Fillings & Restoration

What is a dental filling?

A filling restores a tooth that has lost structure to decay, wear or a fracture. The damaged tissue is removed and the space is rebuilt with a material that bonds to the remaining tooth and takes over its function. Modern fillings are tooth-coloured composite resin, matched to the shade of your enamel so the repair is invisible.

Fillings sit at the conservative end of restorative dentistry. The aim is to intervene early, while the cavity is small, and to preserve as much natural tooth as possible. A well-placed filling now is what prevents the need for root canal treatment or a crown later.

Signs you may need a filling

Early decay is silent. By the time a tooth hurts the cavity has usually reached the dentine or is approaching the pulp. Look out for:

• Sensitivity to sweet, hot or cold that passes quickly
• A visible dark spot, hole or chalky white patch on a tooth
• Food catching between two particular teeth
• A rough edge you can feel with your tongue
• An old filling that has chipped, cracked or discoloured at the margin
• Mild discomfort when biting on one side

How decay is detected

Many cavities form between the teeth where they cannot be seen. Bitewing X-rays, transillumination and careful probing pick up decay before it becomes visible. Your dentist confirms after examination which lesions need filling and which early enamel lesions can be halted with fluoride and improved cleaning.

The filling procedure step by step

A composite filling is usually completed in one appointment of thirty to sixty minutes, depending on the size and position of the cavity.

• Local anaesthetic where the cavity is deep enough to be sensitive; very small fillings may need none
• Rubber dam isolation to keep the tooth dry, which is essential for a reliable bond
• Decayed tissue is removed with fine burs, checking with a caries-detecting dye that only softened dentine is taken
• The cavity is etched and a bonding agent is applied to the enamel and dentine
• Composite is placed in thin layers and each layer is light-cured to reduce shrinkage stress
• The filling is shaped to reproduce the anatomy of the tooth, then the bite is checked and adjusted
• Final polishing so the surface resists staining and feels smooth to the tongue

Composite, inlay, onlay or crown: comparing the options

The right restoration follows how much sound tooth remains after the decay is removed, not the size of the original cavity alone.

• Direct composite: placed in the mouth in one visit, ideal for small to medium cavities and repairs to front teeth
• Ceramic inlay: a laboratory-made piece bonded into a larger cavity that does not involve the cusps; stronger and more wear-resistant than composite
• Ceramic onlay: covers one or more cusps, protecting a weakened tooth without cutting it down for a full crown
• Crown: a full-coverage E-max or zirconia restoration when the walls are thin or the tooth has been root-treated

Replacing old amalgam fillings

Silver amalgam fillings that are intact and sealed do not need to be replaced for cosmetic reasons alone. When they crack, leak or the tooth around them fractures, they are replaced with composite or ceramic. Large amalgams often conceal more decay than expected, and the final restoration is decided once the cavity is clean.

Aftercare and how long fillings last

Composite is fully set when you leave the chair, so you can eat as soon as the anaesthetic wears off. Slight sensitivity to cold for a week or two is common in deeper fillings and settles as the pulp calms. If the filling feels high when you bite, a short adjustment appointment resolves it; a high filling should not be left to wear in.

A well-placed composite typically lasts seven to ten years, and ceramic restorations longer, though the range is wide. Daily interdental cleaning, limiting sugar frequency and a night guard if you grind are what extend the lifespan. Fillings are checked at each review and replaced when a margin begins to leak. See the aftercare guide for practical detail.

What happens if a cavity is not filled

Decay does not stop or reverse once it has broken through enamel into dentine. The cavity enlarges, the tooth weakens and eventually either the pulp becomes infected, requiring root canal treatment, or a cusp fractures under load. A cavity that could have been restored with a small filling ends up needing an onlay, a crown or, in the worst case, extraction and a single implant.

The cost and complexity increase at every stage, which is why routine examinations every six to twelve months are recommended even when nothing hurts.

Risks and limitations

Fillings are low-risk procedures. Post-operative sensitivity, a high bite that needs adjusting and, occasionally, a deep filling that later requires root canal treatment because the pulp was already compromised are the main issues. Composite can pick up stain over years, particularly in heavy tea, coffee or red wine drinkers, and can be polished or replaced.

Very large composite fillings in back teeth are more likely to fail than a ceramic onlay, which is why your dentist may recommend the laboratory-made option for extensively broken-down teeth. These decisions are made with you once the cavity has been cleaned and the remaining tooth can be assessed, as part of the wider general dentistry plan.