The impact of photodynamic therapy on the viability of Streptococcus mutans in a planktonic culture.
OBJECTIVE
This study investigated the effect of photodynamic therapy (PDT) with toluidine blue O (TBO) and a light-emitting diode (LED) on the viability of Streptococcus mutans cells in a planktonic culture.


BACKGROUND
Growth of Streptococcus mutans is the first step in the development of tooth decay. The use of light and dyes promotes cellular death in a noninvasive way, reducing treatment time.


METHODS
The LED used in this study had output power of 116 mW, its energy was 21 J, and the fluency was 2.18 J/cm(2). Samples were prepared and divided into five groups: (1) control group (-); (2) control group (+); (3) TBO; (4) LED; and (5) LED + TBO.


RESULTS
One hundred percent of the bacteria were killed following irradiation with LED and TBO. The biofilm that formed on the glass surfaces was analyzed by SEM and colony count.


CONCLUSIONS
It was demonstrated that PDT was efficient at killing microorganisms and preventing the formation of biofilms.
D018441:Biofilms / Q000254:growth & development / Q000528:radiation effects*; D002470:Cell Survival / Q000528:radiation effects; D004396:Coloring Agents; D054023:Lasers, Semiconductor; D008855:Microscopy, Electron, Scanning; D010778:Photochemotherapy; D010789:Phototherapy / Q000379:methods*; D013295:Streptococcus mutans / Q000502:physiology / Q000528:radiation effects*; D014048:Tolonium Chloride
D004396:Coloring Agents; D014048:Tolonium Chloride