The invention includes a noninvasive method for characterizing dental pulpal vitality of a tooth including the steps of irradiating the tooth with at least partially coherent light, and speckle imaging to provide quantitative feedback to an end user of pulpal blood flow in the tooth, and the tangible records made by such a method. In the apparatus, a liquid crystal display panel has liquid crystal cells arranged at intersections between gate lines and data lines to display an image signal in an image format different from an input image signal. The coincident active clock edges generate coincident noise currents, which elevates the total noise current. When a person presses on the start button, the cam rotates and pushes out the top gum stick enough for a person to pull it completely out of the housing.