Experimental strength analysis of orthodontic extrusion of human anterior teeth

The paper presents the strength tests, in terms of in vitro examinations, of restored mesial incisor crowns after endodontic treatment with modelled orthodontic extrusion procedure. The strength tests were carried out for 25 teeth randomly divided into groups with various degree of root reduction. The analysis was done for the following quantities: the force to fracture, the work to fracture, the energy of the first micro-crackings and breaking, the total displacement. Statistical analysis with the use of the Kruskal-Wallis test was done in order to assess the significance level in four tooth groups. Numerical simulations of periodontal ligament effort due to the orthodontic extrusion have also been carried out.