About a quarter of all children will damage their permanent teeth by l4 years of age, while a third will do some damage to their primary (baby) teeth. As might be expected, twice as many boys damage their teeth. Having prominent (buck) teeth further increases the risk depending on how far forward the front teeth are positioned.
	Dentists today are seeing fewer children with dental injuries, as most children who play contact sports are now required to wear mouth guards. The other main cause of injuries are non-contact leisure activities such as bike riding, skateboarding, in-line skating, swimming etc. Permanent teeth that have been knocked-out can be saved but it is vital that you act quickly:

• Knocked-out tooth (dental avulsion)
   A. DIAGNOSIS
  A dental avulsion occurs when a tooth is completely displaced or knocked out of the dental socket. Dental avulsion injuries occur most frequently in children between the ages of 7 and 9, an age when the alveolar bone surrounding the tooth is relatively resilient. Adult teeth that are avulsed (knocked-out) should be considered for immediate replantation in order to enhance the tooth’s long-term prognosis.
  
  The best way to preserve a tooth that has been knocked out (avulsed) is to put it back into its socket as quickly as possible. The single most important factor to ensure a favorable outcome after replantation is the speed with which the tooth is reimplanted. If immediate replantation isn't possible, the tooth should be placed into a protective solution.
  
  Avulsions are associated with poor post-treatment outcomes. Almost all replanted teeth show replacement resorption and ankylosis – because immediate replantation rarely happens. Replacement resorption leads to fusion of the tooth root with the adjacent alveolar bone. In children who have not achieved skeletal maturity, replacement resorption leads to progressive infraocclusion (the tooth appears unerupted) during the adolescent growth spurt.
  
  Every tooth has a protective layer surrounding the root, which is called the periodontal ligament. The periodontal ligament is very sensitive, and will quickly dry out and die - unless the tooth is immediately placed in a protective solution, such as milk or saline. With every minute that the tooth is left out of the mouth to dry, more cells in the periodontal ligament will die. After 15 minutes of dry storage, irreversible damage to the periodontal cells (the root covering) occurs. If the cells of the periodontal ligament are allowed to die, the child will eventually loose the tooth. The goal of reimplanting the tooth into the socket is to preserve the health of the tooth's outer periodontal ligament.
  
    B. FIRST AID FOR AN AVULSED TOOTH
     I. PRIMARY TOOTH
• A primary tooth that has been avulsed is usually not reimplanted. The risk of injury to the developing permanent tooth bud is high.
     II. PERMANENT TOOTH
• 1. Do not touch the root of the tooth. Handle the tooth by the crown only.
• 2. Rinse the tooth off only if there is dirt covering it. Do not scrub or scrape the tooth.
• 3. Attempt to reimplant the tooth into the socket with gentle pressure, and hold it in position.
• 4. If unable to reimplant the tooth, place it in a protective transport solution, such as Hank's solution, milk, or saline. This will hydrate and nourish the periodontal ligament cells which are still attached to the root. A small container of Hank's Balanced Salt Solution can be purchased in dental emergency kit form at many drug stores. Contact lens solution is not an acceptable storage medium.
• 5. The tooth should not be wrapped in tissue or cloth. The tooth should never be allowed to dry.
• 6. Take the child to a dentist or hospital emergency room for evaluation and treatment.
• 7. Radiographs may need to be taken of the airway, stomach, and mouth if the tooth cannot be found .
• 8. Tetanus prophylaxis should be considered if the dental socket is contaminated with debris.
  
    C. DENTAL OFFICE TREATMENT FOR AN AVULSED TOOTH
     I. PRIMARY TOOTH
• The primary avulsed tooth is generally not reimplanted – to avoid injury to the developing permanent tooth bud.
     II. PERMANENT TOOTH
• 1. Place the tooth in Hank's Balanced Salt Solution.
• 2. Take a medical and dental history, and perform a physical examination. Rule out CNS injury.
• 3. Examine the orofacial area. Inspect the oral soft tissue for embedded tooth fragments, lacerations, or ecchymosis (bruising). Palpate the teeth and dentoalveolar area to check for mobility. Evaluate TMJ function.
• 4. If the tooth is missing, rule out aspiration or ingestion.
• 5. Take a maxillary occlusal radiograph, as well as a lateral anterior radiograph of the injured area. Consider taking a panoramic radiograph to rule out condylar or mandibular fractures.
• 6. Gently aspirate the injured area without entering the socket. If a clot is present, dislodge and remove it using light saline irrigation. Do not curette the socket.
• 7. The tooth should be carefully held by the crown, and not by the root. The avulsed tooth should be reintroduced into the dental socket slowly.
  
