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 f irst premolar caused by trauma during extraction of the precedent primary f irst molar. The mandibular first primary molar had been extracted at the ag e of 4 years 7 months. Compared to the pre-operative radiograph, the post-o perative film showed that the direction of the first premolar tooth germ ha d changed, suggesting that crown dilaceration had been induced by the surgi cal procedures during tooth extraction. From radiographic examinations, the premolar was considered to have erupted spontaneously.