It's a beautiful Saturday morning. The sun is shining. It's been a long week at the office, and you're looking forward to spending the day with your family. Suddenly, the phone rings. It's a patient. Her son was playing and a terrible accident happened. He was hit in the mouth and a permanent front tooth was knocked out! The child is frightened and in pain. The parent is frantic; she sees blood everywhere. She desperately asks, "What should I do?"
Sound familiar? If you have not experienced this scenario, most likely it's just a matter of time until you will. The accidentally avulsed tooth is a frightening experience for any child or parent. As a result of playground or sports mishaps, automobile accidents or other injuries, teeth may be literally knocked out of the mouth. Your quick action may permit such teeth to be replanted and saved for a lifetime. But like the mother above, you may be asking yourself, "What should I do?"
In 1983, the American Association of Endodontists (AAE) brought together teachers, researchers and clinicians who were recognized authorities in the area of dental injuries to develop the AAE's recommended guidelines for treatment of the avulsed permanent tooth. Over the past several years, new information and research has made it necessary to update these guidelines. Therefore, in 1993, the AAE selected a committee of its members who are knowledgeable in this subject to review and revise the guidelines. Their recommendations were printed in the premier issue of ENDODONTICS. In October 1995, the guidelines were revised again. This article has been updated to reflect those changes.
Note that these guidelines are only recommendations. Individual treatment situations may vary. For referral resources or for individual guidance on the treatment of avulsed permanent teeth, contact your local endodontist.
Updated Guidelines
The AAE's guidelines are based on a review of the pertinent literature and clinical experience in managing cases. The literature is divided into four categories: (1) clinical trials, (2) simulated injuries in animal models, (3) case reports and (4) opinion articles. The AAE recognizes that the most definitive information is gathered from properly designed clinical trials. Simulations from animal models are useful but not totally conclusive when applied to human subjects. Case reports and opinion articles have limited application. In studying a subject such as the avulsed permanent tooth, clinical trials are not always available and in many cases are impossible to perform. Therefore, these recommendations represent the current updated guidelines but are subject to revision as additional research and knowledge become available.
Transport Medium
The key to successful replantation of the avulsed permanent tooth is the preservation of the cells of the periodontal ligament (PDL), the attachment apparatus of the tooth. Time is the enemy. With every minute that passes, more of these cells will perish. Whenever possible, the injured person or someone present at the scene of the trauma should replant the avulsed tooth immediately. The tooth's own socket is the very best transport medium. Immediate replantation, however, is rarely accomplished because people at the accident site may be afraid to replant the tooth. The victim is usually in pain, uncooperative and perhaps hysterical. Parents, coaches or friends may be reluctant to attempt replantation due to fear of blood, communicable diseases or further injury to the victim.
If the tooth must be extraorally transported to the dental office for replantation, it should be handled very carefully to minimize injury to the PDL cells. The tooth should be picked up only by the crown and placed in a suitable transport medium.
Hank's Balanced Salt Solution (HBSS), a mammalian tissue culture medium, has been found to be the most suitable transport medium. HBSS can be requested by name from most major biological research supply houses. Small containers of HBSS can also be purchased over-the-counter in dental first aid kits at many local drug stores. Ideally, these small containers would be readily available at playgrounds and athletic events where dental injuries are likely to occur. Patients might also be encouraged to include an HBSS container in their family first aid kits.
If HBSS is not available, milk is considered the next best medium, followed respectively by normal saline, saliva (buccal vestibule) or water. The tooth should be kept moist during transport but not wrapped in a tissue or cloth that would injure the delicate PDL cells.
The injured person and the tooth should then be rushed to the dental office for replantation and splinting of the tooth. It is remarkable how often, in the panic of the moment, the patient arrives at the dental office only to realize the tooth was left at the playground!
When the patient arrives, the dentist must first assess the extent of the injuries. Is the tooth indeed intact, or has it been fractured? Are there any other facial injuries that will need care, such as soft tissue lacerations or fractures of bone? X-rays should be taken to help determine the extent of the injuries.
In the Dental Office
The tooth should be kept moist at all times and handled only by the crown in order to minimize damage to the periodontal ligament. The root tip should not be removed, nor should debris be scraped or brushed off the root. Rather, any surface contamination should be gently rinsed off with HBSS, saline or water. Persistent debris may be removed gently with cotton pliers or a wet gauze sponge. Vigorous, aggressive cleaning of the root surface will damage the PDL cells and lessen the chance of success.
Gently aspirate without entering the socket. If a clot is present, dislodge and remove it using light saline irrigation. Do not curette or vent the socket. The PDL cells in the socket are also easily damaged. A surgical flap is indicated only if bony fragments prevent replantation. After replantation, the facial and lingual bony plates should be manually compressed.
The patient arrives at the dental office with an avulsed maxillary central incisor.
Replantation
If the tooth has been transported in a suitable medium or if it has been out of the mouth for less than one hour, it may be replanted immediately. Some advocate rinsing the tooth in HBSS to reconstitute depleted cellular metabolites and to wash extraneous material and toxic breakdown products from the root surface. If the tooth has had an extraoral dry time greater than one hour, it is recommended that the tooth be soaked in a topical fluoride solution for 20 minutes, then rinsed with saline prior to replantation. Fluoride has been found to reduce the severity of resorption of these teeth. The AAE has not made a specific recommendation for the type or percentage of fluorides to be used, because several authors investigating the efficacy of fluoride have used different fluorides and percentages ranging from 1% to 2.4%.
