Crown dilaceration of a first premolar caused by extraction of its deciduous predecessor: a case report.

This report describes a rare case of crown dilaceration of the mandibular first premolar caused by trauma during extraction of the precedent primary first molar. The mandibular first primary molar had been extracted at the age of 4 years 7 months. Compared to the pre-operative radiograph, the post-operative film showed that the direction of the first premolar tooth germ had changed, suggesting that crown dilaceration had been induced by the surgical procedures during tooth extraction. From radiographic examinations, the premolar was considered to have erupted spontaneously.