Antibacterial and Mechanical Properties of Glass Ionomer Cement Containing Iranian Propolis

Introduction: Plaque accumulation during orthodontic treatment is commonly seen around orthodontic brackets and the cervical margin of the bands. Glass ionomer cement is generally used for cementing orthodontic bands. Although glass-ionomer can release fluoride, it cannot prevent tooth demineralization during orthodontic therapy. This experimental study aimed to determine the effect of adding propolis on mechanical and antimicrobial properties of glass ionomer luting cement used in orthodontics.Materials and Methods: Initially, ethanolic extract of propolis (EEP) was prepared. To evaluate the antibacterial activity, the minimum inhibitory concentration (MIC) and minimum inhibitory bactericidal concentration (MBC) of the mixture of glass ionomer with different concentrations of EEP were determined using the broth dilution method. To assess the shear bond strength, 75 sound premolar teeth were selected and randomly divided into three groups. In the first group, premolar bands were cemented with glass ionomer cement. In the second and third groups, the bands were cemented with glass ionomer cement mixed with 0.05 and 0.075 g propolis, respectively. The maximum force required for debanding was measured with an Instron machine. Mean shear bond strength was compared between the three groups using the Kruskal-Wallis test.Results: The MIC and MBC values of the mixture of glass ionomer and propolis were determined at 0.05 mg/ml and 0.1 mg/ml propolis, respectively. There was not a significant difference between the three groups regarding their mean bond strength.Conclusion: Adding propolis extract to glass ionomer cement increased the antibacterial propolis without adverse effects on the shear bond strength of orthodontic bands.