title: Variation in form of mandibular, light, round, preformed NiTi archwires.
abstract: OBJECTIVE
  To evaluate the variation in form of nickel-titanium (NiTi) archwires by comparing them with the dental arch form of normal Japanese subjects before and after placing them in the first molar tubes.
  
  
  METHODS
  The mandibular dental casts of 30 normal subjects were scanned, and the dental arch depths and widths from the canine to the first molar were measured. Standardized images of 34 types of 0.016-inch preformed NiTi archwires were also taken in a 37°C environment, and the widths were measured and then classified by cluster analysis. Images of these archwires placed in a custom jig with brackets attached at the mean locations of the normal mandibular central incisors and first molar were additionally taken. The widths of the pooled and classified archwires were then compared with the normal dental arch widths before and after placement in the jig and among the groups (P < .05).
  
  
  RESULTS
  The archwires were classified into three groups: small, medium, and large. The archwire widths in the small and medium groups were narrower than those at all examined tooth widths, except in the case of the premolars of the medium group. After placement in the jig, the pooled archwire widths were found to be significantly narrower and wider at the canine and second premolar, respectively, than at the dental arch, but not in the individual comparisons between groups.
  
  
  CONCLUSIONS
  The variation observed in the mandibular NiTi archwire forms significantly decreased following fitting into the normal positions of the first molars.
authors.affiliation: a  Graduate Student, Department of Orthodontics, School of Life Dentistry at Tokyo, The Nippon Dental University, Tokyo, Japan.
authors.forename: Naomi
authors.initials: N
authors.lastname: Saze
authors.affiliation: b  Professor and Chair, Department of Orthodontics, School of Life Dentistry at Tokyo, The Nippon Dental University, Tokyo, Japan.
authors.forename: Kazuhito
authors.initials: K
authors.lastname: Arai
mesh_terms: D003722:Dental Alloys; D003724:Dental Arch; D006801:Humans; D008334:Mandible; D008963:Molar; D009532:Nickel; D009969:Orthodontic Wires; D014025:Titanium
chemical_list: D003722:Dental Alloys; D009532:Nickel; D014025:Titanium
keywords: Dental arch form; Nickel-titanium (NiTi); archwires