**2. How does a CBCT work?**

The process begins with an emitter that directs a very fine beam of X-rays through a collimator (system that from a divergent beam forms a parallel beam). This beam affects the object under study which is crossed or irradiated by a percentage of lightning. This radiation, which has not been absorbed by the object, in the form of a spectrum, is collected by detectors. The detectors depending on the CBCT are of different materials, they can be silicon or selenium or a CCD sensor (digital analog converter) the X-ray source and the detector are connected in such a way that they have a synchronous movement.

The function of the CCD sensor is to convert the information obtained from analog to digital that transforms the electrical signal produced by the interaction of the detector with the patient's emerging X-rays, into a binary signal suitable for processing by software specially designed for each brand of CBCT.

The source-detector assembly rotates and performs the X-ray shot, obtaining a projection or cut of the tooth under study. The team performs several rotations to obtain 360 images or cuts corresponding to each degree of rotation that are reconstructed, thus achieving a three-dimensional image of the skull. This 2D data is then converted through conical beam algorithms [4] into a 3D volume of data for a PC in any of the 3D planes or a 3D image. Normally, transverse images are generated in the three orthogonal planes from the CBCT scan. The professional selects the position and thickness of the cut inside the data volume. The three views can be evaluated simultaneously, since the modification of the cut in one of the planes modifies the rest of the planes displayed. This can be manipulated by PC software to provide more detail of specific areas of interest [5].

**165**

*Applications of CBCT in Endodontics*

(**Figure 1**).

*DOI: http://dx.doi.org/10.5772/intechopen.89956*

plane, which divides the body into left and right halves (Z).

**3. Essential CBCT concepts related to endodontics**

seen on a conventional periapical radiograph [6].

vision and the spatial resolution of the machine.

radiograph or a periapical series [11].

**4. Uses of small-field CBCT in endodontics**

**4.1 Definitive diagnosis of the periapical radiolucent areas**

changes will be identified.

Axial plane: Perpendicular to the longitudinal axis of a body (X).

to overcome the distortions produced by the patient's breathing [7].

Sagittal plane: Perpendicular to the ground and parallel to the middle sagittal

Coronal plane Divide the skull into a ventral part and another dorsal part (Y)

Axial and proximal views are of particular value since they are generally not

Thanks to the cone-beam technology and algorithmic calculations it is possible

The most important concepts in the use of CBCT in endodontics are the field of

The visual field to be studied or Field of View (FOV) is directly related to the area to be scanned which will be digitally represented on the computer. The FOV measurement for face studies in dentistry with conical beam tomography is 14 cm. what determines the quality of the tomographic image (the size of the pixel and the voxel) is the division between FOV and the matrix. Roughly speaking, CBCT systems can be classified into two categories: limited (dental or regional) or complete (ortho or facial). The limited range FOV is 40–100 nm, while the field of view of the full range is 100–200 nm. A typical FOV consists of millions of voxels [8]. In endodontics, the FOV can be small or "focused" (5 cm by 5 cm or less) because the root canal treatment generally involves one tooth in an arch. This reduction in FOV reduces the amount of effective radiation dose [9]. Other advantages of a small FOV field of view are decreased time to process and read the image, better ability to avoid metallic structures that can cause interference, greater spatial resolution and improved diagnostic potential [10]. Most small FOV machines produce an effective radiation dose in the same order of magnitude as a panoramic

The degree of spatial resolution is determined by the voxel size, it is desirable that the resolution of a CBCT machine used for endodontics should not exceed 200 μm, the average width of the periodontal space. Otherwise no pathological

Possible applications in endodontics include the diagnosis of endodontic pathology and its origin, root canal system morphology, root evaluation (fractures and traumas), analysis of external or internal root resorption, invasive cervical resorption, presurgical planning, lesion extension, complicated anatomies, location of calcified root canals, endodontic retreatment, evaluation of iatrogenies such as perforations, separate instruments or extrusion of sealing material [12–14].

Endodontic treatment aims to preserve the tooth with normal function and prevent or cure apical periodontitis. However, periapical radiographs provide a twodimensional view of a three-dimensional object. Therefore, periapical radiographs cannot detect lesions such as apical periodontitis confined within the spongy bone.

**Figure 1.** *Illustration of the 3-dimensional planes.*

#### *Applications of CBCT in Endodontics DOI: http://dx.doi.org/10.5772/intechopen.89956*

*Oral Diseases*

licensed for use in the US [3].

**2. How does a CBCT work?**

that they have a synchronous movement.

more detail of specific areas of interest [5].

Radiology produced the first CBCT, the New Tom 9000, for dental use after Arai's pioneering work in Japan and in Mozzo in Italy, obtaining in 2001 the first CBCT

The process begins with an emitter that directs a very fine beam of X-rays through a collimator (system that from a divergent beam forms a parallel beam). This beam affects the object under study which is crossed or irradiated by a percentage of lightning. This radiation, which has not been absorbed by the object, in the form of a spectrum, is collected by detectors. The detectors depending on the CBCT are of different materials, they can be silicon or selenium or a CCD sensor (digital analog converter) the X-ray source and the detector are connected in such a way

The function of the CCD sensor is to convert the information obtained from analog to digital that transforms the electrical signal produced by the interaction of the detector with the patient's emerging X-rays, into a binary signal suitable for

The source-detector assembly rotates and performs the X-ray shot, obtaining a projection or cut of the tooth under study. The team performs several rotations to obtain 360 images or cuts corresponding to each degree of rotation that are reconstructed, thus achieving a three-dimensional image of the skull. This 2D data is then converted through conical beam algorithms [4] into a 3D volume of data for a PC in any of the 3D planes or a 3D image. Normally, transverse images are generated in the three orthogonal planes from the CBCT scan. The professional selects the position and thickness of the cut inside the data volume. The three views can be evaluated simultaneously, since the modification of the cut in one of the planes modifies the rest of the planes displayed. This can be manipulated by PC software to provide

processing by software specially designed for each brand of CBCT.

**164**

**Figure 1.**

*Illustration of the 3-dimensional planes.*

Sagittal plane: Perpendicular to the ground and parallel to the middle sagittal plane, which divides the body into left and right halves (Z).

Axial plane: Perpendicular to the longitudinal axis of a body (X).

Coronal plane Divide the skull into a ventral part and another dorsal part (Y) (**Figure 1**).

Axial and proximal views are of particular value since they are generally not seen on a conventional periapical radiograph [6].

Thanks to the cone-beam technology and algorithmic calculations it is possible to overcome the distortions produced by the patient's breathing [7].
