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Cbct applications in dental practice a literature review
 

Cbct applications in dental practice a literature review

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    Cbct applications in dental practice a literature review Cbct applications in dental practice a literature review Document Transcript

    • I research _ CBCTCBCT applications in dentalpractice: A literature reviewAuthors_ Dr Mohammed A. Alshehri, Dr Hadi M. Alamri & Dr Mazen A. Alshalhoob, Saudi Arabia _Two-dimensional imaging modalities have follow-up—of CBCT in the various dental disci- been used in dentistry since the first intra-oral plines. The goal of the following systemic review radiograph was taken in 1896. is to review the available clinical and scientific Significant progress in dental im- literature pertaining to different clinical appli- aging techniques has since been cation of CBCT in the dental practice. made, including panoramic imag- ing and tomography, which enable _Materials and methods reduced radiation and faster pro- cessing times. However, the imag- Clinical and scientific literature discussing ing geometry has not changed CBCT imaging in dental clinical applications was with these commonly used intra- reviewed. A MEDLINE (PubMed) search from oral and panoramic technologies. 1 January 1998 to 15 July 2010 was conducted. Cone-beam computed tomography in dentistry Cone-beam computed tomog- was used as key phrase to extend the search to all Fig. 1 raphy (CBCT) is a new medical the various dental disciplines. The search re- imaging technique that generates vealed 540 papers that were screened in detail. Fig. 1_Impacted teeth in close 3-D images at a lower cost and absorbed dose Owing to a lack of relevance to the subject, 406 proximity to vital structures should compared with conventional computed tomog- papers were excluded. Thus, the systemic review be evaluated with CBCT. raphy (CT). This imaging technique is based on consisted of 134 clinically relevant papers, which a cone-shaped X-ray beam centred on a 2-D were analysed and categorised (Table I). detector that performs one rotation around the object, producing a series of 2-D images. These _Analysis images are re-constructed in 3-D using a mo- dification of the original cone-beam algorithm Oral and maxillofacial surgery developed by Feldkamp et al. in 1984.1 Images of the craniofacial region are often collected with CBCT enables the analysis of jaw pathology,3–11 a higher resolution than those collected with a the assessment of impacted teeth (Fig. 1), super- conventional CT. In addition, the new systems are numerary teeth and their relation to vital struc- Figs. 2a & b_Peri-apical lesion more practical, as they come in smaller sizes.2 tures,6,12–21 changes in the cortical and trabecular shown as peri-apical bone related to bisphosphonate-associated os- radiograph (a) and CBCT (b; images Today, much attention is focused on the teonecrosis of the jaw5,22–23 and the assessment courtesy of Dr Fred Barnett). clinical applications—diagnosis, treatment and of bone grafts.24 It is also helpful in analysing and assessing paranasal sinuses6,25 and obstructive sleep apnea.27–28 As the images are collected from many dif- ferent 2-D slices, the system has proven its superiority in overcoming superimpositions and calculating surface distances.28–29 This advantage made it the technique of choice in mid-face frac- ture cases,30–31 orbital fracture assessment and management32 and for inter-operative visualisa- tion of the facial bones after fracture.33–34 Since it is not a magnetic resonance technique, it is the best option for intra-operative navigation duringFig. 2a Fig. 2b procedures, including gun-shot wounds.35–3632 I roots 4_ 2010
