Avulsion is defined as the exarticulation of a tooth, i.e. the tooth is displaced completely out of its socket. The incidence is approximately 0.5% to 16% of dental injuries to the permanent dentition (Andreason, 1994), with over 60% occurring close to the home or school (Hedegard et al, 1973). Predisposing factors include class II div I malocclusion, increased overjet and failure to wear a protective mouthguard playing sports. Avulsions are more common in younger patients, but can also occur in adults.
When a tooth has been avulsed, the immediacy of treatment is vital to the survival of the tooth. Maintenance of the vitality of the periodontal ligament (PDL), which allows its reattachment and reformation, is the mainstay of treatment. If replantation is not possible directly following the trauma, the tooth must be stored correctly until it can be replanted. Suitable storage media, in order of preference, are fresh milk, saliva and saline (Trope, 2002). Water should never be used, as its hypotonicity will lyse the PDL cells. The maturity of tooth development is also an important factor in considering treatment options and outcomes of avulsed teeth.
Initial assessment
Time is of the essence. A rapid assessment must be carried out. If the tooth has not been replaced, it should be stored in moist gauze while the patient is being examined.
Head injury must be ruled out. Signs and symptoms include dizziness, amnesia, nausea and loss of consciousness. Any suspicion of head injury warrants immediate referral to hospital. Referral to hospital is also required when the tooth has not been found after avulsion – in this case inhalation must be ruled out with a chest radiograph.
Immediate replantation is the single most important factor in improving the chance of PDL healing (Andreason, 1995). If, however, the tooth is not replanted when the patient presents to the dental surgery, it is important to establish when the avulsion occurred and how the tooth has been stored.
The extra-oral dry time (EODT) and the conditions of storage are important factors in tooth survival. Dry storage of longer than five minutes greatly reduces the chances of PDL healing and tooth survival (Boyd et al, 2000).
It is also important to document fully the history of the accident and all injuries sustained for future medico-legal issues.
Although important to avoid unnecessary delay before replanting, a full medical and dental history must be taken. A decision to replant an avulsed tooth in patients with certain medical conditions such as severe immunosuppression, congenital heart disease and haemophilia may be difficult.
Dental history is also important: conditions such as hypodontia or previous loss of a tooth make adequate treatment of an avulsed tooth imperative to prevent further reduction in the dentition.
The tetanus status should be checked, especially if the avulsion occurred outdoors. If a booster is required, it needs to be given within 48 hours.
In addition, the aesthetics and psychological importance of anterior teeth should not be ignored and those with a reasonable prognosis are usually replanted in these patients. Immediate follow-up with their medical team is essential.
In summary, the following information must be sought and documented:
• When, where and how the avulsion occurred
• How long the tooth has been out of the mouth (if not replanted immediately)
• The condition under which the tooth has been preserved, e.g. milk, etc
• Signs of head injury: loss of consciousness, nausea, headache, dizziness, amnesia
• Other injuries – cuts, bruises, bony fractures
• Relevant/significant medical and dental history, e.g. immunosuppression, haemophilia, epilepsy, mental disability. If in doubt, liaise with a GP/hospital consultant
• The tetanus status.
The examination
It is important to establish a systematic method of examination for all trauma cases. A trauma emergency form is useful to avoid loss of information.
Soft tissue injuries are common and often bleed copiously. Any blood should first be cleaned away using saline or chlorhexidine. This allows for better visualisation of any injuries and helps to calm both patient and guardians. The patient must be examined for facial fractures, signs of which can include:
• Obvious bony deformities
• Peri-orbital haematoma
• Subconjunctival haemorrhage with no posterior border
• Gagging open of occlusion
• Inability to open the mouth completely
• Deviation on opening
• Sublingual haematoma
• Step-deformity in the occlusion, derangement of occlusion
• En-bloc movement of a group of teeth.
