Study Population: patients undergoing orthodontic treatment in Orthodontic Department at Dental School of Universidad Complutense de Madrid.  Inclusion Criteria:  Completed permanent dentition (third molars are excluded) Completed root formation Need of orthodontic treatment  Exclusion Criteria:  Tooth agenesis in the anterior region (incisors) Included or ankylosed teeth in the anterior region (incisors) Periodontal pocket >3 mm in any anterior teeth (incisors) Need of a combined surgical and orthodontic treatment Root resorptions observed at the initial CBCT (in more than 3 teeth) Delay of the treatment due to a external reason or complication during treatment Systemic disease or cranio-facial malformation Tooth fracture or restoration in the anterior region (incisors) at the beginning of treatment Problems from roots such as lacerated root, trauma or fractures during treatment 10 Severe occlusal attrition