Cone-beam computed tomographic (CBCT) imaging is an advanced imaging modality that provides excellent visual-ization of the dental hard tissues and osseous structures in three dimensions. CBCT imaging has become widely used over the last decade because it has multiple applications in dentomaxil-lofacial diagnosis. The anatomic coverage of CBCT imaging may be limited to the dentoalveolar arch or may extend to encompass a large part of the craniofacial skeleton. Clinicians who use CBCT imaging must be competent in recognizing radiographic manifesta-tions of disease throughout the volume imaged. Similar to two-dimensional images, radiographic identification of abnormalities requires a thorough knowledge of the radiographic appearance of anatomic structures.
Three-dimensional rendering is the 3D visualization of computer-generated objects using special software. It was introduced in the 1970s, and since then it has commonly been em-ployed in video editing, video games, simulators, and special effects in film and television, as well as in architecture to get a realistic model of projects. With the introduction of computed tomography (CT), it soon began to be used in the medical sector to obtain a three-dimensional visualization of tissues, thanks to computed tomography, magnetic resonance imaging (MRI), and positron emission tomography (PET).
Disorders of the temporomandibular joint (TMJ) include all abnormalities that interfere with the normal form or function of the TMJ. These disorders include developmental abnormalities that can result in an abnormal form of the osseous or soft tissue structures of the joint. Other disorders are acquired, such as dysfunction of the articular disc and associated ligaments and muscles, joint arthritides, inflammatory lesions, trauma, and neoplasms.
All of the images discussed in the previous chapters of this text have been two-dimensional. Dental imaging is no longer limited to two dimensions; three-dimensional imaging is now available. In 1999, a technology termed cone-beam computed tomography (CBCT) was introduced that allows for the viewing of structures in the oral-maxillofacial complex in three dimensions. The adoption of three-dimensional digital imaging in dentistry has expanded since that time as the result of numerous technical improvements and commercial marketing. CBCT has become a desired technology because of the accurate and detailed information it provides.
In this section, the various uses of CBCT systems in each specialty will be described in everyday clinical practice. Clinical cases will often be described in detail and step by step so as to underline the three phases when these systems may be really useful to clinicians: diagnosis, treatment planning and follow-up.
Cone-beam computed tomographic (CBCT) imaging is the most significant technologic advance in maxillofacial imaging since the introduction of panoramic radiography. CBCT imaging was initially developed commercially for angiography in the early 1980s.
As cone-beam computed tomographic (CBCT) imaging is inherently a digital volumetric image-capture technology, image visualization should also be by digital display. This demands that clinicians move from static hard copy (printed) images to software-assisted volumetric review. Image display should be dynamic and formatted according to task-specific display protocols. Expanding the use of volumetric data for treatment planning and image guidance of operative and surgical procedures is facilitated by the use of appropriate application of software.
There are seven criteria useful for describing osseous lesions to formulate a differential diagnosis: Number, location, density, shape, size, borders, changes to surrounding anatomic structures such as root resorption and tooth displacement.
A benign tumor represents a new uncoordinated growth that gener-ally has the following characteristics. Benign tumors are slowly growing and spread by direct extension and not by metastases. They tend to resemble the tissue of origin histologically. For example, an ameloblastoma, a tumor thought to be derived from odontogenic epithelium, often is composed of cells that resemble ameloblasts. It is thought that benign tumors have unlimited growth potential. Hamartomas often are included in the category of benign tumors. However, hamartomas are overgrowths of dis-organized normal tissue that have a limited growth potential. For example, an odontoma is a hamartoma of dental tissue (disorganized enamel, dentin, and pulp tissues) derived from the dental follicle that stops growing at approximately the same time as other normal dental tissues. Included in this chapter are hyperplasias. Hyperplasia refers to a growth formed by an increase in the number of cells of a tissue but differs from a hamartoma in that the tissue is in a normal arrangement. Hyperplasia is generally thought to be a reaction to a stimulus, such as inflammation. Therefore, hyper-plasias have limited growth potential and tend to regress when the stimulus is removed.
Patients may read an article in a magazine or on the internet, hear a report in the news or listen to other so‐called authorities with information that contradicts the x‐ray imaging protocol practiced by their personal dentists. A patient may then confront their dental professional about these concerns. The typical patient wants a concise answer that is easy to understand. In cases where the need or frequency of x‐ray exposure is questioned, dental auxiliaries are often the dental professional of choice for the answers. This author believes that the public’s perception of dental auxiliaries is that they are very knowledgeable about dentistry, they do not have x‐ray quotas to fill and they do not receive a bonus for exposing additional numbers of x‐ray images. Therefore, a dental auxiliary is perceived as someone who can offer unbiased answers to their questions. Here are ten questions that a patient may ask their dental professional prior to being exposed to x-radiation. Each question is accompanied by a simple response that should educate and allay the fears of the patient.