Human pleural cavity pressure rises substantially because of Valsalva maneuver during sneezing. However, the deformations in the upper airway respiratory system significantly increase due to flow rate growth in sneezing, and laryngeal fracture can be mentioned as one of the symptoms of this severe deformation during the Valsalva maneuver. Therefore, the accurate study of the distribution of pressure and velocity, in this case, is very important. In the present study, using a real human upper airway model, the pressure and velocity of the air flow, generated in the tract during the sneezing, have been investigated. Moreover, using a spirometer device, the outlet flow rate from the mouth during the sneezing was obtained. The simulation results indicated that the inlet pressure to the tract, existing in the bronchus region, reached a maximum of 14 kPa. By having such pressure input, the highest deformation, created in the upper airway, was calculated using the fluid-structure interaction method and it has been confirmed that the majority of the deformation happened in the maxillary sinus as well as the thyroid cartilage.
Dental implants have been studied over the years to replace missing teeth. One of the conditions for the success of implants is their stability and resistance under the applied forces and minimal tension in the surrounding bone. The purpose of this dissertation is numerical and three-dimensional analysis of jaws with implants under mechanical and thermal loading by the finite element method. For this purpose, implant simulations (including ceramic crown, titanium root, and jaw bone) under dynamic and thermal load have been performed in Abacus software. In this simulation, it is considered that the jawbone is composed of two areas, one area is the superficial bone tissue (cortical) and the other part is the spongy tissue. Implants are usually made of different metals or ceramics with a bone-like structure that are compatible with body tissues. Implants are currently made of titanium metal. Therefore, titanium metal has been used for modeling implants in this dissertation. The implant crown is also considered as a ceramic material. In the simulation, the effect of stresses imposed by the implant on the jawbone is performed. In this simulation, mechanical force is applied to the upper part of the implant and force enters the jawbone through the implant, which causes tension at the junction of the implant to the jawbone. To investigate the effect of thermal loads, different temperature conditions are considered by considering the decrease in temperature and increase in temperature on the tooth surface and its effect on the implant and the jaw bone. After validation and ensuring the accuracy of the modeling, it has been observed that, with increasing mechanical load, the stresses created in all parts of the ceramic coating, titanium implants, and jawbone have increased. It is also observed that the stress created in the titanium implant due to the application of negative heat flux was about twice as much as the stress created due to the application of positive heat flux.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.