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

Imaging techniques in endodontics: an overview

This review provides an overview of the relevance of imaging techniques such as, computed tomography, cone beam computed tomography, and ultrasound, to endodontic practice. Many limitations of the conventional radiographic techniques have been overcome by the newer methods. Advantages and disadvantages of various imaging techniques in endodontic practice are also discussed.

Radiological diagnosis of periapical bone tissue lesions in endodontics: a systematic review

This systematic review evaluates the diagnostic accuracy of radiographic methods employed to indicate presence/absence and changes over time of periapical bone lesions. Also investigated were the leads radiographic images may give about the nature of the process and the condition of the pulp in nonendodontically treated teeth. Electronic literature search included the databases PubMed, Embase and CENTRAL from January 1950 to June 2011. All languages were accepted provided there was an abstract in English. The MeSH terms were 'Cone beam computed tomography (CBCT)', 'Radiography, panoramic', 'Periapical diseases', 'Dental pulp diseases', 'Sensitivity and specificity', 'receiver operating characteristics (ROC) curve', 'Cadaver', 'Endodontics' and 'Radiography dental'. Two reviewers independently assessed abstracts and full text articles. An article was read in full text if at least one of the two reviewers considered an abstract to be potentially relevant. Altogether, 181 articles were read in full text. The GRADE approach was used to assess the quality of evidence of each radiographic method based on studies of high or moderate quality. Twenty-six studies fulfilled criteria set for inclusion. None was of high quality; 11 were of moderate quality. There is insufficient evidence that the digital intraoral radiographic technique is diagnostically as accurate as the conventional film technique. The same applies to CBCT. No conclusions can be drawn regarding the accuracy of radiological examination in identifying various forms of periapical bone tissue changes or about the pulpal condition.

Estimation of paediatric organ and effective doses from dental cone beam CT using anthropomorphic phantoms

OBJECTIVES

Cone beam CT (CBCT) is an emerging X-ray technology applied in dentomaxillofacial imaging. Previous published studies have estimated the effective dose and radiation risks using adult anthropomorphic phantoms for a wide range of CBCT units and imaging protocols.

METHODS

Measurements were made five dental CBCT units for a range of imaging protocols, using 10-year-old and adolescent phantoms and thermoluminescent dosimeters. The purpose of the study was to estimate paediatric organ and effective doses from dental CBCT.

RESULTS

The average effective doses to the 10-year-old and adolescent phantoms were 116 μSv and 79 μSv, respectively, which are similar to adult doses. The salivary glands received the highest organ dose and there was a fourfold increase in the thyroid dose of the 10-year-old relative to that of the adolescent because of its smaller size. The remainder tissues and salivary and thyroid glands contributed most significantly to the effective dose for a 10-year-old, whereas for an adolescent the remainder tissues and the salivary glands contributed the most significantly. It was found that the percentage attributable lifetime mortality risks were 0.002% and 0.001% for a 10-year-old and an adolescent patient, respectively, which are considerably higher than the risk to an adult having received the same doses.

CONCLUSION

It is therefore imperative that dental CBCT examinations on children should be fully justified over conventional X-ray imaging and that dose optimisation by field of view collimation is particularly important in young children.

Cone beam computed tomography in endodontics

Cone beam computed tomography (CBCT) is a contemporary, radiological imaging system designed specifically for use on the maxillo-facial skeleton. The system overcomes many of the limitations of conventional radiography by producing undistorted, three-dimensional images of the area under examination. These properties make this form of imaging particularly suitable for use in endodontics. The clinician can obtain an enhanced appreciation of the anatomy being assessed, leading to an improvement in the detection of endodontic disease and resulting in more effective treatment planning. In addition, CBCT operates with a significantly lower effective radiation dose when compared with conventional computed tomography (CT). The purpose of this paper is to review the current literature relating to the limitations and potential applications of CBCT in endodontic practice.

