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Simpo PDF Merge and Split Unregistered Version - http://www.simpopdf.com I.;~ adiologic examination is essential for evaluat- Tooth Fracture 1...:1 ing the sequelae of trauma, including displa- Intraoral periapical films (a minimum of two) should cement and fracture of teeth and bone, and localizing be taken at differing horizontal angulations of the x-ray foreign objects within the soft tissues. Radiology aids beam. A panoramic film may serve as a survey film, but in identifying the location and orientation of fractures it may not have the image detail to reveal a nondis- and indicates the degree of separation or displacement placed root fracture. of fracture margins. Follow-up radiographs are useful in evaluating the extent of healing after an injury and Tooth Avulsion or Fractured Crown the development of long-term changes resulting from If a tooth or a large fragment of a tooth is missing,a chest the trauma. film may be considered to rule out aspiration of the tooth. If there are lacerations in the lips or cheek, a soft tissueimage maybe obtained by placing an intraoral film in the mouth adjacent to the traumatized soft tissueand then exposing it. If the laceration is in the tongue, a The prescription of appropriate films can be made only standard mandibular occlusal film may be exp9sed or after a careful clinical examination. Multiple projec- the tongue can be protruded and then imaged. tions at differing angles, including at least two views at right angles to each other, are necessary.The applica- Mandibular Fracture tion of ideal radiography may be difficult at times The panoramic film is a good initial survey film for because of the nature of the injury and patient dis- assessingmandibular fracture, but it must not be used comfort. The most common imaging procedures alone. The standard occlusal film provides a good right- applied in various forms of trauma follow. angle image. Other images that may be used include a posteroanterior skull view and a submentovertex skull view. If panoramic images are not available, lateral TRAU MA TO TEETH oblique views of the mandible are useful. The investigation of dental trauma always requires intraoral periapical films to obtain adequate image Trauma to the Mandibular Condyle detail. It is important to radiograph not only the The panoramic view should be supplemented with involved teeth but also the teeth of the opposing arch. either a transorbital view or an open Towne's skull view Depending on the severityof the trauN1aand the ability in casesof suspectedtrauma to the marldibular condyle. of the patient to open the mouth, a bisecting-angle These anteroposterior views are important to supple- technique instead of paralleling technique for intraoral ment lateral views of the joint, especially in casesof radiography, including occlusal views,may be necessary. non displaced greenstick fractures of the condylar neck. 615 616 PART V RADIOGRAPHIC INTERPRETATION OF PATHOLOGY Simpo PDF Merge and Split Unregistered Version - http://www.simpopdf.com These views may be supplemented with tomographic Clinical Features views and a submentovertex skull view. If the fracture The patient usually complains thCj.t the traumatized of the condyle is complex, computed tomography (CT) tooth is painful. On examination, the tooth is sensitive imaging may be required to locate fracture fragments to both horizontal and vertical percussion. It may also anatomically. Soft tissue injury to the joint capsule or be sensitive to biting forces, but patients usually try to articular disk w~nts consideration of arthrography or m<;>difytheir occlusion to reduce pressure on the tooth magnetic resonance imaging (MRI). or teeth. Maxillary Fracture Radiographic Features CT is the imaging method of choice to identify the The radiographic appearance of a dental concussion number and location of fractures of the fine structure is widening of the periodontal ligament space. This of the maxilla. Plain radiographs include posteroan- widening usually occurs only in the apical portion of terior, Waters', Towne's, and submentovertex skull the periodontal ligament space because the raising of views. the tooth out of the socket results in an essentiallypar- allel movement of the coronal two thirds of the root surface with the lamina dura (Fig. 28-1). Reduction in RADIOGRAPHIC SIGNS OF FRACTURE the size of the pulp chamber and pulp canals may The following are general signs that may indicate the develop in the months and years after such traumatic presence of a fracture of bone or tooth: injury (Fig. 28-2). A slow-d~veloping pulp necrosis may 1. The presence of a radiolucent line (usually sharply result in an increase in the width of the pulp chamber defined) within the anatomic boundaries of the and canals compared with the adjacent teeth because structure-If the line extends beyond the bound- of the death of odontoblasts responsible for laying aries of the mandible, for instance, it is more likely down secondary dentin. Pulpal necrosis may occur, to represent an overlapping structure. resulting