Written by Edwin S. Mehlman, DDS Monday, 30 June 2003 19:00
Dentists see patients who have been involved in accidents, sports in-juries, or other incidents resulting in trauma to the jaws and teeth. This article will review the types of traumatic injuries that affect the teeth and the treatment required for each type of injury.
For medico-legal reasons, a thorough history should be taken when the patient first appears in the dental office, prior to treatment. This history should include the time of the accident, the nature of the accident, and whether any other person has rendered treatment for the present injury. The site, location, and size of all soft-tissue wounds should be recorded.
Soft-tissue injuries that occur as a result of trauma can include lacerations, abrasions, concussions, punctures, and penetrations. If teeth are fractured and there is also a laceration of the tongue or lip, a radiograph of the lacerated area should be taken at short exposure and minimal KVP to check for tooth fragments in the wound. All soft-tissue wounds should be thoroughly cleansed and sutured, if necessary.
Traumatic injuries of the teeth may be classified as follows:
(1) Tooth fractures:
•Fracture into enamel
•Fracture into dentin
(2) Nondisplaced injury:
(3) Displaced injury:
•Labial, lingual, mesial, or distal luxation
Any patient who has received trauma to the teeth, no matter how innocuous, should be examined over time. In addition to emergency care, the patient must be recalled periodically to check for pulp vitality of the involved teeth. The author follows up at a minimum of 1 week and 3 months. These examinations should include a radiograph, a pulp test, and periodontal examination of all involved teeth.
The most innocuous injury that may be seen after a traumatic incident is craze lines in the enamel. If these craze lines are aesthetically acceptable, they do not require treatment. However, if they are aesthetically unacceptable, an aesthetic bonding procedure may be utilized.
FRACTURE INTO ENAMEL
A fracture into the enamel of a tooth, which does not expose any dentin, is simply treated with a composite restoration. Alternatively, if there are no aesthetic concerns and the fracture is minor, it may be appropriate to simply smooth the enamel surface.
FRACTURE INTO DENTIN
If the fracture includes both enamel and dentin, a composite buildup must be performed. The technique for the bonding procedure is generally similar to that performed for the fracture into enamel. However, in this case, prior to acid-etching, calcium hydroxide must be applied to cover any exposed dentin.
If the fracture is subgingival, a periodontal procedure may be required to expose tooth structure. After this procedure, etch the enamel using acid gel rather than acid liquid. After drying the area, apply the acid gel. Even if blood enters the area after the gel is placed on the tooth, it will not interfere with the etching. However, it must be emphasized that with either liquid or gel, the acid must not touch the soft tissue or a sloughing of tissue may result.
When a crown-root fracture occurs as a result of trauma, the labial fracture is usually on the crown, and the lingual fracture advances onto the root. Prior to determining treatment or prognosis, all mobile portions of tooth should be removed. If the root fracture is then determined to be greater than one third of the root length, extraction of the tooth is indicated. In this case, regardless of treatment, the long-term prognosis is unsatisfactory. If the fracture involves less than one third of the root length, single-visit root canal treatment should be performed. If this option is selected, the apical 5 mm of the canal is filled with gutta-percha, and a post is cemented into the canal. Prior to cementation of the post, however, a hook should be placed on the portion of the post that extends past the fractured edge of tooth and into the oral cavity. This hook will be used to attach a rubber band so the tooth can be orthodontically extruded so all margins will become supragingival. As soon as adequate extrusion has occurred, a crown is fabricated. To prevent the tooth from intruding back to its original position, it must be stabilized for 6 months by splinting the crown to an adjacent tooth. This therapy requires close cooperation between the restorative dentist, the endodontist, and the orthodontist.
A radiograph of a traumatized tooth may reveal a root fracture. The clinician must determine from the radiograph whether the coronal portion of the tooth exhibits extrusion and is not in close approximation to the apical portion of the root. If there has been extrusion, after administration of local anesthesia, the coronal portion should be repositioned into its proper alignment. These teeth should then be stabilized for 2 months with acid-etch composite that is placed on the labial surface for maxillary anterior teeth, or the lingual surface for mandibular anterior teeth. Whenever composite is used to stabilize a traumatized tooth and an edentulous area is involved, wire should be used in the splint, with composite placed over the wire. Composite cannot be used alone across edentulous spaces, since it will fracture. In these cases, chemically cured rather than light-cured composite should be used because the light-cured material is very difficult to remove when the splint is no longer needed. During the 2 months with the splint, root fractures will often heal with a callous formation between the 2 sections of root.
