Chemically activated, so no light is needed, Powerful 40% hydrogen peroxide gel, Opalescence tooth whitening gel contains PF (potassium nitrate and fluoride). Potassium nitrate has been shown to help reduce sensitivity. Fluoride has been shown to help reduce caries and strengthen enamel. Together they help to improve the overall health of the teeth.1-5, Fresh chemical for each application, Precise delivery, Easy to see for complete removal, Two 20-minute applications for a total of 40 minutes oftreatment time, palDam and OpalDam Green are easily expressed directly where theye needed in the mouth via the simple syringe-and-tip delivery. palDam and OpalDam Green remove easily from the mouth. Simply use an explorer or other instrument to cleanly break the cured resin from undercuts and discard. hen whitening agents with higher concentrations of hydrogen peroxide are used, they can irritate the gingiva. Expressing a ribbon of OpalDam or OpalDam Green along the gingival margin protects the soft tissues, keeping them comfortable during treatment.