The persisting bacterial presence, together with a lack of thoroughly hermetic seal between the prepared tooth walls and the final finished fixed prosthesis walls allow bacterial leakage and thus may be involved in the development of recurrent caries.several species of bacteria may be isolated from plaque associated with carious lesions and pulpal inflammation. Streptococcus mutants is one of the bacteria most frequently implicated in dental caries.Antibacterial activity, during and after setting, assumes clinical relevance because this property may help in the elimination or reduction of bacteria that have remained viable in the cavity wallsor bacteria that may gain access to the cavity through micro leakage channels. This book provides access and compares the incessant antibacterial activity of Glass Ionomer Cement(Ketac-Cem), Zinc Phosphate Cement(Harvard) and Polycarboxylate(Poly-F) in 2 powder: liquid ratios(wt/wt) by undertaking Direct-Contact Test and Agar Diffusion Test