Versatility of the cone beam computed tomography in oral surgery: an overview

Cone beam CT (CBCT) produces threedimensional information on the facial skeleton, teeth and their surrounding tissues; and is increasingly being used in many of the dental specialties. This is usually achieved with a substantially lower effective dose compared with conventional medical computed tomography (CT). Periapical pathologies, root fractures, root canal anatomy and the true nature of the alveolar bone topography around teeth may be assessed. CBCT scans are desirable to assess posterior teeth prior to periapical surgery, as the thickness of the cortical and cancellous bone can be accurately determined as can the inclination of roots in relation to the surrounding jaw. The relationship of anatomical structures such as the maxillary sinus and inferior dental nerve to the root apices may also be clearly visualized. Measurements on CBCT are more accurate when compared with OPG. Therefore, CBCT permits the clinician to have all necessary information when planning dental implants. The purpose of this article is to provide an overview of the unique image display capabilities of maxillofacial CBCT systems and to illustrate specific applications in clinical practice.

Use of cone beam computed tomography in the diagnosis, planning and follow up of a type III dens invaginatus case

AIM

To present the case of a maxillary left lateral incisor with Oehlers' type III dens invaginatus in which cone beam computed tomography (CBCT) was used as an adjunctive resource in the diagnosis as well as in the planning and 2-year follow-up of the nonsurgical/surgical treatment.

SUMMARY

The tooth had two root canals: a primary (main) canal with vital pulp that appeared to be closed apically and an invaginated canal that was necrotic, wide-open at the portal of exit and associated with a large chronic periapical lesion extending to the apex of the maxillary left central incisor. Radiographic tracking of a sinus tract in the labial gingiva of the affected tooth with a gutta-percha point revealed its origin to be the invagination. The CBCT scans revealed that the periapical radiolucency was significantly larger than seen radiographically as well as an increased thickness of the buccal cortical plate. Conventional root canal treatment of the primary canal was undertaken. As nonsurgical access to the invaginated canal was not possible, endodontic surgery was performed for curettage of the lesion, root-end cavity preparation using ultrasonic tips and root canal filling with white mineral trioxide aggregate (MTA). CBCT scanning after 17 months and clinical and radiographic follow-up after 24 months revealed complete periapical repair and absence of symptoms.

KEY LEARNING POINTS

The combination of nonsurgical and surgical treatments produced periapical repair in a tooth with type III dens invaginatus with two root canals. CBCT may aid the diagnosis as well as the management plan and follow-up of teeth with this developmental anomaly.

Clinical technique for invasive cervical root resorption

This clinical case report describes the diagnosis and treatment of an external invasive cervical resorption. A 17-year-old female patient had a confirmed diagnosis of invasive cervical resorption class 4 by cone beam computerized tomography. Although, there was no communication with the root canal, the invasive resorption process was extending into the cervical and middle third of the root. The treatment of the cervical resorption of the lateral incisor interrupted the resorptive process and restored the damaged root surface and the dental functions without any esthetic sequelae. Both the radiographic examination and computed tomography are imperative to reveal the extent of the defect in the differential diagnosis.

Intrusive luxation in primary teeth - Review of literature and report of a case

Luxation injuries such as intrusion are commonly seen in the primary dentition. Intrusion drives the tooth deeper into the alveolar socket, which results in damage to the pulp and peridontium. Difficulty in gaining compliance from a very young child and the risk of damaging the permanent tooth germ makes the management of these injuries challenging. Careful clinical and radiographic examination along with regular follow-up is essential. A case of intrusive luxation to the maxillary central incisor in a 3-year-old patient is reported. Spontaneous reeruption was noted 4 months after injury, but the tooth had developed an abscess and external root resorption. Hence, extraction of the tooth was done and an anterior esthetic fixed space maintainer was placed. Traumatic injuries to the primary dentition should not be ignored by the parents or by the dentist. The paper also includes a literature review of intrusive luxation in the primary dentition.

