Objective: To determine whether orthodontic treatment with removable aligners vs fixed orthodontic appliances is associated with a different frequency of orthodontically induced external apical root resorption (OIEARR) when genetic, radiographic, and clinical factors are accounted for. Materials and Methods: Three hundred seventy-two orthodontic patients treated with removable aligners (Invisalign) or fixed appliances were genetically screened for interleukin 1B gene (IL1B) (rs1143634), interleukin 1 receptor antagonist gene (IL1RN) (rs419598), and osteopontin gene (SPP1) (rs9138/rs11730582). Twelve clinical variables, potentially associated with OIEARR, were also considered. Subjects were divided according to the presence of radiographically determined OIEARR (.2 mm). The association between OIEARR and appliance type, and radiographic, clinical and genetic factors, was assessed using backward stepwise conditional logistic regression. Odds ratios (ORs) and 95% confidence intervals (CIs) were reported. Results: Reliability of the methods was adequate. Clinical case complexity (American Board of Orthodontics [ABO] Discrepancy Index) (OR: 1.032; 95% CI: 1.005-1.061; P ¼ .021) and extent of incisor apical displacement in the sagittal plane (OR: 1.478; 95% CI: 1.285-1.699; P ¼ .001) were associated with an increased OIEARR risk. After adjusting for associations between clinical/ radiographic/genetic factors, there were no statistically significant differences with respect to OIEARR or type of orthodontic appliance used, whether removable aligners or fixed appliances (OR: 1.662; 95% CI: 0.945-2.924; P ¼ .078). Only subjects homozygous for the T allele of IL1RN (rs419598) were more prone to OIEARR during orthodontic treatment (OR: 3.121; CI: 1.93-5.03; P , .001). Conclusions: A similar OIEARR predisposition was identified using either removable aligners (Invisalign) or fixed appliances. (Angle Orthod. 2017;87:3-10)

Introduction To present and discuss the results of five clinical cases treated using the revascularization protocol, showing clinical and radiographic monitoring. Necrotic immature teeth with periapical pathology present a challenge to dentists because the techniques used in apexification leave the tooth susceptible to fracture, since the root does not continue to grow in length and the canal walls are thin. Revascularization has emerged as an alternative to resolve these deficiencies, enabling apical closure, continued development of the roots, and thickening of the dentinal walls. Case Series Five clinically and radiographically diagnosed necrotic immature permanent teeth were treated using revascularization treatment. The therapeutic protocol involved accessing the pulp chamber; irrigating copiously with NaOCl; applying a triple antibiotic paste as intracanal dressing; then provisionally sealing it. After 3 weeks, the canal was cleaned and the apex irritated with a size 15 K-file to induce blood that would serve as a scaffold for pulp revascularization. MTA was used to seal the chamber before final obturation (composite or metallic crown). Conclusion The discussion of the results leads to debate about different restorative materials and other published protocols.