What a filling does
Decay destroys tooth structure, and enamel does not grow back. A filling removes the decayed material and replaces the missing volume with a material that seals the cavity and restores the shape and function of the tooth.
Sealing matters as much as filling. An unsealed cavity keeps collecting bacteria and continues to spread inward toward the nerve. It is tempting to put off a cavity that is not causing trouble, but left alone it can become painful, contribute to bad breath and eventually need root canal treatment or a crown rather than a filling.
Most cavities are found before they hurt — on X-rays and at routine exams — which is the point of finding them early. A small filling is quicker, cheaper and removes less tooth than anything that comes after it.
Composite and the alternatives
Composite resin is tooth-colored, bonds to the tooth, and allows a more conservative preparation because it does not rely on a mechanical undercut to stay in. It is placed in layers and hardened with a curing light, then shaped and polished to match the tooth.
Amalgam — the silver material — is durable and long-established but is not tooth-colored. Inlays and onlays, made in a lab and bonded in, sit between a filling and a crown for larger cavities, where a filling alone would leave the tooth weak but most of it is still sound.
What to expect
- Numbing. The area is usually numbed with a local anesthetic. Very small, shallow fillings sometimes do not need it.
- Removing the decay. The decayed material is removed and the cavity is cleaned and shaped.
- Placing the filling. The material is placed — in layers, each hardened with a light, for composite.
- Checking the bite. The filling is shaped, the bite is checked and adjusted so it does not sit high, and the surface is polished.
Some sensitivity to cold or pressure for a few days afterward is normal, particularly on deeper fillings. The numbness usually wears off within a few hours.
A filling repairs a cavity; it does not change whatever caused it. Brushing twice a day with a fluoride toothpaste, cleaning between the teeth daily, and cutting down how often — not only how much — you have sugary food and drinks makes the biggest difference.
For people prone to decay, fluoride treatment strengthens enamel, and sealants protect the grooves of back teeth where decay most often starts. Regular check-ups catch the next small cavity before it becomes a large one.
Frequently Asked Questions
How do I know if I need a filling?
Often you do not — small cavities have no symptoms, which is why they are found on X-rays and at examinations. Sensitivity to sweet or cold, a rough edge or a dark spot can be signs. Pain usually means the decay is already deep.
How long will a filling last?
It varies widely. The size and position of the filling, the forces of your bite and how well the area is kept clean all matter more than the material alone. The usual reason a filling fails is new decay at its edge.
Can I eat afterward?
Composite is fully set when you leave. The main caution is not chewing while you are still numb, because it is easy to bite your cheek or tongue without feeling it.
Is it normal for the tooth to be sensitive afterward?
Some sensitivity to cold or pressure for a few days, sometimes a couple of weeks, is common — particularly after a deep filling. If biting feels uneven, or sensitivity is getting worse rather than better, call so the bite can be checked.
Should I replace my old silver fillings?
Not automatically. An intact amalgam filling with no decay around it does not generally need replacing just because of the material. Replacement makes sense when a filling is cracked, leaking, has decay beneath it, or when you want a tooth-colored result.
Can a cavity heal on its own?
Very early enamel changes, before a true cavity forms, can sometimes be reversed with fluoride and better cleaning. Once decay has broken through into a cavity, it does not repair itself and needs treatment.
