Prevention and Risk Factors
- Wearing a mouthguard or helmet can reduce the risk of dental injury in contact sports.
- Mouthguards are more effective when properly fitted.
- Despite their availability, mouthguard use is relatively uncommon.
- Many people do not use mouthguards even in high-risk situations or when mandated.
- Certain occlusal traits, such as class II malocclusions and increased overjet, are associated with a higher incidence of dental trauma and can be corrected by an orthodontist.
- Post-normal occlusion
- Over-jet exceeding 4mm
- Short upper lip
- Incompetent lips
- Mouth breathing
Management and Initial Assessment
- Prompt management within 20-40 minutes of dental avulsion affects the prognosis of the tooth.
- Avulsed permanent teeth should be gently rinsed with saline to avoid damaging the root.
- Replantation in the original socket and splinting by a dentist is recommended.
- Failure to re-plant the tooth within the first 40 minutes may result in a less favorable prognosis.
- Avulsed primary teeth should not be re-planted to avoid damage to the permanent dental crypt.
- Patients should be seen quickly and with urgency upon arrival at the dentist.
- Suitable storage medium should be used for the avulsed tooth.
- Thorough extra-oral and intra-oral examinations should be performed.
- Age, injury history, and clinical findings should be considered.
- Safeguarding procedures should be followed if non-accidental injury is suspected.
- Local anesthetic should be administered to minimize discomfort.
- Gentle irrigation with saline removes clots and allows proper re-positioning of the tooth.
- The tooth should be handled via the enamel on the crown, not the root.
- Debris can be removed by dabbing with saline-soaked gauze.
- Soaking the avulsed tooth in an immune-modulating drug prior to re-implantation can increase periodontal healing and tooth survival.
Biologic Basis for Success of Replantation
- The tooth is connected to the surrounding bone by the periodontal ligament.
- Replantation is possible if the halves of the ligament can be kept alive.
- Treatment should focus on preventing cell crushing and loss of normal cell metabolism.
- Tooth root cells must be protected from trauma during handling and transportation.
- Debris should be gently washed off with physiologic saline to avoid further cell crushing.
- Normally metabolizing tooth root cells have an internal cell pressure (osmolality) of 280–300 mOs and a pH of 7.2.
- Uninterrupted blood supply provides all the necessary metabolites (calcium, phosphate, potassium) and glucose for the cells.
- When a tooth is knocked out, the blood supply is cut off, leading to depletion of stored metabolites and cell death.
- Rejection of the replanted tooth by the body can occur due to replacement root resorption, where the tooth root cells become necrotic and are eaten away by the body.
- Root resorption is a slow and non-painful process that can cause bone development problems in growing children.
Storage Media
- Recommended storage media for knocked-out tooth storage include saliva, physiologic saline, milk, and pH balanced cell preserving fluids.
- Water and ice should not be used as storage media as they can damage the tooth root cells.
- Saliva causes more damage than water and can infect the tooth root cells.
- Physiologic saline has a compatible osmolality but lacks the necessary metabolites and glucose for normal cell metabolism.
- Milk is less damaging than water or saliva but does not have regenerative properties for the cells on knocked-out teeth.
Prognosis, Epidemiology, and Research
- Dental avulsion has a poor prognosis, with 73-96% of replanted teeth eventually being lost.
- Prognosis is significantly influenced by the extent of damage to the periodontal ligament (PDL), storage conditions of the avulsed tooth, and duration prior to replantation.
- Replantation within 15 minutes of the accident or storage in an optimal storage medium within one hour can improve prognosis.
- Unfavorable healing of the PDL can lead to the loss of tooth root and fractures of the crown.
- Long-term survival of the tooth depends on favorable healing of the periodontal ligament.
- Research has shown that dental avulsion is a common occurrence.
- The exact prevalence of dental avulsion varies, but it is estimated to affect a significant number of individuals.
- Dental trauma, including avulsion, can occur in both children and adults.
- The incidence of dental avulsion may be higher in certain populations or geographic regions.
- Further research is needed to fully understand the epidemiology of dental avulsion.
- Research has focused on finding the most optimum storage media for knocked-out teeth.
- Hanks Balanced Salt Solution (HBSS) is a well-known and extensively tested storage solution that maintains normal cell metabolism for long periods of time.
- Cells stored in HBSS for 24 hours maintain 90% viability, and after four days, they still have 70% viability.
- Soaking knocked-out teeth in HBSS for 30 minutes prior to replantation can reduce replacement resorption.
- Other storage liquids, such as powdered milk, Enfamil, Gatorade, and contact lens solution, have been found to be ineffective or damaging to avulsed teeth.
- Approximately 5 million teeth are knocked out each year in the United States.
- Dental avulsion is the fourth most prevalent type of dental trauma.
- The prevalence of dental trauma is estimated at 17.5% and can vary geographically.
- Males are three times more likely to suffer from dental avulsion than females.
- Up to 25% of school-aged children and military trainees and fighters experience dental trauma each year.
- The first reported cases of replanting knocked-out teeth date back to 1593.
- In 1966, a
Dental avulsion is the complete displacement of a tooth from its socket in alveolar bone owing to trauma. Normally, a tooth is connected to the socket by the periodontal ligament. When a tooth is knocked out, the ligament is torn.
| Dental avulsion | |
|---|---|
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| Specialty | Dentistry |
Avulsed permanent teeth may be replanted, i.e., returned to the socket. Deciduous teeth are not replanted because of the risk of damaging the permanent tooth germ. Immediate replantation is considered ideal, but this may not be possible if the patient suffered other serious injuries. If properly preserved, teeth may be replanted up to one hour after avulsion. The success of delayed replantation depends on the survival of the cells remaining on the root surface. Storage in an environment similar to the tooth socket can protect these cells until the operation.
