Dilaceration of permanent upper lateral incisors: frequency, direction, and endodontic treatment implications.

A sample of 480 extracted permanent upper lateral incisors was visually examined and the direction of dilaceration was recorded. It was found that 52.1 percent of the roots of these teeth were distolabially dilacerated. Analysis of radiographs of another sample of 442 endodontically treated teeth revealed that distolabial dilaceration occurred in 52 percent of the cases. It is proposed that oversight of the distolabial direction of root dilaceration of upper lateral incisors can be a contributing factor in the failure of endodontic treatment of these teeth.