title: Three-dimensional space changes after premature loss of a maxillary primary first molar.
abstract: BACKGROUND
  A space maintainer is generally preferred when a primary first molar is lost before or during active eruption of the first permanent molars in order to prevent space loss. However, controversy prevails regarding the space loss after eruption of the permanent first molars.
  
  
  OBJECTIVE
  The purpose of this study was to examine spatial changes subsequent to premature loss of a maxillary primary first molar after the eruption of the permanent first molars.
  
  
  METHODS
  Thirteen children, five girls and eight boys, expecting premature extraction of a maxillary primary first molar because of caries and/or failed pulp therapy, were selected. Spatial changes were investigated using a three-dimensional laser scanner by comparing the primary molar space, arch width, arch length, and arch perimeter before and after the extraction of a maxillary primary first molar. Also, the inclination and angulation changes in the maxillary primary canines, primary second molars, and permanent first molars adjacent to the extraction site were investigated before and after the extraction of the maxillary primary first molar in order to examine the source of space loss.
  
  
  RESULTS
  There was no statistically significant space loss on the extraction side compared to the control side (P = 0.33). No consistent findings were seen on the inclination and angulation changes on the extraction side.
  
  
  CONCLUSIONS
  The premature loss of a maxillary primary first molar, in cases with class I molar relationship, has limited influence on the space in permanent dentition.
authors.affiliation: Department of Pediatric Dentistry, The Institute of Oral Health Science, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, South Korea 135-710.
authors.forename: Kitae
authors.initials: K
authors.lastname: Park
authors.forename: Da-Woon
authors.initials: DW
authors.lastname: Jung
authors.forename: Ji-Yeon
authors.initials: JY
authors.lastname: Kim
mesh_terms: D002648:Child; D002675:Child, Preschool; D003724:Dental Arch / Q000033:anatomy & histology*; D005260:Female; D006801:Humans; D021621:Imaging, Three-Dimensional; D008297:Male; D008437:Maxilla; D003765:Models, Dental; D008963:Molar / Q000601:surgery*; D014081:Tooth Extraction / Q000009:adverse effects; D014085:Tooth Migration / Q000209:etiology; D014094:Tooth, Deciduous / Q000601:surgery*