[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [Dentistry](https://durgical.com/en/dentistry/) › [Caries, pulp and tooth wear](https://durgical.com/en/dentistry/areas/caries-pulp/) › Classifying caries: by site, depth and activity

# Classifying caries: by site, depth and activity

- Oral pathology

Caries is described by where it is (Black's classes), how deep it goes (ICDAS) and whether it is active, so the right treatment can be chosen.

Updated Nov 12, 2026

## Key points

- Black classes describe the site; ICDAS describes severity.
- Shiny and hard = arrested; matt and rough = active.
- Non-cavitated lesions are treated without drilling.

## What it is

Several systems describe caries. G. V. Black's classification, over a century old, names cavities by site: Class I in pits and fissures, Class II on the proximal surfaces of back teeth, Class III on proximal surfaces of front teeth, Class IV the same with loss of the incisal edge, Class V at the gum line and Class VI on cusp tips. The International Caries Detection and Assessment System (ICDAS) grades lesions from 0 (sound) to 6 (extensive cavity with visible dentine) by what is seen on a clean, dried tooth. Activity matters too: an active lesion is chalky, rough and near plaque; an arrested lesion is shiny, hard and often dark.

## How to recognise it

- Black Class I: occlusal pits and fissures; Class II: between back teeth; Class V: cervical, at the gum line.
- ICDAS 1–2: visible change in enamel only (manage without drilling).
- ICDAS 3: localised enamel breakdown; 4: dark shadow from dentine; 5–6: cavity into dentine.
- Active lesions are matt and rough; arrested lesions are shiny and hard, even if brown.
- Radiographs grade proximal lesions by depth: outer or inner enamel, outer, middle or inner dentine.

## Differential and risks

- Brown spots are not always active caries: hard, shiny arrested lesions need monitoring, not drilling.
- Early non-cavitated lesions are managed with fluoride, sealants and diet, preserving tooth tissue.
- Deep lesions close to the pulp risk pulp exposure and need prompt care.

## Next step / Initial management

- Non-cavitated active lesions: fluoride varnish, sealants and diet advice; recheck at the next visit.
- Cavities into dentine: refer to the dentist for restoration.
- Deep lesions with symptoms of pulpitis: refer promptly.

## Test yourself

Think of the answer, then tap the question to see it.

## In Black's classification, where is a Class V lesion?

At the gum line (cervical third) of a tooth.

## How does an arrested caries lesion look compared with an active one?

Arrested lesions are shiny and hard, often darker; active lesions are chalky, matt and rough.

## What does an ICDAS score of 1 or 2 mean for treatment?

A visible enamel change without cavity, managed with fluoride, hygiene and diet rather than a filling.

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## Connections

## Related 3

- [How caries forms: biofilm, sugar and demineralisation](https://durgical.com/en/dentistry/how-caries-forms-biofilm-sugar-and-demineralisation/)
- [Dental charting and the DMFT index](https://durgical.com/en/dentistry/dental-charting-and-the-dmft-index/)
- [Dental imaging: bitewing, periapical, panoramic and CBCT](https://durgical.com/en/dentistry/dental-imaging-bitewing-periapical-panoramic-and-cbct/)

## Related conditions 1

- [Dental caries](https://durgical.com/en/conditions/dental-caries/)

[← All of dentistry](https://durgical.com/en/dentistry/)

Educational content; it does not replace assessment by a dentist or doctor and is not a clinical instruction. For facial or neck swelling with difficulty swallowing or breathing, a knocked-out tooth or bleeding that will not stop, go to an emergency department at once.

Sources: [Dental Caries Classification Systems](https://www.ncbi.nlm.nih.gov/books/NBK597361/) (StatPearls Publishing (NCBI Bookshelf), 2023); [Dental Caries Diagnostic Testing](https://www.ncbi.nlm.nih.gov/books/NBK574510/) (StatPearls Publishing (NCBI Bookshelf), 2023).

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Representative model, for educational purposes only.

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