Preparation and characterization of nitinol bone staples for cranio-maxillofacial surgery

The aim of this work was to form NiTi and TiNiCo body temperature activated and superelastic staples for clinical joining of mandible and face bone fractures. The alloys were obtained by VIM technique. Hot and cold processing was applied to obtain wires of required diameters. The martensitic transformation was studied by DSC, XRD, and TEM. The shape memory effects were measured by a bend and free recovery ASTM F2082-06 test. The superelasticity was recorded in the tension stress-strain and by the three-point bending cycles in an instrument equipped with a Hottinger force transducer and LVDT. Excellent superelastic behavior of TiNiCo wires was obtained after cold working and annealing at 400-500 C. The body temperature activated shape memory staples were applied for fixation of mandibular condyle fractures. In experiments on the skull models, fixation of the facial fractures by using shape memory and superelastic staples were compared. The superelastic staples were used in osteosynthesis of zygomatico-maxillo-orbital fractures

Modeling of bone shavings used as bone graft in mandibular reconstruction

Celem pracy była próba zamodelowania wiórów kostnych stosowanych jako przeszczepy w rekonstrukcji żuchwy. Przeprowadzono analizy wytrzymałościowe metodą elementów skończonych MES modeli zrekonstruowanej żuchwy przy obciążeniu na zęby przednie oraz boczne siłą sumaryczną równą 100N. Przypadki analizowane były ze względu na udział objętościowy wiórów kostnych w przeszczepie oraz wielkość elementu użytego do symulacji. Praca stanowi pierwszy etap badań mających na celu opracowanie sposobu modelowania zrostu i odtworzenia układu żuchwa-przeszczep z użyciem różnych materiałów rekonstrukcyjnych.The aim of this study was to model the bone shavings which are used as grafts for reconstruction of the mandible. FEA finite element analyses were provided using models reconstructed mandible with a load on the teeth front and side force equal to the total 100N. Cases were analyzed due to the volume fraction of the graft bone shavings and the size of the element used for analysis. Work is an introduction to further research aimed at improving knowledge and understanding of the process of healing the graft

Computer assessment of correctness of mandiblar bones fracture slit integration based on pantomographic radiograms

The method of objective assessment of the correctness mandible bones fracture slit was proposed in the research. At present, treatment results are evaluated by comparing pantomographic pictures made before and after integration. It is not an objective method; the estimation of the integration correctness coefficient is not possible, either. The use of computer processing enables introducing the relative mandible faction dislocation coefficient. Thanks to this, measurable determination of bone faction reposition correctness on pantomograms made after osteosynthesis is possible

Assessment of the results of mandibular fractures sugrical titanium miniplates treatment on the basis of computer-aided analysis of pantomographical radiograms

At present, in mandibular fractures surgical treatment reposition and titanium miniplates osteosynthesis is the most common method used. The treatment results are assessed on the basis of comparative analysis of two radiograms taken before and after fixations of fractures. In this article the objective method of radiological assessment of osteosynthesis is presented. The crucial part of the method is the computer program which was created at The Institute of Computer Biomedical Systems, Silesian University in Katowice. Comparison of placement of bone fragments on a pair of pantomograms taken before and after a particular surgical operation was done. To make the process of the results evaluation an objective one a new parameter - the relative dislocation coefficient - was implemented. Achieved results enable to assess correctness of bone fracture reposition on the pantomographical pictures taken twice, once before and the next time after osteosynthesis

Mandibular reconstruction : biomechanical strength analysis (FEM) based on a retrospective clinical analysis of selected patients

Restoration of mandible discontinuity defects continues as a challenge for maxillofacial surgeons. Despite the development of algorithms for reconstruction plates fixation and autogenous grafting techniques, complications are still encountered including screw loosening, bone resorption or delayed/incomplete union. The aim of the study was to analyze the possibility of obtaining bone union in the aspect of biomechanical conditions of two mandible reconstructions using an autogenous iliac crest bone graft stabilized with a reconstruction plate, and to attempt to predict patient outcomes based on strength parameters obtained by the finite element analysis. The authors of the present paper were trying to determine to what extent the reconstruction model and changes occurring in hard tissues of the bone and autogenous graft (simulated by changes in material properties) might help predict individual patient courses. The effort of reconstruction plates was defined using the values of the von Mises stress (σHMH) while the effort of bones was determined based on the values of strain intensity εint. The results of the above mentioned simulations are presented in the form of bar graphs and strain/stress distribution maps. Our strength analyses indicate that uncomplicated healing of grafts fixed with reconstruction plates requires that the initial loading of the stomatognatic system should not result in strain intensity exceeding 20–40 [×10–4]. This range of strain intensity evokes an increase in the mineral phase. The state of nonunion between the mandibular bone and the graft might result from prolonged periods of insufficient loading of the mandible during treatment