title: pH and bacterial profile of dental plaque in children and adults of a low caries population.
abstract: OBJECTIVE
  This study compares pH and microbiological profile of dental plaque in children and adults of a low caries population.
  
  
  METHODS
  Thirty-nine children, 12-14 years of age and 45 adults between 20 and 39 years of age in 5 Karen villages of the Tak province, Northern Thailand were examined for plaque, calculus, caries (DMFT) and pH measurements in resting plaque and after a sucrose rinse. Information on dietary and oral hygiene habits was obtained through interviews using a fixed questionnaire. Microbiological profile of plaque samples was analyzed with DNA-DNA checkerboard technique.
  
  
  RESULTS
  Mean DMFT was 0.77 ± 1.56 and 87% of the adults and 67% of the children were caries free (p < 0.05). The mean resting pH was for both age groups in the range of 7.0-7.1 and significantly higher than a Swedish caries free reference group. Karen adult men had significantly lower pH minimum than females and children (p < 0.05). Supragingival plaque samples showed high levels of low acidogenic and anaerobic species, which dominated over strong acid producers such as streptococci.
  
  
  CONCLUSIONS
  The study indicates that the Karen children and adults has a plaque physiology and microbiology predominating by low acidogenic anaerobes, which in addition to the low sucrose intake explains the low caries prevalence in this population.
authors.affiliation: Department of Oral Microbiology and Immunology, Institute of Odontology, Sahlgrenska Academy, University of Gothenburg, Box 450, 40530 Göteborg, Sweden.
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Raner
authors.affiliation: Department of Oral Microbiology and Immunology, Institute of Odontology, Sahlgrenska Academy, University of Gothenburg, Box 450, 40530 Göteborg, Sweden.
authors.forename: Lina
authors.initials: L
authors.lastname: Lindqvist
authors.affiliation: Department of Oral Microbiology and Immunology, Institute of Odontology, Sahlgrenska Academy, University of Gothenburg, Box 450, 40530 Göteborg, Sweden.
authors.forename: Sofia
authors.initials: S
authors.lastname: Johansson
authors.affiliation: Department of Oral Microbiology and Immunology, Institute of Odontology, Sahlgrenska Academy, University of Gothenburg, Box 450, 40530 Göteborg, Sweden.
authors.forename: Haidar
authors.initials: H
authors.lastname: Hassan
authors.affiliation: Department of Oral Microbiology and Immunology, Institute of Odontology, Sahlgrenska Academy, University of Gothenburg, Box 450, 40530 Göteborg, Sweden.
authors.forename: Anette
authors.initials: A
authors.lastname: Carlén
authors.affiliation: Princess Mother Medical Voluntary Foundation, Bangkok, Thailand.
authors.forename: Narong
authors.initials: N
authors.lastname: Suksu-art
authors.affiliation: Department of Oral Microbiology and Immunology, Institute of Odontology, Sahlgrenska Academy, University of Gothenburg, Box 450, 40530 Göteborg, Sweden. Electronic address: dahlen@odontologi.gu.se.
authors.forename: Gunnar
authors.initials: G
authors.lastname: Dahlén
mesh_terms: D000293:Adolescent; D000328:Adult; D001419:Bacteria / Q000145:classification*; D058448:Biota; D002264:Carboxylic Acids / Q000378:metabolism; D002648:Child; D003430:Cross-Sectional Studies; D003773:Dental Plaque / Q000737:chemistry* / Q000382:microbiology*; D005260:Female; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008297:Male; D008875:Middle Aged; D009693:Nucleic Acid Hybridization; D009910:Oral Hygiene; D013395:Sucrose / Q000378:metabolism; D011795:Surveys and Questionnaires; D013785:Thailand
chemical_list: D002264:Carboxylic Acids; D013395:Sucrose
keywords: Acidogenicity; Caries; DNA–DNA hybridization; Dental plaque; Supragingival microbiota; pH