The extramandibular inferior alveolar nerve in cases with severely atrophic lower jaws

There are very few evidences on the extramandibular course (EMC) of the inferior alveolar nerve (IAN). We report here two such cases. The first one was encountered at dissection, in a human adult female cadaver where the right IAN terminal division was identified in the premolar region, above a severely atrophied mandibular body. The second case was a patient evaluated by cone-beam CT, who presented with an extremely atrophic mandible with bilateral extramandibular courses of the IANs. Such severe atrophy of the mandible may be considered as residual ridge class 7 along with the existing Atwood classes. EMCs of the IAN may not only occur in extreme mandibular atrophy, but also in dentate mandibles. In edentulous mandibles, an extramandibular IAN may complicate local surgical procedures or hamper denture wearing.

MR-Imaging of teeth and periodontal apparatus: an experimental study comparing high-resolution MRI with MDCT and CBCT

OBJECTIVES

The aim of this study was (1) to assess the ability of magnetic resonance imaging (MRI) to visualize dental and periodontal structures and (2) to compare findings with multidetector computed tomography (MDCT) and cone beam CT (CBCT).

MATERIALS AND METHODS

Four porcine mandibles were examined with (1) 3T-MRI, (2) MDCT and (3) CBCT. Two observers independently reviewed MR, MDCT and CBCT images and assessed image quality of different dental and periodontal structures. To assess quantitatively the accuracy of the different imaging technique, both observers measured burr holes, previously drilled in the mandibles.

RESULTS

Dental structures, e.g. teeth roots, pulpa chamber and dentin, were imaged accurately with all imaging sources. Periodontal space and cortical/trabecular bone were better visualized by MRI (p < 0.001). MRI could excellently display the lamina dura, not detectable with MDCT and only inconstant visible with CBCT (p < 0.001). Burr hole measurements were highly precise with all imaging techniques.

CONCLUSIONS

This experimental study shows the diagnostic feasibility of MRI in visualization of teeth and periodontal anatomy. Detection of periodontal structures was significantly better with MRI than with MDCT or CBCT. Prospective trials have to evaluate further the potential benefit of MRI in a clinical setting.

Managing severe curvature of radix entomolaris: three-dimensional analysis with cone beam computed tomography

AIM

To present a case of a mandibular first molar with an additional distolingual root [radix entomolaris (RE)] and to discuss the use of cone beam computed tomography (CBCT) for its identification and management during root canal treatment.

SUMMARY

A 52-year-old Caucasian woman was referred for root canal treatment of the right mandibular first molar (tooth 46). After clinical and radiographic examination, a symptomatic irreversible pulpitis was diagnosed. Three periapical radiographs with different horizontal angulations revealed the presence of an additional distolingual root. This extra root, termed RE, has an incidence of <5% in the Caucasian population. A CBCT examination was also taken, which revealed a severe root canal curvature, especially in the middle third, of this supernumerary root. CBCT provided more accurate information in terms of RE inclination and root canal curvature before commencing root canal treatment. The conventional access opening was modified into a more trapezoidal cavity, and five root canals were found. All canals were instrumented with new nickel-titanium (NiTi) files to reduce the risk of fractured instruments. After preparation, the root canals were filled using thermoplastified techniques. The 1-year follow-up periapical radiographs and CBCT images revealed a continuous periodontal space with no signs of apical periodontitis.

KEY LEARNING POINTS

• Cone beam computed tomography imaging is useful in identifying the root canal system and the surrounding structures. • An accurate detection of supernumerary roots, such as RE, can avoid complications during and after root canal treatment. • The analysis of root canal curvature is important because instrument fracture has been linked to angle and radius of curvature. • The use of new instruments can reduce the incidence of instrument fracture.

Detection of vertical root fractures by using cone-beam computed tomography: a clinical study

INTRODUCTION

Vertical root fractures of teeth (VRFs) often pose a diagnostic dilemma because of the difficulty in detection of these in intraoral radiographs except in certain cases with very distinct clinical findings. This often leads to unwarranted extraction of the tooth. Cone-beam computed tomography (CBCT) produces three-dimensional images and allows precise visualization and evaluation of VRFs or cracks in extracted teeth, as reported previously. This clinical pilot study was designed to determine the diagnostic accuracy of noninvasive CBCT for detection of suspected VRFs in endodontically treated teeth by using exploratory surgery to confirm the presence or absence of a fracture.

