title: Decreasing caries prevalence in Japanese preschool children is accompanied with a reduction in mutans streptococci infection.
abstract: OBJECTIVE
  To evaluate the association between decreasing caries prevalence in Japanese preschool children and mutans streptococci (MS) infection.
  
  
  METHODS
  The prevalence of caries and salivary MS was examined in 1- to 3-year-old preschool children in 1995 (n = 135) and 2000 (n = 118).
  
  
  RESULTS
  The caries prevalence for 3-year-old subjects significantly declined from 65.1% to 37.5% (p < 0.01), reflecting the data seen in Japanese national oral health surveys in 1993 and 1999. Salivary MS detection for 3-year-old subjects significantly declined from 68.3% to 37.5% (p < 0.05). On the other hand, the decrease in the prevalence of caries and salivary MS was not significant in 1- and 2-year-olds. The correlation between caries experience (dft) and the salivary MS score for 3-year-old subjects with low caries prevalence in the later examination (r(s) = 0.479, p < 0.001) was comparable with that in 1995 (r(s) = 0.462, p = 0.001).
  
  
  CONCLUSIONS
  The recent decrease in decay in Japan is accompanied with a reduction in MS infection in the deciduous dentition. MS levels are closely related to caries prevalence in preschool children regardless of the extent of caries.
authors.affiliation: Department of Oral Health Sciences and Division of Social Dentistry, Dental Research Center, Nihon University School of Dentistry, Tokyo, Japan. seki-m@dent.nihon-u.ac.jp
authors.forename: Mitsuko
authors.initials: M
authors.lastname: Seki
authors.forename: Yoshihisa
authors.initials: Y
authors.lastname: Yamashita
mesh_terms: D002675:Child, Preschool; D003731:Dental Caries / Q000453:epidemiology* / Q000382:microbiology; D004812:Epidemiologic Methods; D005260:Female; D006801:Humans; D007223:Infant; D007564:Japan; D008297:Male; D012463:Saliva / Q000382:microbiology; D013290:Streptococcal Infections / Q000453:epidemiology*; D013295:Streptococcus mutans