title: New classification of lingual arch form in normal occlusion using three dimensional virtual models.
abstract: OBJECTIVE
  The purposes of this study were 1) to classify lingual dental arch form types based on the lingual bracket points and 2) to provide a new lingual arch form template based on this classification for clinical application through the analysis of three-dimensional virtual models of normal occlusion sample.
  
  
  METHODS
  Maxillary and mandibular casts of 115 young adults with normal occlusion were scanned in their occluded positions and lingual bracket points were digitized on the virtual models by using Rapidform 2006 software. Sixty-eight cases (dataset 1) were used in K-means cluster analysis to classify arch forms with intercanine, interpremolar and intermolar widths and width/depth ratios as determinants. The best-fit curves of the mean arch forms were generated. The remaining cases (dataset 2) were mapped into the obtained clusters and a multivariate test was performed to assess the differences between the clusters.
  
  
  RESULTS
  Four-cluster classification demonstrated maximum intercluster distance. Wide, narrow, tapering, and ovoid types were described according to the intercanine and intermolar widths and their best-fit curves were depicted. No significant differences in arch depths existed among the clusters. Strong to moderate correlations were found between maxillary and mandibular arch widths.
  
  
  CONCLUSIONS
  Lingual arch forms have been classified into 4 types based on their anterior and posterior dimensions. A template of the 4 arch forms has been depicted. Three-dimensional analysis of the lingual bracket points provides more accurate identification of arch form and, consequently, archwire selection.
authors: Graduate School of Clinical Dental Science, The Catholic University of Korea, Seoul, Korea.
authors: Kyung Hee
authors: KH
authors: Park
authors: College of Medicine, The Catholic University of Korea, Seoul, Korea. ; Department of Postgraduate Studies, Universidad Autonóma del Paraguay, Asunción, Paraguay.
authors: Mohamed
authors: M
authors: Bayome
authors: Postgraduate Orthodontic Program, Arizona School of Dentistry & Oral Health, A.T. Still University, Mesa, AZ, USA. ; Graduate School of Dentistry, Kyung Hee University, Seoul, Korea.
authors: Jae Hyun
authors: JH
authors: Park
authors: Private Practice, Incheon, Korea.
authors: Jeong Woo
authors: JW
authors: Lee
authors: Department of Orthodontics, School of Dentistry, Dental Research Institute, Seoul National University, Seoul, Korea.
authors: Seung-Hak
authors: SH
authors: Baek
authors: Department of Orthodontics, Seoul St. Mary's Hospital, The Catholic University of Korea, Seoul, Korea.
authors: Yoon-Ah
authors: YA
authors: Kook
keywords: Cluster analysis; Lingual arch dimensions; Lingual arch form; Normal occlusion; Three-dimensional virtual models