Aim: By using the finite element method (FEM), this study aimed to evaluate the effect of different corticotomy formats on the distribution and magnitude of stress on the periodontal ligament (PDL) during retraction of the maxillary canine. Materials and methods:A geometric model of the left hemi-jaw was created from computed tomography scan images of a dry human skull and loads were administered during distalization movement of the canine. Three trials were performed: (1) without corticotomy, (2) box-shaped corticotomy and perforations in the cortical bone of the canine (CVC) and (3) CVC and circularshaped corticotomy in the cortical bone of the edentulous space of the first premolar.Results: There was no difference in stress distribution among the different corticotomy formats. Conclusion:Different corticotomy formats used to accelerate orthodontic tooth movement did not affect stress distribution in the PDL during canine retraction. Clinical significance. From a mechanical perspective, the present study showed that the stress distribution on the PDL during canine retraction was similar in all the corticotomy formats. When using the Andrews T2 bracket, the PDL presented the highest levels of stress in the middle third of the PDL, suggesting that the force was near the center of resistance. Also, as bone weakening by corticotomies did not influence stress distribution, the surgical procedure could be simplified to a less aggressive one, focusing more on inflammatory cellular stimulation than on bone resistance. A simpler surgical act could also be performed by most orthodontists in their practices, enhancing postoperative response and reducing patient costs. Stress Distribution Evaluation of the Periodontal Ligament in the Maxillary Canine for Retraction by Different Alveolar

From a mechanical perspective, this study showed the stress field generated in MSs with SS and titanium alloy (Ti) mechanical properties and surrounding bone. The stress distribution was concentrated at the MS, mainly at the interface with the cortical bone, and the difference between the stress values for the Ti and SS MSs was very small. Under this condition, the two types of MSs are suitable for orthodontic applications because their yield limits are much higher.