The potential applications of cone beam computed tomography in the management of endodontic problems

Age- and gender-related differences in the position of the inferior alveolar nerve by using cone beam computed tomography

INTRODUCTION

Surgical endodontic procedures require precise knowledge of anatomic structures that might be traumatized. The aim of this study was to evaluate whether differences in patient gender or age are predictive of differences in the relative location of the inferior alveolar nerve (IAN) compared with the roots of the mandibular first molar.

METHODS

We searched a database of 23,000 small-volume cone beam computed tomography scans and evaluated the first 200 patients that met the following inclusion criteria: (1) age between 30-69 years; (2) known gender (n = 25 males and 25 females for each 10-year age bin); and (3) scans containing the mandibular first molar and IAN. Exclusion criteria consisted of any pathosis that might alter the position of the IAN. Anatomic measurements were made by 2 observers with mutual agreement of any discordant measures. Fourteen measurements (in millimeters) were taken at the level of the IAN and mesial and distal root apices. Data were analyzed by 2-way (age, sex) analysis of variance with Bonferroni post hoc test at P <.05.

RESULTS

Regardless of age, females had significantly shorter vertical distances from the IAN to the mesial (P < .01) and distal apices (P < .01) and shorter horizontal distances for total width of mandibular bone at the mesial (P < .01) and distal apices (P < .01). In addition, the overall width of the mandibular bone decreased in both genders from the 3rd-6th decade of life (P < .01).

CONCLUSIONS

Collectively, these data indicate that both gender and age are predictive of surgical endodontic anatomic relationships and should be considered in presurgical planning.

[A new modality for dentomaxillofacial imaging: cone beam CT]

Cone beam CT is an imaging technique used worldwide. It is a reliable and credible alternative to CT scan for dentomaxillofacial imaging. Radiation exposure may vary from one machine to another, but it remains definitely lower than CT dose levels. This technique is compatible with dental implant software. The major diagnostic advantage is the exquisite spatial resolution. The main pitfall is the poor contrast of face and neck soft tissues, due to a lower density resolution compared to CT scan.

External cervical resorption: a review

External cervical resorption (ECR) is the loss of dental hard tissue as a result of odontoclastic action; it usually begins on the cervical region of the root surface of the teeth. The etiology, predisposing factors, diagnosis, and management of ECR are reviewed. Effective management and appropriate treatment can only be carried out if the true nature and exact location of the ECR lesion are known. The role of cone beam computed tomography as a diagnostic adjunct for the management of ECR is also reviewed.

Prevalence of apical periodontitis in root canal-treated teeth from an urban French population: influence of the quality of root canal fillings and coronal restorations

This cross-sectional study determined the prevalence of apical periodontitis in 1035 root canal-treated teeth from adult French patients and investigated the influence of the quality of canal fillings and coronal restorations on the periradicular status. Periapical radiographs were used for analyses, and teeth were classified as healthy or diseased according to the periapical index scoring system. Overall, the prevalence of apical periodontitis in root canal-treated teeth was 33%. Only 19% of the teeth had endodontic treatments rated as adequate. The success rate (number of healthy teeth) for cases with adequate endodontic treatment was 91%, which was significantly higher when compared with teeth with inadequate treatment (61%). Teeth with adequate restorations had significantly decreased prevalence of apical periodontitis (29%) as compared with teeth with inadequate restorations (41%). The combination of adequate endodontic treatment and adequate restorations yielded the highest success rate (93.5%). The quality of the endodontic treatment was the most important factor for success, although the quality of the coronal restoration also influenced the treatment outcome.

Position of the impacted third molar in relation to the mandibular canal. Diagnostic accuracy of cone beam computed tomography compared with panoramic radiography

This study investigated the diagnostic accuracy of cone beam computed tomography (CBCT) compared to panoramic radiography in determining the anatomical position of the impacted third molar in relation with the mandibular canal. The study sample comprised 53 third molars from 40 patients with an increased risk of inferior alveolar nerve (IAN) injury. The panoramic and CBCT features (predictive variables) were correlated with IAN exposure and injury (outcome variables). Sensitivity and specificity of modalities in predicting IAN exposure were compared. The IAN was exposed in 23 cases during third molar removal and injury occurred in 5 patients. No significant difference in sensitivity and specificity was found between both modalities in predicting IAN exposure. To date, lingual position of the mandibular canal was significantly associated with IAN injury. CBCT was not more accurate at predicting IAN exposure during third molar removal, however, did elucidate the 3D relationship of the third molar root to the mandibular canal; the coronal sections allowed a bucco-lingual appreciation of the mandibular canal to identify cases in which a lingually placed IAN is at risk during surgery. This observation dictates the surgical approach how to remove the third molar, so the IAN will not be subjected to pressure.

The detection and management of root resorption lesions using intraoral radiography and cone beam computed tomography - an in vivo investigation

AIM

To compare the accuracy of intraoral periapical radiography with cone beam computed tomography (CBCT) for the detection and management of resorption lesions.

