Classification by ICD-10 code 2013:
- K02.- Dental caries
- K02.0 Caries limited to the enamel of the tooth
- Incl: Opaque spots, white spots, [Initial caries.]
- K02.1 Caries of the dentin (dentine).
- K02.2 Caries of the cementum
- K02.3 Caries mark
- K02.4 Odontoclasia
- Incl: Infantile melanodontia, melanodontoclasia.
- Excl : internal and external resorption (K03.3).
- K02.5 Caries with exposed pulp.
- K02.8 Other caries
- K02.9 Caries, unspecified
WHO caries classification system:
| Classification | Criteria |
| D1 | Clinically apparent enamel lesion with intact surface |
| D2 | Clinically detectable enamel cavitation |
| D3 | Clinically detectable dentinal cavitation |
| D4 | Lesion with pulp involvement |
Classification according to radiological depth of caries:
| Classification | Criteria |
| E0 / S0 | not visible |
| E1 / S1 | In the outer half of the enamel |
| E2 / S2 | in the inner half of the enamel |
| D1 | in the outer dentine third |
| D2 | in the middle dentine third |
| D3 | In the dentine third near the pulp |
Legend: E = enamel; S = enamel; D = dentin.
Classification according to affected tooth structure:
I. Enamel caries: histological zones from outside to inside:
- Surface layer
- Lesion body – lesion center, zone of greatest mineral loss.
- Dark zone
- Translucent zone – zone of progressive demineralization.
II. dentinal caries: histological zones from the outside to the inside:
- Zone of necrosis – consisting of softened dentin, microorganisms, their enzymes and metabolites.
- Zone of penetration – invasion v. a. gram-positive microorganisms, so e. g. Lactobacilli, into the dentinal tubules.
- Zone of demineralization – decalcification and thus softening of the intertubular dentin.
- “dead tract” – no odontoblast processes, thus no communication with the pulp.
- Zone of sclerosis – obliteration (closure) of dentinal tubules as a protective mechanism.
- Reaction dentin – formation of tertiary dentin at the pulp-dentin junction.
III. root caries (cementum caries)Progressive classification into stages:
| Stage | Synonyms | Criteria |
| Initial caries | Early stage caries |
|
| Caries superficialis | Superficial caries | Enamel caries |
| Caries media | Dental caries | |
| Caries profunda | deep caries | Caries down to the dentin near the pulp |
| Caries profunda complicata | Caries penetrans | opening of the pulp due to caries |
Classification according to caries localization:
- Fissure caries – caries in pits and fissures.
- Smooth surface caries
- Approximal caries – caries on the contact surfaces of adjacent teeth.
- Tooth neck caries
- Root caries
Classification according to caries activity:
- Arrested caries – caries mark, arrested caries, caries sicca (dry caries), inactive caries, stationary caries, dormant caries lesion, caries chronica (chronic caries), stalled caries.
- Active caries – Progressive caries, rapidly progressing caries, caries florida (florid caries).
Graduation in visual caries diagnosis in the fissure (after Ekstrand 2004).
| Grade | Clinical findings | Histology | Degree of infection of the enamel-dentin junction. |
| 0 | No or little change in melt translucency after drying > 5 sec.with the air blower | No or very superficial demineralization | – |
| 1 | Opacity / barely visible discoloration, clearly protruding after drying | Enamel demineralization limited to outer half of enamel | – |
| 1a | White: indication of active lesion | – | |
| 1b | Brown: indicative of arrested lesion. | – | |
| 2 | Opacity / discoloration clearly visible without drying | Demineralization that can affect 50% of the enamel and up to one-third of the dentin | Slightly |
| 2a | white: active lesion | ||
| 2b | brown: arrested lesion | ||
| 3 | Localized enamel collapse in opaque altered or discolored enamel and / or gray discoloration starting from the underlying dentin | Demineralistaion extending into the middle third of the dentin | moderate |
| 4 | Cavity formation in opaque or discolored enamel with exposure of dentin | Demineralization into the inner third of the dentin | strong |
Special forms of caries
- Secondary caries – newly developed caries, usually in the marginal area of restorations (at filling margins).
- Caries recurrence – recurrent caries; progression or exacerbation (progression or flare-up) of an already existing caries e.g. under restorations (fillings).
- Radiation caries – radiogenic caries; after radiological therapy.
- Early Childhood Caries (ECC, early deciduous caries) – affecting the first dentition (the primary dentition):
- Type I – mild to moderate: isolated carious lesions deciduous molars or incisors (molars and incisors).
- Type II – moderate to severe: maxillary incisors (incisors) have labial and lingual (on the labial and lingual surfaces) lesions. Deciduous molars may also be affected. The mandibular anterior teeth are not involved.
- Type III – severe: rapidly progressive (progressive) caries on almost all deciduous teeth, including the mandibular anterior even on atypical tooth surfaces.
