The eruption of the canine is known to be a factor for diastema closur
e. In this study the relative changes in the orientation of the unerup
ted canine were assessed using the orthopantomographs of 9854 patients
who sought consultation between April 1984 and March 1993. A total of
38 canines in 32 patients, all aged 11 years or older, were identifie
d as unerupted canines. The features of the patients with unerupted ca
nine showed no significant relation to diastema closure status, but so
me patients had unerupted horizontal or inverted canine without diaste
ma even in the absence of a history of orthodontic treatment, suggesti
ng the presence of a mechanical force due to some phenomenon other tha
n canine eruption as a factor in diastema closure.