Orthodontic Treatment of a Transmigrating Impacted Lower Canine Using a Digitally Designed and 3D-Printed Lingual Appliance Combined with Corticotomy and Laser Therapy-A Case Report.

Abstract

Background: Canines play a vital functional and aesthetic role in human dentition, yet impacted canines, particularly in the mandible, are rare and can lead to functional disorders, such as the absence of canine guidance, while negatively affecting a patient's self-esteem. Transmigration of mandibular canines adds complexity to treatment. One method to reduce the treatment time, especially for impacted teeth, is corticotomy-assisted orthodontic therapy (CAOT). Methods: A 13-year-old patient presented with a horizontally impacted lower right canine, positioned below the roots of the lower incisors, showing transmigration. A digitally designed and 3D-printed lingual appliance was attached to the lower molars with hooks on the lingual side, enabling the application of multi-directional orthodontic forces. CAOT was performed using an Er:YAG laser (LightWalker, Fotona, Ljubljana, Slovenia) at 200 mJ, 12 Hz, 2.4 W, with a pulse duration of 100 µs, and an MSP H14 conical tip (0.6 mm spot diameter). Photobiomodulation (PBM) with a 635 nm diode laser (Lasotronix, Smart ProM, Piaseczno, Poland) was applied at 10 J per point (20 J/cm²) for 100 s per point, with a total energy of 20 J per session to reduce the risk of root resorption, manage pain, and accelerate healing as the tooth was moved into the alveolar ridge. Results: The treatment duration was two and a half years. The lingual appliance with hooks allowed precise traction of the canine, aided by exposure from the lingual side and the attachment of a hook. Gentle forces applied via orthodontic thread gradually moved the canine beneath the oral mucosa. Mid-treatment cone beam computed tomography (CBCT) scans confirmed the absence of root resorption of the lower incisors. A corticotomy, enhanced by laser therapy, was performed before moving the canine into the alveolar ridge. The canine was successfully rotated 180° and positioned without any signs of resorption in the canine or adjacent teeth. Conclusions: The use of a digitally designed and 3D-printed lingual appliance with hooks allowed the precise control of the traction of impacted teeth. When combined with corticotomy and laser therapy, it minimised root resorption risks, reduced pain, accelerated healing, and improved the overall success of the orthodontic treatment.