| Summary: | 碩士 === 國立交通大學 === 材料科學與工程學系所 === 105 === Dental implants are biomimetic medical devices applied to recover the function caused by the loss of one or several teeth. They have been also widely used for fractural bone treatments. To reach successful function for the long time, the dental implants must be well fixed into the bone to be able to resist the external forces. Theoretical finite element studies have demonstrated that a contact region between the implant’s surface and surrounding bone can be designed to induce optimal biomechanical stimulation for bone formation. Cell attachment and biomechanical stimulation are key factors to prevent bone resorption and afterward to gain bone. The design of the bones surrounding the implant’s surface that stimulates bone growth is one of the main subjects presented in this thesis.
The main factor to obtain high anchorage stability is the implant’s design. Thus, different dental implant models were created for the further evaluation for the best shape to fix the screw. In this thesis, the implant design includes four optimized parameters, such as: length and width of the implant body with different shapes of the thread. Therefore, the finite element analysis (FEA) software ANSYS 15.0 was used to automatically build three-dimensional (3-D) geometries to simulate their mechanical behavior. Besides, Wolff’s Law was used to analyze biomechanical behavior at the surrounding bone for further investigation of the bone remodeling due to different implant designs. Results were collected as a volume at disuse, adaptive, repair and overload regions, total volume of the bone; maximum elastic stress, strain distribution and the displacement in surrounding bones. Graphic user interface was created by MATLAB software to build 3-D surface contour and to show how different implant designs influence the osseointegration.
Stress conditions around an implant can also be improved by selecting an appropriate implant’s shape. Therefore, a new shape was taken to analyze its biomechanical behavior, such as T-shape dental implant. Also, information about this shape of the dental implant is insufficient. A numerical method of the bone remodeling process at the implant’s surrounding surface was applied to the T-shape dental implant. Theoretical methods of the bone remodeling were described. The concept of this numerical model was from the definition of bone remodeling according to Wolff’s Law. Next, this method was applied to design healing chamber of T-shape dental implant. The result of the current work can be extended to other medical devices. Moreover, a numerical model for T-shape implant design was taken into account and compared with the International Team for Implantology’s (ITI) dental implant’s healing chamber.
Thus, the present thesis contains two main topics of importance for biomimetic medical devices: i) numerical model based on the bone remodeling and ii) shape optimization of dental implants. This can demonstrate which biomimetic device can allow more bone ingrowth, efficiently reduce stress shielding effect, and therefore may improve long-term implant stability.
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