title: Reduced salivary flow and colonization by mutans streptococci in children with Down syndrome.
abstract: OBJECTIVE
  Although individuals with Down syndrome have considerable oral disease, the prevalence of dental caries in this group is low. The present study aimed to compare known risk factors for dental caries development in children with Down syndrome and a matched population (siblings). In both populations, the number of acidogenic microorganisms, such as mutans streptococci, lactobacilli and Candida species, and the paraffin-stimulated pH, flow rate and IgA concentration in whole saliva were evaluated and compared.
  
  
  METHODS
  Saliva was collected, and the caries index was evaluated in 45 sibling pairs aged between 6 and 18 years old. The salivary IgA concentration was determined by immunoturbidimetry. Salivary mutans streptococci, lactobacilli and Candida species were quantified on mitis salivarius agar containing bacitracin and 20% sucrose, rogosa agar supplemented with glacial acetic acid and sabouraud agar supplemented with chloramphenicol, respectively.
  
  
  RESULTS
  Down syndrome children had a higher caries-free rate (p<0.05) and lower salivary mutans streptococci counts (p<0.03) compared to their siblings. Similar numbers of lactobacilli and Candida species were found in both groups. Salivary flow rates were 36% lower in Down syndrome children compared to their siblings (p<0.05). The salivary pH did not differ between Down syndrome children and controls. The Down syndrome children had an IgA secretion rate 29% lower than that of their siblings, but this difference was not statistically significant.
  
  
  CONCLUSIONS
  In conclusion, the lower number of mutans streptococci in the saliva may be one of the factors contributing to the lower caries rate observed in Down syndrome children, despite evidence of hyposalivation.
authors.affiliation: Faculty of Dental Medicine, Porto University, Porto, Portugal.
authors.forename: Cristina
authors.initials: C
authors.lastname: Areias
authors.forename: Benedita
authors.initials: B
authors.lastname: Sampaio-Maia
authors.forename: Maria de Lurdes
authors.initials: Mde L
authors.lastname: Pereira
authors.forename: Alvaro
authors.initials: A
authors.lastname: Azevedo
authors.forename: Paulo
authors.initials: P
authors.lastname: Melo
authors.forename: Casimiro
authors.initials: C
authors.lastname: Andrade
authors.forename: Crispian
authors.initials: C
authors.lastname: Scully
mesh_terms: D000293:Adolescent; D002175:Candida / Q000302:isolation & purification; D002648:Child; D015169:Colony Count, Microbial; D003731:Dental Caries / Q000382:microbiology*; D004314:Down Syndrome / Q000150:complications*; D005260:Female; D006801:Humans; D007071:Immunoglobulin A, Secretory / Q000032:analysis; D007778:Lactobacillus / Q000302:isolation & purification; D008297:Male; D012307:Risk Factors; D012636:Secretory Rate; D012801:Sibling Relations; D013295:Streptococcus mutans / Q000254:growth & development*; D014987:Xerostomia / Q000382:microbiology*
chemical_list: D007071:Immunoglobulin A, Secretory