Aim of the work: in this review, we tried to show all details about dental implant, its components, types in the market, usage, case selection and diagnosis, indications and contraindications.  Patients and method: Pubmed, Google Scholar have been used to search for papers that addressed dental implantology, preoperative diagnosis of the cases and both of their medical and dental history were considered during searching. Results: it was obvious that dental implant has been the first choice by patients for replacing their missed teeth because of their numerous advantages specially in preserving the adjacent teeth and esthetics, but it may be more expensive than fixed bridges or removable prosthodontics. Conclusion: dental implant is a root-like structure made of titanium. It is composed of three main parts (fixture, abutment, crown). Case selection is the main point for implant success, so, before implant surgical procedure, the dentist asks the patient for full mouth x-ray, medical history and dental history.