title: Retrospective analysis of factors influencing the eruption of delayed permanent incisors after supernumerary tooth removal.
abstract: OBJECTIVE
  This was to assess the predictability of eruption of delayed permanent incisors after supernumerary removal and creation of adequate space, in relation to: root maturity, degree of vertical impaction, and degree of angulation of impaction.
  
  
  METHODS
  The dental records of children with supernumerary teeth delaying the eruption of permanent incisors were analysed. The type of a supernumerary tooth, its location and position were recorded, along with the stage of root maturation, angulation and vertical distance of impaction of the permanent incisor. At the initial surgery, the unerupted supernumerary tooth and any retained primary incisors were removed. The unerupted permanent incisor was not exposed. If necessary, the maxillary primary canines were removed to create sufficient space for eruption of the delayed permanent tooth. A secondary surgical procedure was planned after 18 months if there was no significant progress of the permanent tooth towards eruption.
  
  
  METHODS
  All data were entered onto a Microsoft Excel spread sheet and analysed using Fisher's Exact Tests throughout due to the small numbers.
  
  
  RESULTS
  Sixty-six supernumerary teeth were removed, 22 from boys and 44 from girls with ages ranging from 6 to 10 years 6 months at the time of surgery. Primary canines were extracted in 59.1% of cases. Spontaneous eruption occurred in 89.4% of delayed permanent teeth. The mean time to eruption was 9.2 months (median = 7 months). There was no statistically significant association between tooth eruption and root maturity or the degree of vertical impaction. There was an association between eruption and the degree of the angle of impaction of the permanent incisor (p<0.05).
  
  
  CONCLUSIONS
  The majority of delayed permanent teeth erupt spontaneously if sufficient space is available or created at the time of removal of the unerupted supernumerary. The angulation of impaction of the permanent incisor is associated with a delay in eruption.
authors: Department of Child Dental Care, Glasgow Dental Hospital and School, Glasgow, Scotland. r.bryan@leeds.ac.uk
authors: R A
authors: RA
authors: Bryan
authors: B O
authors: BO
authors: Cole
authors: R R
authors: RR
authors: Welbury
mesh_terms: D002648:Child; D002675:Child, Preschool; D003481:Cuspid / Q000601:surgery; D019229:Dentition, Permanent; D005260:Female; D006801:Humans; D007180:Incisor / Q000254:growth & development*; D008297:Male; D012189:Retrospective Studies; D013997:Time Factors; D014078:Tooth Eruption; D014095:Tooth, Impacted / Q000601:surgery*; D014096:Tooth, Supernumerary / Q000601:surgery*; D014097:Tooth, Unerupted / Q000601:surgery