Transposition of the Mandibular Right Second Premolar Into the First Molar Space: A Case Report

Tooth transposition is an uncommon dental anomaly involving the positional interchange of two adjacent teeth within the same quadrant. Transpositions affecting posterior teeth in the mandible, particularly a premolar and a molar, are rarely reported, and their diagnosis and management can be challenging.

A 39-year-old man presented with difficulty in mastication related to multiple edentulous spaces in both arches. Clinical examination revealed poor oral hygiene, generalized gingival recession, Fordyce granules, a fissured tongue, and spacing of the maxillary anterior teeth. The mandibular right second premolar was found positioned within the first molar region, an incidental finding on intraoral examination. Periapical and panoramic radiographs confirmed the anomalous position of the premolar and demonstrated generalized alveolar bone loss. No reliable history could establish whether the first molar had previously been extracted, was congenitally absent, or had failed to erupt, and no family history of similar dental anomalies was reported. Management addressed the patient's primary complaint through scaling and oral hygiene instruction, restoration of carious teeth, and prosthetic rehabilitation of edentulous spaces; no intervention was directed at the positional anomaly itself, as it was asymptomatic and of no functional or esthetic concern to the patient.

This case illustrates a rare mandibular premolar-molar positional anomaly discovered incidentally in an adult, a presentation most consistent with tooth transposition. It highlights the value of thorough clinical and radiographic examination in identifying atypical dental findings and the importance of longitudinal or cross-sectional imaging in confidently distinguishing true transposition from other causes of anomalous tooth position, such as postextraction migration.