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

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].

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

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.

Bender et al. in 1961 demonstrated in vitro that bone lesions cannot be diagnosed effectively by X-rays unless cortical bone is perforated [15, 16].

Goldman et al. showed that there was considerable disagreement among professionals in the diagnosis of radiolucent areas with radiographs. The reasons for these inconsistencies are the 2D nature of the radiographic image and anatomical distortion that can mislead the professional. Increasing the number of X-rays, taken at different angles improves diagnostic accuracy [17].

Conical beam tomography results in 3D images that eliminate the overlap of anatomical structures. The use of CBCT helps detect periapical radiolucent lesions or areas and make a differential diagnosis with a non-invasive technique that is very accurate (**Figure 2**).

According to Levin et al., the etiology of irreversible pulpitis could be caries or deep restorations, pulp exposure, cracks or any irritating pulp among others [18]. Radiographic visualization of teeth with irreversible pulpitis on conventional periapical radiographs can be normal except for the presence of the etiological cause. Occasionally, if the inflammatory process has spread to the periapical area, a thickening of the periodontal ligament space may be visible [12].

However, the use of 2D radiography still has serious limitations. The studies carried out by Estrela et al. in 2008 evaluated apical periodontitis (AP) in 1508 teeth by 3 methods (panoramic, periapical radiographs and CBCT) concluded that the diagnostic accuracy was significantly higher with periapical radiographs (54.5%) than with panoramic radiographs (27.5%) using the CBCT as a gold standard reference about diagnostic accuracy; apical periodontitis was correctly identified with conventional radiography only when it was sufficiently advanced. Estrela concluded that prevalence of AP was significantly higher with CBCT, overall sensitivity was 0.55 and 0.28 for periapical and panoramic radiographs, respectively and AP was correctly identified with conventional methods when showed advanced status. CBCT was proved to be accurate to identify AP [19].

Lofthag Hansen in 2007 compared the periapical state of 46 maxillary and mandibular molars with two angled periapical radiographs and CBCT scans. CBCT detected 38% more lesions than periapical radiographs [20]. Low et al. in 2008 [21] and Cotton et al. [22] in 2007 give us similar results. García-Silva de Paula in 2009 with an in vivo study examined the periapice of 83 teeth in dogs

**167**

root fractures [31].

*Applications of CBCT in Endodontics*

93% with histology [23, 24].

**4.2 Visualization of root fractures**

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

with periapical radiography and CBCT using histological examination as a gold standard and the conclusions were that CBCT diagnosed healthy areas more accurately than radiography and was more sensitive in detecting apical periodontitis (AP). The AP was detected in 71% of roots with radiography, 84% with CBCT and

Vertical root fractures (VRF) are a type of fractures that extend along the major axis of the tooth. If the diagnosis is not carried out, progressive destruction of the periodontal ligament and alveolar bone occurs which can influence the prognosis of adjacent teeth and future restorations. However, VRF may not produce any signs or symptoms such as pain or discomfort from chewing. Therefore, it is important that VRFs be diagnosed as quickly as possible. The prevalence of VRFs in several populations has been reported between 2 and 5% and depending on the literature reviewed; the percentage of endodontic and fissured teeth varies between 3 and 30%. The highest incidence occurs between 40 and 60 years [25]. The most common teeth where it occurs are lower molars and upper premolars [26]. One third of the VRFs are radiographically detectable, usually when the beam is perpendicular to the fracture

line or the granulation tissue separates fragments [27]. (**Figure 3a** and **b**).

**4.3 Diagnosis and treatment of dento-alveolar trauma**

Mesio-distal fractures are almost impossible to detect with normal radiography [28]. The most effective in vivo diagnostic method of an LRF is surgical exposure of the fracture, and visual inspection under magnification with the help of staining. Edlund et al. examined 32 teeth in 29 patients, which gave symptoms of a VRF, with CBCT and subsequent surgical exploration; the results showed a high correlation between the diagnosis through CBCT and direct visualization, which confirms numerous in vitro studies that support the validity of CBCT in the diagnosis of VRF [29].

