title: Preeruptive changes in maxillary canine and first premolar inclinations: a retrospective study on panoramic radiographs.
abstract: BACKGROUND
  Because of the close anatomic proximity of the maxillary permanent canine and first premolar, we investigated the relationship between their preeruptive positional changes in this retrospective study.
  
  
  METHODS
  Sixty-three pairs of panoramic radiographs obtained 12 to 24 months apart from nonorthodontic subjects between 8 and 10 years old were collected. Canine and premolar inclinations to the midline and mesiodistal sector locations were measured, and their changes over time were estimated. The relationship between changes in canine (Δα) and premolar inclinations (Δπ) was explored alone and after adjustment for intraosseous distance between the teeth (Sc-p) and months between radiographs (ΔM).
  
  
  RESULTS
  Except for right canine sector, both canine and premolar inclinations and sectors showed significant differences between time points. Pearson partial correlation analysis showed a strong, positive correlation between Δα and Δπ after adjusting for Sc-p and ΔM (right: r = 0.766, P <0.05; left: r = 0.785; P <0.05).
  
  
  CONCLUSIONS
  Canine and premolar inclinations and mesiodistal locations varied significantly between 8 and 10 years of age. The strong positive correlation between the preeruptive positional changes of the maxillary canine and the first premolar suggested that with a greater uprighting movement of the long axis of the premolar over time, there was greater uprighting of the long axis of the canine.
authors.affiliation: PhD student, Unit of Orthodontics, Department of Biomedical and Neuromotor Sciences, University of Bologna, Bologna, Italy.
authors.forename: Serena
authors.initials: S
authors.lastname: Incerti Parenti
authors.affiliation: Visiting professor, Unit of Orthodontics, Department of Biomedical and Neuromotor Sciences, University of Bologna, Bologna, Italy.
authors.forename: Ida
authors.initials: I
authors.lastname: Marini
authors.affiliation: Resident, Unit of Orthodontics, Department of Biomedical and Neuromotor Sciences, University of Bologna, Bologna, Italy.
authors.forename: Daniela Rita
authors.initials: DR
authors.lastname: Ippolito
authors.affiliation: Assistant professor, Unit of Orthodontics, Department of Biomedical and Neuromotor Sciences, University of Bologna, Bologna, Italy. Electronic address: giulio.alessandri@unibo.it.
authors.forename: Giulio
authors.initials: G
authors.lastname: Alessandri Bonetti
mesh_terms: D001641:Bicuspid / Q000000981:diagnostic imaging*; D002648:Child; D003481:Cuspid / Q000000981:diagnostic imaging*; D003818:Dentition, Mixed; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D008297:Male; D008437:Maxilla / Q000000981:diagnostic imaging; D009811:Odontometry / Q000379:methods; D011862:Radiography, Panoramic / Q000379:methods*; D012189:Retrospective Studies; D014078:Tooth Eruption; D014097:Tooth, Unerupted / Q000000981:diagnostic imaging*