The use of methylene blue as mouthwash in periodontology

The aim of this study is to investigate the cytotoxicity effects of methylene blue on the human gingival fibroblasts cell-lines in vitro. 3T3 human gingival fibroblast cell-lines were used to evaluate the cytotoxicity of mouthwashes containing methylene blue and chlorhexidine gluconate. The cultured fibroblasts were divided into two groups which subjected into chlorhexidine gluconate or methylene blue in vitro. The cells viability was determined at 30 seconds, 1 minute and 3 minutes of exposure to mouthwashes using by XTT colorimetric assay. Spectrophotometric absorbance was measured at 550 nm using ELISA analyzer. The IC50 values were calculated for each time points for methylene blue and chlorhexidine gluconate mouthwashes. The effect of the methylene blue and chlorhexidine gluconate on the human gingival fibroblast viability was expressed as a percentage of the control groups. Comparison between two groups in different time and concentration values showed that, chlorhexidine gluconate were found to be more cytotoxic on gingival fibroblast than methylene blue. Cell viability exposured to methylene blue in 1% concentration during 3 minutes was 99% and in 100% concentration the cell viability was 88%. The chlorhexidine gluconate at the same conditions was 92% and 18% respectively. Our study demonstrates that 100% chlorhexidine gluconate (0.2% chlorhexidine gluconate concentration in commercially available products) has much more cytotoxic effect than methylene blue to human gingival fibroblast at clinical use time and different concentrations in vitro.