Combined use of microimplants and a self-made four-curvature torquing auxiliary arch to manage labial root fenestration of the maxillary incisors: A case report.

During orthodontic treatment, ensuring the safety of anterior teeth with exposed roots is crucial. Our report describes the case of a 19-years-old female patient who was treated at a local clinic for severe bimaxillary protrusion. The clinic physician extracted the patient's seven premolars and one mandibular lateral incisor, resulting in failure of the orthodontic treatment. After this failed treatment at the local clinic, the patient presented to our hospital for follow-up treatment (second treatment). When the patient was transferred to our hospital, she still exhibited a skeletal Class II relationship (A point-nasion-B point angle (ANB): 12.5°) profile, and her anterior teeth were severely upright, with an initial U1-NA of -1.5° (normal value: 22.8° ± 5.7°). This value changed after treatment to 14.32° (normal value 22.8° ± 5.7°). Cone beam computed tomography showed that the roots of the anterior teeth had penetrated the labial cortical bone, and it was challenging to ensure the safety of the second treatment. In our patient, the roots of the anterior teeth safely entered the center of the maxilla, with the U1-NA changing from -1.5° to 11° after treatment with our self-made four-curvature torquing auxiliary arch. Moreover, root length did not change, and root absorption did not occur.