Salivary IgA Antibody in Protective Immunity to Dental Caries

Salam, Mohammad, Hassan Oueis, and Michael O'Regan

Objective: the aim of the present study was to investigate the role of salivary IgA antibody in the protective immunity against dental caries pathogens mutans streptococci (ms).  Methods: a total of 45 5-12 year-old children from the out-patient Clinic at School of Dentistry, University of Detroit Mercy were recruited. Whole saliva stimulated by paraffin-chewing was collected and children were investigated for decayed, missing, and filled surfaces [DMFS]) and teeth (DMFT) according to WHO criteria. The Dentocult SM and Dentocult LB Strip were used to estimate ms and LB count in stimulated saliva. Oral hygiene was determined according to the simplified Oral Hygiene Index (OHI-S) of Greene and Vermillion. The level of Salivary IgA antibody against SM was determined by ELISA. Data were statistically analyzed. Results: Based on the quantity of ms in saliva four grades of ms count were classified: Grade 0 (<103cfu/ml), Grade I (<105 cfu/ml), Grade II (105-106 cfu/ ml, and Grade III (>106 cfu /ml). A significant correlation was observed between salivary ms counts and caries incidences, those with lower ms count generally have low DMFS scores and those with the higher ms count showed high DMFs scores. The result also showed that children with low caries prevalence had a significantly high amount of salivary IgA antibody against S. mutans compared to those with high caries prevalence. Significant correlation between salivary LB counts, salivary flow rate and caries prevalence were also observed. Conclusions: the results of the present study suggest that salivary anti-S. mutan antibodies are involved in the prevention and control of human dental caries. Our results also demonstrated that salivary ms and LB are strongly correlated with caries prevalence and should be considered as risk factors for dental caries.