METHODS

Thirty-two teeth in 29 patients with clinical signs and symptoms suggestive of VRF were included in the study after informed consent was obtained. They underwent a limited area CBCT evaluation. All CBCT studies were blinded, and 2 board-certified oral and maxillofacial radiologists assessed the presence or absence of VRF through sequential evaluation of the three-dimensional volume. Subjects underwent surgical exploration as part of treatment, which helped establish the presence or absence of VRF.

RESULTS

Pearson correlation coefficient by using surgical finding to confirm presence/absence of fracture was 0.602, positive predictive value was 91%, and negative predictive value was 67%. The sensitivity was 88%, and specificity was 75%.

CONCLUSIONS

This study revealed the superior diagnostic accuracy of CBCT for detection of VRF.

Mesiobuccal root canal anatomy of Korean maxillary first and second molars by cone-beam computed tomography

OBJECTIVE

The aim of this study was to investigate the types of canal configurations and the incidence of a second mesiobuccal (MB2) canal in Korean maxillary molar mesiobuccal (MB) roots by analyzing cone-beam computed tomographic (CBCT) images.

STUDY DESIGN

Three-dimensional CBCT images of 458 maxillary first molars and 467 second molars from 276 Korean patients were analyzed to determine the incidence of an MB2 canal, the types of canal configurations, and the correlations between the incidence of an MB2 canal and age, gender, and tooth position.

RESULTS

The incidence of 2-canaled MB roots was 71.8% in first molars and 42.2% in second molars, with the most common configurations being Weine types III and II. The frequency of an MB2 canal decreased with age in both molars (P < .05).

CONCLUSIONS

Types III and II canal configurations were the most prevalent in the 2-canaled MB roots of Korean maxillary molars.

The use of cone beam computed tomography in the management of dens invaginatus affecting a strategic tooth in a patient affected by hypodontia: a case report

AIM

To report on the use of cone beam computed tomography (CBCT) in the diagnosis and management of dens invaginatus.

SUMMARY

Chronic apical periodontitis of an invaginated maxillary lateral incisor was diagnosed in a patient suffering from hypodontia and awaiting active orthodontic therapy. Loss of the tooth would have complicated orthodontic treatment. Conventional periapical radiographs provided insufficient information about the nature of the invagination and its relation to the root canal to formulate an appropriate plan for treating the tooth. A small volume CBCT scan of the tooth revealed that the invagination and the root canal were completely separate, non-communicating spaces and that the wall of the invagination acted as an obstruction to the effective chemomechanical debridement of the infected root canal. An innovative method of accessing the infected root canal, based on information from the CBCT images, was adapted to permit its instrumentation, disinfection and filling.

KEY LEARNING POINTS

• Teeth with dens invaginatus requiring endodontic treatment present diagnostic and technical challenges. • CBCT can provide essential information in the management of dens invaginatus.

Periapical bone defects of root filled teeth with persistent lesions evaluated by cone-beam computed tomography

AIM

To evaluate and categorize the bone defects of root filled teeth with persistent periapical lesions by cone-beam computed tomography (CBCT).

METHODOLOGY

Slice images of 532 teeth with persistent periapical lesions were obtained by CBCT in 427 patients and were examined by two endodontists. The periapical lesions were categorized into five types according to the characteristics of the bone defect based on CBCT images. The prevalence of each type was determined and analysed statistically at a 5% significance level using logistic regression.

RESULTS

Of the 532 teeth analysed, 67% had buccal or labial bone plate defects (type II), 4% palatal or lingual bone plate defects (type III), 7%'through and through' defects (type IV) and 10% apical root protrusions from the bone plate (type V). Mandibular teeth had a significantly greater prevalence of type I lesions (P=0.0005) and a significantly lower prevalence for types IV (P=0.041), V (P=0.001), V-1 (P=0.015) and V-2 (P<0.001) as compared to maxillary teeth.

