The document classifies dental caries in several ways:
1. Based on anatomical site such as occlusal, root, and smooth surface caries. Occlusal caries are most prevalent.
2. Based on progression as acute, chronic, or arrested caries. Acute caries progresses rapidly while chronic caries is slow.
3. Based on the initial involvement of the tooth surface as primary or recurrent caries. Primary caries is the initial attack while recurrent caries occurs around restorations.