Abstract: Aim and Hypothesis: The aim of the study was to compare the potential antibacterial and antibiofilm formation of Revamil® and manuka honey solutions alone as well as in combination. The hypothesis being tested is that the combination of Revamil® with manuka will have more antibacterial and antibiofilm formation than Revamil® and manuka used alone. Materials and method: The antimicrobial ... read moreproperties of Revamil®, manuka, a 1:1 mixture of both as well as a sugar control were tested at 50, 25, 12.5, 6.25, 3.12, 1.56 % (w/v) concentrations against four plaque-associated bacteria: Streptococcus mutans (S. mutans), Streptococcus salivarious, Streptococcus sanguinis, and Aggregatibacter actinomycetemcomitans. The minimum bacteriostatic concentrations (MIC) and the half maximal inhibitory concentration (IC50) were determined for each testing solution. Methylglyoxal (MGO) titration assay with 6.25% Revamil® was used to recreate the synergy of the combined honey. A biofilm disruption assay was performed using different concentrations of honey on S. mutans, S. sanguinis, A. actinomycetemcomitans and a mixture of all the bacteria including S. salivarius. Finally, the pH of the honey solutions at all the tested concentrations was determined. Kruskal-Wallis test with pair wise Mann-Whitney U test was utilized to compare between the groups. Results: The results indicated that manuka and the combined honey solution had more efficacy than Revamil® on all tested organisms. A. actinomycetemcomitans was more sensitive to all tested honey solutions with MIC of 6.25% compared to the other bacteria that had MICs ranging from 12.5 to 25%. The synergy analysis revealed that experimental additivity exceeded theoretical additivity (p <0.001). The MGO analysis showed a potentiating effect when MGO was mixed with 6.25% Revamil® compared to MGO alone. The biofilm disruption assay yielded insignificant results except for the multi-species biofilm in which manuka had more effect on biofilm disruption than the combined honey (p =0.08). The pH analysis revealed that all used solutions aside from 50 and 25% (pH 4-6) were on the neutral side with a pH =7. Conclusion: Although the sugar control had antibacterial effect this study highlights the bactericidal properties of both Revamil® and manuka, which is enhanced when both honeys are combined regardless of the sugar content and pH. Similarly, MGO bactericidal activity is enhanced when combined with Revamil®.