Recovery of incisor torque loss with clear aligners after lingual orthodontic treatment: A case report

Clear aligners and lingual appliances are two aesthetic orthodontic treatment options with different characteristics and biomechanics; however, they can be combined to maximise treatment efficiency. Lingual tipping of incisors during space closure occurs frequently in fixed orthodontic treatment, especially with lingual appliances because the force is applied to the lingual side of the teeth. This case report presents a skeletal Class II patient with the chief complaint of maxillomandibular protrusion, for whom the treatment plan involved the extraction of the four first premolars to create space for incisor retraction. After 18 months of treatment with lingual appliances, significant anterior torque loss was observed, despite the use of pre-torqued archwires during space closure. A decision was made to correct the anterior torque loss using clear aligners. After 6 weeks of aligner treatment, both maxillary and mandibular incisor torque were significantly improved. Thus, clear aligners could be employed to correct incisor torque loss after fixed orthodontic treatment. Keywords: anterior torque loss, clear aligners, hybrid treatment, lingual appliances, protrusion