Destruction of cariogenic biofilms by antimicrobial photodynamic therapy mediated by phycocyanin and toluidine blue along with sodium fluoride varnish or titanium tetrafluoride.

OBJECTIVE

Evaluation of the effect of phycocyanin (PC) and toluidine blue (TBO) along with sodium fluoride varnish (FV) or titanium tetrafluoride (TiF) under the conditions of antimicrobial photodynamic therapy (PDT) on a dual-species cariogenic biofilm and on remineralization process.

DESIGN

After the development of Streptococcus mutans and Lactobacillus acidophilus dual-species biofilms on the human enamel disks, they were divided into 11 groups (n = 9): Control (0.9 % saline), PC, TBO, FV, and TiF alone, PC and TBO in combination with a 635 nm diode laser (PDT treatment), PC-PDT (PC + FV or TiF + 635 nm diode laser), and TBO-PDT (TBO + FV or TiF + 635 nm diode laser). After the treatment, crystal violet assay was performed to determine the reduction of cariogenic biofilms. Enamel remineralization changes were analyzed using energy dispersive X-ray spectroscopy (EDX) and field emission scanning electron microscopy (FESEM) for the calcium and phosphorus (Ca/P) ratio.

RESULTS

Only TBO-PDT showed superior antibiofilm activity when TiF was applied. Furthermore, the highest Ca/P ratio was found after treatment of enamel surfaces with TiF-TBO-PDT. The FESEM images showed that the enamel disks treated with TiF plus TBO-mediated PDT exhibited surface coating. However, TiF plus PC-mediated PDT cannot repair demineralized enamel.

CONCLUSIONS

These data suggest that TBO-PDT along with TiF can effectively reduce cariogenic biofilms and significantly remineralize enamel disks, opening new avenues in caries prevention.