title: Dental plaque pH and ureolytic activity in children and adults of a low caries population.
abstract: OBJECTIVE
  The aim of this study was to evaluate the plaque pH level and ureolytic activity among children and adults of Karen Hill tribes.
  
  
  METHODS
  Thirty-four children aged 6-10 years and 46 adults aged 20-38 years were interviewed regarding oral hygiene practices, sucrose intake and betel chewing. Caries experience (DMFT and DT), calculus, bleeding on probing (BoP) and Plaque index (PlI) were registered. Ureolytic activity in supragingival plaque was tested at two interproximal sites (11/12 and 41/42) with the rapid urease test (RUT). Registration of plaque pH was performed at two interproximal sites (15/16 and 31/41) before, during and 30 min after rinsing with an urea solution (0.25%). Four interproximal plaque samples (one from each quadrant) per individual were collected to test the bacterial composition using the checkerboard technique.
  
  
  RESULTS
  Children and adults had similarly low DMFT and DT values. Children had a higher baseline pH and a higher ureolytic activity in the maxilla (p < 0.05) compared with adults. A significant correlation (r (2) = 0.63) was found between baseline pH and urease activity in the mandibular anterior teeth. Caries-free individuals had a higher baseline pH compared with caries active individuals in the anterior mandibular region (p < 0.01). The microbiological composition was characterized by an anaerobic low acidiogenic microbiota.
  
  
  CONCLUSIONS
  Dental plaque pH is related to the ureolytic activity, which explains the low acidogenic plaque microflora and the low caries levels in the Karen population.
authors: Department of Oral Microbiology and Immunology, Institute of Odontology, Sahlgrenska Academy, University of Gothenburg , Sweden.
authors: Linnea
authors: L
authors: Appelgren
authors: Anna
authors: A
authors: Dahlén
authors: Cecilia
authors: C
authors: Eriksson
authors: Narong
authors: N
authors: Suksuart
authors: Gunnar
authors: G
authors: Dahlén
mesh_terms: D000328:Adult; D002648:Child; D003731:Dental Caries / Q000453:epidemiology* / Q000378:metabolism; D003773:Dental Plaque; D006801:Humans; D006863:Hydrogen-Ion Concentration; D011795:Surveys and Questionnaires; D014508:Urea / Q000378:metabolism*
chemical_list: D014508:Urea