Finite Element Analysis to Evaluate the Biomechanical Effects of the Different Cortical Cuts on Canine and Related Supporting Tissues During Retraction.

Background: Corticotomy-assisted orthodontics (CAOT) has shown potential in accelerating tooth movement by reducing alveolar bone resistance. However, the biomechanical effects of varying corticotomy designs on canine retraction remain insufficiently explored. Materials and methods: A cone-beam computed tomography (CBCT) scan of a 26-year-old male with bimaxillary protrusion was used to create a three-dimensional finite element model of the maxillary dentition, including alveolar bone, periodontal ligament (PDL), teeth and orthodontic appliances. Twenty-four corticotomy configurations were modeled based on varying anatomical positions (e.g., mesial, distal, labial, lingual), proximity (2 mm and 4 mm from distal cut) and cut widths (0.6 mm, 0.8 mm). A standardized 100-cN retraction force was applied using miniscrews in a segmented arch technique. ANSYS 14.5 software was used to analyze stress (von Mises), strain (in PDL) and initial displacement. Results: The continuous circumscribing cut showed the greatest canine displacement and PDL strain, followed by distal + labial + lingual and distal cut configurations. The highest stress in trabecular bone was seen with 0.8 mm wide cuts, while the greatest strain in PDL occurred with mesial cut. Tooth displacement decreased as the distance of corticotomy from the canine increased (distal > 4 mm > 2 mm). Among widths, 0.4 mm distal cuts (not explicitly simulated but inferred) were biomechanically more favorable than 0.6 mm and 0.8 mm. Conclusion: Distal corticotomy cuts, particularly those closer to the canine and of optimal width, exhibit biomechanical advantages similar to circumscribing cuts with lower surgical morbidity. These designs may reduce resistance to movement, optimize force distribution and enhance clinical outcomes during canine retraction.