Eye movements, vision and hearing should also be assessed. A complete intra-oral examination should include both soft tissues (looking for lacerations, contusions, swellings and abrasions) and hard tissues (checking all of the teeth for injury – concussion, subluxation, luxation, avulsion and fracture). Damaged, neighbouring and opposing teeth should also be assessed for mobility and baseline vitality. Finally, the injured areas and, if tooth fragments are missing, adjacent soft tissues should be radiographed.
In summary, complete examination should consist of:
• Extra-oral for fractures and other injuries
• Intra-oral of both hard and soft tissues
• Radiographs.
Initial treatment
The emergency treatment involves replanting the tooth and stabilising it to allow healing. Damage to the PDL cells must be kept to a minimum. Healthy, alive PDL cells can reattach and repopulate the root surface – 75% have been shown to reattach within three days (Andreason, 1994). An extra-oral dry time of less than 15 minutes is critical for survival of the PDL cells (Barrett et al, 1997).
EODT < 60 minutes
Closed apex
Local anaesthesia is usually required. Unnecessary manipulation must be avoided. If the tooth is contaminated, rinse it carefully with a stream of saline. Avoid touching the root. Gently flush the socket with saline to remove the coagulum. Examine the socket walls for fracture – if present reposition with a blunt instrument. Replant slowly with gentle finger pressure, protecting the airway with gauze while doing so.
Once correctly positioned, the tooth should be splinted for seven to 10 days. A flexible, light splint is essential to allow physiological movement and help prevent ankylosis. All traumatised teeth and one healthy tooth on either side are splinted together using composite and a flexible material, e.g. fishing line, a paper clip, light orthodontic wire or a titanium trauma splint (Von Arx et al, 2001). If isolation is difficult, glass ionomer or TempBond (Kerr) may be used instead of composite.
Seven to 10 days is considered the optimum period for splinting; any longer increases the risk of ankylosis (Andreason, 1994). The only indication for a longer splinting period is where there is concomitant alveolar fracture. Four to eight weeks is recommended as an appropriate splinting time in these cases. A suitable radiograph should be exposed at this stage to ensure correct positioning of the tooth in the socket.
If the tooth has been replanted at the site of injury, a full examination and history must still be carried out as detailed above.
Antibiotics should be prescribed as they are thought to be useful in preventing inflammatory resorption in the short term. Doxycycline (if the patient is older than 12 years) or amoxycillin are suitable (Trope, 1998) (use age-appropriate doses). Instruction on oral hygiene and soft diet should be given and a chlorhexidine mouthrinse recommended until splint removal.
Open apex
The AAE guidelines recommend placing immature, open apex teeth in doxycycline (100mg/20ml saline) for five minutes before replanting. This is thought to increase the chance of revascularisation (Trope, 2002), although it is not supported at present by clinical studies in humans. Again, the most important factor in survival of these teeth is immediate replantation.
EODT > 60 minutes
If the tooth has been stored dry for longer than 60 minutes, the PDL cells are damaged beyond repair. If left in place, these dead cells will invoke an inflammatory reaction, preventing PDL reattachment and healing, and instead initiate resorption of bone and root. Bone also contacts the root surface in the absence of vital PDL cells and physiological bone remodelling will eventually lead to the entire root being replaced by bone. Therefore different treatments are required with the aims of minimising these reactions from the dead cells and necrotic pulp and maintaining the tooth for as long as possible in the mouth before its inevitable loss due to ankylosis and resorption.
All debris and necrotic PDL must be removed from both socket and tooth with a scaler and/or pumice. The tooth should then be immersed in any available sodium fluoride solution for at least five minutes before replanting (AAE guidelines, 2004).
Fluoride incorporated into the root surface helps to delay the onset of ankylosis. The pulp can also be extirpated extra-orally at this stage. The tooth can now be replanted and splinted as previously described. Antibiotics and a tetanus booster (if required) should be prescribed. It is important to stress to the parents and patient that the tooth will eventually be lost.
Open apex
It is recommended not to replant open apex teeth with a dry storage time of greater than 60 minutes, as the inevitable ankylosis will lead to infra-occlusion and a bony defect in a growing child.
