12 Signs You Need a Filling (and When to See a Dentist)

Not sure if that twinge, rough edge or stubborn dark spot means you need a filling? Tooth decay often starts quietly. You might feel fine for months while acids in plaque gradually soften enamel, then dentine, until a small cavity grows into a painful problem. The earlier it’s treated, the simpler and more affordable the fix — usually a quick filling. Leave it and you risk ongoing sensitivity, toothache, infection, or even needing root canal treatment or an extraction.

This guide pinpoints 12 clear signs that suggest a filling could be needed. For each one, you’ll see what you’re likely to notice, why it points to decay or structural damage, and what to do next — including when it’s time to book a routine appointment and when symptoms are urgent. Whether you’re overdue a check-up or worried about a specific tooth, use the checklist below to act with confidence and protect your smile. If you’re in or around Luton, the team at Wigmore Smiles & Aesthetics can confirm what’s going on and help you treat it promptly.

1. You haven’t had a check-up in 6–12 months (book with Wigmore Smiles & Aesthetics)

Early decay is sneaky. It often produces no symptoms until a cavity has grown. Routine check-ups catch problems early, when a simple filling can prevent toothache or infection.

What you’ll notice

Probably nothing obvious. You may have mild, fleeting sensitivity or see minor staining, but many people feel fine while decay slowly progresses.

Why it can mean you need a filling

Plaque acids soften enamel and dentine over time. Small cavities and cracked edges are easiest to spot and fix during regular exams, before pain or root canal treatment becomes likely.

What to do next

If it’s been 6–12 months, book a check-up. Adults should not leave it over two years; under‑18s usually need yearly reviews. In Luton, Wigmore Smiles & Aesthetics can assess accurately using 3D iTero scans and advise if a filling is needed.

2. Tooth sensitivity to hot, cold, sweet or acidic foods

What you’ll notice

You’ll feel a brief, sharp zing in one tooth with cold or hot drinks, or when you eat sweets or acidic foods. It often comes and goes, and you can usually point to a single tooth.

Why it can mean you need a filling

Plaque acids gradually dissolve enamel, exposing dentine. Its tiny tubules transmit temperature and sweetness, so sensitivity is a common early sign of decay — and often the first clue you need a small filling.

What to do next

Use fluoride toothpaste and clean between teeth, but don’t ignore ongoing sensitivity. Book a check-up; early decay may be treated with fluoride varnish or a quick filling. In Luton, Wigmore Smiles can help.

3. Sharp pain when you bite or chew

A sharp, pinpoint pain when you bite or chew is hard to ignore. This biting pain is one of the clearest signs you need a filling, often flaring with harder foods and settling once you stop chewing.

What you’ll notice

The pain is localised to one tooth and may feel like an electric jab. You might also notice discomfort when chewing on one side, or when biting on a seed, nut, or crust.

Why it can mean you need a filling

Bacteria-driven decay can hollow out enamel and dentine, leaving weakened walls that hurt under pressure. A fresh cavity, a chipped edge or recurrent decay around an old filling are common causes — all typically repaired with a new filling.

What to do next

Avoid chewing on that tooth and book a prompt exam. Early treatment can stabilise the tooth with a composite or amalgam filling; if pain lingers or you notice swelling, your dentist will assess for deeper infection and discuss root canal treatment.

4. A visible hole, pit or rough area you can feel with your tongue

If your tongue keeps catching on a rough edge, or you can see a small pit or hole, don’t ignore it. Cavities often start as softened enamel that breaks away, leaving a tiny defect that’s easy to feel long before there’s pain.

What you’ll notice

A snaggy, sandpaper-like patch or a definite dip on the chewing surface or between teeth. You might notice food collecting in that spot, or see a small shadowed pit in the mirror. Around older fillings, the edge can feel uneven or “crumbly”.

Why it can mean you need a filling

Acids from plaque dissolve enamel and dentine, creating a cavity with fragile margins. Once there’s a visible hole or roughness, the tooth can’t repair itself; bacteria and food pack in, and decay spreads, sometimes under existing fillings (recurrent decay).

