The effect of various concentrations of iodine potassium iodide on the antimicrobial properties of mineral trioxide aggregate – a pilot study

Abstract – Background: Mineral trioxide aggregate (MTA) is a multi‐purpose dental material with various uses in dentistry. Iodine potassium iodide (IKI) is the most commonly used iodine compound in endodontics. We aimed to assess the antimicrobial activity of tooth‐colored ProRoot MTA combined with IKI. Materials and methods: The antimicrobial activity of IKI was assessed at three concentrations (1%, 2%, and 4%) as the mixing agents combined with MTA against Enterococcus faecalis, Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, and Candida albicans. For each microorganism, three plates were inoculated with 100 μl of a microbial suspension (McFarland 0.5). Four wells were prepared in each plate. MTA (70 mg) was mixed with any of the three concentrations of IKI (25 μl) or sterile distilled water (25 μl) and placed in each well. The plates were incubated for 24 h at 37°C. Zones of inhibition (ZOI) were measured in millimeters by a blinded observer. Data were analyzed using analysis of variance and the Dunnett t‐test. Results: All MTA mixtures with water or IKI solutions showed inhibitory zones. The mean ZOI of each MTA/IKI mixture was not significantly different from MTA/water mixture (P > 0.05). MTA/1% IKI had smaller ZOI than MTA/water against E. coli, E. faecalis, and C. albicans. MTA/2% IKI showed larger ZOI only against P. aeruginosa. MTA/4% IKI showed larger ZOI against P. aeruginosa and E. coli (P < 0.05). Conclusions: Substitution of IKI solutions (1%, 2%, and 4%) for water did not significantly increase the antimicrobial activity of MTA.