Dental caries is one of the serious public health problems affecting children and adults worldwide. The prevalence of the disease is high in children. It is the most important oral disease and is of medical, social and economic importance. The disease is the result of a dental decay process in which mainly acidogenic and aciduric bacteria residing in a complex biofilm degrade tooth structure, leading to demineralization and cavitation. Unlike classical infectious diseases, which are caused by microbial pathogens, dental caries is caused by resident oral microflora. Streptococcus mutans appears to play an important role in the initiation of dental caries since its activities lead to colonization of the tooth surface, dental plaque or oral biofilm formation and demineralization of tooth enamel by acids (Loesche. 1986).