DMFT caries index (1930s) The DMFT (decayed, missing, filled teeth) index is the most commonly used index in UK epidemiological surveys of caries. It was developed by Klein and Palmer in the 1930s and the fact that it is still in use today indicates its success [4]. An important point to remember with this index is that large-case letters (DMFT) denote permanent teeth, while small-case letters (dmft) denote deciduous teeth.