Most maxillofacial traumatic injuries involve only teeth (50%) or teeth and adjacent soft tissue (36%) while those affecting the alveoli are 13.6% remaining [30]. Unfortunately, periapical radiography has low sensitivity for the diagnosis of minimal displacements of teeth, alveolar or root fractures, however CBCT has the advantage that it is more comfortable for the traumatized patient; extraoral scan generates a multidimensional image avoiding the need for multiple intraoral radiographs. Bernardes et al. in 2009 compared, retrospectively, conventional periapical radiographs and CBCT images in 20 patients with suspected root fractures and found that CBCT was able to detect fractures in 90% of patients, while radiography could only detect fractures in 30–40% of patients. In conclusion, they reported that CBCT was an excellent complement to conventional radiography in the diagnosis of

**4.4 Identification of the apices of the teeth in relation to anatomical structures**

Conventional radiographs do not always allow for the evaluation of the spatial relationship of roots with their surrounding anatomical structures [32]. This is important in the context of surgical planning and treatment [21]. Radiological identification of the position of the roots and their apices against structures vitals such as the maxillary sinus or the dental canal is essential for pre-surgical evaluation for endodontic microsurgery and to prevent injury during root canal filling. Velvart et al. studied 55 patients with 44 lower molars and 6 lower premolars, which had been referred for apical surgery due to persistent periapical areas.

**Figure 2.** *Images of the CBCT scan.*

*Oral Diseases*

accurate (**Figure 2**).

Bender et al. in 1961 demonstrated in vitro that bone lesions cannot be diagnosed

Conical beam tomography results in 3D images that eliminate the overlap of anatomical structures. The use of CBCT helps detect periapical radiolucent lesions or areas and make a differential diagnosis with a non-invasive technique that is very

According to Levin et al., the etiology of irreversible pulpitis could be caries or deep restorations, pulp exposure, cracks or any irritating pulp among others [18]. Radiographic visualization of teeth with irreversible pulpitis on conventional periapical radiographs can be normal except for the presence of the etiological cause. Occasionally, if the inflammatory process has spread to the periapical area, a

However, the use of 2D radiography still has serious limitations. The studies carried out by Estrela et al. in 2008 evaluated apical periodontitis (AP) in 1508 teeth by 3 methods (panoramic, periapical radiographs and CBCT) concluded that the diagnostic accuracy was significantly higher with periapical radiographs (54.5%) than with panoramic radiographs (27.5%) using the CBCT as a gold standard reference about diagnostic accuracy; apical periodontitis was correctly identified with conventional radiography only when it was sufficiently advanced. Estrela concluded that prevalence of AP was significantly higher with CBCT, overall sensitivity was 0.55 and 0.28 for periapical and panoramic radiographs, respectively and AP was correctly identified with conventional methods when showed advanced status.

Lofthag Hansen in 2007 compared the periapical state of 46 maxillary and mandibular molars with two angled periapical radiographs and CBCT scans. CBCT detected 38% more lesions than periapical radiographs [20]. Low et al. in 2008 [21] and Cotton et al. [22] in 2007 give us similar results. García-Silva de Paula in 2009 with an in vivo study examined the periapice of 83 teeth in dogs

Goldman et al. showed that there was considerable disagreement among professionals in the diagnosis of radiolucent areas with radiographs. The reasons for these inconsistencies are the 2D nature of the radiographic image and anatomical distortion that can mislead the professional. Increasing the number of X-rays, taken at

effectively by X-rays unless cortical bone is perforated [15, 16].

thickening of the periodontal ligament space may be visible [12].

different angles improves diagnostic accuracy [17].

CBCT was proved to be accurate to identify AP [19].

**166**

**Figure 2.**

*Images of the CBCT scan.*

with periapical radiography and CBCT using histological examination as a gold standard and the conclusions were that CBCT diagnosed healthy areas more accurately than radiography and was more sensitive in detecting apical periodontitis (AP). The AP was detected in 71% of roots with radiography, 84% with CBCT and 93% with histology [23, 24].
