As the aged population growth in recently, the dental implant is highlighted due to the increased demand of dental implant. However, one of technical problems in dental implant is fracture of dental abutment and fixture. The significant presumption cause of dental abutment and fixture failure is loosening between the abutment and the fixture. In order to quantitatively analyze the reason of dental implant failure in the aspect of mechanical behavior, finite element analysis of dental implant was performed by the different masticating force and loosening conditions. The higher residual stress which occurred at fastening the abutment and the fixture made the higher probability of implant failure. Therefore, we propose a new dental implant model, a wedge-shaped dental implant model, that can prevent loosening between the abutment and the fixture.