Think you have a cavity? Tooth decay and fillings: what it is, and how it is treated

What decay is, and how to spot it

The bacteria in your mouth feed on the sugar and starch you eat, and they give off acid. The acid draws minerals out of the surface of the tooth, and your saliva puts some of them back between meals. When the acid wins time after time, the first thing to show is a dull white spot; if it keeps winning, the surface breaks open and a cavity forms. A cavity does not close up on its own, and it grows if it is left. But caught early, it usually needs only a simple filling.

Who a filling is for

• Decay that has become a cavity, but has not reached the nerve. This is the case a filling is made for. The nerve, or pulp, is the living part inside your tooth: nerves and blood vessels that feed it from within.
• An old filling that has broken, fallen out, or has decay under it. It is replaced, and the examination shows how much of the tooth is left underneath.
• A small chip at the edge of a tooth. If the tooth is still strong, it can often be repaired with the same tooth-coloured material, without trimming the whole tooth.

How you can tell

• Sensitivity to sweet or cold in the same tooth, that comes and goes.
• A brown or black spot on the surface of a tooth or between two teeth. Not every dark spot is decay, and the examination tells the difference.
• Food catching in the same place every time, or floss that catches or shreds at one particular tooth.
• Brief pain that comes with eating or drinking, then goes.

And sometimes there is no sign at all. Decay between the teeth, or under an old filling, cannot be seen by eye, and at the start you often do not feel it. That is where a regular check-up, and a digital x-ray in the clinic if one is needed, catch it early, while it is still small and simpler to treat.

Its stages

The earlier it is caught, the simpler the treatment, and the less of your tooth is removed.

1. A white spot, at the start. The surface of the tooth has not broken yet. At this stage decay can sometimes be stopped with fluoride and a change of habits, with no filling at all. The examination decides whether it is watched or needs something.
2. A cavity in the enamel, or in the layer beneath it. Here the cavity needs a filling: the decayed part is removed, and the space is sealed with a tooth-coloured material. The smaller the cavity, the smaller the filling.
3. Close to the nerve, or into it. If the decay is deep and close to the nerve, sometimes a filling with extra protection for the nerve underneath is enough. When decay reaches the nerve, the tooth usually hurts, and sometimes the pulp dies and an abscess forms. Then a root canal is usually the treatment: if the tooth can still be kept, a root canal removes the source of the infection and leaves your tooth in place on its own root, and the examination and the x-ray decide. The details are in two articles: Extraction or root canal: how it is decided, and Your tooth after a root canal: how it stays with you.
4. Decay large enough to break the tooth. When little of the tooth is left, the filling becomes bigger than the tooth can carry, and the thin walls around it can crack. Then a crown is usually the fix: it holds the whole tooth together and protects it, sometimes after a root canal. More on Dental crowns.

And your children’s teeth? Baby teeth get decay too, it moves faster in them, and many are treated with tooth-coloured fillings; the examination decides. Fluoride and fissure sealants lower the chance of it from the start. The details are on Children's dentistry.

How a filling is done, step by step

A routine filling is usually done in the same visit. Here are the steps as they are, with no minutes attached, because the timing for your case is something you find out at the examination.

1. 1

   The examination, and an x-ray if neededThe doctor examines the tooth, sees how deep the decay goes, and whether there is more that cannot be seen. The x-ray shows what is between the teeth and under old fillings, and how close the decay is to the nerve. You are told what your tooth needs, and why, before anything starts.

2. 2

   Local anaestheticThe area is numbed before we begin: you are told before the injection, not after it. The prick itself is short and you do feel it; then the area goes numb. Once it is numb, you feel pressure and movement, and hear the sound of the work. If you feel pain, you raise your hand and we stop, and more anaesthetic is given if it is needed.

3. 3

   Removing the decayThe decayed part is removed, and the healthy part of your tooth stays. The aim is to keep as much of your tooth as possible, with the filling sealing onto clean edges. If the decay is deep and close to the nerve, a thin softened layer right over the nerve is sometimes left on purpose and sealed under the filling, so that the nerve is not exposed. If it turns out deeper than expected, you are told there and then, before any further step.

4. 4

   Building the filling in tooth colourThe tooth-coloured material is placed in the space layer by layer, and each layer is set hard with a special light. Its shade is chosen close to the colour of your tooth.

5. 5

   Checking your bite, and polishingYou bite and move your jaw, and the doctor adjusts any high spot on the filling until your teeth close normally. Then it is polished, so that it is smooth and food does not catch on it.

6. 6

   AfterwardsThe numbness wears off after a few hours. Until it does, do not eat on the numb side, and do not drink anything hot, so you do not bite your cheek or tongue, or burn yourself, without feeling it. After that you eat normally. Mild sensitivity to cold or when you bite is possible for a few days, and it usually settles on its own; if it does not, or your bite feels high, call.

