The palatal canine and the adjacent lateral incisor: a study of a west of Scotland population.

The hypothesis that palatally-displaced canines are associated with smaller than average lateral incisors or with congenital absence of adjacent lateral incisors was tested on a West of Scotland population. A retrospective study of the records of orthodontic patients attending Glasgow Dental Hospital was carried out. One-hundred-and-eighty-two subjects with palatally displaced canines were identified. The tooth length of lateral and central incisors was measured on radiographs and the crown widths of lateral incisors were measured on study casts. One-hundred-and-six extracted maxillary lateral incisors were examined to allow more accurate measurement of crown width and root length than was possible from radiographs. An association was sought between the size of the lateral incisor or its absence, the position of the adjacent maxillary canine, and between crown size and root length of the lateral incisor. The conclusions supported the hypothesis that there is a weak association between palatally displaced maxillary canines and lateral incisors of smaller than average crown width. There was weak support for the association between palatal canines and absence of the adjacent lateral incisor. There was no correlation between lateral incisor crown width and root length.