    • research _ CBCT I CBCT is largely used in orthognathic surgeryplanning when facial orthomorphic surgery isindicated that requires detailed visualisation ofthe inter-occlusal relationship in order to aug-ment the 3-D virtual skull model with a detaileddental surface. With the aid of advanced soft-ware, CBCT facilitates the visualisation of softtissue to allow for control of post-treatmentaesthetics, for example in cleft palate cases toevaluate lip and palate bony depressions.37–42 Research is underway to assess its ability to Fig. 3a Fig. 3bdetect salivary gland defects.43 Honda et al.44describe a clinical case in which the time needed CBCT can also be used to determine root Figs. 3a & b_Apical cyst shown asto complete a tooth auto-transplant case was morphology, the number of roots, canals and orthopantomogram (a) and CBCT (b).significantly shortened owing to the application accessory canals, as well as to establishing theof CBCT. working length and angulations of roots andEndodontics Specialty Number of articles in % CBCT is a very useful tool in diagnosing apical Oral and maxillofacial surgery 36 26.86lesions (Figs. 2a & b).21,45–56 A number of studies Endodontics 32 23.88have demonstrated its ability to enable a diffe-rential diagnosis of apical lesions by measuring the Implantology 22 16.42density from the contrasted images of these le- Orthodontics 16 11.94sions, in whether the lesion is an apical granulomaor an apical cyst (Figs. 3a & b).49,55–57 Cotton et al.46 General dentistry 14 10.45used CBCT as a tool to assess whether the lesion Temporomandibular joint disorder 8 5.97was of endodontic or non-endodontic origin. Periodontics 5 3.73 CBCT also demonstrated superiority to 2-D Forensic dentistry 1 0.75radiographs in detecting fractured roots. Vertical Table Iand horizontal root fracture detection is de-scribed in several clinical cases.21,46,55–59 It is alsoagreed that CBCT is superior to peri-apical radi- canals.21,25,46,55–56,58,65–67 It also is accurate in as-ographs in detecting these fractures, whether sessing root-canal fillings.47,51,56,58 Owing to its Fig. 4a_Orthopantomogram forthey are bucco-lingual or mesiodistal.60–61 accuracy, it is very helpful in detecting the pulpal a full-mouth rehabilitation case. extensions in talon cusps68 and the position of Only limited data can be obtained In cases with inflammatory root resorption, fractured instruments.69 from this image.lesions are detected much easier in early stages Fig. 4b_CBCT images for the samewith CBCT compared to conventional 2-D X-ray.21,62 It is also a reliable tool for pre-surgical as- patient. Data obtained from theseIn other cases, such as external root resorption, sessment of the proximity of the tooth to adja- images regarding bone quality,external cervical and internal resorption, not only cent vital structures, size and extent of lesions, implant length and diameter,the presence of resorption was detected, but also as well as the anatomy and morphology of roots implant location and proximitythe extent of it.21,46,54,56,63–64 with very accurate measurements.21,46,48,50,54–58,69–72 to vital structures is magnificent. Fig. 4a Fig. 4b roots 4 _ 2010 I 33
    • I research _ CBCT Additionally, in cases in which teeth are assessed CBCT is a reliable tool in the assessment of the after trauma and in emergency cases, its appli- proximity to vital structures that may interfere cation can be a useful aid in reaching a proper with orthodontic treatment.104–105 In cases in which diagnosis and treatment approach.46,55,73–74 mini-screw implants are placed to serve as a temporary anchorage, CBCT is useful for ensuring Recently, owing to its reliability and accu- a safe insertion106–108 and to assess the bone den- racy, CBCT has also been used to evaluate the sity before, during and after treatment (Fig. 6).109–110 Fig. 5a Fig. 5b Fig. 5c Fig. 5a_Clinical picture of multiple canal preparation in different instrumentation Having different views in one scan, such as implants placed in 2005. techniques.75–76 frontal, right and left lateral, 45-degree views Fig. 5b_Peri-apical radiograph and sub-mental, also adds to the advantages for the implants replacing teeth #8 Implantology of CBCT.111,124 As the images are self-corrected and #9. Little data can be from the magnification to produce orthogonal collected from such an image. With increased demand for replacing missing images with 1:1 ratio, higher accuracy is ensured. Fig. 5c_The CBCT image clearly teeth with dental implants, accurate measure- CBCT is thus considered a better option for the demonstrates the amount ments are needed to avoid damage to vital clinician.113 of bone loss. structures. This was achievable with conven- tional CT. However, with CBCT giving more Temporomandibular joint disorder accurate measurements at lower dosages, it is the preferred option in implant dentistry today One of the major advantages of CBCT is its (Figs. 4a & b).2,6,11,18,70,77–89 ability to define the true position of the