Methods, systems, and apparatus, including computer programs encoded on a computer storage medium, for receiving an image of the area of the mouth. Identifying a feature of interest within the image. Determining an actual reflectance and an actual topology of the feature of interest. Determining a desired reflectance and a desired topology of the feature of interest. Calculating an amount of DCA to be applied to a portion of the feature of interest based on comparing the actual reflectance to the desired reflectance and the actual topology to the desired topology. Causing the calculated amount of DCA to be applied to the portion of the feature of interest.