Follow-up treatment
The follow-up treatment depends upon at least three factors: the immediacy of replantation, how the tooth was stored before it was replanted and the maturity of the tooth.
Open apex teeth stored wet before replantation have the potential to revascularise. Treatment therefore involves removing the splint no longer than 10 days after placement and regular monitoring. Note that sensitivity testing may take up to three months to respond positively. Reviews at seven to 10 days, three weeks, one, three and six months, and then yearly for five years are appropriate. Both patient and guardians should be advised of the signs and symptoms of pulp necrosis (see later) and to attend the dental surgery should any develop. Open apex necrotic teeth will require apexification treatment with calcium hydroxide or MTA after extirpation and before obturation can be completed.
Closed apex teeth are non-vital after avulsion injury and the necrotic pulp tissue is very susceptible to bacterial contamination. The pulp therefore needs to be extirpated no later than 10 days post-avulsion; it is often easier to prepare the access cavity with the splint in place. The root canal should be filled with calcium hydroxide (Ca(OH)2) and left for at least one month. Obturation should not be carried out until a complete and intact PDL can be seen on radiographs and until certain that there are no signs or symptoms of pathology. Ca(OH)2 can be kept in the root canal, being changed three- to six-monthly, until such time.
Review and monitoring
Monitoring tests involve vitality testing, colour observation, percussion, mobility and radiographs.
Vitality testing using both cold and electric pulp testing should be carried out at every review appointment for open apex teeth. Most teeth will test negative to EPT immediately following trauma, so root canal treatment should be delayed until there is at least one other sign of loss of vitality.
Colour observation of a replanted tooth, especially of the palatal surface where change is more obvious, can be a useful hint as to the pulp status. Pink colouration indicates pulpal haemorrhage, a frequent sequel of trauma. Brown or yellow discolouration indicates sclerosis of the dentinal tubules and pulp obliteration – an attempt at repair. Grey discolouration is important to notice as it signals pulp necrosis, which warrants immediate treatment.
If the tooth becomes tender to percussion, pulp necrosis has most likely occurred. Inflammatory exudate leaking out into the periapical tissues causes inflammation and pain. The sound a tooth gives on percussion is important also – a metallic or ‘cracked tea-cup’ sound on percussion is a sign the tooth is becoming ankylosed.
Mobility can also be a useful indicator; an increase in mobility can signal periapical inflammation and abscess formation whereas a decrease in mobility often indicates ankylosis.
Radiographs can be ambiguous but if correctly interpreted can also be helpful tools. Small periapical radiolucencies, which may be the obvious beginning of periapical periodontitis in non-traumatised carious teeth, may in fact be transient apical breakdown in recently traumatised teeth – a temporary phenomenon that resolves spontaneously. Loss of the PDL space is a reliable indicator of ankylosis, while scooped-out radiolucencies on the root surface indicate external inflammatory resorption. Widening of the pulp canal space indicates internal inflammatory resorption. Conversely, a normal PDL and pulp space indicates healing.
Possible outcomes
Revascularisation and healing
This occurs in 18% to 41% of open apex teeth (Yanpiset, 2000). This is only possible in open apex teeth either immediately replanted or stored correctly until possible to do so.
External inflammatory resorption (EIR) (Finucane and Kinirons, 2003)
Evident within three weeks to four months, EIR signals pulp necrosis. It is initiated by PDL inflammation following trauma, causing resorption cavities in the cementum. Infected pulpal contents can then leak out through the open dentinal tubules, stimulating further inflammation in the PDL and prolonging the resorptive process. EIR is asymptomatic, presenting on radiographs as saucer-shaped radiolucencies on the root surface and is progressive unless treated. Treatment involves immediate pulp extirpation, debridement and filling with non-setting calcium hydroxide. Ca(OH)2 should be kept in the canal until the EIR has arrested, which usually takes 12 to 18 months.
