Tooth-coloured vs silver fillings

Reviewed by Dr. Samar Fadavi, DDS

Short answer: Tooth-coloured fillings (composite resin) match your natural tooth, bond to it and usually need less healthy tooth removed. Silver fillings (amalgam) are very durable and tolerate moisture well, but they are visible and contain mercury bound in an alloy. Most fillings placed in Canada today are tooth-coloured. Your dentist recommends a material based on the size and location of the cavity and your health.

Why the choice matters

A filling repairs a tooth that has been damaged by decay or a small fracture. The material your dentist uses affects how the tooth looks, how much of the natural tooth is kept, how the filling handles chewing forces and how it holds up over the years. Many adults in Scarborough and East Toronto have a mix of older silver fillings and newer white ones, and it is common to wonder whether the old ones should be replaced.

This guide compares the two most common filling materials, explains other options for larger repairs and answers common questions about safety and replacement. It is general information. For how check-ups and fillings work at our clinic, see our family dentistry and check-ups page.

What tooth-coloured fillings are

Tooth-coloured fillings are usually made of composite resin, a mix of plastic resin and fine glass or ceramic particles. The dentist chooses a shade that matches your tooth, places the material in layers and hardens each layer with a blue curing light. The filling is then shaped and polished.

Composite bonds to the tooth using an adhesive. Because it sticks to the tooth, the dentist can often remove only the decayed part and keep more healthy tooth structure. The bond also helps support the remaining tooth.

Strengths of tooth-coloured fillings:

• They match the colour of your tooth, so they are hard to see.
• They bond to the tooth, often allowing a smaller, more conservative preparation.
• They contain no mercury.
• They can repair small chips and worn edges as well as cavities.
• They can usually be repaired or added to later.

Limits of tooth-coloured fillings:

• They are sensitive to moisture during placement; the tooth must be kept dry, which takes more time.
• Very large composite fillings on back teeth under heavy biting forces may wear or chip sooner than amalgam.
• Some people notice short-term sensitivity to cold or biting after placement.
• They can pick up stains over time, especially with coffee, tea or smoking, though polishing helps.

What silver fillings are

Silver fillings are made of dental amalgam, a mix of mercury with a powdered alloy of silver, tin and copper. When mixed, the mercury binds with the other metals to form a stable, hard material. Amalgam has been used for well over a century.

Strengths of silver fillings:

• They are strong and handle heavy chewing forces on back teeth well.
• They tolerate a bit of moisture during placement, which can help in hard-to-reach areas or with patients who have difficulty keeping still.
• They are quick to place.
• They often last many years.

Limits of silver fillings:

• They are visible and can darken the surrounding tooth over time.
• They do not bond to the tooth, so the dentist must shape the cavity to hold the filling mechanically, which can mean removing more healthy tooth.
• Metal expands and contracts with temperature, and older large amalgams can be linked with cracks in the surrounding tooth. Our guide on cracked teeth explains the signs.
• They contain mercury, which raises environmental and personal concerns for some people.

Side by side

• Appearance: composite matches the tooth; amalgam is silver and visible.
• Tooth structure kept: composite often allows a smaller preparation; amalgam needs a shape that holds it in place.
• Strength on large back-tooth fillings: amalgam is very durable; modern composite performs well but very large composites may wear sooner.
• Placement: composite needs a dry field and more time; amalgam is faster and more forgiving of moisture.
• Repairs: composite can often be patched; amalgam is usually replaced.
• Mercury: composite has none; amalgam contains mercury bound in an alloy.

Is amalgam safe?

Health Canada considers amalgam fillings safe for most people, while also advising dentists to consider non-mercury materials for certain groups: children’s baby teeth, people who are pregnant, people with kidney problems and people with an allergy to mercury. Canada, like many countries, is also working to reduce mercury use over time for environmental reasons, and most fillings placed in Canadian offices today are tooth-coloured.

Amalgam releases very small amounts of mercury vapour, mostly during placement and removal and with heavy grinding. For people without the conditions listed above, health authorities do not recommend removing intact amalgam fillings just because they contain mercury. Drilling out a sound filling removes more tooth and releases more vapour than leaving it in place.

Should old silver fillings be replaced?

An old filling is usually replaced when there is a reason, such as:

• New decay at the edges of the filling.
• A crack in the filling or the tooth.
• A broken or missing piece of filling.
• Gaps between the filling and the tooth that trap food.
• A cosmetic concern on a visible tooth that you would like to change.
• A medical reason discussed with your doctor and dentist.

If your amalgam fillings are intact and the teeth around them are healthy, your dentist will often suggest leaving them alone and checking them at each visit. If you would like them replaced for appearance, talk with your dentist about the options and what is involved.

Other filling and repair options

Not every repair is a simple filling. Depending on how much tooth is left, your dentist may suggest:

• Glass ionomer fillings: tooth-coloured and release fluoride. They are often used near the gum line, on root surfaces in older adults and in children’s teeth. They are less wear-resistant than composite.
• Inlays and onlays: made in a lab or by a dental milling unit from porcelain or other materials, then bonded into the tooth. They are used when a cavity is too large for a filling but a full crown is not needed.
• Crowns: cover the whole tooth and are used when the tooth is badly broken down, cracked or has had a root canal. See our crowns and bridges page.
• Temporary fillings: placed to calm a tooth or protect it until the permanent repair.