  TOOTH REIMPLANTATION GUIDELINES
• 1. For A Mature Tooth With A Closed Apex: If the extraoral dry time is <60 minutes, reimplant as soon as possible. If the extraoral dry time is >60 minutes, soak in citric acid or curette the root; then soak in stannous fluoride for 10 minutes. Rinse with saline. Perform root canal therapy one week following the trauma.
• 2. For An Immature Tooth With An Open Apex: If the extraoral dry time is <60 minutes, soak in doxycycline (1mg/20 ml saline) for 5 minutes. If the extraoral dry time is >60 minutes, provide the same treatment as for a closed apex.
• 3. Apply a flexible, functional splint for 7 to 10 days. If an alveolar fracture is present, provide a very rigid splint for 4-6 weeks.
• 4. After reimplantation, gently compress the facial and lingual bony plates. Suture any lacerations.
• 5. Provide antibiotic coverage for 10 days to prevent infection. Consider prescribing tetracycline or penicillin. Penicillin is prescribed as: PenVK 500mg, 4X per day, for 10 days.
• 6. Prescribe chlorhexidine gluconate rinses, and provide oral hygiene and diet instructions.
• 7. Provide analgesics to control pain. For children, consider prescribing acetaminophen and codeine (Tylenol #3) for mild to moderate pain. The dose is 15 mg/kg/dose of acetaminophen, every 4 hours. Do not exceed 2.6 g/day of acetaminophen.
• 8. Arrange for tetanus vaccination if the wound was dirty, or if the vaccination requires updating.
  
  FOLLOW-UP CARE AFTER 7 TO 10 DAYS
• 1. For a tooth with an open apex, the goal is revascularization of the pulp. For a tooth with an open apex and extraoral dry time <60 minutes: no endodontic treatment is initially required. Re-evaluate every 3-4 weeks for pathosis. In case of pulp pathosis, begin an apexification procedure.>
• 2. For a tooth with an open apex and extraoral dry time >60 minutes: begin an apexification procedure.
• 3. For a tooth with a closed apex: provide traditional endodontic treatment and obturation. This is done to prevent of eliminate toxins from entering the root canal space.
• 4. Remove the splint at this 7 to 10 day treatment visit.
• 5. Patients are recalled to the dental office every 3-4 weeks of sensitivity testing. Thermal tests using difluorodichloromethane or “Endo Ice” may be used.
• 6. Long-term follow-up is essential for 2 to 3 years after the reimplantation procedure.
  
  ENDODONTIC OBTURATION FOR AVULSED TEETH WITH CLOSED APICES
• 1. For a tooth with endodontic treatment started 7 to 10 days after avulsion, obturate after 1 to 2 months of treatment with calcium hydroxide paste.
• 2. For a tooth with radiographic signs of resorption or pathosis, or for a tooth which had endodontic treatment started more than 14 days after the avulsion, treat long term with a dense mix of calcium hydroxide. The calcium hydroxide is changed about every 3 months. Obturate when an intact lamina dura can be visualized.
   

Summary of Emergency Care by Parents would be:

1. Find the tooth. Search around the scene of the accident as teeth can be thrown a surprising distance. Check the person's clothing for teeth that are thought to be lost. Remain calm. The injury often looks worse than it actually is.

2. If the tooth is clean, replant immediately into the socket. The best place for the tooth is back inside the socket. Use the other teeth as a guide. Hold the tooth by the crown. Do not touch any part of the root of the tooth as this can damage the delicate cells on the surface. Push the tooth into the socket. This should be done quickly and the tooth will normally click back into position.

3. If the tooth is dirty, then rinse in milk or saline and then replant.

4. If the tooth cannot be re-planted, store the tooth in milk. The tooth must be kept moist, but DO NOT USE WATER. Milk is the best fluid in which to store the tooth before seeing your dentist. It is readily available, is cold, generally sterile and will keep the cells on the outside of the root alive. If milk is unavailable then use saline (for contact lenses); plastic cling wrap; or place the tooth under the tongue or between the person's lip and gums.

5. See your dentist immediately. The tooth will need to be held in place with a splint for about two weeks. After this time the pulp (nerve) needs to be removed and a root canal therapy performed. It is essential that a root canal therapy (RCT) is started within two weeks, otherwise the tooth may be rejected by the body.

Even if all the above points are followed, the tooth may still be lost. The prognosis is determined by the amount of time out of the mouth; the damage to the root surface of the tooth; and whether or not the tooth was kept moist.

Never throw away a broken tooth fragment or a tooth that has been knocked-out. Even those teeth with a poor long-term prognosis can still be replanted to guide normal growth and dev-elopment of the teeth.

In summary, replant the tooth as soon as possible or store in milk, and see your dentist quickly.