Water and aqueous sodium hypochlorite indicating endodontic monitoring devices include a cone-shaped water absorptive material and color changing system applied thereto that selectively changes to different colors when exposed to either water or aqueous sodium hypochlorite within a root canal chamber. The devices include a pH changing material, pH indicator, and pH insensitive dye. The dye imparts an initial color when the device is dry. The pH changing material and pH indicator react with water to yield a second color. In the presence of aqueous sodium hypochlorite, the device changes to a third color different from the initial color and second color as a result of bleaching the dye and/or pH indicator. Color changing devices are manufactured by applying an aqueous solution that includes a pH changing material and dye to a water absorptive cone, drying the cone, applying an anhydrous pH indicator solution, and then drying the cone again.
