Little used Dial Calipers in his study to measure the distances on a plaster model taken of mandibular arches.
The number correspond to the distance in mm of the sum of horizontal displacements of the anatomical contact points of the mandibular anterior teeth.
Some of the disadvantages of this index includes assigning high score to Malocclusion which involve a severe rotation of one or more tooth.
The treatment of a case like this may be simple compared to the high score of crowding it received from this index.
The index also does not take into account other features of malocclusion before assigning a score to an individual.