Decay or trauma involving the root structure of the tooth leads to death of the tooth. When the pulp becomes infected due to a deep cavity or fracture that allows bacteria to seep in, or injury due to trauma, it can die. Damaged or dead pulp causes increased blood flow and cellular activity, and pressure cannot be relieved from inside the tooth. Pain and sensitivity are the first symptoms of a root canal infection. Pain in the tooth is commonly felt when biting down, chewing on it and applying hot or cold foods and drinks. Root canal treatment is a procedure done to save the damaged or dead pulp in the root canal of the tooth by cleaning out the diseased pulp. A crown with or without a post may be placed over the tooth for further long-term protection. The only alternative to root canal therapy is to extract the tooth. Though a simple extraction may be cost less initially, the space left behind will require an implant or a bridge, which ultimately can cost more.