This document discusses various indices used to assess dental caries, including the DMFT index, DMFS index, and deft/dfs indices. The DMFT index quantifies a person's lifetime caries experience in permanent teeth based on the number of Decayed, Missing, and Filled Teeth. It provides information on caries prevalence, experience, and treatment needs in a population over time. The DMFS index is similar but examines individual tooth surfaces. Indices for primary teeth include the deft and dfs indices which parallel the DMFT and DMFS indices. Caries indices are never combined for mixed dentition which examines permanent and primary teeth separately.