title: Immediate and six-month space changes after premature loss of a primary maxillary first molar.
abstract: BACKGROUND
  Premature loss of primary maxillary first molars has been associated with a number of consequences (such as tipping of the first permanent molar). The aim of the authors' study was to investigate dental-arch space problems arising as a result of premature loss of a primary maxillary first molar.
  
  
  METHODS
  This study was composed of 19 children who experienced unilateral premature loss of a primary maxillary first molar. The authors used each patient's intact contralateral arch segment as a control. The authors obtained maxillary dental study casts two or three days after the tooth was extracted, as well as six months later.
  
  
  RESULTS
  The D + E space from the extraction side six months after removal of the tooth (mean +/- standard deviation, 15.62 +/- 1.13 millimeters) was significantly smaller than the space on the control side (16.88 +/- 1.12 mm) and the initial D + E space (16.70 +/- 0.69 mm). The authors found a significantly shorter arch length (25.47 +/- 1.58 mm) and larger intercanine width (31.29 +/- 2.49 mm) six months after the tooth was extracted compared with the initial arch length (25.66 +/- 1.64 mm) and intercanine width (30.42 +/- 2.64 mm).
  
  
  CONCLUSIONS
  The early space changes to the maxillary arch subsequent to premature loss of a primary maxillary first molar are primarily distal drift of the primary canines toward the extraction space and palatal migration of the maxillary incisors. Although 1 mm of space was lost, which is statistically significant, this is not likely to be of sufficient clinical significance to warrant use of a space maintainer. If palatal movement appears to be needed, the dentist should consider use of a palatal arch rather than a band-and-loop maintainer.
  
  
  CONCLUSIONS
  The effects of space maintainers need to be re-evaluated in cases of unilateral premature loss of a primary maxillary first molar.
authors.affiliation: Pediatric Dentistry, Chang Gung Memorial Hospital-Kaohsiung Medical Center, Chang Gung University College of Medicine, Kaohsiung, Taiwan.
authors.forename: Yai-Tin
authors.initials: YT
authors.lastname: Lin
authors.forename: Wen-Hsien
authors.initials: WH
authors.lastname: Lin
authors.forename: Yng-Tzer J
authors.initials: YT
authors.lastname: Lin
mesh_terms: D002648:Child; D002675:Child, Preschool; D003724:Dental Arch / Q000033:anatomy & histology*; D005260:Female; D006801:Humans; D008297:Male; D008963:Molar; D015588:Observer Variation; D009811:Odontometry; D015203:Reproducibility of Results; D016388:Tooth Loss / Q000150:complications*; D014094:Tooth, Deciduous