Tooth bleaching by using a helium-based low-temperature atmospheric pressure plasma jet with saline solution

In this study, tooth bleaching was performed by using a helium-based low temperature atmospheric-pressure plasma jet (He-APPJ) with saline solution to avoid ozone and hydrogen peroxide (H2O2) harm. In this study, tooth samples were treated through three approaches, namely a helium flow with saline, H2O2 gel, and He-APPJ with saline. The bleaching efficacy of the He-APPJ treatment was the highest among the three groups. Furthermore, scanning electron microscopy images showed that enamel treated with He-APPJ was much less damaged than that treated with H2O2 gel. In addition, ozone tests showed that APPJ produced little ozone (