What's the difference between dmfs, dmft and deft dental caries index?

Persons age. These are terms that are used for dental research. Decayed, missing( from tooth decay), filled surfaces (dmfs) describes each tooth surface with fillings. Decayed, missing (from tooth decay), filled teeth (dmft) describes if any filling is present or not. Dmfs and dmft are used for permanent teeth. Decayed, extracted (because of tooth decay), filled teeth (deft) is used for primary (baby) teeth.
Specific definitions. Dmfs: decayed, missing, filled surfaces-more detailed information dmft: decayed, missing, filled teeth-slightly less detailed deft: decayed, (needs) extraction, filled teeth-missing teeth not considered. This is mostly used with kids.