The international caries detection and assessment system (ICDAS) was established in 2002, based on the statements from two consensus conferences held around year 2000, that there was no association between the sign of caries on the surface and the severity of the same lesion. A group of scientists met in Dundee and looked through all the caries recording systems used that far and found that the ERK system showed a substantial association between the external sign of caries on the occlusal surface and the underlying histological changes (Ekstrand et al., 1998).