ObjectivesThis study investigated the relationship between urease and arginine deiminase system (ADS) activities and dental caries through a cross-sectional study.Material and MethodsUrease 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.ResultsThe 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.ConclusionsCaries-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.

Higher levels of ureolytic (statistically significant) and arginolytic activity (trend) in saliva were associated with lower DMFT/dmft scores in 8 year old children. There was a higher production of ammonia from the arginine deiminase system than the urease enzyme in saliva (p>0.05).

ABSTRACT. Introduction: the objective of this study was to use real-time qPCR to identify and quantify the Streptococcus mutans species in