Composite fillings—often referred to as white fillings—have become the preferred choice for restoring decayed or damaged teeth. Designed to blend seamlessly with natural tooth colour, they offer both functional strength and aesthetic appeal. However, like all dental restorations, composite fillings are not permanent. Over time, wear, stress, and oral conditions can affect their integrity.
When to Replace Composite Fillings: Symptoms & Dental Guide
Understanding when a composite filling needs to be replaced is essential to prevent further tooth damage, discomfort, or infection.
This guide explains the key warning signs, compares composite fillings with alternatives such as amalgam, and outlines what patients should expect during replacement.
What Is a Composite Filling?
A composite filling is a tooth-coloured restorative material made from a mixture of resin and fine glass particles. It is commonly used to repair cavities, minor fractures, or worn enamel and is suitable for both front and back teeth.
Modern dentistry also uses bulk fill composite, an advanced type of composite material that allows deeper layers to be placed in a single increment, reducing chair time while maintaining strength and durability.
Composite Filling vs Amalgam
- Composite (white filling): Tooth-coloured, bonds to enamel, conservative preparation
- Amalgam: Silver-coloured, highly durable, but more visible and requires removal of more tooth structure
While amalgam fillings can last longer in some cases, composite fillings are now widely preferred due to improved materials and aesthetics.
How Long Do Composite Fillings Last?
On average, composite fillings last 5 to 10 years, depending on:
- Bite force and chewing habits
- Location of the filling
- Oral hygiene practices
- Quality of the original placement
- Use of bulk fill composite versus traditional layering
Regular dental check-ups are crucial to monitor the condition of fillings before problems arise.
Common Signs Your Composite Filling Needs Replacement
1. Visible Cracks or Chipping
Composite material can fracture over time, especially in molars that endure heavy chewing forces. Small cracks may not be painful initially but can allow bacteria to seep underneath the filling.
Why it matters: Cracks compromise the seal between the filling and the tooth, increasing the risk of decay beneath the restoration.
2. Tooth Sensitivity
Sensitivity to hot, cold, or sweet foods may indicate:
- Marginal gaps between the filling and tooth
- Wear of the composite material
- Exposure of underlying dentine
Persistent sensitivity should never be ignored, as it may signal that the filling is no longer functioning properly.
3. Discolouration Around the Filling
Although composite fillings resist staining better than older materials, they can still discolour over time. Dark edges or yellowing around a white filling may suggest leakage or ageing material.
This is particularly noticeable in visible teeth, where aesthetics are important.
4. Pain When Biting or Chewing
Pain during chewing may occur if:
- The filling has shifted
- There is a crack in the filling or tooth
- The bite is no longer properly balanced
Such discomfort often indicates structural issues that require prompt assessment.
5. Rough or Uneven Surface
A composite filling should feel smooth and natural. If you notice roughness with your tongue, it may be due to surface wear or partial breakdown of the material.
Rough surfaces also attract plaque more easily, increasing the risk of secondary decay.
6. Recurring Decay Around the Filling
Composite fillings do not decay, but the surrounding tooth structure can. If bacteria enter through microscopic gaps, decay may develop underneath the filling without obvious symptoms.
This is one of the most common reasons fillings need replacement.
7. Filling Falling Out or Feeling Loose
A filling that feels loose—or has fallen out completely—requires immediate dental attention. Leaving the tooth unprotected can lead to rapid decay or sensitivity.
Composite vs Bulk Fill Composite: Does It Affect Longevity?
Bulk fill composite materials are designed to:
- Cure more deeply
- Reduce internal stress
- Improve durability in posterior teeth
When placed correctly, bulk fill composites can offer comparable longevity to traditional composite fillings, particularly for larger cavities.
However, even advanced materials still require monitoring over time.
How Dentists Assess Whether a Filling Needs Replacement
Dentists rely on several methods:
- Visual examination
- Dental X-rays
- Bite assessment
- Sensitivity testing
Not all worn fillings require immediate replacement—some may only need polishing or minor adjustment. A professional evaluation ensures the most conservative and appropriate treatment.
What Happens During a Composite Filling Replacement?
The procedure typically involves:
- Removing the old composite or amalgam material
- Cleaning the underlying tooth structure
- Assessing for decay or cracks
- Placing new composite or bulk fill composite
- Shaping and polishing for a natural bite
The process is usually completed in one visit and is performed under local anaesthesia for comfort.
Can Old Amalgam Fillings Be Replaced with Composite?
Yes. Many patients choose to replace amalgam fillings with composite for aesthetic or functional reasons. This decision should be made after discussing:
- Tooth strength
- Bite forces
- Cavity size
- Long-term durability
Replacement should only be done when clinically appropriate, not purely for cosmetic reasons.
How to Extend the Life of Your Composite Fillings
Patients can help prolong filling lifespan by:
- Maintaining good oral hygiene
- Avoiding excessive teeth grinding (use a night guard if needed)
- Limiting hard or sticky foods
- Attending regular dental check-ups
- Addressing sensitivity or discomfort early
When to See a Dentist
You should schedule a dental visit if you experience:
- Persistent pain or sensitivity
- Visible damage to a white filling
- Changes in bite or chewing comfort
- Discolouration around a filling
Early intervention often prevents more extensive and costly treatments.
Final Thoughts
Composite fillings are a reliable, aesthetic solution for restoring teeth, but they are not permanent. Recognising the early signs of wear or failure allows timely replacement, preserving tooth structure and preventing complications.
A professional dental assessment ensures your fillings continue to protect your teeth effectively—supporting long-term oral health and comfort.
If you suspect your filling may need attention, schedule a consultation with our dental team today.