Handling the tooth carefully, touching only the crown, the dentist reinserts the tooth into the alveolar socket.
Splinting
Splinting to stabilize the injured tooth is indicated in most cases. The splint allows for fibrous reattachment of the severed periodontal ligament. An acid etch/composite resin splint on the facial surfaces of the avulsed and adjacent teeth is usually all that is required. A flexible nylon monofilament attached to each tooth with resin allows for stabilization with some functional movement of the replanted tooth. The splint will allow short term fixation without interfering with normal occlusion and function. Check the incisal edges to be certain the avulsed tooth is in the proper position. Other splinting devices may be used, but circumferential wire splints that impinge on the cervical tissues are contraindicated. Long term splinting promotes replacement resorption and ankylosis. Therefore, the splint should be removed in 7-10 days and the tooth checked for excessive mobility. Functional movement of the tooth and periodontal attachment apparatus are necessary as soon as possible to discourage ankylosis. Bony fractures may result in mobility requiring longer splinting. Replantations involving fractures of the alveolar socket should be rigidly splinted for six to eight weeks.
The reimplanted tooth is splinted with soft arch wire and acid etch/composite resin.
Other Considerations
Before concluding the emergency visit, be sure to suture any soft tissue lacerations. Evaluate the patient's injuries to determine the need for systemic antibiotics and analgesics, and prescribe as needed. Chlorhexidine rinses may be beneficial in maintaining good oral hygiene of the injured dentition. Also, remember to refer the patient to a physician for a tetanus consultation. Tetanus vaccinations need to be renewed at least every ten years.
Endodontic Therapy
When a tooth is avulsed, the dental pulp is severed at the apex. In the young adult tooth with an open (divergent) apex, however, there is the possibility of revitalization of the neurovascular bundle. If a permanent tooth with an open apex has been replanted less than one hour after avulsion, the tooth should be observed every three to four weeks for evidence of pathosis. Such evidence would include pain, swelling, change in tooth color, new mobility after initial reattachment or radiographic evidence of pathosis. If any pathosis is noted, root canal therapy should be initiated immediately. The canal should be thoroughly cleaned and filled with calcium hydroxide (apexification procedure). Apexification should continue until root-end closure has occurred and the tooth is ready to obturate with gutta-percha (usually 6-24 months).
For a permanent tooth with a partially to completely closed apex and less than one hour of extraoral dry time, the pulp should be removed 7-14 days after the initial replantation. This can often be completed during the same visit in which the splint is removed. The canal system is thoroughly cleaned, shaped and medicated with calcium hydroxide. A nonsetting preparation of Ca(OH)2, commercially available from many dental manufacturers, is commonly used. This light-bodied paste is easily introduced into the canal and is readily removed when it is time to obturate the tooth. Research has shown that medicating the tooth with calcium hydroxide for as long as practical (up to 6-12 months), may inhibit destructive external inflammatory root resorption. This intracanal medicament should be changed regularly (every three months) until final obturation of the root canal system with gutta-percha and sealer.
Most often, external replacement resorption of the root, months or even years after injury, is the cause of the eventual loss of replanted permanent teeth. The exact mechanism of replacement resorption, however, is unknown. Calcium hydroxide, when placed inside the root canal system of a replanted avulsed tooth, can inhibit or even prevent resorption. This discovery has helped to increase the long term success of replanted teeth.
For permanent teeth with partially to completely closed apices and greater than one hour of extraoral time, the root canal therapy can be performed either intraorally or extraorally. Although these teeth may enjoy short term success, this long period of extraoral time will result in significant damage to the periodontal attachment apparatus. Root resorption and eventual loss of these teeth is likely. However, even short term retention of a tooth may be in an individual patient's best interest.
After the pulp is removed, the canal is cleaned and filled with Ca(OH)2 (left). Note that Ca(OH)2 is the same radiodensity as dentin. After the Ca(OH)2 is removed, the canal is obturated with gutta-percha and sealer (right).
Prognosis
Inflammatory resorption, replacement resorption (ankylosis) and delayed or lack of eruption are potential complications of the avulsed tooth. The nature and severity of the injury, the length of time the tooth is out of the mouth, the type of transport medium used and the patient's immune response to injury are factors beyond the dentist's control. The most significant factor in the prognosis of these injuries is the length of time the tooth is out of the patient's mouth. The dentist can improve the chances for successful replantation of an avulsed tooth with proper splinting, calcium hydroxide intracanal medication and endodontic treatment of the tooth. In spite of the severity of this injury, many avulsed permanent teeth can be successfully treated and continue to function for a lifetime.
These recommendations are only guidelines.
The AAE's recommended guidelines for treatment of the avulsed permanent tooth are just that—guidelines. They are intended to aid the practitioner in the management and treatment of the avulsed permanent tooth. Practitioners must always use their best professional judgement, taking into account the needs of each individual patient when choosing a treatment plan. The AAE neither expressly not implicitly warrants any positive results associated with the application of these guidelines. Although it is impossible to guarantee permanent retention of a tooth that has been avulsed, timely and proper treatment of the tooth can maximize the chances for success.
