Healthy teeth are translucent (transparent/transparent) and have micropores in the enamel, the number of which, with repeated demineralisation processes, increases. This leads to a change in the refractive value of the enamel, which is considered the first sign of caries.

Progressive and repeated demineralisation processes lead to increasingly porous teeth, eventually resulting in the formation of a cavity. Early caries therefore looks like a saliva-covered surface. The visual method is a method of diagnosing dental cavities in the IDC AS system, which is so easy to perform that it only takes a few seconds to dry the tooth with compressed air and the surface is ready for visual inspection.

A round-ended probe can also be used for the examination. Based on this examination, the degree of caries progression is determined using the following scale:

• 0 - No cavity,
• 1 - Dry cavity only visible,
• 2 - Visible cavity on moist surface,
• 3 - Localized defect in the enamel,
• 4 - Localized lesion in enamel + darkened dentin
• 5 - Prominent hole + darkened dentin + cavity,
• 6 - Extensive, prominent cavity[1]