouth gets a bit acidic, say, after your morning coffee or a bout of stress, BPA can leach out of the filling, sneak into your bloodstream, and start playing dress-up as estrogen.

So, if you’ve swapped mercury for Bisphenol, congratulations: you’ve replaced one form of poison with another.

The Defence of the Silver Brigade

Amalgam loyalists are still out there, sharpening their probes. They insist that composites are fickle, fragile, and flaky, that they shrink, crack, and invite tooth decay like an open bar invites bad decisions.

There’s truth in that, to a point. Composites can contract as they set, leaving micro-gaps that bacteria find irresistible. They can also absorb water over time, swell slightly, and harbour a revolting cocktail of microbes.

Then there’s the accusation that composites lack the stamina to survive in your molars, those hardworking back teeth that grind through several thousand meals a year. “They just can’t cope with the pressure,” sigh the amalgam advocates.

But here’s the twist: they can. The new-generation composites, fortified with ceramic particles and engineered by people who read molecular diagrams for fun, are more than capable of standing up to a life of mastication.

Yes, they can age. So do we. The trick, as ever, is maintenance: brush properly, see your dentist regularly, and perhaps stop chewing toffee like it’s a dare.

Allergies, Additives, and the Eternal Compromise

Some composites contain monomers like TEGDMA and HEMA, which can provoke allergic reactions in dentists and patients alike. Two percent of Danish dentists, apparently, broke out in rashes just handling the stuff. But dentistry, ever adaptive, now offers BPA-free and allergen-free versions, the vegan leather of the filling world.

So, What’s the Verdict?

Amalgam, once the gold standard (or rather, the silver one), now looks increasingly like the rotary phone of dental materials, clunky, outdated, and vaguely toxic. It sadly remains that most composite fillings contain fluoride.

Composites, for all their molecular melodrama, have matured beautifully. The latest generations are durable, aesthetic, and mercifully less hormonally mischievous.

For large cavities, though, the connoisseur’s choice remains ceramic inlays, bespoke pieces of dental porcelain crafted by technicians with the precision of Swiss watchmakers. They don’t leach, don’t warp, and look so convincingly tooth-like that your molars might blush.

Don’t Look Back and Wish You’d Known More

Your mouth is real estate too precious for nostalgia. Mercury belongs in thermometers, not in teeth. BPA belongs in cautionary tales.
The truth is that amalgam is the dental world’s cigarette, defended long after its sell-by date, tolerated for convenience, and destined for an eventual, embarrassed phase-out.

You deserve something better between your bites.

In my book ‘Shut Your Mouth and Open Wide’, I cover the challenges of mercury, fluoride, root canal treatments, osteoporosis and much more.