For as long as dental surgeons have been placing implants, there have been continuous advancements and innovations. One of the areas where innovation has flourished is in guided implant surgery. Early implant planning consisted of 2D radiography and bone sounding, requiring clinicians to visualize structures by reflecting flaps. Accordingly, early implant surgery tended to be unpredictable because of the many unknowns involved in the procedure.
Restorative guides have been extensively used during implant planning and placement. A restorative‐based guide is a pattern or template that will aid the surgeon in visualizing the proposed position of the final restorations. An example would be a clear duplicate denture or an acrylic “suck‐down” of a mocked‐up tooth on a model, (Figs. 10.1 and 10.2). One major problem with a restorative guide is that the restorative goals and the bony architecture do not always match up; a situation that can render the guide ineffective and create a restorative compromise.
Radiography has been a mainstay in dentistry since the mid‐1900s, and X‐rays are an effective way of finding, and identifying, various oral problems. Although ubiquitous, the information discernible from a conventional radiograph can be limited and lack precision regarding the location of abnormalities and lesions which can present problems when planning implant dentistry.
Greater radiologic precision became possible with the introduction of X‐ray computed tomography (CT), also known as computerized tomographic imaging or computerized axial tomography (CAT) [1–4]. This diagnostic imaging method is now considered by the American Academy of Oral and Maxillofacial Radiology to be one of the parameters of care in dental implant planning .
In fact, there are two categories of X‐ray CT and they differ in their modes of acquiring imaging data based on their respective X‐ray beam geometries although both use a low‐dose beam of X‐rays. These two modalities or categories are fan beam X‐Ray CT and Cone Beam Computed Tomography (CBCT).
In fan‐beam scanners, a narrow fan‐shaped X‐ray beam is projected through the patient’s head and collected by a single scanner/detector mounted in the same axial plane as the X‐ray source but on the opposite side of the stabilized patient head. Thus, the X‐ray source and detector move synchronously around the patient’s head. In operation, images are taken slice‐by‐slice and these images are then “stacked” by sophisticated computer software and processed to produce a detailed 2D cross‐sectional image of the head at a greater precision than possible with conventional radiographs . Further, modern imaging systems use multi‐detector arrays so that scanning times are markedly reduced, and considerably lower X‐ray dosages are used compared to single detector fan‐beam CT systems. Further, 3D images are possible with such modern instrumentation.