Tooth hurts when you eat sweets: what it usually means

What’s probably going on

Enamel, the hard outer layer of a tooth, doesn’t feel much. Under it is dentin, which is full of tiny channels leading toward the nerve. When dentin is uncovered, sugar can reach those channels and set off a sharp, quick pain.

The most common causes, roughly in order:

• A cavity. This is the usual reason. Early decay rarely hurts, but as it grows it can make a tooth sensitive to sweets, hot or cold. If one tooth reacts to sweets and it’s getting worse, a cavity is the first thing to rule out.
• Exposed root surfaces. When gums pull back, the root shows. Roots aren’t covered by enamel, so sweets and cold can reach the nerve more easily. Gum recession also raises the risk of cavities on those roots.
• A worn, loose or cracked filling. An old filling can wear down or loosen at its edge, leaving a gap where sweets and cold can get in. See tooth pain after a filling if the filling is new.
• A cracked tooth. A crack can let sweets and cold reach the inside of the tooth, often with pain when you bite. See cracked tooth.
• Worn enamel. Acidic drinks and hard brushing can thin enamel over time, so several teeth may feel it at once.

The clue that matters most is how long it lasts. A zing that fades within a few seconds generally isn’t serious on its own. Pain that lingers more than 30 seconds after hot or cold can mean the nerve has been damaged by deep decay, and the tooth may need a root canal to save it.

What to do tonight

Pain with sweets alone can usually wait for a regular appointment, but don’t let it wait for months.

1. Rinse with water after anything sweet. Swish and spit to clear sugar from the sore spot.
2. Brush gently with a fluoride toothpaste. Use a soft brush and don’t scrub. Clean between your teeth too.
3. Skip the trigger for now. Candy, soda and sweetened coffee will keep setting it off. Chew on the other side if you can.
4. Take an over-the-counter pain reliever if it aches. Use it as the label directs, and ask a pharmacist first if you take other medicines, are pregnant, or have stomach, kidney or bleeding problems.
5. Book a dentist visit. A cavity doesn’t heal once it has broken through the enamel. The sooner it’s filled, the smaller the filling.

A sensitivity toothpaste can help if the cause turns out to be exposed roots or worn enamel. It won’t fix a cavity, so don’t use it to put off the visit. See the best toothpaste for sensitive teeth.

What not to do

• Don’t wait for it to become a toothache. Decay that reaches the nerve can turn a filling into a root canal or an extraction.
• Don’t take leftover antibiotics. They don’t treat a cavity.

How a dentist fixes it, and what it costs

A dentist looks at the tooth, often takes an X-ray, and checks old fillings and your gumline. The fix depends on what they find.

• Very early decay. Before it breaks through, a fluoride treatment can help enamel rebuild itself.
• A cavity. The dentist removes the decay and fills the hole. This is the most common fix.
• A worn, leaky or cracked filling. It’s replaced, or the tooth may need a crown if too little is left. See crown cost.
• Exposed roots. An in-office fluoride gel, bonding over the root, or in bigger cases a gum graft.
• Decay that reached the nerve. A root canal and usually a crown, or the tooth is taken out. See root canal cost.

The price depends on the size of the filling, the material, the tooth, where you live and your coverage. For typical price ranges, see how much a filling costs, or try the dental cost estimator. Ask for a written estimate before any work starts.

If you don’t have dental insurance, a dental savings plan (a discount membership, not insurance) can cut the price at participating dentists.

How to keep it from coming back

Decay happens when bacteria in plaque feed on sugars and starches and make acid that dissolves enamel. How often you have sugar matters as much as how much.

• Keep sweets with meals. You make more saliva during a meal, and saliva washes food away and weakens acid. Sweets eaten as part of a meal cause less harm than snacks through the day.
• Don’t sip all day. Nursing a soda or sweet coffee for hours keeps your teeth under attack. Finish it, then drink water.
• Drink tap water. Water rinses away sugar, and fluoridated water strengthens teeth against cavities.
• Brush twice a day with fluoride toothpaste. Fluoride helps enamel repair early damage.
• Clean between your teeth once a day.
• Get regular checkups, so small cavities and worn fillings are caught before they hurt.

Saliva protects teeth, so a mouth that is often dry can raise your risk of cavities. See dry mouth and cavities.