In vitro antimicrobial activity of six pulp-capping agents

The antimicrobial activity of six commonly used pulp-capping agents was compared to reagent Ca(OH)2 by means of an in vitro microbiologic assay. Microbial samples were collected from deep carious lesions in each of twelve teeth and plated onto T-soy blood agar. Uniform disks of each pulp-capping agent were pressed slightly below the surface of each agar dish, and zones of bacterial inhibition were measured at 24 hours to the nearest 0.1 mm. All agents, including IRM, demonstrated significantly more antimicrobial activity than reagent Ca(OH)2 with the exception of Pulpdent. This tends to indicate that the antibacterial properties associated with these capping compounds are not entirely due to the high pH associated with Ca(OH)2.