Fusion of an Impacted Third and Supernumerary Fourth Molar Tooth with Concrescence of the Second Molar

We report the case of a symptomatic 41-year-old female presenting with fusion of an impacted third (LL8) and fourth (LL9) mandibular molar tooth with concrescence of the second molar tooth (LL7). Cone-beam computed tomography showed direct contact with the inferior dental nerve (IDN) and lingual aspect of the double tooth. The patient underwent surgical removal of the LL8–LL9 using piezoelectric surgery. We present the first case of successfully using pre-operative CBCT in the planning of surgery and piezoelectric surgery to separate an impacted fused LL8–LL9 from a concrescent LL7 without causing trauma to the LL7 or intimately positioned IDN. CPD/Clinical Relevance: An impacted fused mandibular third and supernumerary fourth molar with concrescence of the second molar requires very careful management.