Dental post. Close-up of the lower jaw of a patient showing a dental post. The original damaged canine tooth has been removed. The post is surgically embedded in a hole drilled in the jawbone in place of the root. This is used to support a tooth-like crown. On the left dental plaque has built up at the base of the incisors, and the gums are receding. Bacteria in plaque break down sugar in the mouth, producing an acid which progressively destroys the teeth. It is sometimes necessary to repair a damaged tooth with a filling, or extract it and replace it with a crown.