Text A. Traumatic Injuries of the Teeth
The teeth are subjected to many uses which may cause minor or major injuries. Man makes use of his teeth in many ways to aid him in domestic and industrial pursuits. Even mastication may produce abnormal wear, especially in food of very hard character in habitually eaten or if there are certain abnormalities of the occlusion. This occurs in spite of the fact that teeth are built to resist mechanical injury, being covered by the hardest tissue of the body, enamel, and supported by a more elastic structure, dentine.
War injuries cause frequent trauma to the teeth.
Both in cases of fracture of the jaw as well as in instances where no fracture is present, teeth may be traumatized. The trauma may be mild so that only concussion results. Frequently the trauma is so severe that teeth become luxated, fractured, or even comminuted.
Concussion. Direct violence is most common. The patient may receive a blow with some hard object, as often occurs in the pursuit of sports; or a fall, automobile accident, or fist fight may be the cause. Indirect violence occurs to a tooth when the jaws strike together hard as may happen when the patient is struck or jumps on his heels.
The patient complains of the tooth sore, if the condition does not subside in a day or two a total periodontitis will develop and cause elongation of the tooth which then becomes loose and very painful to percussion. The immediate findings may be insignificant but later the tooth may become discolored due to intradental hemorrhage or necrosis of the pulp. For such cases the rest of the tooth is of importance. Often it is necessary to grind the tooth or open the bite on other teeth to accomplish this. If the pulp becomes necrotic it must be removed.
Luxation. In luxation the tooth becomes displaced from its normal position, incompletely or completely formed teeth may be affected. Many teeth may be involved simultaneously after an automobile accident, for example.
The incompletely formed not yet erupted tooth is occasionally luxated during operative procedures or while the corresponding deciduous tooth is being extracted. Injury, therefore, may occur while the tooth is still completely embedded on the jaw or when it is partly erupted but with the root not completely formed.
In completely formed erupted teeth luxation occurs in case of direct or indirect violence which does not vary from that described for cases of concussion except perhaps in severity. The displacement may be partial or total. A totally displaced tooth may be replanted but generally should be removed especially if many teeth are involved. In partial dislocation the luxation is reduced and the tooth is held in its natural position with wires or a specially designed splint.
Fracture. In extreme cases of trauma there may be fracture of the tooth. The anterior teeth are more often involved then the posterior ones. The most common causes are injuries following sports and accidents. Fractures also may be due to direct or indirect violence. Root-filled teeth that have become brittle often fracture from undue occlusal stress, especially if large fillings or inlays have left only a small base of dentine for the cusps.
Fractures of the teeth may be classified in a variety of ways: first, according to the location so that we may speak of fractures of the crown (extra-alveolar). and those involving both crown and root. Fractures also may be spoken of as horizontal, oblique, or vertical. The following is a useful classification.
1. Single fractures:
a. fissural fracture of the crown without loss of tissue,
b. complete simple fracture of the crown with loss of tissue.
2. Complicated fractures:
a. simple compound extra-alveolar fracture,
b. simple compound ultra-alveolar fracture,
c. comminuted compound fracture.
The treatment of some cases may render favorable results while in some fractures the prognosis is unfavorable.
