Package of 12 pcs. For the inspection the oral cavity, to view a mirror image of the teeth in locations of the mouth where visibility is difficult or impossible. They also are used for reflecting light onto desired surfaces, indirect vision, and with retraction of soft tissues to improve access or vision.. Reflection layer is at the glass-underside and the image is reflected from below the glass-surface. More durable as they are coated on the back surface, protected by the glass. Regular mirrors reflect light from the top of the glass as well as from the silver layer. This could cause a double image. Simple stem mirror heads have a shank that is straight..