condyle in the fossa, which often reveals possible dis- With new software that constructs surgical location of the disk in the joint, and the extent guides, damage is also reduced further.77,84,90–93 of translation of the condyle in the fossa.18,56,114 Heiland et al.94 describe a technique in which With its accuracy, measurements of the roof of CBCT was used inter-operatively in two cases the glenoid fossa can be done easily.115–116 An- to navigate the implant insertion following mi- other advantage of some of the available devices crosurgical bone transfer. is their ability to visualise soft tissue around the TMJ, which may reduce the need for magnetic CBCT enables the assessment of bone quality resonance imaging in these cases.117 and bone quantity.18,26,70,80–81,85,88,95–97 This leads to reduced implant failure, as case selection can Owing to these advantages, CBCT is the imag- be based on much more reliable information. ing device of choice in cases of trauma, pain, dys- This advantage is also used for post-treatment function, fibro-osseous ankylosis and in detect- evaluation and to assess the success of bone ing condylar cortical erosion and cysts.70,87,118–120 grafts (Figs. 5a–d).18,88 With the use of the 3-D features, the image- guided puncture technique, which is a treatment Orthodontics modality for TMJ disk adhesion, can safely be performed.121 Orthodontists can use CBCT images in ortho- dontic assessment and cephalometric analy- Periodontics sis.6,70,84,98–99 Today, CBCT is already the tool of choice in the assessment of facial growth, age, CBCT can be used in assessing a detailed mor- airway function and disturbances in tooth erup- phologic description of the bone because it has tion.100–103 proved to be accurate with only minimal error34 I roots 4_ 2010
    • research _ CBCT Imargins.56,122 The measurements proved to be as demonstrate that 134 papers were clinically rel-accurate as direct measurements with a peri- evant and that the most common clinical appli-odontal probe.56,123 Furthermore, it also aids in cations are in the field of oral and maxillofacialassessing furcation involvements.20,56,116 surgery, implant dentistry, and endodontics. CBCT has limited use in operative dentistry owing CBCT can be used to detect buccal and lingual to the high radiation dose required in relationdefects, which was previously not possible with to its diagnostic value.conventional 2-D radiographs.56,124 Additionally,owing to the high accuracy of CBCT measure-ments, intra-bony defects can accurately bemeasured and dehiscence, fenestration defectsand periodontal cysts assessed.56,125–127 CBCT hasalso proved its superiority in evaluating theoutcome of regenerative periodontal therapy.124General dentistry Based on the available literature, CBCT is notjustified for use in detecting occlusal caries, since Fig. 5d Fig. 6the dose is much higher than conventional radi-ographs with no additional information gained.However, it proved to be useful in assessing prox- The literature on CBCT is promising and needs Fig. 5d_Total buccal plate destructionimal caries and its depth.20 Table II shows exam- further research, especially with regard to its use is evident in this CBCT image.ples of typical doses of various dental radiologi- in forensic dentistry, in order to explore more Fig. 6_CBCT image to assess thecal procedures in dental practice. potentially beneficial indications in that area. bone density during treatment. No literature concerning direct CBCT indicationsForensic dentistry in prosthodontics was found. However, several overlapping indications were found in other den- Many dental age estimation methods, which tal specialties attributing to the final standard ofare a key element in forensic science, are de- care in prosthodontic treatment. These indica-scribed in the literature. CBCT was established tions include but are not limited to bone grafting,as a non-invasive method to estimate the age of soft-tissue grafting, prosthetically driven im-a person based on the pulp–tooth ratio.128 plant placement, maxillofacial prosthodontics and temporomandibular joint disorder. CBCT im-_Discussion ages can also be of great value in special cases in which multiple teeth have to be assessed for CBCT scanners represent a great advance in restorability (Figs. 7a–e).dento-maxillofacial (DMF) imaging. This tech-nology, introduced into dental use in the