Rehabilitation with implants is the first choice of treatment in the replacement of missing teeth. Increasing patient expectations for cheaper, faster, more aesthetic and less invasive dental implant treatment have also led to a shift of current research interests to implant design features. Smaller diameter dental implant fixtures are one such design feature that may help to simplify the treatment process. Conventional implants exhibit good long-term results but also present some limitations such as cost, difficulty with placing the implant in reduced buccolingual dimensions of bone without the need for bone- grafting procedures, and the presence of chronic systemic diseases that can prevent most advanced surgeries such as bone grafts. To overcome these limitations the Mini dental implants and narrow diameter implants are introduced. In this book, we have discussed mainly the role of mini implants and narrow diameter implants in the field of prosthodontics.