Table 1: Stages of evolution according to the classification of carious cervical lesions.

Stage 0 Colored cemento-dentin surface and more or less eroded.
Stage 1 Superficial cavitation which concerns the external third of the dentine, the amelo-dentinal junction is spared.
Stage 2 Cavitation of the middle third of the dentine, it extends in an apical and proximal direction.
Stage 3 Distinct cavitation of the internal third of the dentine, it extends towards the proximal surfaces.
Stage 4 Deep cavitation, creeping, extending all the way around the root canal. There is a risk of coronal fracture.