Implant systems are usually classified according to the material, shape, surface structure and connection of the implant. The clinical practice of oral implantology has led to the simplification of contemporary oral implant materials and implant forms. The implants are mainly made of grade 4 commercial pure titanium, and the threaded columnar and root implants have become the most accepted implant form worldwide. Studies have shown that moderately rough surface structures can increase implant surface area and osseointegration. Therefore, the implant systems currently used in clinical practice are generally rough surfaces with different degrees of roughness obtained through various surface treatments. The implant is connected to the prosthesis above it by a certain structure, which is mainly divided into two types: external connection and internal connection.