When root fractures occur, the pulp may remain vital, and root canal therapy will not be necessary. However, the pulp will often become necrotic coronal to the fracture line, but remain vital in the apical portion of the root. Thus, if there is no mobility of the coronal portion of the tooth, no response to pulp tests 3 months posttrauma, and no periapical pathology, the root canal should be cleaned and shaped, and filled with gutta-percha to the fracture line only. Just as this procedure is performed to prevent the toxins from the necrotic coronal portion of the pulp from interfering with the healing callous formation that is occurring between the 2 portions of root, it is imperative that no cement be pushed into the fracture line, since this also will interfere with the healing of the fracture. If there is mobility of the coronal portion of the tooth at this 3-month period, and the fracture is in the coronal one third of the root, the crown and root to the fracture line should be extracted and the remaining portion of the tooth can be managed as described in the previously discussed crown-root fracture section for a fracture involving less than one third of the root. However, if the fracture is greater than one third of the root length, the entire tooth must be extracted.
Radiographs should be taken of this tooth routinely. If a periapical lesion occurs, the root canal must now be cleaned and shaped to the apex and filled with gutta- percha. Again, no filling material should be pushed into the fracture line.
Concussion is the condition in which a tooth is not mobile after trauma, but pain is elicited when the tooth is percussed or upon mastication. This condition requires that the tooth be stabilized with composite for 1 week. The pulp should be tested for vitality when the splint is removed and again 3 months later. Because the pulp may recover from this type of injury, the 1-week pulp test should be used as a baseline for comparison with a 3-month test and should not be used to determine treatment. A nonresponsive pulp test at 3 months indicates that the pulp has become necrotic, and root canal treatment should be accomplished as soon as possible. A positive test at 3 months indicates that root canal treatment will probably never be necessary. However, the dentist should continue to observe the tooth each time the patient comes to the office for any other procedures.
Subluxation is when a tooth is mobile following trauma but has not been displaced. Bleeding is usually observed around the gingival crevice, indicating that the periodontal ligament has been injured. This tooth should be stabilized with composite for 2 weeks. As is the case with concussion, the pulp of the subluxated tooth may recover.
The decision to perform root canal therapy is made based on tooth vitality 3 months after the trauma.
Tooth displacement can be divided into 3 categories: (1) extrusion; (2) intrusion; and (3) mesial, distal, labial, or lingual luxation.
When extrusion occurs, the dentist must determine if there is merely damage to the periodontal ligament or if there is a comminuted fracture of bone. In either situation, the tooth should be manipulated back to its original position and splinted. If only the periodontal ligament is damaged, the tooth is stabilized for 2 to 3 weeks, whereas if there is a comminuted bone fracture, the period of stabilization is 6 to 8 weeks. In either case, within 2 weeks of the trauma, the root canal is completely cleaned and shaped, and a radiopaque calcium hydroxide, which will be visible on the radiograph, is placed in the canal. Care must be taken so calcium hydroxide is not pushed through the apex, since this may cause root resorption in the apical portion of the root.
It should be emphasized that any time calcium hydroxide is used in the treatment of teeth that have been traumatized, the material should be changed at 2 months and 4 months. If the prognosis looks favorable at the 6-month visit (ie, no active root resorption, normal mobility, and healthy gingival attachment), the root canal should be filled with gutta-percha.
If intrusion occurs to a primary tooth, the dentist must determine whether the apex of the intruded tooth has been displaced to the labial or lingual. If the apex is inclined to the labial and is not through the cortical plate of bone, the tooth does not require treatment and will probably re-erupt on its own. If the apex has been pushed through the labial cortical plate, the tooth should be repositioned into its original position. However, the situation is different if the apex is inclined to the lingual, because there is a distinct possibility that damage to the permanent tooth bud has occurred. This type of intruded tooth should be repositioned as soon as possible to move the deciduous root away from the permanent tooth bud and minimize damage to the bud. After the tooth has been repositioned, it should be closely observed. Extraction is indicated if pain, mobility, periapical pathology, and/or a sinus tract are observed. In some cases, the lingually inclined deciduous tooth cannot be repositioned. In these cases, the tooth should be immediately extracted.
