title: Agenesis and microdontia of permanent teeth as late adverse effects after stem cell transplantation in young children.
abstract: BACKGROUND
  The objective of the current study was to examine the occurrence of tooth agenesis and microdontia in pediatric stem cell transplantation (SCT) recipients.
  
  
  METHODS
  The impact of total body irradiation (TBI) and age at SCT on agenesis and microdontia of permanent teeth was examined in 55 patients from panoramic radiographs. Assessment A1 (for tooth agenesis and microdontia) excluded the third molars, and assessment A2 (for tooth agenesis) included the third molars. Patients were grouped according to TBI status (the TBI group vs. the non-TBI group) and age at SCT (patients age < or = 3.0 years [Group Y], patients ages 3.1-5.0 years [Group M], and patients age > or = 5.1 years [Group O]).
  
  
  RESULTS
  From 1 to 12 teeth were missing in 77%, 40%, and 0% of patients (assessment A1) in Groups Y, M, and O, respectively (Group Y vs. Group M, P=0.055; Group Y vs. Group O, P < 0.001; and Group M vs. Group O, P=0.002), increasing to 83%, 78%, and 43%, respectively, when the third molars were included (assessment A2; P values were not significant). Correspondingly, 75%, 60%, and 13%, respectively, of patients had 1-12 microdontic teeth (assessment A1: Group Y vs. Group M, P=0.306; Group Y vs. Group O, P <0.001; and Group M vs. Group O, P=0.003). Recipient age at the time of SCT was found to have a negative correlation with the number of missing teeth (P=0.001) and microdontic teeth (P=0.005). TBI appeared to have little effect on the prevalence of tooth agenesis (assessment A1: TBI group, 32%; non-TBI group, 29%; assessment A2: TBI group, 72%; non-TBI group, 46%; P values were not significant) or on the prevalence of microdontia (assessment A1: TBI, 41%; non-TBI, 50%; P value was not significant). A tendency toward an increased number of affected teeth was noticed in the group of patients who received TBI.
  
  
  CONCLUSIONS
  Depending on their age at SCT, 50-100% of pediatric SCT recipients will later present with agenesis and/or microdontia of permanent teeth that may jeopardize occlusal development. Young age (< or = 5.0 years) at SCT was found to be a stronger risk factor than TBI, although TBI caused additive impairment.
authors.affiliation: Department of Pedodontics and Orthodontics, Institute of Dentistry, University of Helsinki, Helsinki, Finland. paivi.holtta@helsinki.fi
authors.forename: Päivi
authors.initials: P
authors.lastname: Hölttä
authors.forename: Satu
authors.initials: S
authors.lastname: Alaluusua
authors.forename: Ulla M
authors.initials: UM
authors.lastname: Saarinen-Pihkala
authors.forename: Jaakko
authors.initials: J
authors.lastname: Peltola
authors.forename: Liisa
authors.initials: L
authors.lastname: Hovi
mesh_terms: D000367:Age Factors; D002648:Child; D002675:Child, Preschool; D003744:Dental Enamel Hypoplasia / Q000209:etiology*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D015995:Prevalence; D012307:Risk Factors; D033581:Stem Cell Transplantation / Q000009:adverse effects*; D014070:Tooth / Q000254:growth & development; D014071:Tooth Abnormalities / Q000453:epidemiology / Q000209:etiology*; D014916:Whole-Body Irradiation / Q000009:adverse effects