title: Association between mesially displaced maxillary first premolars and early displaced maxillary canines.
abstract: OBJECTIVE
  To evaluate the association between the mesially displaced maxillary first premolar (MDP) and the early displacement of the adjacent permanent canine (EDC) before their eruption.
  
  
  METHODS
  A sample of 1247 subjects in the intermediate mixed dentition stage was assessed for the presence of MDP and EDC. All subjects were divided into two groups: MDP group and noMDP group. For each subject two angular measurements (premolar-occlusal plane η and л premolar-midline angles) were analysed on panoramic radiographs. The chi-square test with Yates correction was performed to compare the prevalence rate of EDC in MDP (MDP-EDC) and noMDP groups. The statistical comparisons for the values of η and л angles between MDP vs noMDP, MDP vs MDP-EDC, and noMDP vs MDP-EDC groups were performed by means of ANOVA with Bonferroni correction.
  
  
  RESULTS
  The prevalence rate of EDC in the MDP group was significantly greater than in the noMDP group (66% vs. 12.1%). MDP-EDC group showed a significantly larger л angle than in the MDP group resulting in an increased mesial inclination of displaced premolars.
  
  
  CONCLUSIONS
  MDP can be considered a dental anomaly associated to maxillary canine displacement.
authors: Department of Orthodontics, University of Rome "Tor Vergata", Rome, Italy.
authors: M
authors: M
authors: Mucedero
authors: Department of Surgery and Translational Medicine, Orthodontics, University of Florence, Florence, Italy.
authors: L
authors: L
authors: Franchi
authors: Department of Orthodontics, University of Rome "Tor Vergata", Rome, Italy.
authors: M R
authors: MR
authors: Ricchiuti
authors: Department of Orthodontics, University of Rome "Tor Vergata", Rome, Italy.
authors: P
authors: P
authors: Cozza
mesh_terms: D001641:Bicuspid / Q000000981:diagnostic imaging*; D002508:Cephalometry / Q000379:methods; D002648:Child; D003481:Cuspid / Q000000981:diagnostic imaging*; D003818:Dentition, Mixed; D005260:Female; D006801:Humans; D007558:Italy / Q000453:epidemiology; D008297:Male; D008437:Maxilla / Q000000981:diagnostic imaging*; D009805:Odontogenesis / Q000502:physiology; D009811:Odontometry / Q000379:methods; D015995:Prevalence; D011862:Radiography, Panoramic; D014079:Tooth Eruption, Ectopic / Q000453:epidemiology*; D014083:Tooth Germ / Q000000981:diagnostic imaging; D014097:Tooth, Unerupted / Q000000981:diagnostic imaging