CONCLUSION

CBCT accurately identified the type of periapical bone defect in persistent lesions. Because 10% of the teeth had apical root protrusions, which could not be identified by periapical radiography, the diagnostic information obtained by CBCT was an essential component of the treatment planning process.

Utilizing spiral computerized tomography during the removal of a fractured endodontic instrument lying beyond the apical foramen

AIM

To present a case that used spiral computerized tomography (CT) to locate and successfully remove a fractured endodontic instrument lying beyond the apical foramen using a surgical approach.

SUMMARY

The fracture of an endodontic instrument beyond the apical foramen is rare. In this case report, after an attempt to remove a fractured instrument failed, a multi-slice spiral computerized tomography (MSCT) was used for diagnosis and treatment planning. The fractured segment was precisely located and found in the soft tissue and successfully removed by surgery. For the successful removal of a fractured endodontic instrument beyond the apical foramen, the following are necessary: (i) knowledge of the cause of fracture and how to plan treatment; (ii) determining the precise location of the fractured segment using CT; and 3) skilful operation.

KEY LEARNING POINTS

•  Fractured endodontic instruments might lie within the soft tissue. •  Computerized tomography is an effective diagnostic aid for localizing the precise position of fractured instruments.

Accuracy of 3D Reconstructions Based on Cone Beam Computed Tomography

Three-dimensional imaging of teeth will increase its impact in clinical practice if reconstructions are metrically accurate. We hypothesized that, with cone beam computed tomography (CBCT) data, three-dimensional images of teeth can be reconstructed with the same accuracy and precision as with in vitro micro-computed tomography (micro-CT) data acquisition, the current reference standard. We used a sample of CBCT and micro-CT data taken of tooth germs. Volumes obtained with CBCT and micro-CT devices were statistically similar (n = 120, Passing-Bablok regression). Geometric deviations between CBCT and micro-CT three-dimensional surface reconstructions did not show any areas of important and systematic errors. Future investigations with the use of larger samples may also demonstrate that CBCT data will be helpful for a more in-depth study of other aspects of dental morphology—for example, assessing tooth development. With sufficient accuracy for clinical situations, potential future medical applications of such measurements with CBCT are envisaged.

The use of cone beam computed tomography in the conservative management of dens invaginatus: a case report

AIM

To report the use of cone beam computed tomography (CBCT) in the assessment of dens invaginatus.

SUMMARY

Chronic periradicular periodontitis associated with an infected invagination was diagnosed in an immature mandibular lateral incisor tooth. A CBCT scan revealed essential information for the management of the tooth. There was no communication between the invagination and the main root canal. Endodontic treatment was carried out on the invagination. The root canal with a vital pulp was left untreated, thus allowing the tooth to mature and continue to develop.

KEY LEARNING POINTS

* The true nature of dens invaginatus cannot always be estimated from conventional radiographs. * Cone beam computed tomography is a useful diagnostic tool in the management of dens invaginatus.

Maxillary second molar with 5 roots and 5 canals evaluated using cone beam computerized tomography: a case report

This case report presents the endodontic management of maxillary right second molar exhibiting 5 roots and 5 root canals. The diagnosis was confirmed with the help of cone beam computerized tomography (CBCT). The article also describes the varied morphology associated with maxillary second molar and the use of a high-end diagnostic imaging modality like CBCT in diagnosing and negotiating these anatomic variations.

Use of cone beam computed tomography in endodontics

Cone Beam Computed Tomography (CBCT) is a diagnostic imaging modality that provides high-quality, accurate three-dimensional (3D) representations of the osseous elements of the maxillofacial skeleton. CBCT systems are available that provide small field of view images at low dose with sufficient spatial resolution for applications in endodontic diagnosis, treatment guidance, and posttreatment evaluation. This article provides a literature review and pictorial demonstration of CBCT as an imaging adjunct for endodontics.

Maxillary first molar with seven root canals diagnosed with cone-beam computed tomography scanning: a case report

INTRODUCTION

The purpose of this article was to emphasize the importance of having a thorough knowledge about the root canal anatomy.

