Prosthodontic treatment using implants has many advantages in comparison with conventional treatment. However, it is reported that there are several complications associated with implants. They are divided into mechanical, biological, and esthetic aspects in prosthodontics. To overcome them, there have been numerous attempts such as a connection type of abutment-fixture, microthread, crestal module design, and abutment profile. Recently, one of the methods involves the development of a 1-piece implant. A 1-piece implant has many advantages in comparison with previous 2-piece implant. It is free of mechanical complications such as screw looseness, screw fracture, and fixture fracture. Also, in a biological aspect, absence of microgap, micromovement, and dis/reconnection of abutment leads to the stable maintenance of soft and hard tissue. However, 1-piece implants have limited indications. Selection of abutment is very strict and correction of the path is difficult after the installation of the fixture. Also, bone quality and primary stability are very important factors in 1-piece implants because it is based on immediate provisionalization. Although there are not many kinds of available 1-piece implants, one of the most well-known 1-piece implants is NobelDirect® (Nobel Biocare). However, clinical results of NobelDirect® are controversial and improvement is necessary. In most studies, it is reported that long term studies and improvements of implant design are required. Therefore, this research focuses on the advantages, design, clinical application and practical result of 1-piece implants.