Objective: The aim of this study was to evaluate the mechanical behavior of different rigid fixation methods in mandibular angle fractures.
Materials and Methods: Three different three-dimensional ...finite element models of the mandible were developed to simulate the biomechanical responses of titanium plates and screws. The fracture lines were fixed with double 4-hole straight, 4-hole square, and 5-hole Y plates with monocortical screws. 150 N incisal occlusal loads were simulated on the models. The commercial ANSYS software was utilized to calculate the Von Mises stresses on fixative appliances.
Results: The highest Von Mises stress values were observed in the Y plate, whereas the lowest stress values have been found in the square plate.
Conclusions: The use of square plate led to better stability and lower mechanical stresses than other techniques.
Lornoxicam and iv paracetamol are commonly preferred to be used for postoperative analgesia. Although Aspirin is a well known non-steroid anti-inflammatory drug that decreases the erythrocyte ...deformability, there is no study comparing lornoxicam and iv paracetamol regarding their effects on erythrocyte deformability recorded in literature. The aim of this study was to compare the effects of lornoxicam and IV paracetamol on blood perfusion and erythrocyte deformability on rats.
Twenty male Wistar Albino rats were randomly divided into three groups as Lornoxicam group (Group L), IV paracetamol group (Group P), and control group (Group C). Intraperitoneal administrations were done in all groups except Group C. Liver and renal blood flows were conducted by laser Doppler and euthanasia was performed via intraabdominal blood uptake. Erythrocyte deformability was measured using a constant flow filtrometer system.
Lornoxicam increased the relative resistance which shows the erythrocyte deformability in rats (p<0.05). The comparison of Groups C and P revealed no statistically different results (p=0.731) while Group L revealed statistically higher results than Group C (p=0.022). No statistically significant differences were found between groups L and P (p=0.073). Liver and renal blood flow values in Group L were just numerically decreased not statistically whilst no statistically significant difference was found between the three groups.
Lornoxicam have lead to functional disorders related to tissue perfusion as a result of both decreased blood flow and erythrocyte deformability (Fig. 3, Ref. 21). Full Text in PDF www.elis.sk.
Objective: The aim of the study was to evaluate the mechanical behavior of three different fixation methods used in the bilateral sagittal split ramus osteotomy.
Materials and Methods: Three ...different three-dimensional finite element models were created, each corresponding to three different fixation methods. The mandibles were fixed with double straight 4-hole, square 4-hole, and 5-hole Y plates.
150 N incisal occlusal loads were simulated on the distal segments. ANSYS software ((v 10; ANSYS Inc., Canonsburg, PA) was used to calculate the Von Mises stresses on fixative appliances.
Results: The highest Von Mises stress values were found in Y plate. The lowest values were isolated in double straight plate group.
Conclusions: It was concluded that the use of double 4-hole straight plates provided the sufficient stability on the osteotomy site when compared with the other rigid fixation methods used in this study.
Abstract The study aimed to calculate the location and intensity of the maximum stress fields on the fixation plates and surrounding maxilla following Le Fort I osteotomies after advancement ...procedures using three-dimensional finite element analysis. The models were generated using skull CT scan data. Le Fort I osteotomy simulations were made and two separate impacted maxillary models were designed. The ADV-2 model has 2 plate fixations bilaterally at the piriform rims, the ADV-4 model has 4 plate fixations at the zygomatic buttresses and piriform rims. The stress fields on bone, plate and screws were computed for each model. Posterior occlusal loads were simulated on one side in the molar–premolar region, in all three directions, reflecting the chewing forces. The increased locations of highest Von Mises stresses on the plates and highest maximum principle stresses on the bones were determined in ADV-2 models especially under horizontal and oblique loads when compared with ADV-4 models. Evaluation of the highest Von Mises stress values and maximum principal stress revealed that oblique load in the ADV-2 model received the highest values. 4-plate fixation following Le Fort I advancement surgery exerts less stress on the maxillary bones and fixation materials than 2-plate fixation.
Having studied the effect of maxillary advancement and maxillary impaction in parts 1 and 2 of this research, the purpose of this study was to investigate the biomechanical behavior of different ...fixation models in inferiorly and anteriorly repositioned maxilla following Le Fort I osteotomy. Two separate three-dimensional finite element models, simulating the inferiorly advanced maxilla at Le Fort I level, were used to compare 2- and 4-plate fixation. Model INF-2 resulted in 247,897 elements and 53,247 nodes and INF-4 consisted of 273,130 elements and 59,917 nodes. The stresses occurring in and around the bone and plate-screw complex were computed. The highest Von Mises stresses on the plates and maximum principal stresses on the bones were found in INF-2, especially under horizontal and oblique loads, when compared with INF-4. The present biomechanical study shows that the traditionally used 4-plate fixation technique, following Le Fort I inferior and anterior repositioning surgery, without bone grafting, provides fewer stress fields on the maxillary bones and fixation materials.
Unrecoverable internal failures of modules in the CDF Run2 Silicon detector have been observed since its installation in early 2001. A fraction of these failures has been categorized as infant ...mortality. Other failures occurring later were strongly correlated with fixed trigger conditions. These failures are explained by wire-bonds breaking due to fatigue stress induced by resonant vibration. These resonant vibrations are a direct consequence of the oscillating Lorentz forces induced by the
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magnetic field on wire-bonds carrying non-DC current. Changes have been implemented in data-taking procedures in order to minimize the occurrences of such failures and to prolong the lifetime of the detector itself. A more general analysis of the topic has been pursued. Changes in the packaging and assembly processes for future applications have been investigated.
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