Composite (White) Fillings: When Are They Used and How Long Do They Last?
What a composite filling is, when it is used, how it differs from amalgam, what affects how long it lasts, sensitivity afterwards and when another restoration is needed.
What Is a Composite (White) Filling?
A composite filling is a restoration in which a tooth-coloured, resin-based material is bonded to the tooth with an adhesive system, placed in layers and hardened with a special light. It is commonly known as a white filling. Because shades can be chosen, a tooth-coloured appearance can be achieved.
When is it used?
- For loss of tooth structure caused by decay
- For small fractures and chipped edges
- For wear at the neck of the tooth
- To replace old fillings with leaking margins or decay underneath
How it differs from an amalgam filling
An amalgam filling relies on mechanical retention in the cavity, so some sound tissue may also be removed while shaping the cavity. Because composite is bonded to the tooth, in most cases it can be placed with less removal of sound tissue. Replacing an amalgam filling that is not leaking and has no decay underneath simply because it is old is not advised; each replacement means some loss of tissue.
How is a filling placed?
Local anaesthesia is given if needed, the decayed tissue is removed and the area is isolated from saliva; this step matters because composite is affected by moisture. After the adhesive system is applied, the material is placed in layers and hardened with light. The filling is then shaped, the bite is checked and it is polished. Most fillings are completed in a single visit.
How long does it last?
No single lifespan can be given for a composite filling. Its size, the position of the tooth in the mouth, chewing forces, clenching habits, oral hygiene and diet all affect it; large fillings generally last less long than small ones. Regular check-ups allow problems with the margins to be noticed early.
Sensitivity after a filling
Temporary sensitivity to cold or biting may occur in the first days and usually eases by itself. A filling that feels high when biting, or pain that starts on its own or keeps increasing, needs to be assessed; a high contact can be corrected with a simple adjustment.
When is another restoration needed instead of a filling?
When the loss of structure reaches the cusps of the tooth or involves most of the tooth, a direct filling may not be sufficient against chewing forces. In that case options such as a laboratory-made inlay or onlay or a crown are considered. Details of the decision process are explained in the filling or crown article.
Habits that help protect a filling
- Brushing twice a day with a fluoride toothpaste and cleaning between the teeth
- Limiting how often sugary and acidic foods are consumed
- Wearing a night guard, after a dentist's assessment, if you clench your teeth
- Check-ups at the intervals your dentist recommends
This article is for general information purposes and does not replace a clinical examination. The right type of restoration for your tooth is determined after clinical examination and, where necessary, radiological assessment.
Frequently Asked Questions
How many visits does a composite filling take?
Most composite fillings are completed in a single visit. The length of the visit depends on the size of the filling, the position of the tooth and the depth of the decay. If the decay is close to the nerve or the loss of structure is very large, a different approach or further assessment may be needed.
When can I eat after a filling?
Because a composite filling is hardened with light, there is no need to wait for it to set before eating. However, if anaesthesia was given, it is advised not to eat until the numbness wears off; unknowingly biting a numb lip or cheek is common.
Do white fillings change colour?
Over time, composite material can be affected by staining agents such as tea, coffee and smoking; surface staining and darkening at the margins may appear. Surface stains can often be reduced by polishing at check-ups. Marked darkening at the margin is assessed for leakage.
Should old amalgam fillings be replaced with white fillings?
Replacing an amalgam filling that is not leaking, whose margins are intact and beneath which there is no decay simply because it is old is not advised; each replacement means some loss of sound tissue. Where there is leakage, a fracture or decay beneath the filling, replacement is considered.