Effect of Propolis Aqueous Extract on Antimicrobial Activity and Flexural Strength of Conventional and Highly Viscose Glass Ionomer

Abstract

Background: This study aimed to assess the effect of adding propolis to glass-ionomer cements (GICs) on their antimicrobial and physical properties. Methods: For the evaluation of the antimicrobial properties of conventional (Fuji II) and high-viscous (Fuji IX) GICs containing propolis, 120 glass-ionomer disks with the dimensions of 10 × 2 mm were prepared in three groups of control, 25% propolis, and 50% propolis. Then, these GICs were placed in the Streptococcus mutans culture media. After 24 h of incubation, the inhibition zone diameters of the disks were recorded. For the evaluation of flexural strength, 30 samples (six groups of 5) with the dimensions of 2 × 2 × 25 mm were prepared and measured by a universal testing machine. The Kolmogorov-Smirnov test and SPSS software (version 21.0) were used for statistical analysis and ensuring normal data distribution. One-way analysis of variance was used for comparing the mean values of the groups, and Tukey’s HSD test was used for pairwise comparison of the groups. The duration of the study setup was 9 months. Results: An inhibition zone was not observed in any of the study groups. There was no significant difference between the flexural strength values of the three groups of the Fuji IX (P = 0.905) and also between the three groups of the Fuji II (P = 0.096). However, the Fuji IX samples had higher flexural strength values than the Fuji II glass-ionomer specimens (P < 0.001). Conclusions: The addition of different concentrations of propolis aqueous extract to conventional and high-viscous GICs did not have a significant effect on their antimicrobial properties and flexural strength.