title: [Salivary factors associated to the prevalence and increase of dental caries in rural schoolchildren].
abstract: OBJECTIVE
  To evaluate the association between saliva and prevalence of dental caries.
  
  
  METHODS
  Two-year longitudinal study in rural schoolchildren at Cruz del Eje, Argentina between 2000 and 2002. The study population comprised all schoolchildren (N=196) aged 5 to 14 years of both sexes attending eight rural schools. They were assessed at three different time points (N=46): baseline, 12 and 24 months. Salivary components and DMFT and dmft indexes were used. Nominal variables, "decay" and "new decay", were created to assess risk of decay at baseline, 12, and 24 months, respectively. Principal component analysis was applied to select salivary factors associated to decay and then they were categorized according to the median as a cutoff value.
  
  
  RESULTS
  High prevalence of decay (50%-90%) was found at the three time points of study. There was significantly increase in caries at 12 months (p=0.000) compared to that seen at 24 months. At baseline there were homogeneous low levels of calcium and phosphate and a significant association (p<0.050) between calcium and phosphorus and calcium/phosphorus molar ratio and decay.
  
  
  CONCLUSIONS
  Phosphorus levels and calcium/phosphorus molar ratio can be considered risk factors for the development of caries in populations with characteristics similar to those studied.
authors.affiliation: Equipo de Investigación en Prevención Contextualizada, Facultad de Odontología, Universidad Nacional de Córdoba, Córdoba, Argentina. lilacor@hotmail.com
authors.forename: Lila Susana
authors.initials: LS
authors.lastname: Cornejo
authors.forename: Mabel
authors.initials: M
authors.lastname: Brunotto
authors.forename: Elena
authors.initials: E
authors.lastname: Hilas
mesh_terms: D000293:Adolescent; D001118:Argentina / Q000453:epidemiology; D002648:Child; D002675:Child, Preschool; D004245:DMF Index; D003731:Dental Caries / Q000453:epidemiology* / Q000209:etiology; D005260:Female; D006801:Humans; D008297:Male; D009909:Oral Health; D015995:Prevalence; D011446:Prospective Studies; D012307:Risk Factors; D012423:Rural Health; D012424:Rural Population; D012463:Saliva / Q000737:chemistry*; D012574:Schools; D013997:Time Factors