METHODOLOGY

Digital intraoral radiographs and CBCT scans were taken of patients with internal resorption (n = 5), external cervical resorption (n = 5) and no resorption (controls) (n = 5). A 'reference standard' diagnosis and treatment plan was devised for each tooth. Sensitivity, specificity, positive predictive values, negative predictive values and receiver operator characteristic (ROC) curves, as well as the reproducibility of each technique were determined for diagnostic accuracy and treatment option chosen.

RESULTS

The intraoral radiography ROC Az values were 0.780 and 0.830 for diagnostic accuracy of internal and external cervical resorption respectively. The CBCT ROC Az values were 1.000 for both internal and external cervical resorption. There was a significantly higher prevalence (P = 0.028) for the correct treatment option being chosen with CBCT (%) compared with intraoral radiographs (%).

CONCLUSION

CBCT was effective and reliable in detecting the presence of resorption lesions. Although digital intraoral radiography resulted in an acceptable level of accuracy, the superior accuracy of CBCT may result in a review of the radiographic techniques used for assessing the type of resorption lesion present. CBCT's superior diagnostic accuracy also resulted in an increased likelihood of correct management of resorption lesions.

Analysis of the internal anatomy of maxillary first molars by using different methods

The success of endodontic treatment depends on the identification of all root canals so that they can be cleaned, shaped, and obturated. This study investigated internal morphology of maxillary first molars by 3 different methods: ex vivo, clinical, and cone beam computed tomography (CBCT) analysis. In all these different methods, the number of additional root canals and their locations, the number of foramina, and the frequency of canals that could or could not be negotiated were recorded. In the ex vivo study, 140 extracted maxillary first molars were evaluated. After canals were accessed and detected by using an operating microscope, the teeth with significant anatomic variances were cleared. In the clinical analysis, the records of 291 patients who had undergone endodontic treatment in a dental school during a 2-year period were used. In the CBCT analysis, 54 maxillary first molars were evaluated. The ex vivo assessment results showed a fourth canal frequency in 67.14% of the teeth, besides a tooth with 7 root canals (0.72%). Additional root canals were located in the mesiobuccal root in 92.85% of the teeth (17.35% could not be negotiated), and when they were present, 65.30% exhibited 1 foramen. Clinical assessment showed that 53.26%, 0.35%, and 0.35% of the teeth exhibited 4, 5, and 6 root canals, respectively. Additional root canals were located in this assessment in mesiobuccal root in 95.63% (27.50% could not be negotiated), and when they were present, 59.38% exhibited 1 foramen. CBCT results showed 2, 4, and 5 root canals in 1.85%, 37.05%, and 1.85% of the teeth, respectively. When present, additional canals showed 1 foramen in 90.90% of the teeth studied. This study demonstrated that operating microscope and CBCT have been important for locating and identifying root canals, and CBCT can be used as a good method for initial identification of maxillary first molar internal morphology.

Conebeam CT of the head and neck, part 2: clinical applications

SUMMARY

Conebeam x-ray CT (CBCT) is being increasingly used for point-of-service head and neck and dentomaxillofacial imaging. This technique provides relatively high isotropic spatial resolution of osseous structures with a reduced radiation dose compared with conventional CT scans. In this second installment in a 2-part review, the clinical applications in the dentomaxillofacial and head and neck regions will be explored, with particular emphasis on diagnostic imaging of the sinuses, temporal bone, and craniofacial structures. Several controversies surrounding the emergence of CBCT technology will also be addressed.

A comparative evaluation of Cone Beam Computed Tomography (CBCT) and Multi-Slice CT (MSCT) Part I. On subjective image quality

AIMS

To compare image quality and visibility of anatomical structures in the mandible between five Cone Beam Computed Tomography (CBCT) scanners and one Multi-Slice CT (MSCT) system.

MATERIALS AND METHODS

One dry mandible was scanned with five CBCT scanners (Accuitomo 3D, i-CAT, NewTom 3G, Galileos, Scanora 3D) and one MSCT system (Somatom Sensation 16) using 13 different scan protocols. Visibility of 11 anatomical structures and overall image noise were compared between CBCT and MSCT. Five independent observers reviewed the CBCT and the MSCT images in the three orthographic planes (axial, sagittal and coronal) and assessed image quality on a five-point scale.

RESULTS

Significant differences were found in the visibility of the different anatomical structures and image noise level between MSCT and CBCT and among the five CBCT systems (p=0.0001). Delicate structures such as trabecular bone and periodontal ligament were significantly less visible and more variable among the systems in comparison with other anatomical structures (p=0.0001). Visibility of relatively large structures such as mandibular canal and mental foramen was satisfactory for all devices. The Accuitomo system was superior to MSCT and all other CBCT systems in depicting anatomical structures while MSCT was superior to all other CBCT systems in terms of reduced image noise.

