title: Maxillary first premolar inclination in 8- to 11-year-old children: An observational cross-sectional study on panoramic radiographs.
abstract: BACKGROUND
  In this study, we examined first premolar inclination in a large sample.
  
  
  METHODS
  First premolar inclination, canine inclination, and mesiodistal location were measured on 797 panoramic radiographs of orthodontically untreated children (ages, 8-11 years; 381 boys, 416 girls). The sample comprised 1496 premolars and 1496 canines. A linear mixed-effects model was used to determine the contribution of age, sex, canine inclination, canine sector location, second molar maturational stage (D-G), and dental arch side on premolar inclination.
  
  
  RESULTS
  First premolar inclination values (medians and interquartile ranges) were 12.76° (8.12°-19.05°) at 8 years, 11.82° (7.87°-16.04°) at 9 years, 10.40° (6.38°-15.46°) at 10 years, and 9.03° (5.42°-12.81°) at 11 years; 13.86° (8.60°-18.78°) at stage D, 10.56° (7.39°-14.77°) at stage E, 10.43° (6.08°-15.09°) at stage F, and 8.00° (4.62°-10.74°) at stage G. The following equation was selected (Akaike information criteria = 424.99): first premolar inclination (°) = -2.211 + 2.240 (8 years) + 1.363 (9 years) + 0.955 (10 years) + 0.387 (canine inclination) + 0.902 (right side) + 2.320 (stage D) + 6.320 (sector 1) + 5.446 (sector 2) + 3.803 (sector 3). There was no difference between percentiles constructed by age and maturational stage.
  
  
  CONCLUSIONS
  First premolar inclination decreases during the mixed dentition and is moderately correlated with canine inclination.
authors.affiliation: Associate 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
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: Postgraduate student, Department of Orthodontics, School of Dentistry, University of Brescia, Brescia, Italy.
authors.forename: Giulia
authors.initials: G
authors.lastname: Garulli
authors.affiliation: Assistant professor, Unit of Orthodontics, Department of Biomedical and Neuromotor Sciences, University of Bologna, Bologna, Italy.
authors.forename: Maria Rosaria Antonella
authors.initials: MR
authors.lastname: Gatto
authors.affiliation: Associate professor, Department of Orthodontics, School of Dentistry, University of Brescia, Brescia, Italy.
authors.forename: Luca
authors.initials: L
authors.lastname: Visconti
authors.affiliation: Professor, Department of Orthodontics, School of Dentistry, University of Brescia, Brescia, Italy.
authors.forename: Corrado
authors.initials: C
authors.lastname: Paganelli
mesh_terms: D001641:Bicuspid / Q000033:anatomy & histology* / Q000000981:diagnostic imaging*; D002648:Child; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D008297:Male; D008437:Maxilla / Q000000981:diagnostic imaging*; D011862:Radiography, Panoramic