A novel approach to microsurgical teaching in head and neck surgery leveraging modern 3D technologies.

The anatomically complex and often spatially restricted conditions of anastomosis in the head and neck region cannot be adequately reproduced by training exercises on current ex vivo or small animal models. With the development of a Realistic Anatomical Condition Experience (RACE) model, complex spatial-anatomical surgical areas and the associated intraoperative complexities could be transferred into a realistic training situation in head and neck surgery. The RACE model is based on a stereolithography file generated by intraoperative use of a three-dimensional surface scanner after neck dissection and before microvascular anastomosis. Modelling of the acquired STL file using three-dimensional processing software led to the model's final design. As a result, we have successfully created an economical, sustainable and realistic model for microsurgical education and provide a step-by-step workflow that can be used in surgical and general medical education to replicate and establish comparable models. We provide an open source stereolithography file of the head-and-neck RACE model for printing for educational purposes. Once implemented in other fields of surgery and general medicine, RACE models could mark a shift in medical education as a whole, away from traditional teaching principles and towards the use of realistic and individualised simulators.

Treatment of Necrotic Teeth by Apical Revascularization: Meta-analysis.

Each year ~5.4 million children and adolescents in the United States suffer from dental infections, leading to pulp necrosis, arrested tooth-root development and tooth loss. Apical revascularization, adopted by the American Dental Association for its perceived ability to enable postoperative tooth-root growth, is being accepted worldwide. The objective of the present study is to perform a meta-analysis on apical revascularization. Literature search yielded 22 studies following PRISMA with pre-defined inclusion and exclusion criteria. Intraclass correlation coefficient was calculated to account for inter-examiner variation. Following apical revascularization with 6- to 66-month recalls, root apices remained open in 13.9% cases (types I), whereas apical calcification bridge formed in 47.2% (type II) and apical closure (type III) in 38.9% cases. Tooth-root lengths lacked significant postoperative gain among all subjects (p = 0.3472) or in subgroups. Root-dentin area showed significant increases in type III, but not in types I or II cases. Root apices narrowed significantly in types II and III, but not in type I patients. Thus, apical revascularization facilitates tooth-root development but lacks consistency in promoting root lengthening, widening or apical closure. Post-operative tooth-root development in immature permanent teeth represents a generalized challenge to regenerate diseased pediatric tissues that must grow to avoid organ defects.