[Orthodontics in general practice 4. Impaction of maxillary front teeth].

Eruption failures in the maxillary frontal region occur during the mixed dentition period. Dislocation and impaction of central incisors are diagnosed during or at the end of the early mixed dentition stage. These failures can be caused by crowding, premature loss of deciduous teeth, trauma or supernumerary teeth. Occasionally, a preventive orthodontic treatment is desirable to release the obstructed eruption path of a canine. Sometimes, a surgical intervention may be indicated to expose an obstructed central incisor and to remove supernumerary teeth. Retention and impaction of canines are generally discovered late in or after the late mixed dentition stage. In the agenesis of the lateral incisors or peg-shaped teeth, there is frequently impaction of the canines. General dental practitioners must be alert for possible deviations in the pattern of change in dentition right from the early mixed dentition period. Conventional two-dimensional radiographs can sometimes unjustifiably suggest a bad prognosis of an impacted tooth. Cone-beam CT scanning, which gives a three-dimensional image, can provide important additional diagnostic information.