Gloss & Floss Answers · Oral Health & Prevention

How do I know if I have a cavity?

Author: Gloss & Floss Dental Care® · Clinically reviewed by a dentist at Gloss & Floss Dental Care®

Short answer

You may have a cavity if a tooth becomes sensitive to cold, sweets or chewing, if food keeps getting stuck in one area, if you see a dark spot, white chalky area, hole or broken edge, or if toothache develops. However, many early cavities cause no symptoms at all. The only reliable way to know if you have a cavity is a dental examination, often supported by X-rays when decay between teeth or under old fillings is suspected.

Why cavities can be difficult to notice

A cavity starts when tooth enamel loses minerals and the tooth surface begins to break down. Early decay may look like a white chalky mark, a small shadow or nothing visible at all. This is why a tooth can have a cavity before you feel pain.

Symptoms usually become clearer when decay gets deeper, reaches dentin, creates a hole, affects an old filling or irritates the tooth nerve. Waiting for pain is not a safe way to detect cavities early.

Common signs of a cavity

Sensitivity to cold drinks, sweets or acidic foods
Pain or discomfort when chewing
Food trapping between the same teeth repeatedly
A visible hole, pit or rough edge in the tooth
A dark brown, black or grey spot
A white chalky area near the gumline or between teeth
Floss shredding or catching between two teeth
Bad taste or smell from one specific area
A broken filling or leaking old filling
Toothache that comes and goes
Pain that becomes spontaneous or wakes you at night

Cavity symptoms and what they may mean

Sign or symptom	What it may suggest	Why assessment matters
White chalky spot	Early enamel demineralisation or an early cavity lesion.	May still be managed preventively if the surface has not broken down.
Sensitivity to sweets or cold	Decay may have reached dentin, or another sensitivity cause may be present.	The dentist needs to distinguish cavity pain from gum recession, enamel wear or cracks.
Food trapping	A cavity, broken filling, open contact or tooth shape change may be present.	Food trapping can worsen decay and gum irritation if not corrected.
Dark spot or visible hole	Decay, staining, old filling margin or enamel breakdown may be present.	Not every dark spot is a cavity, but visible changes should be examined.
Pain when biting	A deep cavity, cracked tooth, high filling or inflamed tooth nerve may be involved.	Biting pain needs diagnosis because causes and treatment options differ.
Spontaneous toothache	The tooth nerve may be irritated or infected.	Deep decay may need urgent assessment and sometimes root canal treatment or extraction.

Can you have a cavity without pain?

Yes. Many cavities do not hurt in the early stages. Decay between teeth can grow quietly because it is hidden from view. Cavities under old fillings or crowns can also be difficult to notice without an examination and X-rays.

Pain often means the problem has become more advanced. A dental check-up can detect cavities before they become painful, larger or more complicated to treat.

What affects the answer?

Whether the suspected cavity is on a visible surface or between teeth
Whether the tooth has an old filling, crown or crack
Whether the symptom is sensitivity, chewing pain or spontaneous pain
Whether decay is limited to enamel or has reached dentin
Whether the tooth nerve is irritated
Whether the gums have receded and exposed the root surface
Whether dry mouth increases cavity risk
Whether you often snack or sip sugary or acidic drinks
Whether plaque is difficult to remove between teeth
Whether X-rays show hidden decay
Whether the tooth is restorable if the cavity is deep

What happens at Gloss & Floss?

At Gloss & Floss Dental Care® in Södermalm, Stockholm, possible cavities are assessed by checking symptoms, tooth surfaces, old fillings, gumline areas, contact points between teeth, plaque levels, diet, dry mouth risk and oral-hygiene routines. X-rays may be recommended when decay between teeth, under fillings or near the tooth nerve needs assessment.

If a cavity is found, the treatment depends on depth and activity. Early enamel changes may be managed with prevention, fluoride and monitoring. A formed cavity may need a tooth-coloured filling. Deep decay may require further treatment if the tooth nerve is affected. For English-speaking patients, we explain the diagnosis, X-ray findings, treatment options and cost estimate in clear English before treatment begins.

How cavities are diagnosed

Visual examination of tooth surfaces
Checking rough, soft or broken areas carefully
Assessing old fillings and crown margins
Testing sensitivity when clinically useful
Checking bite pain or cracked-tooth signs
Using bitewing X-rays to detect decay between teeth
Assessing caries risk, diet, dry mouth and fluoride exposure
Deciding whether the area needs monitoring, prevention or treatment

What can you do at home?

Brush twice daily with fluoride toothpaste
Clean between teeth every day
Reduce frequent snacking and sugary drinks
Avoid sipping acidic or sweet drinks over long periods
Use fluoride products as recommended by your dental team
Do not ignore repeated food trapping
Book an examination if floss catches or breaks in one area
Seek care if sensitivity becomes stronger or more localised
Do not wait for severe pain before checking a suspected cavity

When should you seek care?

Book a dental assessment if you notice sensitivity, food trapping, a visible hole, dark spot, broken filling, rough edge, bad taste or pain when biting. Seek care sooner if toothache becomes spontaneous, wakes you at night, lingers after cold or heat, or is combined with swelling, fever, pus or difficulty chewing.

Frequently asked questions

Can I see a cavity myself?

Sometimes, especially if there is a visible hole or dark area. However, many cavities form between teeth or under old fillings and cannot be seen clearly without a dental examination and X-rays.

Does a cavity always hurt?

No. Early cavities often do not hurt. Pain usually becomes more likely when decay reaches deeper tooth layers or irritates the tooth nerve.

Can a white spot be an early cavity?

Yes. A chalky white spot may be early enamel demineralisation. It should be assessed to decide whether prevention, fluoride, monitoring or treatment is needed.

Can a cavity heal by itself?

Early enamel demineralisation may sometimes be stabilised with fluoride, better cleaning and diet changes. Once the tooth surface has broken down into a hole, it usually cannot repair itself and may need a filling.

Why does food get stuck where I have a cavity?

Food may trap because decay has changed the tooth shape, a filling edge is leaking, a contact between teeth has opened or a tooth surface has broken. This should be checked.

When is a cavity urgent?

A suspected cavity is more urgent if there is severe toothache, swelling, fever, pus, pain when biting, a broken tooth, or pain that lingers after hot or cold triggers.

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Disclaimer

This article provides general information from Gloss & Floss Dental Care® in Stockholm. It does not replace an individual dental examination, caries-risk assessment, X-ray review, diagnosis, fluoride recommendation, filling assessment or treatment plan.

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