title: Oral microflora in preschool children attending a fluoride varnish program: a cross-sectional study.
abstract: BACKGROUND
  To compare the oral microflora in preschool children attending a fluoride varnish program with a reference group receiving a standard oral health program without fluoride varnish applications. A second aim was to relate the microbial composition to the caries prevalence.
  
  
  METHODS
  Five hundred seven 3-year-old children were enrolled from a cohort of 3403 preschool children taking part in a community based oral health project. Two hundred sixty-three of them had attended caries-preventive program with semi-annual applications of a fluoride varnish since the age of 1 year (test group) while 237 had received standard preventive care (reference group). Oral samples were collected with a sterile swab and analysed with checkerboard DNA-DNA hybridization using 12 pre-determined bacterial probes. Caries and background data were collected from clinical examinations and questionnaires.
  
  
  RESULTS
  Gram-positive streptococci (S. intermedius, S. salivarius, S. oralis) were most frequently detected and displayed the highest counts in both groups. There were no significant differences between the groups concerning prevalence of any of the selected bacterial strains except for S. oralis that occurred less frequently in the reference group. In children with caries, V. parvula were significantly more common (p < 0.05) while strains of Lactobacillus, Bifidobacterium and Neisseria were more prevalent among the caries-free children (p < 0.05).
  
  
  CONCLUSIONS
  A 2-year community program with semi-annual fluoride varnish applications did not seem to significantly influence the oral microflora in preschool children.
  
  
  BACKGROUND
  www.controlled-trials.com (ISRCTN35086887) 20131216 'retrospectively registered'.
authors.affiliation: Division of Pediatric Dentistry, Department of Dental Medicine, Karolinska Institutet, Huddinge, Sweden. maria.anderson@ftv.sll.se.|Department of Pediatric Dentistry, Eastman Institute, Public Dental Service, Stockholm, Sweden. maria.anderson@ftv.sll.se.|Pedodonti, Folktandvården Eastmaninstitutet, Dalagatan 11, SE-11324, Stockholm, Sweden. maria.anderson@ftv.sll.se.
authors.forename: Maria
authors.identifier: http://orcid.org/0000-0003-2765-5931
authors.initials: M
authors.lastname: Anderson
authors.affiliation: Division of Pediatric Dentistry, Department of Dental Medicine, Karolinska Institutet, Huddinge, Sweden.|Department of Pediatric Dentistry, Eastman Institute, Public Dental Service, Stockholm, Sweden.
authors.forename: Margaret
authors.initials: M
authors.lastname: Grindefjord
authors.affiliation: Division of Pediatric Dentistry, Department of Dental Medicine, Karolinska Institutet, Huddinge, Sweden.
authors.forename: Göran
authors.initials: G
authors.lastname: Dahllöf
authors.affiliation: Department of Oral Microbiology and Immunology, Sahlgrenska Academy at the University of Gothenburg, Gothenburg, Sweden.
authors.forename: Gunnar
authors.initials: G
authors.lastname: Dahlén
authors.affiliation: Department of Odontology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.
authors.forename: Svante
authors.initials: S
authors.lastname: Twetman
mesh_terms: D002327:Cariostatic Agents; D002675:Child, Preschool; D003430:Cross-Sectional Studies; D004245:DMF Index; D003731:Dental Caries / Q000517:prevention & control*; D005260:Female; D005459:Fluorides; D005460:Fluorides, Topical; D006801:Humans; D008297:Male
chemical_list: D002327:Cariostatic Agents; D005460:Fluorides, Topical; D005459:Fluorides
keywords: Bacteria; Caries prevention; Community health program; Fluoride varnish; Preschool children