What to do next

Avoid picking at the area and keep it clean with careful brushing and flossing. Book a prompt exam — small cavities are usually fixed quickly with a filling; delaying risks deeper decay and more complex treatment like root canal or extraction.

5. White, brown or black spots that don’t brush away

Colour changes that stick around, even after thorough brushing, can be early clues of decay. The NHS lists white, brown or black spots among common symptoms, and they often appear before you feel any pain.

What you’ll notice

Chalky white patches (often near the gumline or in grooves) or small brown/black pinpoints that don’t shift with brushing or toothpaste. The area may feel slightly rough or “sticky” to your tongue or floss, and can sit next to an older filling.

Why it can mean you need a filling

White marks suggest early enamel demineralisation; darker spots often signal deeper decay in dentine. As enamel becomes porous, pigments and bacteria penetrate, and once a tiny cavity forms, the tooth cannot self‑repair — a filling is the usual fix.

What to do next

Cut down on sugar and acids, keep up twice‑daily brushing with fluoride toothpaste, and book an exam. Early lesions may be stabilised with fluoride varnish; visible cavitation usually needs a small composite or amalgam filling. In Luton, Wigmore Smiles & Aesthetics can confirm the cause and treat it promptly.

6. Food frequently gets trapped between the same teeth

What you’ll notice

After most meals, the same gap collects fibres, seeds or meat strands and you find yourself picking at it. The area may feel tender or a bit sore by evening, and you might notice a lingering bad taste from that spot.

Why it can mean you need a filling

Interdental decay often erodes the contact point between two teeth, creating a tiny ledge or gap where food packs in. A chipped edge or worn/defective old filling can do the same. Trapped food feeds plaque, accelerates decay, and can inflame nearby gums.

What to do next

Clean the area gently after meals with floss or small interdental brushes and keep up twice‑daily fluoride toothpaste. Avoid using hard objects to pick. Book a dental exam — a small composite filling or replacing a worn filling can close the trap. In Luton, Wigmore Smiles & Aesthetics can assess and restore the contact.

7. Dental floss frays, catches or tears in one spot

If floss keeps snagging in exactly the same place, treat it as one of the early signs you need a filling. Floss should glide; catching usually points to a rough edge or hidden cavity.

What you’ll notice

Your floss repeatedly shreds, snaps or gets stuck between the same two teeth. You may also feel a tiny “click” as it passes the contact, or notice a slight bad taste from that area after meals.

Why it can mean you need a filling

Decay can erode the contact point or leave a sharp, broken margin that snags floss. Recurrent decay around an old filling can do the same, creating rough, plaque‑retaining edges that fray threads.

What to do next

Don’t force the floss. Clean gently with floss or small interdental brushes and keep using fluoride toothpaste. Book a check‑up — smoothing the edge, replacing a worn filling, or placing a small composite can restore a clean, snag‑free contact. In Luton, Wigmore Smiles & Aesthetics can assess and fix this promptly.

8. A chipped, cracked or fractured tooth

Even a small chip or hairline crack leaves enamel unsealed and vulnerable. The rough edge traps plaque, inviting decay and sensitivity. These are common signs you need a filling to seal the area and restore strength before deeper damage occurs.

What you’ll notice

A jagged edge that catches your tongue or lip, a sudden twinge with cold air or drinks, or a piece flaking off after biting something hard. You may spot a fine line in the mirror.

Why it can mean you need a filling

Damage exposes dentine and creates plaque‑retaining surfaces. A composite filling can reseal and rebuild the tooth; larger fractures sometimes need an inlay/onlay or a crown to protect chewing surfaces.

What to do next

Avoid chewing on that side, keep the area clean, and book a prompt assessment. Bring any broken fragment. If pain is severe or swelling appears, seek urgent care — deeper cracks can affect the nerve and may need root canal treatment.

9. A broken, loose or missing filling

Fillings don’t last forever. If one cracks, loosens or drops out, the exposed tooth becomes sensitive and vulnerable, and decay can quickly spread under any remaining edges. It’s one of the most obvious signs you need a filling repaired or replaced promptly.

What you’ll notice

A rough edge or visible hole, food packing in the spot, floss snagging or tearing, and sudden sensitivity to hot, cold or sweet. You may feel a sharp bite pain or notice a bad taste coming from that tooth.

