Pose, smile, click, and a selfie is taken and may go viral on social media with a perfect smile revealing shiny white teeth. For those who resort to tooth whitening to enhance their smile, a bifunctional photodynamic dental therapy (PDDT) strategy newly developed by researchers in Tianjin will well meet their demands in a more convenient and efficient way.

Compared to traditional physical whitening treatments like polishing and veneer coverage that may cause irreversible damage to the enamel, chemical bleaching technology provides a safer alternative.It is based on the degradation of chromogen by reactive oxygen species (ROS) that can oxidize colored chromogen caused by smoking or drinking beverages to colorless smaller compounds, and disintegrate biofilm as well.

Synthetic route for ZMP and schematic illustration of using PDDT for tooth whitening 

and biofilm eradication.

PDDT strategy is such kind of chemical bleaching technology designed by Prof. Zhang Lei’s team from Tianjin University and Prof. Zhang Xu’s team from the Stomatological Hospital affiliated to Tianjin Medical University. They synthesized a highly water-soluble, biocompatible zwitterion-modified porphyrin (ZMP) and raised the reactive oxygen species output roughly 8 times higher.

According to Prof. Zhang Lei, this new strategy can not only whiten teeth harmlessly by degrading the chromogen, but also eradicate about 95% of the biofilm by disintegrating the extracellular polymeric substances.

By Eva Yin