Skip to main content
Anodyne

Educational guide

What is the ICDAS index?

ICDAS (International Caries Detection and Assessment System) is a common language for describing the severity of tooth decay. In this system the condition of each tooth surface is recorded with a code from 0 (sound) to 6 (extensive cavity).

Why does ICDAS matter?

Tooth decay doesn't form overnight; it starts with very small changes in the enamel and, if not controlled, leads to a cavity and dentin involvement. ICDAS divides this path into defined stages so dentists can record lesion severity more precisely, compare changes over time and choose preventive, minimally invasive treatments for the early stages.

What codes 0 to 6 mean

Codes are assigned by visual examination of the clean tooth surface, before and after drying. A simplified summary of the codes:

  1. 0

    Sound surface

    Sound

    After drying the tooth surface completely (about 5 seconds), no sign of decay is visible.

  2. 1

    First visual change in enamel

    Initial decay

    Discoloration or opacity of the enamel that is only visible after prolonged drying or is limited to the fissures.

  3. 2

    Distinct visual change in enamel

    Initial decay

    An opaque white or brown spot that is visible even when the tooth surface is wet.

  4. 3

    Localized enamel breakdown

    Moderate decay

    A small breakdown of enamel without visible dentin; a stage also called a "microcavity".

  5. 4

    Dark dentin shadow under enamel

    Moderate decay

    A gray, brown or blue shadow is visible from beneath the enamel, with or without localized enamel breakdown.

  6. 5

    Distinct cavity with visible dentin

    Extensive decay

    A clear cavity in which the tooth's dentin is visible.

  7. 6

    Extensive cavity with visible dentin

    Extensive decay

    A large, deep cavity involving a large part (more than half) of the tooth surface.

How do ICDAS codes affect treatment?

In general, initial lesions (codes 1 and 2) are often controlled with preventive measures such as hygiene education, fluoride and periodic monitoring. Moderate and extensive lesions usually need a more detailed assessment and restorative treatment. The choice of treatment depends on many factors, such as whether the lesion is active, the person's caries risk and supplementary imaging, and only a dentist can decide it.

How does Anodyne use ICDAS?

Anodyne analyzes intraoral and radiographic images, marks suspicious areas and gives an estimated ICDAS code with a confidence score for the findings. This estimate is image-based, whereas ICDAS is defined for direct examination of a clean, dried tooth surface. That is why Anodyne's output is diagnostic support, and the dentist confirms or corrects it with a clinical examination.

To see how the report is structured, see the Anodyne report guide . To learn more about the stages of decay, read the article Stages of tooth decay .

Resources

  1. Ismail AI, et al. The International Caries Detection and Assessment System (ICDAS): an integrated system for measuring dental caries. Community Dent Oral Epidemiol. 2007;35(3):170-178.
  2. Pitts NB, et al. International Caries Classification and Management System (ICCMS) Guide for Practitioners and Educators. 2014.
  3. World Health Organization — Oral health fact sheet

Last updated:

See the ICDAS report for your images

Anodyne marks and reports suspicious areas once processing finishes; the final decision is the dentist's.

Sign up for AnodyneExplore the report
What is the ICDAS index? Tooth decay codes 0 to 6 in plain language | Anodyne