title: Caries-free subjects have high levels of urease and arginine deiminase activity.
abstract: OBJECTIVE
  This study investigated the relationship between urease and arginine deiminase system (ADS) activities and dental caries through a cross-sectional study.
  
  
  METHODS
  Urease and ADS activities were measured in saliva and plaque samples from 10 caries-free subjects and 13 caries-active. Urease activity was obtained from the ammonia produced by incubation of plaque and saliva samples in urea. ADS activity was obtained from the ammonia generated by the arginine-HCl and Tris-maleate buffer. Specific activity was defined as micromoles of ammonia per minute per milligram of protein. Shapiro-Wilk statistical test was used to analyze the distribution of the data, and Mann-Whitney test was used to determine the significance of the data.
  
  
  RESULTS
  The specific urease activity in saliva and plaque was significantly higher in individuals with low DMFT scores. ADS activity in saliva (6.050 vs 1.350, p=0.0154) and plaque (8.830 vs 1.210, p=0.025) was also higher in individuals with low DMFT scores.
  
  
  CONCLUSIONS
  Caries-free subjects had a higher ammonia generation activity by urease and arginine deiminase system for both saliva and plaque samples than low caries-active subjects. High levels of alkali production in oral environment were related to caries-free subjects.
authors.affiliation: Faculty of Dentistry, University of Chile, Santiago, Chile.
authors.forename: Evelyn
authors.initials: E
authors.lastname: Reyes
authors.affiliation: Department of Operative Dentistry, Faculty of Dentistry, University of Chile, Santiago, Chile.
authors.forename: Javier
authors.initials: J
authors.lastname: Martin
authors.affiliation: Department of Operative Dentistry, Faculty of Dentistry, University of Chile, Santiago, Chile.
authors.forename: Gustavo
authors.initials: G
authors.lastname: Moncada
authors.affiliation: Institute for Research in Dental Sciences, Faculty of Dentistry, University of Chile, Santiago, Chile.
authors.forename: Miguel
authors.initials: M
authors.lastname: Neira
authors.affiliation: Department of Pathology, Faculty of Dentistry, University of Chile, Santiago, Chile.
authors.forename: Patricia
authors.initials: P
authors.lastname: Palma
authors.affiliation: Department of Operative Dentistry, College of Dentistry, Health Science Center, University of Florida, Gainesville, USA.
authors.forename: Valeria
authors.initials: V
authors.lastname: Gordan
authors.affiliation: Odontological Science Department, Faculty of Dentistry, Universidad Andres Bello, Santiago, Chile.
authors.forename: Juan Fernando
authors.initials: JF
authors.lastname: Oyarzo
authors.affiliation: Institute for Research in Dental Sciences, Faculty of Dentistry, University of Chile, Santiago, Chile.
authors.forename: Ismael
authors.initials: I
authors.lastname: Yevenes
mesh_terms: D000468:Alkalies / Q000378:metabolism; D000641:Ammonia / Q000032:analysis; D016022:Case-Control Studies; D003430:Cross-Sectional Studies; D004245:DMF Index; D003731:Dental Caries / Q000201:enzymology*; D003773:Dental Plaque / Q000737:chemistry / Q000201:enzymology*; D005260:Female; D006801:Humans; D006867:Hydrolases / Q000032:analysis*; D008297:Male; D012016:Reference Values; D012307:Risk Factors; D012463:Saliva / Q000737:chemistry / Q000201:enzymology*; D018709:Statistics, Nonparametric; D014510:Urease / Q000032:analysis*
chemical_list: D000468:Alkalies; D000641:Ammonia; D006867:Hydrolases; D014510:Urease; C019723:arginine deiminase