Compounds that competitively inhibit binding of CSP to S. mutans histidine kinase are provided. The compounds are preferably a peptide or an antibody, and are preferably a derivative of [SEQ ID NO:2], a fragment of [SEQ ID NO:2] or a derivative of a fragment of [SEQ ID NO:2]. Methods of making these compounds and their use for inhibiting the growth of S. mutans, for inhibiting dental caries, and for improving dental health are also disclosed.