title: Longitudinal growth changes in subjects with open-bite tendency: a retrospective study.
abstract: BACKGROUND
  This study was a cephalometric evaluation of the growth changes in untreated subjects with minimal overbite at 4 time points during 4 developmental stages from the early mixed dentition to the permanent dentition, as well as from the prepubertal phase to young adulthood.
  
  
  METHODS
  A sample of 24 untreated subjects with minimal overbite (<1.5 mm) was selected retrospectively from the University of Michigan Growth Study and the Denver Child Growth Study. The sample was followed longitudinally from about 9 years of age through 17 years of age. Dentofacial changes at the 4 times (T1-T4), defined by the cervical vertebral maturation method, were analyzed on lateral cephalograms. Nonparametric statistical analysis was used for comparisons.
  
  
  RESULTS
  Overbite on average increased by 2.3 mm during the overall observation period. Improvement occurred during the prepubertal interval (T1-T2; 2.4 mm), whereas no significant changes occurred in the pubertal and postpubertal stages. From prepubertal ages to young adulthood, the open-bite tendency improved in 91% of the subjects, with self-correction in 75%. Logistic regression analysis on the cephalometric variables at T1 with the value of overbite at T4 did not show a statistically significant correlation.
  
  
  CONCLUSIONS
  Subjects with an open-bite tendency show improvement of their occlusal condition during the prepubertal stage, but there is no significant improvement after this. These results provide useful indications for appropriate orthodontic treatment timing for patients with an open-bite tendency.
authors.affiliation: Orthodontist, Discipline of Orthodontics, Faculty of Dentistry, University of Sydney, Surry Hills, New South Wales, Australia.
authors.forename: Angie
authors.initials: A
authors.lastname: Phelan
authors.affiliation: Research professor, Department of Orthodontics, University of Florence, Florence, Italy; Thomas M. Graber Visiting Scholar, Department of Orthodontics and Pediatric Dentistry, School of Dentistry, University of Michigan, Ann Arbor, Mich.
authors.forename: Lorenzo
authors.initials: L
authors.lastname: Franchi
authors.affiliation: Deceased.
authors.forename: Tiziano
authors.initials: T
authors.lastname: Baccetti
authors.affiliation: Professor and chair, Discipline of Orthodontics, Faculty of Dentistry, University of Sydney, Surry Hills, New South Wales, Australia. Electronic address: adarende@mail.usyd.edu.au.
authors.forename: M Ali
authors.initials: MA
authors.lastname: Darendeliler
authors.affiliation: Thomas M. and Doris Graber Endowed Professor of Dentistry, Department of Orthodontics and Pediatric Dentistry, School of Dentistry; research professor, Center for Human Growth and Development, University of Michigan, Ann Arbor; private practice, Ann Arbor, Mich.
authors.forename: James A
authors.initials: JA
authors.lastname: McNamara
mesh_terms: D000293:Adolescent; D000365:Age Determination by Skeleton / Q000379:methods; D002508:Cephalometry / Q000379:methods; D002574:Cervical Vertebrae / Q000254:growth & development; D002648:Child; D003818:Dentition, Mixed; D019229:Dentition, Permanent; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D007180:Incisor / Q000473:pathology; D008137:Longitudinal Studies; D008297:Male; D008334:Mandible / Q000473:pathology; D008437:Maxilla / Q000473:pathology; D008445:Maxillofacial Development / Q000502:physiology*; D009295:Nasal Bone / Q000473:pathology; D024343:Open Bite / Q000503:physiopathology*; D010159:Palate / Q000473:pathology; D011627:Puberty / Q000502:physiology; D012075:Remission, Spontaneous; D012189:Retrospective Studies; D019291:Skull Base / Q000473:pathology