TREATMENT OF DENTOALVEOLAR INJURIES, PART II

This is the second part of a series of articles which attempt to describe the classification and treatment of dentoalveolar injuries. Please refer to the first article in the series which has been archived.

Extrusive Injuries

The tooth should be repositioned as close to its original position as possible using digital pressure and then splinted. Approximately 64% of such teeth undergo pulpal necrosis and approximately undergo external resorption. The treatment of lateral luxation is essentially the same.

Avulsion Injury

May occur alone or in conjunction with alveolar bone fracture. Children are especially at risk for this type of injury due to the fluid state of the periodontium as teeth develop and erupt. The supporting bone is highly elastic and permits bodily movements of teeth (avulsion) more readily than simple fracture. The most frequently avulsed tooth is the maxillary central incisor. The survival of avulsed teeth is dependent on the maintenance of viable periodontal ligament cells. Thus handling of the avulsed tooth and its subsequent treatment is aimed at maximizing cell survival. The PDL is usually restored within 3-4 weeks of replantation. Cell decay studies have shown that replantation can be successful up to two hours post-avulsion. However, there is an inversely proportional relationship between time out of the mouth and survival. Outcome is also affected by the degree of closure of the dental apex and there are specific guidelines to deal with different situations. Teeth with immature apices have a better prognosis than those with closed apices. Teeth that have been avulsed should be handled carefully with attention to preservation of the PDL. The root surface should not be curretted. Ideally the tooth should be replaced in the socket as soon as possible. If this is not possible the tooth should be stored in milk or preferably Hanks solution if available. Milk is a short term storage medium and can support a tooth for up to 6 hours provided that the tooth is placed therein within 15 to 20 minutes of avulsion. Milk does not restore cell morphology; it does slow cell death in the PDL. Hanks solution is an ideal storage medium and with it time to replantation is no longer a critical factor within reasonable limits. Teeth that have been extraoral for 15-120 minutes should be soaked in Hanks solution for 30 minutes prior to replantation. When the tooth has been replanted it should be splinted and the patient should be given antibiotic therapy for 7 - 10 days to lessen the chance of secondary infection. The tooth should be relieved from the occlusion, preferably by adjusting the opposing tooth.

If the tooth has been extraoral for more than 120 minutes then it should have its PDL removed either chemically and/or mechanically and the tooth should be prepared in the hand for endodontic therapy prior to replantation. Further treatment of the root involves citric acid, stannous fluoride and doxycycline soaks of the root to attempt to maximize the prognosis for the tooth.

Prognosis for Dentoalveolar Trauma

The basic reactions of teeth to trauma include hyperaemia, pulpal hemorrhage and necrosis, pulpal calcification, internal and external resorption, inflammatory and surface resorption.

The complications of dental injuries to the primary and permanent dentition include: Failure to erupt; color change; infection and abscess; loss of space; ankylosis; injury to the developing tooth; abnormal exfoliation; resorption of root structure; cost of therapy. Studies have shown a 50% (range 12% to 69%) incidence of damage to the permanent tooth bud from displacement/avulsion injuries of the primary dentition.

A high frequency of disturbance is seen in the development of permanent teeth in intrusion (69%) and avulsion (52%); Extrusion and subluxation represent lower risks. Disturbance to the permanent dentition is seen more often in injuries in the under 4 year old group. It should be stressed that the full extent of injury to the damaged area cannot be assessed until the permanent teeth have fully erupted.

Intrusion and avulsion injuries of the primary incisors have the most serious effect on the developing permanent dentition, with more than half of such injuries resulting in damage to the permanent dentition. The younger the patient the more likely the chance of damage to the permanent dentition.

The prognosis for pulp survival in dental injury depends largely on the state of apex development, with open apex teeth having approximately twice the rate of survival over time as compared with teeth with closed apices.

Avulsed teeth that have been replaced after 2 hours out of the mouth are virtually certain to undergo replacement resorption.

With any type of displacement injury remember to utilized the skill of an orthodontist to guide final tooth position. Pulpal vitality should be monitored and endodontic therapy started as soon as necessary based on the clinical findings at the time.

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