Enzyme activity of urease and arginine deiminase in saliva and dental plaque in children and their relationship on dental caries

Objectives: This cross sectional study assessed the enzyme activity of urease and arginine deiminase (ADS) in saliva and dental plaque in 6 and 8 year-old children and correlated them with their caries status.
Methods: One hundred twenty-seven 6 to 8 year-old children, with lower and lower middle socioeconomic levels, were randomly chosen for assessment of the enzyme activity of urease and ADS in saliva and dental plaque. Calibration curves ammonium and total protein were performed to measure ammonium concentration and specific enzymatic activity of ADS and ureases by spectrophotometry. DMFT and dmft indexs (inter-examiner Kappa=0.77) were gathered. Caries activity was scored and divided in 3 groups: Group A: Index zero: without lesions; Group B: Moderate Index: 1 to 3 enamel caries lesions; and Group C: High Index: more than 4 enamel caries lesions. The saliva and dental plaque of children were sampled under fasting condition and children refrained from any oral hygiene procedures during the 12 hours that preceded the sample collection. Kruskal-Wallis and Mann Whitney tests were used for group comparisons.
Results: Children distribution per group were A=33, B=58 and C=36. DMFT average were: 0.37(±0.74) and dmft: 3.58(±3.48). For plaque, Urease activity results (µmol/min/mg/protein) were statistically significant different (p=0.00): Group A=75.06 (±264.03); Group B=48.40(±145.28); and Group C=13.65(±23.45). ADS activity was statistically significant different (p=0.00): Group A=101.13(±259.90), Group B=60.04 (±50.95) and Group C=14.63(±16.86). For saliva, Urease activity results (µmol/min/mg/protein) were statistically different (p=0.00): Group A=7.91(+10.72); Group B=5.51(±8.18); and Group C=3.18(±9.83). ADS activity was statistically significant (p=0,00): Group A= 30.12 (±17.42), Group B= 23.35 (±15.51) and Group C= 16.07 (±25.33). In plaque there was a higher ADS enzyme activity than urease .
Conclusions: Higher levels of ureolytic and arginolytic activity in plaque were associated with lower DMFT/dmft scores in 6 to 8 year old children.
Ascribed to project FONIS-CONICYT-SA13I20205