The DEFT/DEFS index is traditionally applied to which dentition?

• A. Primary dentition
• B. Permanent dentition
• C. Mixed dentition
• D. All dentitions

Answer: (A)

This index is designed to capture caries experience specifically in the primary (deciduous) dentition. It records decayed, extracted (due to caries), and filled teeth or surfaces, depending on the version (DEFT or DEFS). The reason it fits primary dentition is that young children have teeth that will eventually exfoliate, so using “missing” teeth as a measure in permanent- dentition indices would be misleading. Extractions in primary teeth are often caries-related, and counting them as part of caries experience (rather than as natural tooth loss) provides a stable snapshot of caries burden before the permanent teeth erupt. Therefore, this index is traditionally applied to the primary dentition, whereas for permanent dentition the DMFT/DMFS indices are used.