late The latest CBCT units have a higher resolution,1990s,129 has advanced dentistry significantly. lower exposure, are less expensive and designed forThe number of CBCT-related papers published use in dentistry. Additionally, the flat-panel detec-each year has increased tremendously in the last tors appear to be less prone to beam-hardeningyears. The above systematic review of the lite- artefacts. There are, however, several important Table II_Typical doses of variousrature related to CBCT-imaging applications disadvantages as well, such as susceptibility to dental radiological procedures.in dental practice was undertaken in order tosummarise concisely the indications of this newimage technique in different dental specialties. Intra-oral (F speed, rectangular collimator) 0.001 mSv Intra-oral (E speed, round collimator) 0.004 mSv Cone-beam computed tomography in dentis-try was used as key phrase in this systemic review. Full-mouth set (E speed, round collimator) 0.080 mSvOther terminology encountered in the literature,such as cone-beam volumetric scanning, volu- Lateral cephalogram (F speed, rare-earth screen) 0.002 mSvmetric computed tomography, dental CT, dental Dental panoramic technique (F speed, rare-earth screen) 0.015 mSv3-D CT and cone-beam volumetric imaging, didnot result in additional relevant papers.130 CBCT (both jaws) 0.068 mSv The clinical applications for CBCT imaging in Hospital CT scan (both jaws) 0.6 mSv Table IIdentistry are increasing. The results of this review roots 4 _ 2010 I 35
    • I research _ CBCT movement artefacts, low contrast resolution, 3. CBCT examinations should potentially add new limited capability to visualise internal soft tissues information to aid the patient’s management. and, owing to distortion of Hounsfield Units, 4. CBCT should not be repeated on a patient CBCT cannot be used for the estimation of bone ‘routinely’ without a new risk/benefit assess- density. ment having been performed. 5. When accepting referrals from other dentists It is crucial that the ALARA principle (As Low for CBCT examinations, the referring dentist As Reasonably Achievable) is respected during must supply sufficient clinical information Fig. 7a Fig. 7b Fig. 7c Fig. 7a_Multiple endodontically treatment, as far as the radiation dose of CBCT (results of a history and examination) to allow treated teeth with a history imaging is concerned. CBCT imaging will improve the CBCT practitioner to perform the justifi- of peri-apical surgery. patient care, but users have to be trained to be cation process. Fig. 7b_Peri-apical image showing able to interpret the scanned data thoroughly. 6. CBCT should only be used when the question a compromised crown-to-root ratio. Dentists should ask themselves whether these for which imaging is required cannot be Fig. 7c_CBCT image showing the imaging modalities actually add to their diag- answered adequately by lower dose conven- absence of the buccal plate and nostic knowledge and raise the standard of den- tional (traditional) radiography. a compromised palatal plate, tal care or whether they only place the patient at 7. CBCT images must undergo a thorough clin- indicating that the teeth need to be a higher risk. Continuous training, education and ical evaluation (radiological report) of theextracted and site grafting performed thorough research are thus absolutely essential. entire image dataset. before implant placement. 8. Where it is likely that evaluation of soft tis- One of the most clinically useful aspects of sues will be required as part of the patient’s CBCT imaging is the highly sophisticated soft- radiological assessment, the appropriate im- ware that allows the huge volume of data aging should be conventional medical CT or collected to be broken down, processed or recon- MR, rather than CBCT. structed.131 This makes data interpretation much 9. CBCT equipment should offer a choice of vol- more user friendly, if the appropriate technical ume sizes, and examinations must use the and educational knowledge is available. smallest that is compatible with the clinical situation, if this provides a lower radiation The increasing popularity of CBCT resulted in dose to the patient. numerous CBCT-unit manufacturers, frequent 10. Where CBCT equipment offers a choice of presentations at conferences and an increase resolution, the resolution compatible with an in published papers. This