- Cracked Teeth: Apart from injury to the tooth, habits such as teeth grinding, clenching and chewing on hard objects can cause cracked teeth. Symptoms of cracked teeth include erratic pain from chewing and temperature extremes. Pulp irritation and damage may result. Extensive cracks can lead to pulp tissue infection, which may spread to the bone and gum tissue surrounding the teeth.

Since pulp damage is common with cracked teeth, root canal treatment often is needed. Following root canal treatment, your dentist will restore your tooth with a crown to hold the pieces together and protect the cracked tooth. If the crack spreads below the gum line, or if the cracked tooth has irreparably deteriorated, tooth extraction will be necessary. However, pulp damage and root canal treatment are not always consequences of cracked teeth. For example, when the pointed part of a tooth's chewing surface (cusp) breaks off naturally or has to be removed by a dentist, the pulp is seldom damaged and rarely needs root canal treatment. Instead, your dentist usually will place a full crown restoration.

- Chipped, Fractured and Broken Teeth: While minor chips or fractures do not require immediate care, they should be treated to avoid sharp edges that can cut soft oral tissue (tongue, lips) and for esthetic reasons. If a piece of the outer tooth is chipped off, but the pulp is undamaged, your dentist may simply smooth out the rough edges or replace the missing portion using tooth-colored composite. In other instances, it may be possible to bond a broken tooth fragment back in place. If you lose a larger part of the tooth, but the pulp is not irrevocably damaged, your dentist may restore and protectively cover the tooth with a porcelain veneer or crown ("cap"). If the pulp has been seriously damaged, the tooth will require root canal treatment before a crown can be placed. A tooth that is vertically fractured or fractured below the gum line will require root canal treatment and a protective restoration. If there isn't sufficient structure remaining to hold a crown, tooth extraction may be needed. Your dentist may then recommend placement of bridges, implants or a removable appliance.

- Dislodged (Luxated) Teeth: When injured, a tooth may be pushed to one side, or out of or into its socket. Luxated teeth need to be repositioned and stabilized by your dentist as soon as possible. The quicker the stabilization, the better the long term potential for saving luxated teeth. Dislodged permanent teeth usually need root canal treatment; treatment should begin approximately one week after the injury. Children between seven and 12 years old may not need a root canal since their teeth are still developing. Research indicates that stem cells present in children's pulp tissue can be stimulated to complete root growth and heal the pulp after injuries and/or infection. Consult an endodontist to see if this might be the case with your child's injured tooth.

- Knocked Out (Avulsed) Teeth: If a tooth is completely knocked out, you must seek dental/medical care immediately. If possible, it's best to put the tooth back in its socket (except with children under 12 years old, who may swallow it). Hold the tooth by the crown (chewing edge), never the roots. If dirty, rinse with saliva or water. Do not use soap or other cleaning agents; never scrape, scrub or brush the tooth. Making sure it's facing the right way, place the tooth back into its socket as quickly as possible. The less time the tooth is out of its socket, the better the chance of saving it (two hours is the most for survival). To stabilize the tooth and minimize bleeding, gently bite on clean gauze, a wet tea bag or a wad of cloth until you reach your dentist/hospital emergency room.

If you're unable to put the tooth back in its socket, it's critical to keep the tooth moist. Immediately place the tooth in a cup of cold milk, saliva, cool water with saline solution (not contact lens solution or tap water), or special first-aid solutions (such as Save-A-Tooth) available at drugstores. You also can put the tooth between your gum and cheek or underneath your tongue.

If you can get to dental/medical care within 30 minutes and the tooth has been properly preserved, chances are good that it can be successfully re-implanted. In most cases, only permanent (adult) teeth are re-implanted. Primary (baby) teeth usually are not re-implanted to avoid injury to the developing permanent tooth growing inside the bone.

- Broken Jaws: After an accident, if you can't bring your upper and lower teeth together, your jaw may be broken. Seek immediate attention from your dentist/hospital emergency room. A broken jaw must be set back into its proper position and stabilized with wires as it heals (six weeks or more, depending on your age and severity of fracture). An oral/maxillofacial surgeon usually performs this procedure.
(http://www.yourdentistryguide.com/tooth-injury/)