Distalization of mandibular molar with iatrogenic root fracture in Class III malocclusion: a case report.

Background: Placement of interradicular orthodontic miniscrews poses a potential risk of root damage, including superficial root contact and root fracture. This case report describes the iatrogenic root-injured tooth movement of a 27-year-old male with skeletal Class III malocclusion as nonsurgical orthodontic treatment.

Case presentation: An orthodontic miniscrew between the mandibular right first and second molars perforated the distal root of the mandibular first molar. A root fracture was discovered 4 months after miniscrew placement. Owing to the potential risk of ankylosis related to surgical intervention, a direct orthodontic distalizing force was applied towards the fractured distal root segment without additional treatment, resulting in considerable movement of the fractured tooth with maintaining tooth vitality. However, gradual root resorption of a fractured tooth with a separate root segment was observed. The mandibular arch distalization of skeletal Class III malocclusion was successfully performed and retained for 3 years 8 months with stable occlusion.

Conclusions: This case reveals a clinical remedy when root movement of a tooth with root fracture is indicated. The use of extra-alveolar miniscrews or miniplates can be considered for mandibular arch distalization to prevent potential root injuries caused by miniscrew placement.

Clinical trial number: Not applicable.