Antimicrobial activity and pH measurements of bioactive materials

Objectives: The purpose of this in vitro study was to compare the antimicrobial effect and pH of two calcium silicate cements (Mineral Trioxide Aggregate - MTA Angelus HP and iRoot BP Plus) and new bioactive restorative resin composite (ACTIVA) against aerobic bacteria: Enterococcus faecalis, Enterococcus faecum, Staphylococcus aureus and Streptococcus mutans, and strictly anaerobic bacteria: Prophyromonas gingivalis, Actinomyces israelii and Peptostreptococcus anaerobius and a yeast: Candida albicans by using Agar diffusion test.
Methods: The materials were tested immediately after manipulation and applied to the agar plates, NaOCl was used as a positive control while dry filter paper was used as a negative control. The size of inhibition zone for each material was measured after 12, 24 and 48 hours. For pH measurement, materials were prepared and crushed and distilled water was used as a control and media for measurement
Results: The one-way Anova test revealed that iRoot BP Plus significantly showed superior antimicrobial efficacy compared to MTA-HP against the following species; Staphylococcus aureus, Streptococcus mutans, Enterococcus faecalis, Enterococcus faecium, Peptostreptococcus anaerobius and Candida albicans (P<0.05). All of the tested materials did not show any antimicrobial effect against Porphyromonas gingivalis and Actinomyces israelii. The new bioactive resin composite material (ACTIVA) showed the least antimicrobial activity against the previously mentioned microorganisms except E. faecalis. NaOCl significantly showed the highest antimicrobial activity among the test group (P < 0.05). iRoot BP Plus was more alkaline (pH 12.1±0.14/ 11.9±0.25) in comparison to MTA-HP (pH 11.6±0.16/ 11.2±0.10) while ACTIVA was slightly acidic (pH 5.4±0.09/ 6.5±0.08)
Conclusions: Calcium silicate retrograde filling materials had superior antimicrobial efficacy and higher alkaline pH when compared to resin composite materials.