Internal inflammatory resorption (IIR)
IIR is caused by pulpal inflammation stimulating dentine resorption. Being asymptomatic, it presents on radiographs as an enlarged root canal space. If occurring in the cervical third, the crown can take on a pinkish tinge. Treatment is as for EIR, involving removing the infected tissue and disinfecting the root canal with Ca(OH)2.
Replacement resorption and ankylosis
These processes involve progressive replacement of tooth structure with bone and are initiated by damage to the PDL and loss of PDL cells. The normal remodelling process of bone continues, not recognising tooth structure as different to bone due to the absence of PDL cells, and bone and tooth become fused. This remodelling is progressive with no treatment, resulting eventually in loss of the tooth. It presents with loss of mobility of the tooth, a high metallic percussion tone and loss of the PDL space on radiograph. In adults, replacement resorption can allow retention of the tooth for a long time. In children, however, ankylosis of the traumatised tooth results in lack of alveolar development at that site and subsequent infraocclusion that will cause a significant alveolar defect. This complicates restorative care in the future.
Other less common outcomes include arrest of root development and pulp canal obliteration.
It is important to recognise that replantation of an avulsed tooth in children is essentially a temporary measure to maintain alveolar bone height and tooth space until the child is old enough to have an implant or bridge placed. In adults, however, the tooth can be maintained for much longer as the rate of bone turnover is much slower. How long the tooth will remain in the mouth depends on the condition of the tooth when it was replanted and the rate of alveolar growth of the patient. The most important factor to note in tooth survival, however, is the immediacy of replantation.
Recommendations
Since time is critical, prepare reception staff to deal with an avulsion injury over the telephone. It may be a good idea to keep an information sheet with immediate treatment guidelines near the telephone.
Use a trauma form when examining patients to ensure all essential information is collected and documented.
Keep up to date with trauma guidelines – the RSCEng and AAE guidelines are the most useful and are available on their respective websites:
• www.rcseng.ac.uk/fds/clinical_guidelines
• www.aae.org/dentalpro/guidelines.htm.
References
American Association of Endodontics (2004) Recommended guidelines for treatment of traumatic dental injuries
Andersson L et al (1983) Fiber-glass splinting of traumatised teeth. ASDC Dent Child. 3: 21
Andreasen JO, Andreasen FM (1994) Textbook and color atlas of traumatic injuries to the teeth. 3rd ed. Copenhagen and St Louis, Munksgaard and CV Mosby
Andreason JO et al (1995) Replantation of 400 avulsed permanent incisors: Parts 1-3. Endod Dent Traumatol. 11: 51-75
Barrett EJ, Kenny DJ (1997) Avulsed permanent teeth: a review of the literature and treatment guidelines. Endod Dent Traumatol. 13: 153-163
Boyd DH et al (2000) A prospective study of factors affecting survival of replanted permanent incisors in children. Int J Paed Dent. 10: 200-205
Finucane D, Kinirons MJ (2003) External inflamm-atory and replacement resorption of luxated and avulsed replanted permanent incisors: a review and case presentation. Dent Traumatol. 19: 170-174
Hedegard B, Stallone I (1973) A study of permanent teeth in children aged 7-15 years. Part 1. Swed Dent J. 66: 431-438
RCS England Clinical Guidelines (1997) Treatment of avulsed permanent teeth in children
Trope M (2002) Clinical management of the avulsed tooth: present strategies and future directions. Dent Traumatol. 18: 1-11
Trope et al (1998) Effect of systemic tetracycline and amoxicillin on inflammatory root resorption of replanted dog’s teeth. Endod Dent Traumatol. 14: 216-228
Von Arx et al (2001) Splinting of traumatised teeth with a new device – TTS (titanium trauma splint). Dent Traumatol. 17: 180-184
The author would like to thank Dr Anne O’Connell, a consultant paedodontist at Dublin Dental Hospital who provided Figures 1 to 3 and checked that all the information presented in this article is correct and complete.
