Article
Traumatic dental injuries (TDIs) are common, affecting almost 1 in 10 children with permanent incisors and, unlike dental caries, are not associated with socioeconomic status.1,2 It is suggested that one billion living people have sustained some form of TDI.3 Those who have suffered one TDI may be susceptible to repeat injury.4 TDIs to the anterior dentition, which occur during the period of root formation, may have implications for the health and longevity of the affected teeth and, subsequently, for the dental and social experiences of the children affected. Avulsion injuries, or the complete displacement (knocking out) of a tooth from its socket, account for 0.5–3% of TDIs affecting the permanent dentition.5 The most commonly affected teeth are the maxillary central incisors, which are most frequently traumatized at ages 7–9 years, at a time when apexogenesis and root development is underway.6
The general dental practitioner (GDP) has an imperative role in the management of TDIs. Following injury, patients most commonly present to their primary care GDP for treatment.7 Furthermore, follow-up care post avulsion injury may be provided by GDPs, sometimes on a shared care basis with paediatric or endodontic specialists.8 Although avulsion is a relatively uncommon TDI, appropriate management impacts prognosis and, consequently, patient outcomes and experience. Inclusion of a trauma risk assessment in dental history may identify those at heightened risk of trauma, such as children who participate in contact sports, ride bikes, and have trampolines at home. Primary prevention of injuries with the use of sports guards, helmets and faceguards may be helpful for some. However, not all injuries are preventable, and the role of GDPs in the secondary prevention, that is the diagnosis and timely management of injuries before significant morbidity occurs, cannot be overestimated.9 Avulsion injuries tend to appropriately present as an emergency, giving rise to stress for patients, their guardians, and their dentists alike. Consequently, it is important for dentists to feel confident in managing the situation calmly, and to collect appropriate information to inform the treatment plan and aid prompt specialist referral. A number of phone apps are available to guide dentists in their decision-making.10
Prognosis and tooth survival
Appropriate immediate management of TDIs impacts prognosis and tooth survival. Tooth survival is widely defined in the endodontic literature as the functional retention of a tooth, with resolution of clinical signs and symptoms of inflammation and radiographic signs of healing.11 Tooth survival is also related to periodontal healing.12 Children and their families may be inclined to consider that the ideal outcome is to incorporate both aesthetic and functional tooth retention. Prognosis is impacted by loss of vitality, and by inflammatory or replacement root resorption.
Dental injury may result in loss of tooth vitality. In the case of immature teeth, this leads to cessation of apexogenesis, root growth and development. An immature tooth without a fully formed apex against which a root canal filling can be placed, requires a root end closure procedure prior to completion of endodontic intervention.13 Furthermore, a non-vital, immature tooth is rendered thin dentinal root walls, which may be prone to future fracture. However, when loss of vitality is detected, clinically and/or radiographically, the necrotic pulp should be extirpated without delay, and the root canal dressed with a suitable material, such as non-setting calcium hydroxide. The timely commencement of endodontic treatment is advised to limit the subsequent risk of inflammatory root resorption.
Immature avulsed teeth, replanted within an extra-oral dry time of less than 30 minutes and a total extra-alveolar time of less than 90 minutes, can be reviewed clinically and radiographically to determine whether pulp regeneration and healing occurs. There may be situations when these ideal time limits have been exceeded and the clinician decides to give pulpal regeneration a chance, for example, in the case of a very wide-open apex with little root development. It is important to monitor these teeth closely, and initiate pulp extirpation without delay, if signs of pulp necrosis or inflammatory resorption arise.
Avulsed mature teeth can be expected to undergo pulp necrosis.14 The pulp can be extirpated between day 7–10 and dressed with non-setting calcium hydroxide.