CONCLUSIONS

CBCT image quality is comparable or even superior to MSCT even though some variability exists among the different CBCT systems in depicting delicate structures. Considering the low radiation dose and high-resolution imaging, CBCT could be beneficial for dentomaxillofacial radiology.

Use of cone-beam volumetric tomography in the diagnosis of root fractures

OBJECTIVES

The diagnosis of root fractures by conventional radiographs is still difficult because of limitations of 2D images. Cone-beam volumetric tomography improves the diagnosis capacity in dentistry, such as increased radiation dose to the patient and presence of artifacts on the image.

STUDY DESIGN

This study compared the images obtained on conventional periapical radiographs and 3D scans (Accuitomo 3DX) for the diagnosis of root fractures. Twenty patients with suspected root fractures were submitted to examination by periapical radiography and CBCT. Two professionals, unaware of the symptomatology, examined these radiographs and CBCT images according to pre-established scores, which were later checked against the signs and symptoms.

RESULTS

The results revealed statistical difference for cone-beam volumetric tomography compared with conventional radiographs in the diagnosis of root fractures.

CONCLUSION

It could be concluded that cone-beam volumetric tomography was better than conventional radiography in the diagnosis of root fractures, thereby constituting an excellent alternative for diagnosis in general practice.

Interpretation of chemically created periapical lesions using 2 different dental cone-beam computerized tomography units, an intraoral digital sensor, and conventional film

OBJECTIVE

To assess the diagnostic potential of 2 different cone-beam computerized tomography (CT) units and compare this with intraoral digital and conventional film in the detection of chemically created periapical lesions.

STUDY DESIGN

Periapical lesions were created chemically in 27 intact roots of 23 teeth (6 incisors, 4 canines, 6 premolars, and 7 molars). Cone-beam CT and digital and film images of the teeth were obtained before and after the lesions were created. Three observers separately used a 5-point scale to rate the images for the presence or absence of periapical pathology. Images were scored twice by each observer, with an interval of 4 weeks. Kappa values were calculated to assess intra- and interobserver agreement. Data were analyzed using repeated-measures analysis of variance for nested designs. R(2) values were used to assess the models for each observer for each method. Differences between observers and methods were tested for statistical significance with the paired t test.

RESULTS

Kappa coefficients for intraobserver agreement ranged from 0.196 to 0.542 for the 2-dimensional (2D) images and from 0.533 to 0.699 for the cone-beam CT images, whereas kappa coefficients for interobserver agreement ranged from 0.223 to 0.302 for the 2D images and from 0.417 to 0.461 for the cone-beam CT images. The R(2) values for each observer showed that cone-beam CT images were superior to 2D intraoral images. There was no difference between the 2 cone-beam CT units tested (P > .05), and no difference was found between the 2 intraoral radiographic techniques tested (P > .05).

CONCLUSION

The 2 cone-beam CT units tested performed similarly, and both performed better than intraoral digital and film radiography in detecting chemically created periapical lesions.

Management of dens invaginatus diagnosed by spiral computed tomography: a case report

A thorough knowledge of the normal anatomy of the root canal system as well as the possible aberrancies is imperative for success of endodontic therapy. The challenge lies in diagnosing these conditions properly, complete debridement of the root canal system, and 3-dimensional sealing of the same. Conventional diagnostic aids like radiographs play an important role in assessment of complex root canal morphologies. These modalities, however, do not provide detailed information of the complexity as a result of their inherent limitations. This calls for use of more advanced imaging modalities such as spiral computed tomography, which can help the clinician in making a more accurate diagnosis. This report discusses the usefulness of spiral computed tomography in accurate diagnosis of a case of dens invaginatus and its successful management.

A new periapical index based on cone beam computed tomography

The purpose of this study was to evaluate a new periapical index based on cone beam computed tomography (CBCT) for identification of apical periodontitis (AP). The periapical index proposed in this study (CBCTPAI) was developed on the basis of criteria established from measurements corresponding to periapical radiolucency interpreted on CBCT scans. Radiolucent images suggestive of periapical lesions were measured by using the working tools of Planimp software on CBCT scans in 3 dimensions: buccopalatal, mesiodistal, and diagonal. The CBCTPAI was determined by the largest lesion extension. A 6-point (0-5) scoring system was used with 2 additional variables, expansion of cortical bone and destruction of cortical bone. A total of 1014 images (periapical radiographs and CBCT scans) originally taken from 596 patients were evaluated by 3 observers by using the CBCTPAI criteria. AP was identified in 39.5% and 60.9% of cases by radiography and CBCT, respectively (P < .01). The CBCTPAI offers an accurate diagnostic method for use with high-resolution images, which can reduce the incidence of false-negative diagnosis, minimize observer interference, and increase the reliability of epidemiologic studies, especially those referring to AP prevalence and severity.