0. Sound tooth surface : No evidence of caries after 5 sec air drying.
1. First visual change in enamel: Opacity or discoloration (white or brown) is visible at the entrance to the pit or fissure seen after prolonged air drying
2. Distinct visual change in enamel visible when wet, lesion must be visible when dry
3. Localized enamel breakdown (without clinical visual signs of dentinal involvement) seen when wet and after prolonged drying
4. Underlying dark shadow from dentine
5. Distinct cavity with visible dentine
6. Extensive (more the half the surface) distinct cavity with visible dentine