Dental caries is an irreversible microbial disease of the calcified tissues of the teeth and it has a multifactorial origin. In India, the dental caries prevalence in 35-44 year olds was reported to be 80-95% in a DCI survey. Among the elderly in the 65-74 years age group, the DCI survey reported the caries prevalence to be about 70%, while the present survey reported it to be 51- 95% in various states. Surveys which were done on school children in India showed a carie prevalence of approximately 58%.Among the U.S. population, a survey showed an incidence of 93.8% in adults with either past or present coronal caries and an incidence of 45.3% in children 23. In countries like Brazil and China, it is reaching epidemic proportions. Thus, more effective public-health measures are needed to combat dental caries. Mutans streptococci is one of the main microorganisms which are associated with the aetiology of dental caries. Preclinical studies of immunological interventions have shown that the disease can be interrupted. Clinical trials have indicated that a mucosal immune response to Streptococcus mutans crucial antigens can influence the pathogenesis of dental caries. The dental caries vaccine, when it is used in appropriate individuals at the appropriate time, can reduce the reemergence of the disease.