METHODS

This case report presents the endodontic management of a maxillary first molar with three roots and seven canals. The clinical detection of the seven canals was made using a surgical operating microscope and confirmed using cone-beam computed tomography (CBCT) scanning.

RESULTS

CBCT axial images showed that both the palatal and distobuccal root have a Vertucci type II canal pattern, whereas the mesiobuccal root showed a Sert and Bayirli type XV canal configuration.

CONCLUSION

This report describes and discusses the variation in canal morphology of maxillary first molar and the use of latest adjuncts in successfully diagnosing and negotiating them.

Case report: Cone-beam ct imaging in the management of a double tooth

BACKGROUND

The diagnosis and management strategies of double teeth have largely relied on clinical examination and conventional radiographic findings. Cone-Beam Computed Tomography (Cone-beam CT) was developed in the late 1990's and, therefore, is a relatively recent addition to the imaging armamentarium for use in Maxillofacial Radiology. There have been no publications in the dental literature demonstrating the use of Cone-beam CT or 3D stereolithography in the diagnosis and surgical planning of the management of double teeth.

CASE REPORT

An 11 year old girl presented with a double left lateral maxillary incisor. Conventional plain film radiography failed to provide the requisite information for pre-operative planning. Cone-beam Computed Tomography (Cone-beam CT) allowed determination of location of fusion, three-dimensional (3D) visualisation of pulpal anatomy and the construction of a 3D stereolithographic model for surgical planning. The double tooth was surgically divided in situ under local analgesia. The redundant distal unit was extracted and the residual mesial unit built up in composite resin following physiological mesial drift of displaced maxillary left canine. No endodontic therapy was required.

FOLLOW-UP

At a 10-month follow-up visit, clinical and radiographic vitality and success was noted.

CONCLUSION

The great amount of radiological information which Cone-beam CT can offer not only improves pre-operative and surgical planning, but the 3D models provided can be used to further educate and inform patients and guardians in the management of double teeth.

Accuracy and precision of linear measurements in cone beam computed tomography Accuitomo tomograms obtained with different reconstruction techniques

OBJECTIVES

To assess the accuracy and precision of linear measurements, the influence of different object positions in cone beam CT (CBCT) images and the effect of different systems for reformatting and viewing the tomograms on measurement values.

METHODS

An object consisting of Plexiglas plates with metal spheres was radiographically examined in three positions using the CBCT unit Accuitomo. Tomograms were reformatted using the i-Dixel software and Sectra picture archiving and communication system (PACS) multiplanar reformatting (MPR). Two observers measured 20 linear distances in axial, frontal and sagittal planes. Physical measurements of actual distances by means of a digital caliper served as the gold standard.

RESULTS

For measurements performed on the Accuitomo and Sectra PACS workstations, the mean differences between repeated measurements were below 0.13 mm (standard deviation (SD) 0.13 mm) and 0.21 mm (SD 0.18 mm), respectively. Mean differences between the two observers were below 0.11 mm (SD 0.07 mm) and 0.15 mm (SD 0.09 mm). The mean difference between the gold standard and the basic position when using the Accuitomo workstation, was -0.08 mm (SD 0.21 mm) and for a deviated/rotated position -0.08 mm (SD 0.23 mm) and -0.09 mm (SD 0.20 mm). None was statistically significant (P > 0.05). For measurement performed on MPR tomograms using the Sectra PACS workstation, mean differences were -0.09 mm (SD 0.17 mm) for basic position, and -0.08 mm (SD 0.19 mm) and -0.13 mm (SD 0.15 mm) for deviated and rotated positions, respectively. The mean difference between gold standard and basic/rotated positions was statistically significant, with P = 0.032 and P = 0.002.

CONCLUSIONS

Our study confirms previous findings indicating that measurements in 3DX Accuitomo FPD (flat panel detector) tomograms show a high level of agreement with actual distances. Our findings suggest the possibility of minor distortion in tomograms reformatted by means of Sectra PACS MPR.