The word caries is derived from latin, meaning 'rot' or decay . It is similar to the Greek word ker meaning death. Dental caries is defined as an infectious microbiologic disease of the teeth that results in localized dissolution and destruction of calcified tissue. There is presently alarming rate of increase in the prevalence of dental caries in developing countries. Dental caries is a multi factorial disease in which there is an interaction between three principal factors, a. A susceptible Host tissue (b) Micro flora with a cariogenic potential (c) A suitable local substrate. In addition...