چكيده به لاتين
Abstract:
Implant geometry is available in three main models, nonetheless todays the thread-shaped implants are used. In recent biomechanical studies in dental implants, most of the increase in performance and efficiency of screw-type implants carried out via the changes in screw parameters such as the pitch, diameter, shape of threads, etc. But the foregoing optimization has some weaknesses that can not be eliminated by changing these parameters. To deal with these flaws, a new approach is needed. This thesis was designed to improve performance of dental implants using changes in implant geometry and its geometric optimization. this study was aimed at examination of dental implants problems and attempting to eliminate their defects. Firstly, dental implants and the involved distributed stress were examined from a geometric standpoint. After examining and finding the defects of threaded implants, a completely new design is needed to solve these problems. After a one-year review of various dental implants studies and inventions around the world, a novel idea and design, called the HOSSAD Dental Implant, was designed which is the author’s invention. The fundamental idea derived by considering the high shear force in screw-type dental implants which can be reduced due to the lower bone resistance to it.
This dental implant was examined from a biological perspective. Mechanically, the stress and force distribution in the dental implant and bone was optimized and then compared with the ones in the screw type using the finite element method.In the numerical analysis, the design parameters of the proposed dental implant were extracted and analyzed to achieve optimal geometry. Subsequently, this geometry was compared to the one in ITI dental implant, which is widely used in Iran and globally. For sake of this comparison, the geometry of the ITI implant was modeled and then validated by the comparison to the results of the experimental analysis of photoelastic method. Upon validation, the thread geometry in ITI implant geometry has been optimized and finally compared to the new proposed model. The maximum stress value in ITI implant was roughly 2.1 times the one in the proposed implant. In all of these analyzes, the material of all the components was considered to be elastic isotropic. Moreover, it was assumed that the contact of the implant and bone was completely osseointegrated. The decrease in the maximum stress could be explained by the obtained better distribution of stress and forces, reduced stress concentration, and the fact that more shear forces converted to compressive forces in the proposed implant relative to the ITI implant, which cut down the destructive movements and mechanical damage.
This aforementioned reduction might lead to a decrease in the treatment time and also an increase in the amount of osseointegration, which consequently might provide a more successful treatment procedure for patients with osteoporosis chronic steroid use.
