The diagnostic value of lateral extraoral radiography for intruded maxillary primary incisors.

PURPOSE The purpose of the study was to assess the contribution of a lateral extraoral radiograph for diagnosing the relation between the root of intruded maxillary primary incisors and their permanent successors. METHODS Three pediatric dentists examined intruded primary teeth 0-7 days after injury. The relations between the primary and permanent teeth were assessed in three separate steps: 1) evaluation of clinical signs only; 2) evaluation of a periapical radiograph (no lateral radiograph); 3) evaluation of a lateral extraoral radiograph. The clinical and radiographic signs used to assess the relations were recorded. The lateral extraoral radiograph was regarded as contributory to diagnosis if the assessment after the third step differed significantly from that made after the first and second steps. Ninety-three evaluations of 53 intruded teeth in 37 children were available for analysis. RESULTS The lateral extraoral radiograph was found valuable for assessment of the primary incisor's root alignment in only 5% (5/93) of the evaluations in which neither the clinical examination nor the periapical radiograph were contributory. Four of these five cases were in children less than 20 months old. In all other cases, the lateral radiograph was not contributory for two main reasons: It could not be evaluated due to overlap of multiple intruded teeth and/or when the teeth intruded were lateral incisors, and when the clinical and periapical radiographs were sufficient for diagnosis. CONCLUSIONS Lateral extraoral radiographs should not be used routinely in cases of intrusion of primary incisors. The operator should base his or her diagnosis on clinical findings and examination of a periapical radiograph. The lateral extraoral radiograph should be taken only when its expected contribution to diagnosis can be confirmed, as in cases of children younger than 20 months.