Dental fillings are among the most frequently provided treatments in general dentistry, yet many patients are unsure how long they should expect their fillings to last or how to know when one needs replacing. Whether you had a filling placed years ago or have recently had decay treated for the first time, understanding the lifespan of different filling materials and the signs of wear helps you stay on top of your dental health and avoid more complex problems down the line.
This guide covers everything you need to know about the longevity of dental fillings, the factors that influence how long they last, and when you should speak to your dentist about a replacement.
Types of Dental Fillings and Their Expected Lifespan
Not all fillings are made from the same material, and the type used has a significant bearing on how long it is likely to last. The most common options available in the UK are:
Amalgam Fillings
Amalgam, the silver-coloured material that was the standard filling material for many decades, is extremely durable. When properly placed, amalgam fillings can last anywhere from 10 to 15 years, and many remain functional for 20 years or more. They are particularly resilient in high-pressure areas such as the back molars.
However, amalgam fillings are now less commonly used in NHS dentistry in Scotland. From 2024, routine use of dental amalgam has been phased out across the UK in line with European environmental regulations, due to mercury content. Existing amalgam fillings are safe and do not need to be proactively removed.
Composite (Tooth-Coloured) Fillings
Composite resin fillings blend with the natural colour of the tooth and have become the most widely used filling material. They bond directly to the tooth structure, which can make them more conservative in terms of how much healthy tooth is removed. However, they are generally less durable than amalgam and typically last between 5 and 10 years, sometimes longer with excellent oral hygiene and careful aftercare.
Glass Ionomer Fillings
Glass ionomer fillings release fluoride, making them a useful choice for patients prone to decay or for fillings in areas that do not bear heavy chewing load. They tend to be less durable than both amalgam and composite, lasting around 5 years on average. They are commonly used for baby teeth or as a temporary measure.
Gold and Ceramic Inlays and Onlays
Gold and ceramic restorations are indirect fillings — meaning they are made in a laboratory and cemented into place rather than shaped in the mouth. They are exceptionally durable and can last 15 to 30 years or more. They are typically more expensive but offer superior longevity for larger restorations on back teeth.
Filling Lifespan Comparison
| Filling Type | Average Lifespan | Appearance | NHS Available? |
|---|---|---|---|
| Amalgam (silver) | 10–20+ years | Silver/grey | Limited (phased out) |
| Composite (tooth-coloured) | 5–10 years | Natural tooth colour | Yes |
| Glass ionomer | 3–5 years | Off-white/translucent | Yes |
| Gold inlay/onlay | 15–30+ years | Gold-coloured | No (private) |
| Ceramic inlay/onlay | 15–25 years | Natural tooth colour | No (private) |
Factors That Affect How Long a Filling Lasts
The figures above are averages — in practice, the lifespan of a filling depends on a number of individual factors:
- Location in the mouth: Fillings on back teeth that take the most force during chewing wear down more quickly than those on front teeth.
- Size of the filling: Larger fillings that cover a greater proportion of the tooth surface are under more stress and may not last as long as smaller ones.
- Oral hygiene: Good brushing and flossing habits help protect the edges of fillings where new decay can begin, known as secondary or recurrent decay.
- Diet: Frequent consumption of sugary or acidic foods and drinks accelerates decay around filling margins.
- Teeth grinding (bruxism): Grinding places significant force on fillings and can cause them to crack or wear down prematurely. A night guard can help protect your fillings if you grind your teeth.
- Quality of placement: A well-placed filling, properly shaped and finished, will outlast one that is poorly contoured or has gaps at the margins.
Signs That a Filling May Need Replacing
Fillings do not always announce their failure with obvious symptoms, which is why regular check-ups are so important. However, there are signs to look out for between appointments:
- Pain or sensitivity: New or increased sensitivity to hot, cold, or sweet foods near a filled tooth may indicate the filling has cracked, worn down, or that decay has developed underneath.
- Visible damage: If you can see or feel a crack, chip, or rough edge on a filling, it should be assessed by your dentist.
- A dark spot or discolouration: Staining or darkening around the edges of a filling can be a sign of marginal decay.
- Food getting stuck: If food consistently traps in a particular area near a filling, the margin may have broken down.
- A piece of filling has fallen out: Even if the tooth is not immediately painful, a missing filling needs prompt attention as the exposed dentine can become sensitive and vulnerable to decay.
What Happens When a Filling Is Replaced?
Replacing a filling is generally straightforward. Your dentist will remove the old filling material, check for any underlying decay, clean and prepare the tooth, and place a new filling. In some cases — particularly where a filling has failed repeatedly or where the cavity has grown — the tooth may need a larger restoration such as a crown rather than another direct filling.
The NHS Inform page on dental fillings provides a useful summary of what to expect from filling treatment in Scotland.
Should You Replace Old Amalgam Fillings?
This is a question many patients ask, especially following coverage of the amalgam phase-out. The answer, generally, is no — not unless a filling is failing, causing problems, or needs replacing for clinical reasons. Removing amalgam fillings that are intact can expose you to a brief spike in mercury vapour during removal and is not recommended as a routine measure. If your amalgam fillings are sound and your dentist has no clinical concerns, they can be left in place until they need attention.
Composite Fillings on Back Teeth: What You Need to Know
Since the phase-out of amalgam for routine use, composite has become the standard filling material for most patients in Scotland. On back teeth — which bear the greatest biting force — composite requires a little more care in day-to-day life to ensure a good lifespan. Patients with composite fillings in their molars should:
- Avoid biting very hard foods such as ice, hard sweets, or crusty bread directly on the filled tooth where possible
- Wear a night guard if they grind their teeth, as grinding is particularly damaging to composite restorations
- Attend regular check-ups so that any early wear or marginal breakdown can be addressed before a full replacement is needed
In some cases where a very large cavity needs to be filled in a back tooth, a dentist may recommend a ceramic or gold inlay rather than a direct composite filling, as these indirect restorations offer superior strength and longevity for larger restorations.
What Happens If a Filling Falls Out?
If a filling falls out, do not panic — the tooth is unlikely to be in immediate danger, but it should be seen promptly. An exposed cavity is vulnerable to bacteria, temperature sensitivity, and further decay. In the meantime, pharmacies stock temporary filling materials that can be used to cover the cavity until you are able to attend the practice. Avoid chewing on the affected side and keep the area clean. Do not attempt to re-cement the old filling — it is better for your dentist to assess the cavity fresh and place a new, properly sealed restoration.
How Often Should You Have Your Fillings Checked?
Attending regular dental check-ups — typically every six months to a year depending on your individual risk level — allows your dentist to monitor existing fillings and catch any signs of failure early. X-rays taken periodically can reveal decay beneath or around fillings that would not be visible to the naked eye.
At Tarbert Dental Surgery, we check the condition of all existing restorations as part of every routine examination. If we have any concerns about a filling, we will discuss the options with you clearly and recommend the most conservative treatment available. To book a check-up or to ask about a filling that may need attention, call us on 01880 820387 — we are always happy to help patients across Tarbert and Kintyre with straightforward, honest dental advice.