Caries-free subjects have high levels of urease and arginine deiminase activity

Objectives: this study investigated the relationship between urease and arginine deiminase system (ads) activities and dental caries through a cross-sectional study. material and 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: cariesfree 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.