A New Design of Dental Implant Coating Using Functionally Graded Material

Abstract

Abstract Dental implantation treatment has developed into one of the most successful prosthetic technologies. A critical progress made in this area was the development of biocompatible materials to enable an engineered device (implant) to integrate within its surrounding bony tissues. Titanium and its alloys have been widely adopted as such materials due to their excellent biocompatibility. However, their mechanical properties largely differ from those in host bony tissues, which is problematical in osseointegration and bone remodeling. The challenge to face in prosthetics is to develop both biologically and mechanically compatible biomaterials for this purpose. Few existing research has been reported to develop an optimized design of functionally graded material (FGM) dental implant for promoting a long-term success. One of the authors of the present Contributions has previously designed a new FGM dental implant coating graded in axial direction from titanium at the apex to collagen at the basis of the dental implant. The aim of this investigation is to design a new gradation direction of FGM dental implant coating as well as studying the effect of coating thickness on the maximum von Mises stresses in bone adjacent to the coating layer. The gradation of the elastic modulus is changed along the longitudinal direction. Stress analysis using a finite element method showed that using a coating of 150 μm thickness, which is functionally graded from titanium at the outer shell adjacent to the bone to collagen at the inner shell adjacent to the implant, will reduce the maximum von Mises stress by 16 % and 13 % compared with the common conventional coating materials such as collagen and hydroxyapatite coatings, respectively. However, using FGM coating graded from hydroxyapatite at the outer shell to titanium at the inner shell reduces the maximum von Mises stress by 8 % and 5 % compared with collagen and hydroxyapatite coatings, respectively, but this gradation can improve the biocompatibility and can also achieve a full integration of the implant within the living bone, which increases the life of the implant.