Antibacterial effects of conventional glass ionomer cement

OBJECTIVES

The antibacterial activity of conventional glass ionomer cement against three different microorganism strains alone and following incorporation of 1, 2 and 3% Benzalkonium Chloride and Cetylpyridinium Chloride was evaluated.

METHODS

Agar diffusion method was used to determine the inhibitory effect of the conventional glass ionomer cement ChemFlex on Streptococcus mutans, Lactobacillus casei and Actinomyces viscosus. Bacterial strains were inoculated into BHIB, and incubated in an anaerobic atmosphere (37 °C). From the bacteria grown in the liquid medium, the density of the inoculum was set to be equivalent to McFarland 2 standard. In Shaedler agar, 350 μL of the bacterial suspension were equally spread. Specimens (4 mm × 6 mm) were prepared from the cement without and with addition of 1, 2 and 3% Benzalkonium Chloride and Cetylpyridinium Chloride. The inhibition zones were determined after 48 hours, after 2, 7 and 21 days of incubation.

RESULTS

The combination ChemFlex + Benzalkonium Chloride has the best effect on the three analysed bacteria. The Benzalkonium Chloride antibacterial compound has a stronger antibacterial effect than Cetylpyridinium Chloride.

CONCLUSIONS

Glass ionomer cements can potentially be used as a medium for slow release of active antimicrobial components, and they have the potential to improve clinical outcomes of the cements (Tab. 3, Fig. 3, Ref. 31).

Compressive strength and setting time determination of glass-ionomer cements incorporated with cetylpyridinium chloride and benzalkonium chloride

Because of the relatively frequent occurrence of recurrent caries after a restorative treatment, and because of the huge number of cariogenic microorganisms present in the oral cavity, which present a potential risk factor regarding the development of new carious lesions, attention has increasingly been directed towards the therapeutic antimicrobial effects of restorative materials. The glass ionomer cements distinguish themselves as the most acceptable restorative materials possessing the positive characteristics of fluorine in the processes of remineralisation and antimicrobial action. In addition to the release of fluoride ions, GICs can potentially be used as templates for the release of other active antimicrobial components. The addition of antimicrobial compounds in the glass ionomer cements and analysis of their physical characteristics are very important especially for use in the posterior region of milk teeth. The aim of this study was to analyse the physical characteristics of ChemFlex and Fuji IX, conventional glass ionomer cements incorporated with the antimicrobial components Cetylpyridinium Chloride and Benzalkonium Chloride, through measurements of their setting times, and determination of their compressive strengths. Five samples of each glass ionomer with no antimicrobial compounds added were prepared--to serve as a control group; and collections of five samples of each cement with different concentrations of Cetylpyridinium Chloride and Benzalkonium Chloride--1%, 2% and 3%--added to them were also prepared--a total of 60 samples. The results of the analysis point out that it is possible to incorporate these antimicrobial agents in conventional GICs, and this is especially true when the added amount of the antimicrobial agents is 1%.

On the possibility of incorporating antimicrobial components into glass-ionomer cements

Apart from their release of fluorine ions, GICs can potentially be used as templates for the release of other active antimicrobial ingredients. The aim of this study was to investigate the possibility of incorporating an antimicrobial compound into a glass-ionomer cement. For the realization of the aim set we used the commercially available ChemFlex glass-ionomer cement, a material widely used in restorative dentistry. Three groups of the commercial ChemFlex glass-ionomer were prepared, with no antimicrobial compound added, of 5 samples each - to serve as a control group; and another three groups of the same cement of 5 specimens each were also prepared, but each with a different concentration of benzalkonium chloride added to it - 1%, 2% and 3%, respectively - a total of 15 samples. The concentrations of released ions - fluoride and chloride - were measured at predetermined time instants. In order to determine the amount of ions (Cl(-) and F(-)) released into the medium (deionized water) in which the samples had been placed, we conducted measurements with ion-selective electrodes for chloride and fluoride at different time instants. We carried out an analysis of the release of chloride in order to see whether and in what concentrations such release of chlorine, a constituent of benzalkonium chloride, occurs, and thus to conclude about the possibility of the antimicrobial effect of the glass-ionomer cement. The common feature of all three percentages of benzalkonium chloride was that there were differences between the concentrations of chloride released by the samples with and without the antimicrobial compound added.