Abstract
There are many reports which present the effect of traumatic injuries to primary teeth on their permanent successors.
We observed crown malformations of the maxillary right incisors in a boy aged 8 years 10 months. A history obtained from his mother revealed that the right deciduous central incisor was intruded when, at the age of 18 months, he fell. He was immediately taken to a practitioner, and the intruded tooth was extracted. He was diagnosed as A. L. L. at the age of 4 years 7 months.
We observed no disturbance except for the maxillary right incisors in the oral examination, so we judged that crown malformations resulted from the injury to the primary tooth. On the maxillary right central incisor, the gingival half crown was covered with enamel, but in the incisal half crown there was no enamel without a distal line angle area and yellow dentin was observed. He complained of pain when this dentin was scratched. Roentogenographical examination revealed the abscence of enamel in the incisal half crown, so we diagnosed this tooth as enamel hypoplasia. On the maxillary right lateral incisor, the incisal half crown was surrounded with yellowish hard tissue. The surface of this hard tissue was rough but in some places whitish and bright.
We eliminated this hard tissue for aesthetic reasons, and examined it histopathologically. This hard tissue proved to be mainly irregular tubular dentin, and enamel was observed in some places. We could not reject the existence of cement. From these findings, we judged the crown malformation of this lateral incisor as an odontome-like malformation called by Andreasen et. al..
