Inverted eruption of a supplemental lower premolar: report of an unusual case

Eruption of an inverted tooth is a rare condition. This case report describes the inverted eruption of a supplemental lower premolar in a 10-year-old Caucasian female. The tooth erupted in a downward direction and reached the lower cortical border of the mandible 2 years later. During an 8-year follow-up period, the tooth did not interfere with eruption of permanent teeth and the patient remained symptom-free. Considering clinical examination, medical and dental history as well as scientific evidence, the inverted eruption was most likely caused by a developmental abnormality with an inverted location of the tooth bud. This reported eruption of an inverted tooth is extremely rare and requires a radiographic follow-up to evaluate the relative position of this tooth in the jaw bone and its potential interference with neighbouring teeth or anatomic structures.