Localized enamel hypoplasia of the primary canine.

An abnormality of enamel formation, detected only recently in living children, was found in a majority of prehistoric children, some from more than 20,000 years ago. The lesion, roughly a circular area of enamel hypoplasia approximately one millimeter in diameter, occurs on the labial surface of the primary canine tooth. A clinical examination of 2,367 school children in the Vancouver, Canada, area showed the defect occurring in fewer than one percent.