Antimicrobial Potential of Two Oral Care Gels

Objective: To determine the antimicrobial potential of two Oral Care Gels in eight microbes compared to Crest Pro-Health Mouthrinse and Colgate Total Toothpaste using MIC and MBC assays. Methods: Overnight cultures of E. coli, S. mutans, F. nucleatum, P. intermedia, P. gingivalis, E. brachy, A. viscosus, and C. albicans were standardized to O.D. 0.11 at 570 nm. The assay was done following Baron et al. (1994). The test agents [Oral Care Gels #359 and #724 (Matrixx Initiatives, Inc., Phoenix, AZ), Crest Pro-Health Mouthrinse (Procter and Gamble, Cincinnati, OH) and Colgate Total Toothpaste (Colgate-Palmolive Company, New York, NY)] were serially diluted (1:2 dilution) to a total volume of 1 mL. The standardized organism was added to the diluted test agents (2 mL total volume). The control was a mixture of equal volume of media and standardized organism. The MIC was determined after 24 hours of incubation. A 100 µL of the mixture was plated on the appropriate agar plates to determine the MBC. Results: Colgate Total Toothpaste has no definitive MIC in six microbes due to its abrasives but it showed strongest bactericidal effect (MBC) in six of the eight microbes (e.g., 1:4096 on P. gingivalis) compared to the other three agents. Both Oral Care Gel #724 and Crest Pro-Health Mouthrinse showed comparable MIC. Oral Care Gel #724 showed a stronger MBC (1:1024) in five of the eight microbes compared to Crest Pro-Health Mouthrinse. Oral Care Gel #359 was the least effective in both the MIC and MBC assays. Conclusions: Colgate Total Toothpaste has the strongest MIC and MBC in most microbes tested, while the antimicrobial effect of Oral Care Gel #359 is minimal. Oral Care Gel #724 shows significantly better bactericidal effects than Crest Pro-Health Mouthrinse in five of the eight microbes tested.