title: Cluster analysis of tooth size in subjects with normal occlusion.
abstract: BACKGROUND
  Tooth-size studies are important in orthodontics. Our aim in this study was to establish normative data on tooth size with a clustering method.
  
  
  METHODS
  Dental casts of 307 subjects with normal occlusion were examined. In these subjects, the tooth-size data sets in the maxilla and the mandible were clustered for men and women by using multivariate normal mixture models. This analysis clustered the data sets into groups of observations that were cohesive and separate from the other groups. The parameters were estimated with expectation-maximization procedures, and the number of clusters was selected via the Bayesian information criterion.
  
  
  RESULTS
  Seven heterogeneous clusters in men and 4 clusters in women were identified. This study indicated that, in normal occlusion, tooth sizes are variable. These heterogeneities in the normal occlusion group seem to have contributed to the variability found in normative data.
  
  
  CONCLUSIONS
  The method used in this study seems to provide a more substantive design for artificial teeth and add an additional dimension in the process of diagnosis of patients. Further applications seem possible in dental anthropometry by simultaneously dealing with the full dentition as a data set.
authors: Department of Orthodontics, School of Dentistry and Dental Research Institute, Seoul National University, Seoul, Korea.
authors: Shin-Jae
authors: SJ
authors: Lee
authors: Sungim
authors: S
authors: Lee
authors: Johan
authors: J
authors: Lim
authors: Sug-Joon
authors: SJ
authors: Ahn
authors: Tae-Woo
authors: TW
authors: Kim
mesh_terms: D000293:Adolescent; D000328:Adult; D001499:Bayes Theorem; D016000:Cluster Analysis; D019229:Dentition, Permanent; D005260:Female; D006801:Humans; D007723:Korea; D008297:Male; D009811:Odontometry; D009929:Organ Size; D012016:Reference Values; D012727:Sex Characteristics; D014070:Tooth / Q000033:anatomy & histology*