Why it can mean you need a filling

Gaps at the filling margin let bacteria in, causing recurrent decay around the old restoration. Leave it and decay can reach the pulp (often needing root canal treatment) or the tooth can fracture, leading to more complex care.

What to do next

Avoid chewing on that side, keep the area clean, and book a prompt appointment to repair or replace the restoration. Your dentist may place a temporary filling if needed the same day. If you develop swelling or persistent throbbing, seek urgent care. In Luton, Wigmore Smiles & Aesthetics can help quickly.

10. Localised gum tenderness, swelling or bleeding near one tooth

Soreness or bleeding focused around a single tooth often points to a problem on that tooth, not just your gums. Cavities at the gumline or between teeth, or a rough/broken filling, can trap plaque and food, inflaming the gum in that spot.

What you’ll notice

Tenderness when you press the gum beside one tooth, bleeding when you brush or floss that area, and slight puffiness. You may also notice food repeatedly getting stuck at that contact.

Why it can mean you need a filling

Interdental or gumline decay erodes the contact point or edge, creating a plaque trap that irritates the gum. Recurrent decay around an old filling can do the same. Restoring the contour with a smooth, well‑sealed filling usually resolves the irritation.

What to do next

Keep the area clean with gentle flossing or interdental brushes and fluoride toothpaste. Avoid picking with hard objects. Book an exam — a small composite or replacing a worn filling can close the trap and calm the gum. If swelling spreads or pain worsens, seek urgent care. In Luton, Wigmore Smiles & Aesthetics can assess and treat promptly.

11. Persistent bad breath or unpleasant taste from one area

Bad breath or a sour taste from one spot isn’t normal morning breath. Localised odour often signals a plaque trap, decay or a leaking filling.

What you’ll notice

A smell or taste that returns soon after brushing, seemingly from one tooth. Floss there may smell, and food collects in the same place.

Why it can mean you need a filling

Cavities and worn fillings harbour bacteria and decaying food, producing odour. Without treatment this irritates gums and may progress to infection.

What to do next

Clean gently between those teeth and use fluoride toothpaste, but don’t mask it with mouthwash. Book a check‑up; Wigmore Smiles & Aesthetics can confirm the cause and treat it with a simple filling if needed.

12. Swelling, throbbing pain or a pimple on the gum (possible abscess)

Swelling, a gum “pimple”, or deep throbbing pain can signal a dental abscess — a build‑up of pus from infection that often starts with untreated decay. This is urgent; prompt care can still save the tooth.

What you’ll notice

Expect constant, throbbing toothache that worsens on biting or when you lie down, with tenderness in the gum or face. You may notice a small pimple that releases a bad taste when it drains and heightened sensitivity to heat or cold.

Why it can mean you need a filling

Decay may have reached the pulp, allowing bacteria to infect the root tip and surrounding tissues. Abscessed teeth usually need root canal treatment to clear the infection; afterwards the tooth is sealed and rebuilt with a filling or crown to prevent reinfection.

What to do next

Book an emergency appointment today. Take paracetamol or ibuprofen if suitable for you and avoid heat; don’t try to pop the pimple. If swelling spreads, you develop fever, or swallowing/breathing is affected, seek urgent care immediately. In Luton, call Wigmore Smiles & Aesthetics.

Your next steps

If you’ve ticked off one or more signs, act now. Small cavities are quick to fix; delay and you risk toothache, infection or more complex treatment. Even without pain, persistent sensitivity, rough edges or spots that don’t brush away deserve a professional check. Keep brushing twice daily with fluoride toothpaste and clean between teeth — then book.

• Book soon if: you’re overdue a check-up, have sensitivity for over a week, can see/feel a hole, or food and floss keep catching.

• Book promptly if: a tooth is chipped or a filling is loose, broken or missing.

• Seek urgent care today if: there’s swelling, a gum pimple, throbbing pain, fever or spreading discomfort.

For gentle, thorough care in Luton — including same‑day emergencies, iTero 3D scans and 0% finance — book with Wigmore Smiles & Aesthetics. We’ll confirm what’s going on and get you comfortable fast.