Dental fillings don’t last forever. Over time, they can weaken, crack, or develop decay around their edges. In many Glen Iris patients, worn fillings also cause sensitivity or soreness in the tooth underneath. When this happens, it usually means a small gap has formed between the filling and the natural tooth. This tiny space can trap bacteria, eventually allowing decay to reach the pulp and potentially cause an abscess.

Below are the most common reasons we replace old fillings here at Tooronga Family Dentistry in Glen Iris:

Why Fillings Need to Be Replaced

1. Decay around the filling

When bacteria collect around an ageing filling, new decay can develop. If not treated, this can spread deeper and require root canal treatment.

2. Cracks or structural damage

Old fillings—particularly large metal amalgam ones—can contribute to cracks forming in the tooth. These cracks can cause pain, sensitivity, and may eventually lead to a fracture.

3. Cosmetic concerns

Amalgam fillings can give teeth a dark, shadowed appearance. This happens because metal ions gradually migrate into the tooth structure.

4. Personal preference

Some patients wish to replace older metal fillings due to concerns about mercury content or simply to upgrade to natural-looking white fillings.

5. When a filling falls out

If a filling has loosened or fallen out, it must be replaced promptly to prevent infection or further damage.

Amalgam Fillings –

For decades, amalgam (silver) fillings were the standard treatment for cavities. These fillings were made from a mixture of silver, tin, copper and liquid mercury, forming a strong and long-lasting metal alloy. They were widely used because they were durable, cost-effective, and easy to place.

However, over time dentists discovered several drawbacks:

Temperature Expansion and Contraction

Amalgam fillings expand in heat and contract in cold. This constant movement can place stress on the surrounding tooth structure.

Corrosion Over Time

Amalgam fillings can oxidise or “rust.” This corrosion weakens the bond between the filling and the tooth.

Cracking of Tooth Structure

Because amalgam doesn’t bond to the tooth, it can act like a wedge. As it expands and contracts, it can cause the surrounding tooth walls to crack.
Many Glen Iris patients come to us because a large old metal filling has caused a significant fracture.

Appearance

Amalgam fillings darken the tooth, and many patients now prefer tooth-coloured options.

For these reasons, a large number of people around Glen Iris are choosing to have their old metal fillings replaced with safer, stronger and more natural-looking alternatives.

Modern Alternatives to Amalgam Fillings

Thanks to major advancements in dental materials, we now offer several excellent alternatives at Tooronga Family Dentistry, including:

Composite Resin (White Fillings)

A natural-looking option that bonds directly to the tooth, strengthening the remaining structure.

Porcelain

Highly aesthetic, stain-resistant and ideal for larger restorations such as inlays, onlays, or crowns.

Zirconia

Extremely strong and durable—an excellent choice for back teeth or patients who grind.

Gold

Still considered one of the most durable materials available, though used less commonly today.

Dr. Daniel Kaufman will explain the benefits of each material and help you choose the best option for your tooth, your smile and your long-term oral health.

If You Need a Filling Replaced in Glen Iris

If you have an old filling that looks dark, feels sensitive, or may be cracked, it’s best to have it assessed promptly. You can book online or 👉Call

📍 Serving Glen Iris, Tooronga, Malvern & Hawthorn East

Why Old Fillings Need to Be Replaced – Glen Iris Dental Guide