The objective of this work was to determine the effect of different concentrations of chlorhexidine digluconate (CHX) on setting time, surface hardness, maximum tensile bond strength and antibacterial activity of a glass ionomer cement (GIC). The material used as control was Ketac Molar Easymix GIC. CHX was incorporated into the GIC during its manipulation at concentrations of 0.5, 1.0 and 2.0%. Antimicrobial activity against S. mutans and L. acidophilus was evaluated by means of agar diffusion test. Tensile bond strength data were analyzed statistically using Analysis of variance and Tukey's test. Setting time, Vickers hardness and agar diffusion test were analyzed using Kruskal-Wallis and Mann-Whitney tests at a significance level of 5%. It was observed that adding CHX at concentrations of 1% and 2% increased significantly the setting time of the material (p=0.012 and p=0.003, respectively). There was no significant difference between control and 0.5% CHX groups regarding the setting time. Addition of 2% CHX decreased significantly the surface hardness in relation to the control group (p=0.009), followed by the 1% CHX group (p=0.009). The tensile bond strength of the material also decreased significantly after adding CHX at a concentration of 2% (p=0.001). Addition of CHX promoted formation of an inhibition halo in both bacterial strains for all concentrations. The results showed that the best option for clinical use of GIC with CHX is at 0.5% concentration, since antibacterial activity increased and the physical-mechanical properties remained unchanged.

Although the use of LCS has not decreased the porosity of the material, this insertion method is easy, accessible, and low cost, which makes it a viable alternative of use in the ART technique and in others bucal health programs.

ResumoIntrodução: Por apresentar ampla atividade antibacteriana, a clorexidina (CHX) tem sido amplamente utilizada em odontologia, podendo ser facilmente incorporada ao cimento de ionômero de vidro (CIV) e liberada consequentemente na cavidade bucal. Objetivo: O objetivo neste estudo foi avaliar a porosidade e resistência à compressão de um CIV, ao qual foi adicionado diferentes concentrações de CHX. Material e método: Os espécimes foram preparados com CIV (Ketac Molar Esaymix) e divididos em 4 grupos de acordo com a concentração de CHX: controle, 0,5% e 1% e 2% (n=10). Para análise dos poros os espécimes foram fraturados com auxílio de martelo e cinzel cirúrgicos, de modo que a fratura era realizada no centro do corpo de prova, dividindo-o ao meio e as imagens obtidas no microscópio eletrônico de varredura (MEV) analisadas no software Image J. O teste de resistência à compressão foi realizado na máquina de ensaios mecânicos (EMIC -Equipamentos e Sistemas de Ensaios Ltda, São José dos Pinhais, PR, Brazil). A análise estatística foi realizada por ANOVA, complementada pelo teste de Tukey. Nível de significância adotado de 5%. Resultado: Não se observou alteração estatisticamente significante entre os grupos estudados tanto para o número de poros quanto para a resistência à compressão. Conclusão: O uso de CIV associado ao gluconato de CLX a 1% e 2% é a melhor opção para ser utilizada na clínica odontológica. Descritores: Cimentos de ionômeros de vidro; clorexidina; porosidade. AbstractIntroduction: For presenting wide antibacterial activity, chlorhexidine (CHX) has been extensively used in dentistry and can be easily incorporated into the glass ionomer cement (GIC) and consequently released into the oral cavity. Aim: The aim of this study was porosity and compression strength of a GIC, that was added to different concentrations of CHX. Material and method: Specimens were prepared with GIC (Ketac Molar Esaymix) and divided into 4 groups according to the concentration of CHX: control, 0.5% and 1% and 2% (n = 10). For analysis of pores specimens were fractured with the aid of hammer and chisel surgical, so that the fracture was performed in the center of the specimens, dividing it in half and images were obtained from a scanning electron microscope (SEM) analyzed in Image J software. The compressive strength test was conducted in a mechanical testing machine (EMIC -Equipment and Testing Systems Ltd., Joseph of the Pines, PR, Brazil). Statistical analysis was performed by ANOVA, Tukey test. Significance level of 5%. Result: No statistically significant changes between the study groups was observed both for the number of pores as well as for the compressive strength. Conclusion: The use of GIC associated with CHX gluconate 1% and 2% is the best option to be used in dental practice.