title: Malposition of unerupted mandibular second premolar in children with cleft lip and palate.
abstract: OBJECTIVE
  To determine whether distoangular malposition of the unerupted mandibular second premolar (MnP2) is more frequent in children with unilateral clefts of the lip and palate.
  
  
  METHODS
  This retrospective study examined panoramic radiographs from 45 patients with unilateral clefts of the lip and/or palate who had no previous orthodontics. A control sample consisted of age- and sex-matched patients. The distal angle formed between the long axis of MnP2 and the tangent to the inferior border was measured. The mean, standard deviation, and range were calculated for the angles measured in the cleft and the control groups. The significance of the differences between the means was evaluated by the paired t-test. The angles of the cleft and noncleft sides were also measured and compared.
  
  
  RESULTS
  The mean inclination of the MnP2 on the cleft side was 73.6 degrees , compared with 84.6 degrees in the control group. This difference was highly significant statistically (P < .0001). The difference in angles from the cleft and noncleft sides was 0.7 degrees , not statistically significant. A significant association was found between clefting and distoangular malposition of the developing MnP2, suggesting a shared genetic etiology. This association is independent of the clefting side, ruling out possible local mechanical effects.
  
  
  CONCLUSIONS
  Clinicians should be aware of the potential for anomalous development of MnP2 in children with clefts.
authors.affiliation: Harvard School of Dental Medicine, Developmental Biology (Orthodontics), Boston, MA 02115, USA. mshalish@hsdm.harvard.edu
authors.forename: Miri
authors.initials: M
authors.lastname: Shalish
authors.forename: Leslie A
authors.initials: LA
authors.lastname: Will
authors.forename: Stephen
authors.initials: S
authors.lastname: Shustermann
mesh_terms: D001641:Bicuspid / Q000000981:diagnostic imaging*; D002508:Cephalometry; D002648:Child; D002675:Child, Preschool; D002971:Cleft Lip / Q000150:complications*; D002972:Cleft Palate / Q000150:complications*; D004812:Epidemiologic Methods; D005260:Female; D006801:Humans; D008297:Male; D008310:Malocclusion / Q000209:etiology*; D011859:Radiography; D014097:Tooth, Unerupted / Q000000981:diagnostic imaging*