The first question most patients have but never ask out loud
You’re told you have a cavity. The dentist talks about treatment. And somewhere in that conversation, a question forms in your head: Does the material actually matter?
It does. More than most people realize.
The two most common filling materials used today are composite resin (tooth-coloured) and dental amalgam (silver). Both fix cavities. Both have been used for decades. But they are made from completely different materials, behave differently inside your tooth, and each comes with its own trade-offs worth knowing before you make a decision.
Here’s what you actually need to know.
What silver fillings are made of
Silver fillings are not pure silver. Dental amalgam is a mixture of metals, including silver, tin, copper, and mercury. Mercury makes up roughly 50% of the compound. It’s the ingredient that binds everything together and gives the material its workability when first placed.
Amalgam has been used in dentistry for over 150 years. That track record is genuinely impressive. It’s hard, durable, and tolerates heavy chewing force well. Back molars that take on most of your bite strength have been reliably restored with amalgam for generations.
The controversy around amalgam comes down to the mercury content. Health Canada reviewed the evidence in 2020 and concluded there is no clear link between mercury in dental amalgam and negative health effects for most people. However, Health Canada has recommended minimizing amalgam use in children, pregnant women, and patients with kidney disease since 1996. The United Nations Minamata Convention on Mercury, which Canada has signed, is driving a global phase-down, with 43 countries, including the entire European Union, having already moved to ban or phase out amalgam use. The UN agreed to end amalgam use globally by 2034.
Whether or not the mercury in an existing filling poses a personal health risk, the direction of dentistry is clearly moving away from it.
What tooth-coloured fillings are made of
Composite resin fillings are made from a blend of plastic resin and finely ground glass particles. They are mixed to closely match the natural shade of your tooth, placed in layers, and hardened with a curing light. The result looks like part of the tooth because it is designed to.
Modern composite materials are significantly stronger than early versions. Formulations have improved to handle the stress and wear of back teeth that older composites struggled with. At Discover Dental, we use advanced composite materials and CEREC technology, which means restorations can be designed and placed with precision in a single visit.
Safety: what the evidence actually says
This is where things get nuanced, so it’s worth being direct.
On amalgam safety: Health Canada’s official position is that dental amalgam is safe for most adults. The Canadian Dental Association agrees. There is currently no confirmed causal link between amalgam fillings and diseases like Alzheimer’s, multiple sclerosis, or autism, despite ongoing public concern. That said, amalgam continuously releases small amounts of mercury vapour, especially during chewing and grinding. Health Canada advises against its use in higher-risk groups.
On composite safety: Composite resins have their own considerations. Some contain derivatives of bisphenol A (BPA). The World Health Organization concluded in 2010 that dental materials are unlikely to be a meaningful source of BPA exposure, comparing the risk to levels found in everyday food packaging. Modern composite formulations have also moved toward reducing or eliminating BPA-containing compounds.
The honest answer is that both materials are considered clinically safe for the general population. Your dentist in Kelowna will discuss your specific health history and any individual factors that might make one material more appropriate for you.
Strength and durability: side by side
Here is where the two materials genuinely differ.
Longevity Amalgam fillings typically last 10 to 15 years, sometimes longer. Composite fillings generally last 7 to 10 years before replacement may be needed. That gap is real and worth knowing, particularly for large restorations in back teeth under heavy chewing force.
Structural behaviour Amalgam expands and contracts slightly with temperature changes from hot and cold food and drinks. Over time, this can stress the surrounding tooth structure and contribute to hairline cracks. Composite does not behave this way. It bonds directly to the tooth surface, which helps stabilize the remaining tooth and reduces the risk of fracture.
How much tooth needs to be removed? Amalgam requires a specific cavity shape to hold the material mechanically. This means removing more healthy tooth structure than necessary for the filling to stay in place. Composite bonds chemically to the tooth, so the cavity preparation can be smaller and more conservative. Preserving more natural tooth structure is one of the key principles of modern dentistry, and composite makes that easier.
Appearance
Silver fillings are visible. That’s not an opinion, it’s just a fact. A dark metallic filling on a back molar may not bother everyone, but many patients notice it, especially as the filling ages and darkens further against their natural tooth colour.
Composite fillings are matched to your tooth shade before placement. Done well, they are essentially undetectable. For front teeth and teeth visible when you smile, composite is the clear choice. For back teeth, many patients still prefer composite for the same reason.
Which is right for you?
There’s no universal answer, but here’s a practical way to think about it.
Tooth-coloured composite fillings tend to suit:
- Front teeth and visible smile areas
- Patients who prefer to avoid mercury-containing materials
- Smaller to medium-sized cavities where tooth preservation matters
- Patients who have existing cracks or weakened tooth walls that need bonding support
Silver amalgam fillings may still be considered for:
- Very large cavities in back teeth, where longevity under extreme chewing force is the top priority
- Situations where moisture control makes composite placement difficult
- Cost-sensitive situations, as amalgam is generally less expensive
At Discover Dental, we primarily work with tooth-coloured composite materials. Our team will discuss the full picture during your appointment and make a recommendation based on the specific tooth, your bite, and your preferences. No material is pushed on any patient. Informed consent and honest information are part of every visit.
Book your filling appointment in Kelowna
If you have a cavity that needs attention, or old silver fillings that are worn, cracked, or bothering you cosmetically, we’re here to help.
Discover Dental serves patients across Kelowna and the Okanagan, including Lower Mission, Rutland, West Kelowna, Lake Country, Peachland, Summerland, and surrounding areas. Led by Dr. Jeremie Hallet, DMD, our team has been providing full-service family dental care since 2004.
We are always welcoming new patients.
Call us at (778) 477-5554.
Discover Dental 3975 Lakeshore Rd, Suite 301, Kelowna, BC V1W 1V3 Monday to Friday: 8:00 AM to 5:00 PM
