Impaction of Mandibular First Molar by Tooth-Like Hard Tissue.

Impaction of permanent teeth during the mixed dentition stage is relatively common in clinical practice, but impaction of mandibular first molars is rare. This case report presents an impaction of the mandibular first molar due to a tooth-like hard tissue lesion. An 8-year-old girl was diagnosed with an impacted mandibular first molar. The roots of the impacted molars were almost completely developed. A spherical tooth-like hard tissue with a diameter of approximately 2 mm was observed at the alveolar crest between the impacted mandibular first and second molars. The lesion causing the impaction was excised, and the first molar was fenestrated and allowed to erupt naturally. We showed that even if the tooth root is almost complete, natural eruption can be expected if the lesion is removed and space for eruption is secured.