When a permanent tooth is intruded, the root canal should be completely cleaned and shaped and filled with calcium hydroxide at the first emergency visit. These teeth exhibit the most rapid rate of root resorption, which can often be observed radiographically within 2 weeks. After the calcium hydroxide is placed, the tooth must be stabilized for 6 to 8 weeks, at which time it is brought back into position with orthodontic therapy.
Sometimes a permanent tooth is totally intruded or intruded to the point where one is unable to perform the root canal treatment. This tooth should be moved coronally with a forceps to a position where it is possible to perform the required endodontic procedure. Composite is used to stabilize the tooth in this position, after which the root canal is completely cleaned, shaped, and filled with calcium hydroxide. The composite splint may be removed in 6 to 8 weeks, then the tooth should be positioned into its normal position with orthodontic therapy. Any patient with an intruded tooth should be placed on antibiotics as a precautionary measure. Penicillin V or amoxycillin is the antibiotic of choice. Erythromycin should be prescribed if a penicillin allergy exists.
The patient should be instructed to take the prescribed antibiotic 4 times each day for a period of 1 week.
If labial, lingual, mesial, or distal luxation occurs, the tooth should be repositioned immediately and stabilized for 6 to 8 weeks. Cleaning and shaping of the root canal and placement of the calcium hydroxide should be accomplished within 2 weeks of the traumatic event.
The prognosis for the totally avulsed tooth is dependent upon the length of time the tooth is out of the socket. When the tooth is reinserted in the socket within 30 minutes, the prognosis for successfully retaining the tooth is 90%, whereas if it takes 60 minutes, the prognosis de-creases to 50%.
When a parent or patient calls the dental office to report a total avulsion, the following instructions should be given: (1) close the drain in the sink; (2) hold the tooth by the crown; (3) wash the tooth under cool tap water; (4) reposition the tooth in the socket without forcing it in, because—if in the proper position—it will go in very easily; (5) have the patient bite down on gauze or a handkerchief; and (6) the patient should immediately come to the office.
If the parent and patient cannot reinsert the tooth into the socket, they are instructed to place the tooth in a glass of milk and to come into the office immediately with the tooth. The periodontal ligament can remain viable for up to 12 hours in milk. Other storage mediums in order of preference are saliva (in the patient’s or the parent’s muco-buccal fold or under the tongue), physiologic saline, and tap water.
When the patient arrives at the office, take a radiograph of the socket and then —if the patient has not reinserted the tooth—using local anesthesia, reinsert the tooth in the proper position and stabilize with composite. The patient is placed on antibiotics and referred for a tetanus vaccination if this immunization is not current.
The patient should be seen in 1 week, at which time a rubber dam is placed, and the root canal is completely cleaned, shaped, and filled with calcium hydroxide. Again, care is observed so that calcium hydroxide is not forced through the root apex, since this may increase resorption. Using a periodontal probe, the clinician determines if the periodontal ligament has reattached. If so, the splint should be removed. If the periodontal ligament has not reattached at 1 week, the splint should be left in place for 1 additional week. If attachment has occurred at the 2-week visit, the splint is removed. If reattachment has not occurred at 2 weeks it will not occur, and the tooth should be extracted.
If an avulsed tooth has been out of the socket for 6 hours or more, the root canal should be cleaned, shaped, and filled with gutta-percha with the tooth held in the dentist’s hand. The tooth should then be placed in fluoride for 20 minutes before it is reimplanted, because fluoride has been shown to inhibit resorption. The tooth should then be stabilized for 1 week. However, the prognosis for this tooth is poor.
Teeth that have been traumatized and exhibit craze lines, fracture into enamel, fracture into dentin, root fracture, concussion, or subluxation should be pulp tested 3 months after the accident. If the tooth has a vital pulp, root canal treatment likely will not be required. Teeth that have a crown-root fracture should receive immediate endodontic therapy, and—if needed—can be extruded orthodontically. An intruded tooth should have endodontic therapy the same day, with calcium hydroxide placed into the canal. Teeth that have been extruded, displaced in any direction, or totally avulsed must have the canal completely cleaned, shaped, and filled with calcium hydroxide within 1 or 2 weeks post trauma.
Clinical research concerning traumatized teeth is ongoing, and it is incumbent upon each practitioner to keep abreast of the current literature. This review has discussed treatment modalities that are recommended at this time.
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