What happens when you get a tooth-coloured filling, step by step

1. Diagnosis. Your dentist finds the cavity at an exam, often with the help of x-rays. Our guide on how dentists find cavities early explains this.
2. Freezing. Local anesthetic is usually used, though very small fillings sometimes do not need it.
3. Isolation. The tooth is kept dry with cotton rolls or a rubber dam. Our guide to the rubber dam explains why it helps.
4. Removing decay. The dentist removes the decayed tooth and shapes the area.
5. Bonding. The tooth is prepared with a gel and an adhesive that helps the filling stick.
6. Layering and curing. Composite is placed in layers, each hardened with a curing light.
7. Shaping and polishing. The filling is shaped, your bite is checked with marking paper and the surface is polished.

Aftercare

• Wait until the freezing wears off before eating, to avoid biting your cheek or tongue.
• Composite fillings are fully set when you leave; you can chew normally once the freezing is gone.
• Mild sensitivity to cold or biting for a few days or weeks is common, especially with deeper fillings.
• If your bite feels high or uneven after the freezing wears off, call the clinic. A quick adjustment usually fixes it.
• If sensitivity gets worse instead of better, or you notice lingering pain after hot or cold, book a check.

How long fillings last

Both composite and amalgam fillings can last many years. How long a filling lasts depends less on the material and more on the size of the filling, the position of the tooth, how hard you bite, whether you grind your teeth, your diet and how well you clean around it. A small filling in a well-cleaned tooth can last a very long time; a large filling on a molar in someone who grinds may need attention sooner.

The edges of any filling are where new decay tends to start. Brushing with fluoride toothpaste, cleaning between the teeth and keeping sugary snacks and drinks to mealtimes help fillings last.

What to avoid

• Chewing ice, hard candy or pens, which can chip fillings and teeth.
• Using your teeth to open packages.
• Ignoring a filling that feels rough, catches floss or traps food.
• Grinding at night without protection; ask about a night guard if you grind. See our night guards and TMJ page.
• Asking for sound fillings to be removed without discussing the trade-offs with your dentist.

Fillings for children and older adults

For children, tooth-coloured composite or glass ionomer materials are generally used. Baby teeth are smaller and the enamel is thinner, so the dentist may also suggest sealants and fluoride to prevent new cavities. Our children’s dentistry page explains our approach.

For older adults, decay often appears on root surfaces near the gum line, especially with dry mouth from medicines. Glass ionomer or composite materials are often used there. Regular fluoride and frequent check-ups help prevent new root cavities.

Coverage and planning

Most dental insurance plans include fillings, though some plans cover tooth-coloured fillings on back teeth differently from amalgam. The Canadian Dental Care Plan includes restorative services such as fillings. Our team direct bills most insurers and gives you a written estimate before treatment, so you know how your plan applies. See our CDCP dentist page for how the plan works here.

Fillings and sensitive teeth

Some people notice that a tooth feels sensitive after a new filling, especially to cold air, cold drinks or biting. With composite fillings this usually comes from the tooth reacting to the cleaning and bonding steps, or from a deep cavity that was close to the nerve. It most often fades over a few days to a few weeks. Using a desensitizing toothpaste and avoiding very cold drinks for a while can help.

Sensitivity that lingers for more than a few seconds after a cold or hot drink, wakes you at night or keeps getting worse is different. It can mean the nerve inside the tooth is inflamed. Your dentist will test the tooth and may take an x-ray. Some teeth with deep decay need root canal treatment even after a careful filling. Our guide what happens during a root canal? explains that treatment.

Preventing the next filling

• Use fluoride toothpaste twice a day and spit rather than rinse, so the fluoride stays on the teeth longer.
• Keep sugar to mealtimes. Frequent sipping of sweet drinks, including juice and sweetened coffee, feeds decay all day.
• Clean between your teeth daily. Many cavities start between teeth where a brush does not reach.
• Ask about sealants and fluoride varnish for children and for adults with a high cavity risk.
• Keep regular check-ups so small cavities are found while they are still small.

When to see a dentist

Book a visit if you notice a dark spot or hole in a tooth, sensitivity to sweets or cold, food catching between teeth, a filling that feels broken or rough, or a dull ache when biting. Call the same day if you have a severe toothache, swelling or a filling that has fallen out and left a sharp edge; see our emergency dentist page. For check-ups and fillings, see our family dentistry and check-ups page.

Questions about fillings

Are white fillings as strong as silver ones?

For small and medium fillings, modern composite performs very well. For very large fillings on back teeth under heavy biting, amalgam can be more wear-resistant, and an onlay or crown may be a better option than either.

Can I choose which material I get?

Yes, within what is clinically suitable. Your dentist will explain the options for your tooth and the reasons for any recommendation.

Do tooth-coloured fillings take longer?

Usually a little, because the tooth must be kept dry and the material is placed in layers.

Will a white filling change colour?

Composite can pick up surface stains from coffee, tea, red wine and smoking. Polishing at cleanings helps. It does not whiten with whitening products, so if you plan to whiten, do it before fillings on front teeth.

Is it safe to have amalgam removed during pregnancy?

Removing intact amalgam fillings is generally not recommended during pregnancy, since removal releases more mercury vapour than leaving them. Talk with your dentist and doctor.

Why does my tooth hurt after a new filling?

Mild sensitivity is common and usually settles. A high bite is a frequent cause of pain when chewing and is easy to adjust. Lingering or worsening pain should be checked.

Can a filling fall out?

It can, especially if new decay forms underneath or the tooth cracks. Keep the piece if you can and call the clinic.