Inflammatory resorption is fast, radiolucent, and may lead to rapid tooth loss. Bacterial products within an infected root canal can track through the dentinal tubules to the external root surface, providing a stimulus for progressive inflammatory resorption whilst the necrotic pulp tissue remains in situ. Inflammatory resorption can be arrested by pulp extirpation, thorough irrigation, and root canal dressing with non-setting calcium hydroxide. Calcium hydroxide has a high pH, which acts to inhibit further microbial activity and favourably influence healing. If detected and managed prior to resorptive perforation of the root canal, once stabilized these teeth can be obturated and monitored.15
Conversely, replacement resorption is a slower process of ankylosis, which cannot be arrested once it starts. The process may occur relatively rapidly in children entering teenage years who have a higher rate of bone turnover in line with their growth and development. Ankylosis that occurs before puberty can become clinically apparent in a matter of several months. Replacement resorption that occurs prior to, or during, facial growth, may present clinically as infraocclusion of the traumatized tooth, with a high-pitched metallic note on percussion. Radiographically, a loss of the normal periodontal space is noted, with gradual replacement of the tooth with bone. Late diagnosis of infraoccluded teeth may be associated with an alveolar defect due to lack of vertical bone growth. Such alveolar defects may present a complex restorative challenge in early adulthood and give rise to aesthetic concern. Furthermore, they may complicate any intended orthodontic management plan. It is, therefore, useful to document the height of the incisal edges of the traumatized and adjacent teeth following replantation of an avulsed tooth. This may help to reduce the likelihood of failing to diagnose infraocclusion at follow-up, in case of misinterpretation as intrusion or continuing dental development. Teeth which are suspected to be undergoing infraocclusion should be referred, as soon as possible, to a paediatric dentist or orthodontist, for specialist management.12
The amount of time that an avulsed tooth spends outside of the mouth (extra-alveolar time), and the amount of time that an avulsed tooth is outside of the mouth and is dry (extra-alveolar dry time) has particular impact on prognosis and tooth survival. Avulsion injuries result in tearing of the periodontal ligament, and may also result in damage to the protective layer of cementum. The cementum is susceptible to damage during the time that a tooth is outside of the mouth, and damage to this protective layer predicts unfavourable healing and increases the risk of replacement resorption.16 A maximum extra-alveolar time of 90 minutes has been recommended for an avulsed tooth stored in an appropriate storage solution (commonly saliva, saline or milk). If an avulsed tooth is presented to you dry (often wrapped in a tissue), a maximum of 30 minutes extra-alveolar time is recommended, as damage to the periodontal ligament and subsequent resorption can be expected. However, in the absence of medical immunocompromise, head injury, or other serious facial injuries that might take priority, the decision to replant a tooth is the correct decision if there is a workable socket in which to place it.
In a healthy child, and in the absence of signs and symptoms of infection, a replanted tooth may act as a space maintainer, preserving space that is rapidly lost during facial growth, in order to allow for prosthetic replacement at an elected time. A successfully replanted tooth will preserve alveolar bone, increasing future restorative options. Furthermore, replantation of an avulsed tooth will allow patients and their families time to adjust to the idea of tooth loss, even when the prognosis is hopeless.
An important note to remember: an infraoccluding, ankylosed tooth, in a growing child is not a suitable space maintainer in the longer term (Figures 4 and 5). Infraocclusion requires prompt referral and intervention planned by a multidisciplinary specialist team, frequently led by a paediatric dentist. Treatment planned may include surgical decoronation of the crown, burial of the root, space maintenance prior to orthodontic space redistribution and long-term prosthetic rehabilitation.17
Taking a timely and effective history
When time is critical, immediate management is indicated. A succinct, yet informed, history is advised (Table 1) prior to replantation of an avulsed tooth. An aide memoir might be a useful thing to have to hand to guide trauma history-taking at a busy appointment.18 Dental trauma outcomes can be unpredictable, however, the history is invaluable for guiding the intervention required, whilst also indicating prognosis, outcomes and the possibility of safeguarding concerns.19 In an emergency situation such as an avulsion, when a child is accompanied by an adult who does not have parental responsibility, it is best practice to attempt to contact those with parental responsibility via telephone. However, do not delay replantation, as treatment in the case of avulsion should be carried out in the best interests of the child.20
| Mechanism of injury |
What happened? |
Establishing the mechanism of injury helps to identify safeguarding concerns, and informs immediate management and prognosis. |
| Ruling out head injury | Signs of head injury: loss of consciousness, amnesia, nausea or vomiting | Referral for emergency medical assessment is required if there are signs of head injury. |
| Medical history | Emphasis on identification of: cardiac conditions, immunosuppression and bleeding disorders. Tetanus status | In these cases, it is reasonable to liaise with the patient's medical team and follow their guidance before replanting. |
| Avulsed tooth | Extra-alveolar time Extra-alveolar dry time Storage solution | Informs immediate management and prognosis |
| Dental history | Previous dental trauma Previous experience of dental treatment | Previous trauma may affect the acute presentation, the injury sustained, and is likely to impact on prognosis. Young patients may be anxious; however, replantation should be attempted with agreement whenever possible, without LA if necessary, in their longer-term oral health interests. |
Clinical tips for replantation
The ability of children to co-operate with the acute management of an avulsion injury will provide an indication of their likely compliance with any treatment indicated. Children can face lengthy and complex treatment, over a multitude of visits, and in a variety of dental environments following an avulsion injury. If a child has difficulty accepting treatment, rarely it may be that replantation is not the best option for the individual, particularly if trauma history indicates that prognosis may be poor. However, it is important to remember that a dental injury is a traumatic event for children and their family, and acting in their best interests is also likely to include understanding and accepting this, whilst encouraging the best possible compliance with your plan by reassuring all those present. It is the experience of the authors that, once the knocked out tooth is replanted, compliance tends to improve as the initial shock subsides, offering an opportunity for acclimatization and behavioural management techniques, such as tell-show-do, rewarding of helpful behaviour with praise, and the use of stop signals such as a raised hand, to be used effectively. Self-help guides for children that are designed to aid their ability to cope with dental treatment can be very useful, and some, such as ‘Your Teeth You Are in Control’ available at https://llttf.com/, include resources for dental professionals.21
Splint materials
Splinting is required to provide stabilization of the tooth and encourage periodontal ligament (PDL) healing.22,23 Rigid or prolonged splinting may lead to ankylosis or replacement resorption. Furthermore, rigid splinting with tooth-coloured materials, such as composite and glass ionomer cement bonded in a strip across the teeth, is likely to result in iatrogenic damage when the splint is removed. There are various splinting techniques available (Table 2), however, splint type is typically determined by the materials which are available. Novel materials, such as the titanium trauma splint, may offer improved aesthetics for patients and ease of handling and placement for dentists.24 Splints should be kept free of the gingival marginal tissues and should not impair oral hygiene practices, as plaque accumulation may delay healing.
