For past three decades dentistry has witness with immense advances in all branches. For more than 25 years digital radiograph are available in dentistry. Starts from the basic intra-oral periapical x-rays to the highly developed techniques like CT, MRI found place in modern dentistry. Deepness of structure cannot be obtained and localized using 2-dimentional static imaging. Three dimensional imaging gained a valuable place in dentistry.3-D imaging and modelling technologies such as cone beam computed tomography , with relatively long history of CAD CAM,it will become of increasing importance. Nowadays digital radiograph are more common and dentists are wondering that how it impossible to replace plain film with digital system,but it has been proved successfull