a dental composition and method for bleaching vital and non - vital teeth , comprising a preselected , concentrated , aqueous solution of hydrogen peroxide and a nonaqueous component mixed to form an aqueous gel or paste , with the nonaqueous component including an inert silica gelling agent , an accelerator , a plasticizer and thickening agent , and means for establishing a substantially fixed time period for treating the teeth in response to the application of optical energy . a redox color indicator is used to transform from one color to another over the fixed time period to provide a visual indication that the treatment is completed , as well as an indication that the peroxide solution was active .