| Titanium trauma splint (TTS) (Figures 2 and 3) | TTSs are flexible and easy to place. Although TTSs are more expensive than orthodontic wire, a small amount of material is required and TTSs are associated with optimal patient acceptance, low incidence of soft tissue trauma, are easy to keep clean, and are well retained, making them a worthy investment for primary dental practice. |
| Composite and orthodontic wire (commonly 0.3 mm stainless steel) | A commonly used splint as the materials are often readily available. Care is required to ensure that the wire is passive and not exerting orthodontic force. |
| Orthodontic brackets and wire splint | A patient who is undergoing orthodontic treatment at the time of injury might have an appliance suitable for adjustment to splint an avulsed tooth. |
| Composite splint | Not recommended. Rigid splint which is prone to fracture, difficult to remove without inducing iatrogenic damage and difficult to clean. |
| Laboratory-made splint (frequently acrylic or ethylene-vinyl acetate) | May be useful in situations where there is difficulty placing a direct splint, however, a replanted tooth needs to be stabilized as soon as possible to encourage PDL healing. Examples include patients in the mixed dentition with spacing, mobile teeth or surrounding traumatized teeth. This splint is unsuitable if there is no laboratory on the premises. Furthermore, impressions will be required. |
Following replantation: what's next?
Once the replanted tooth has been splinted, take a baseline periapical radiograph to aid monitoring of healing and root development (in the case of immature teeth), and to detect loss of vitality, replacement and inflammatory root resorption. Ensure that adjacent and contralateral teeth are also included in the baseline clinical and radiographic assessment in case of less immediately evident injury. An immature tooth that fails to develop with the contralateral incisor can be diagnosed as non-vital. Vitality testing may be unreliable in the initial period after trauma.
Oral discomfort following TDI often hampers maintenance of oral health. Encourage patients to persevere with twice daily toothbrushing with a soft bristle brush, and to pay attention to plaque removal from the splinted teeth. Consider the prescription of a chlorhexidine or fluoride mouthwash if oral health is compromised and if caries risk is increased. Eating a soft diet will ease discomfort and will encourage the periodontal favourable healing.
Age appropriate analgesia might be recommended. There is debate regarding the need for prescription of antibiotics following an avulsion injury, and dentists are advised to adhere to accepted national guidelines.25 Commonly, antibiotics might be prescribed if the avulsed tooth is visibly contaminated by debris, if the patient is immunocompromised, or if there are soft tissue injuries.
Remember to advise that patients check their tetanus status with their general medical practitioner, in case a ‘booster’ vaccination is required. Since 1961, children born in the UK have been eligible for vaccination. Vaccine coverage varies over time between approximately 70% and 95%, with a number of people not completing the full vaccination schedule of five injections required for long-lasting protection. There is no herd immunity effect and individual vaccination is essential. Diagnosis of tetanus is often clinical. Symptoms include trismus, painful muscle spasms, pyrexia, tachycardia and sweating.
Children and their families should be informed of the potential long-term complications of avulsion injuries. They should be made aware of signs and symptoms which may arise indicating loss of vitality or resorption, which could include toothache, development of a sinus, facial swelling, persistent discoloration, increasing mobility and the appearance of a tooth ‘sinking in the gum’. Advise them to make earlier contact to enable a planned follow-up appointment to be brought forward if they have any worries. Multiple review appointments are required even in the absence of these complications. If root end closure or specialist endodontics is required, referral to a paediatric dentist is indicated, and tooth discoloration might be expected. It is wise to reiterate your advice at follow-up appointments, when the drama of the initial visit has subsided.
Splint removal and follow-up
Splinting following an avulsion injury is recommended for 7–14 days, increasing if multiple injuries, or an associated alveolar fracture, are present.26 A majority of splints are removed by the GDP in the event that any referral made to a specialist in paediatric dentistry may not have yet been undertaken.
The splint should be removed from the traumatized tooth and mobility assessed. A small amount of horizontal tooth movement might be expected initially, however, if there is vertical tooth movement, consider replacing the splint for an additional 7 days before reassessing. Remember, prolonged splinting may lead to ankylosis and it is important that the child and his/her family understand the need for splint removal as arranged.
Clinical and radiographic follow-up should take place at 4 weeks, 3 months, 6 months, 1 year and then yearly thereafter for a period of 5 years.26