title: Assessing skeletal maturity by using blood spot insulin-like growth factor I (IGF-I) testing.
abstract: BACKGROUND
  Accurate determination of skeletal maturity and remaining growth is crucial to many orthodontic, orthognathic, and dental-implant timing decisions. Cervical vertebral stages and hand-wrist radiographs are currently used to identify peak mandibular bone growth. These are highly subjective techniques that not only involve radiographic exposure but also lack the ability to determine the intensity of the growth spurt and the end of growth. Insulin-like growth factor I (IGF-I) is a circulating growth hormone-dependent factor whose level correlates with sexual maturity; it is used to diagnose growth hormone deficiency and excess. We hypothesized that IGF-I levels would also correlate with cervical skeletal maturity and would be highest at the cervical stages that correspond to the greatest amount of facial growth.
  
  
  METHODS
  We measured mean blood spot IGF-I levels in a cross-sectional study of 83 patients (44 female, 39 male) on recall to begin orthodontic treatment, in active treatment, or in posttreatment follow-up.
  
  
  RESULTS
  Mean blood spot IGF-I levels were significantly higher in the late pubertal stages than in the prepubertal, early pubertal, and postpubertal stages. Linear correlation showed that IGF-I levels had a significant positive correlation with cervical skeletal maturity from the prepubertal to the late pubertal stages, and a significant negative correlation from the late pubertal to the postpubertal stages. In the postpubertal stage, IGF-I levels had a negative linear correlation with increasing time since the onset of puberty and with chronological age.
  
  
  CONCLUSIONS
  Blood spot IGF-I could be used as a skeletal maturity indicator and might be useful in detecting residual mandibular growth in young adults.
authors.affiliation: Department of Orthodontics, Harvard School of Dental Medicine, Boston, MA 02115, USA. masoudortho@gmail.com
authors.forename: Mohamed
authors.initials: M
authors.lastname: Masoud
authors.forename: Ibrahim
authors.initials: I
authors.lastname: Masoud
authors.forename: Ralph L
authors.initials: RL
authors.lastname: Kent
authors.forename: Nour
authors.initials: N
authors.lastname: Gowharji
authors.forename: Laurie E
authors.initials: LE
authors.lastname: Cohen
mesh_terms: D000293:Adolescent; D000328:Adult; D000365:Age Determination by Skeleton / Q000592:standards*; D000704:Analysis of Variance; D001846:Bone Development / Q000502:physiology*; D002508:Cephalometry; D002574:Cervical Vertebrae / Q000000981:diagnostic imaging / Q000254:growth & development*; D002648:Child; D002675:Child, Preschool; D003430:Cross-Sectional Studies; D005147:Facial Bones / Q000254:growth & development; D005260:Female; D006801:Humans; D007334:Insulin-Like Growth Factor I / Q000032:analysis*; D008297:Male; D011627:Puberty / Q000097:blood*; D012015:Reference Standards; D012016:Reference Values; D016037:Single-Blind Method; D013223:Statistics as Topic
chemical_list: D007334:Insulin-Like Growth Factor I