in the development of a periapical lesion. In 2. A change in the normal anatomic outline or shape rare casesinternal root resorption may occur (see Fig. of the structure-For instance, a mandible that is 28-2). noticeably asymmetric between the left and right sides may indicate a fracture. A fracture of the Management mandible often showsa sharp change in the occlusal Because displacement of the tooth or teeth does not plane at the location of the fracture. occur:, the appropriate treatment is conservative and 3. A defect in the outer cortical boundary, which may may include slight adjustment of ~ oppo~ing teeth appear as a deviation in the smooth outline, a gap (if necessary),repeated vitality tests, and radiographic in the outer cortical bone, or a steplike defect. examination during the period after the injury. 4. An increase in the density of the bone, which may be caused by the overlapping of two fragments of bone. A fracture may be missed if the plane of the fracture is not in the same direction as the x-ray beam. For this reason, multiple films at different angulations should be used. Traumatic Injuries of the Teeth CONCUSSION Definition The term concussionindicates a crushing injury to the vascular structures at the tooth apex and to the periodontal ligament, resulting in inflammatory edema. Only minimal loosening or displacement of the tooth occurs. The injury frequently results in the elevation of the tooth out of the socket so that its occlusal surface FIG. 28-1 Dental concussion has resulted in widening of makes premature contact on mandibular closing. the periodontal ligament spaces of the incisors. CHAPTER 28 TRAUMA TO TEETH AND FAC.lAL STRUCTURES 617 Simpo PDF Merge and Split Unregistered Version - http://www.simpopdf.com teeth are in their normal location but are abnormally mobile. There may be some blood flowing from the gin- gival crevice, indicating periodontal lIgament damage. Subluxated teeth are extremely sensitive to percussion and masticatory forces. The clinical crowns of intruded teeth may appear shortened. Maxillary incisors may be driven so deeply into the alveolar ridge that they appear to be avulsed (lost). The displaced tooth may cause some damage to adjacent teeth, including any devel--oping succedaneousteeth. Depending on the orientation and magnitude of the force and the shape of the root, the root may be pushed through the buccal or, less commonly, the lingual alveolar plate, where it can be seenand palpated. On repeated vitality testing, the sen- sitivity of a luxated tooth may be temporarily decreased or nondetectable, especially shortly after the accident. Vitality may return, however, after weeks or even several months. FIG. 28-2 Dental concussion has resulted in obliteration The teeth most frequently subjected to luxation are of the pulp chamber but not the pulp canal; internal root the maxillary incisors in both the deciduous and per- resorption and an incisal fracture of the left central incisor manent dentitions. The mandibular teeth are seldom and necrosis of the pulp of the right central incisor resulting involved. The type of luxation varies with age, possiblyas in a wide pulp chamber and canal extending to the apex of an expressionof change in the nature of maturing bone. the tooth. Intrusions and extrusions are the primary dislocations found in the deciduous teeth. In the permanent dentition, the intrusive type of luxation is seenless frequently. LUXATION When teeth are luxated, in either dentition, usually two Definition or more are involved, and seldomjust a single tooth. Luxation of teeth is dislocation of the articulation (rep- resented by the periodontal attachment) of the tooth. Radiographic Features Such teeth are both abnormally mobile and displaced. Radiographic examinations of luxa~d teeth may Subluxation of the tooth denotes an injury to the sup- demonstrate the extent of the injury to the root, peri- porting structures of the tooth that results in abnormal odontal ligament, and alveolar bone. A radiograph loosening of the tooth without frank dislocation. made at the time of injury servesas a valuable reference Traumatic forces, depending on their nature and ori- point for comparison with subsequent radiographs. As entation, can causeintrusive luxation (displacement of with dental concussion, the minor damage associated teeth into the alveolar bone) , extrusive luxation (partial with subluxation may be limited to elevation (of the displacement of teeth out of the sockets), or lateral tooth out of the socket. The sole radiographic finding displacement (movement of teeth other than axial may be a widening of the apical portion of the peri- displacement). In intrusive and lateral luxation, com- odontal ligament space. Slight elevation of the tooth minution (crushing) or fracture of the supporting may not be radiographically apparent. alveolar bone accompanies dislocation of the tooth. The identification and evaluation of dislocated teeth The movement of the apex and disruption of the cir- may require multiple radiographic projections.

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