The downsides and the limits, before the advantages

You are told the limits of a filling before its advantages, so you know exactly what to expect from it:

• Temporary sensitivity afterwards. Sensitivity to cold or when you bite does happen for a few days, especially when the decay was deep, and it usually settles on its own. If it does not, if it gets worse, or if the filling feels high when you bite, call: often a small adjustment sorts it out.
• A filling does not last for ever. With chewing and time it wears, its colour can change, or its edge can break down, and it is replaced when it needs to be. How long it lasts depends on its size, where it sits and how you look after it, and a regular check-up catches wear early.
• Decay can come back at its edge. The filling itself does not decay, but the tooth around it can if it is not kept clean, especially along the line where the filling meets the tooth. The protection is in your hands: a fluoride toothpaste, floss, and regular check-ups.
• A large filling on a weak tooth may not be enough. When little of the tooth is left, a crown protects it better (stage four above), and the examination decides.

And the advantages

• It removes the decay and seals the space, so it stops the decay growing inward from there, as long as its edges stay sealed and clean.
• It takes as little of your tooth as possible. Only the decayed part is removed and the rest stays, and that is the difference between a filling and a crown, which covers the whole tooth after it has been trimmed.
• It is tooth-coloured. Its shade is matched close to your tooth, so it usually blends in when you smile.

When it is not right for now, or should wait

Sometimes a filling is not the first step, or not the only one, and sometimes it is not needed yet. In these cases you are told what has to happen first, or instead:

• Pain that wakes you, or lingers after cold. Pain that comes on its own, lingers after the cold has gone, or wakes you at night usually means the nerve has been affected. A filling alone is not enough then: usually a root canal comes first, if the tooth can still be kept, and the examination and the x-ray decide.
• Swelling or an abscess. The infection is treated before any filling, and then what the tooth needs is decided.
• Not enough of the tooth is left. A filling needs walls to hold on to. If decay has eaten away most of the tooth, a crown is usually needed instead, sometimes after a root canal and building the tooth up from the inside.
• A white spot that has not become a cavity. Here the filling can wait altogether: sometimes the spot stops with fluoride and better habits, and it is watched at the next check-up. Not all decay needs a filling.
• Decay in more than one tooth. They do not all have to be done in one day. You are told the order: the deepest and closest to the nerve first, and the rest at the visits after.
• Pregnancy. Mention it on the first call. Treatment for decay is usually not put off until after the birth, because decay grows, and the doctor plans the timing and any x-ray around your case and how far along you are, in coordination with your obstetrician if needed.

What to do from now until your appointment

1. 1

   Book the examinationIt tells you where the decay is, how deep it goes, how it is treated, and whether there is more that has not shown yet.

2. 2

   If you are in Amman for a whileIf you are only in Amman for a stretch, a posting, a contract, a semester, or you come and go, say so before anything starts. A routine filling is usually done in the same visit, but if more than one tooth needs work, the visits are planned around your dates as far as the work allows, the most important first. If you have had fillings done in another clinic or another country, bring what you know about them: roughly where, and when. Your teeth can be examined here, and whether an old filling needs replacing is decided at the examination.

3. 3

   Brush twice a day with a fluoride toothpasteMorning and before bed. After brushing, spit the toothpaste out and do not rinse with a lot of water, so the fluoride stays on your teeth. If a tooth is sensitive, do not avoid it: clean it gently, and keeping it clean slows the decay until your examination.

4. 4

   Floss once a dayDecay between the teeth starts where the brush does not reach. If the floss catches or shreds at one particular tooth, mention it at the examination.

5. 5

   Cut down on sweet things between mealsIt is not only how much sugar, but how often. Every time you have something sweet, or a sweetened drink, between meals, the acid gets back to work on your teeth. So if you want something sweet, have it with a meal rather than through the day, and drink water between meals.

6. 6

   No acidic drink straight after something sweetJuice and fizzy drinks are acidic, and straight after something sweet they add acid on top of acid. After something sweet, drink water and rinse your mouth with it.

When to call

Most decay is treated at an ordinary appointment soon, not as an emergency. But some signs say it has moved on, or that a filling needs a look:

• Call this week: sensitivity to sweet or cold that keeps coming back in the same tooth, or a new brown or black spot.
• Call this week: a filling that has fallen out or broken, a piece of a decayed tooth that has broken off, or food that has started catching where it never used to.
• Call this week: sensitivity after a new filling that has not eased after a few days, or has grown stronger, or a bite that feels high.
• Call today: pain that comes on its own, even if it comes and goes, or wakes you at night, or pain that lingers after the cold has gone.
• Call today: swelling in the gum or the cheek, or a bump on the gum with pus coming from it.

Call and we will find you the earliest slot, and tell you what to do until you arrive. Before any painkiller, ask the doctor first, so it suits your case. If a tooth hurts or there is swelling right now, or pain wakes you at night: Toothache: what to do right now.

Questions people ask