In Peck and Peck index, mesiodistal and buccolingual measurements of which of the following tooth is taken:

 # In Peck and Peck index, mesiodistal and buccolingual measurements of which of the following tooth is taken: 

A. Maxillary central incisor 

B. Mandibular central incisor

C. Maxillary premolars 

D. Mandibular molars 

The correct answer is B. Mandibular central incisor.

Peck and Peck index: 

The mandibular incisors in persons with no crowding will have smaller mesiodistal width and large labiolingual width than in persons with incisal crowding.

The proportion of the mesiodistal width of each tooth to the labio lingual thickness is calculated using the formula:

M.D.W./L.L.W x100 

Mean value for lower central incisor should be 88 to 92%. 

Mean value for lower lateral incisor should be 90 to 95% 

If the calculated value is greater than mean value, it indicates that the mesiodistal width is more than labiolingual width and hence proximal stripping is indicated.