Influence of orthodontic moment-to-force ratio on tooth movement in orthodontic treatment

Ovim radom analiziran je utjecaj omjera ortodontskog momenta i sile na položaj središta rotacije i gibanje gornjeg desnog sjekutića kod ortodontske terapije. 3D model je izrađen pomoću CT snimaka nepoznatog pacijenta u programskom paketu Mimics Medical 17.0. Model se sastoji od zuba, parodontnog ligamenta i alveolne kosti koja se sastoji od kortikalne i trabekularne kosti. Analiza opterećenja je napravljena u programskom paketu Abaqus 6.10 pomoću metode konačnih elemenata. Na krunu zuba je postavljena sila iznosa 1 N, koja predstavlja ortodontsku silu koja se javlja u bravici fiksnog ortodontskog aparata, u tri različita hvatišta. U svaku od ta tri hvatišta sile, postavljen je i moment, a njegove vrijednosti su 1 Nmm, 3 Nmm, 5 Nmm, 6 Nmm i 7 Nmm. Analizom je obuhvaćen utjecaj ovih različitih 15 vrsta opterećenja na položaj središta rotacije i središta otpora za slučaj izotropnih svojstava cijelog modela i za slučaj kada su se alveolnoj kosti zadala ortotropna svojstva, a zubu i PDL-u ostavila izotropna svojstva. Promjenom hvatišta sile i omjera ortodontskog momenta i sile, mijenja se položaj središta rotacije i krajnji položaj zuba.Analyzes done in this thesis describe the influence of orthodontic moment-to-force ratio on the center of rotation and movement of the upper right incisor in orthodontic treatment. 3D model was obtained from CT scans of unknown patient in the Mimics Medical 17.0 software package. The model consists of the tooth, periodontal ligament and alveolar bone that is divided into cortical and trabecular bones. The load analysis was made in the Abaqus 6.10 software using the finite element method. The load used in analyses is representing orthodontic load which is produced by fixed orthodontic apparatus. Load is put on tooth crown and it consists of force and moment. Force is put in three different vertexes and its value is 1 N. At each vertexes there is also a moment. Moment is changing its value at each vertexes and its values are 1 Nmm, 3 Nmm, 5 Nmm, 6 Nmm and 7 Nmm. At the end, there were 15 different types of load, and results of it gives position of center of rotation and center of resistance. In the analyses PDL and tooth were isotropic, and alveolar bone was isotropic and orthotropic. First, all 15 cases were made with whole model kept isotropic and afterwards, using the same load, analyses were made with using orthotropic properties for whole alveolar bone. By changing vertexes of force and orthodontic moment-to-force ratio, position of center of rotation and uttermost position of the tooth was changed