resulted in an uncon- adequate diagnosis and the lowest achiev- trolled and non-evidence based exchange of ra- able dose should be used. diation dose values and attributed to the limited 11. A quality assurance programme must be technical knowledge about medical imaging de- established and implemented for each CBCT vices for new-user groups. As a result, the Euro- facility, including equipment, techniques and pean Academy of DentoMaxilloFacial Radiology quality-control procedures. has developed the following basic principles on 12. Aids to accurate positioning (light-beam the use of CBCT in dentistry:132 markers) must always be used. 13. All new installations of CBCT equipment 1. CBCT examinations must not be carried out should undergo a critical examination and de- unless a history and clinical examination have tailed acceptance tests before use to ensure been performed. that radiation protection for staff, members 2. CBCT examinations must be justified for each of the public and patient are optimal. patient to demonstrate that the benefits 14. CBCT equipment should undergo regular rou- outweigh the risks. tine tests to ensure that radiation protection,36 I roots 4_ 2010
    • I research _ CBCT for both practice/facility users and patients, logist or by a clinical radiologist (medical has not significantly deteriorated. radiologist). 15. For staff protection from CBCT equipment, the guidelines detailed in Section 6 of the _Conclusion European Commission document Radiation protection 136: European guidelines on ra- CBCT is most frequently applied in oral and diation protection in dental radiology should maxillofacial surgery, endodontics, implant den- be followed. tistry and orthodontics. CBCT examination must Fig. 7d_Extractions done for teeth #7, 8, 9 and 10 were atraumatic and bone grafting was performed. Fig. 7e_Temporisation done andhealing of the grafted sites for future implant placement is awaited. Fig. 7d Fig. 7e 16. All those involved with CBCT must have re- not be carried out unless its medical necessity ceived adequate theoretical and practical is proven and the benefits outweigh the risks. training for the purpose of radiological prac- Furthermore, CBCT images must undergo a thor- tices and relevant competence in radiation ough clinical evaluation (radiological report) of protection. the entire image dataset in order to maximise the 17. Continuing education and training after benefits. qualification are required, particularly when new CBCT equipment or techniques are Future research should focus on accurate data adopted. with regard to the radiation dose of these units. 18. Dentists responsible for CBCT facilities, who CBCT units have small detector sizes and the have not previously received ‘adequate theo- field of view and scanned volumes are limited, retical and practical training’, should un- which is the reason that CBCT units specific to dergo a period of additional theoretical and orthodontic and orthognathic surgery are not practical training that has been validated by yet available. Additional publications on CBCT an academic institution (university or equiv- indications in forensic dentistry and prostho- alent). Where national specialist qualifica- dontics are also desirable._ tions in dento-maxillofacial radiology exist, the design and delivery of CBCT training programmes should involve a DMF radiolo- Editorial note: A complete list of references is available gist. from the publisher. 19. For dento-alveolar CBCT images of the teeth, their supporting structures, the mandible and the maxilla up to the floor of the nose (for example, 8 cm x 8 cm or smaller fields of _about the authors CAD/CAM view), clinical evaluation (radiological report) should be done by a specially trained DMF Dr Mohammed A. Alshehri is a Consultant radiologist or, where this is impracticable, for Restorative and Implant Dentistry at the an adequately trained general dental practi- Riyadh Military Hospital, Department of tioner. Dentistry and Assistant Clinical Professor 20. For non-dento-alveolar small fields of view at the King Saud University, College of Dentistry, (for example, temporal bone) and all cranio- Department of Restorative Dental Sciences. facial CBCT images (fields of view extending He can be contacted at dr_mzs@hotmail.com. beyond the teeth, their supporting struc- tures, the mandible, including the TMJ, and Dr Hadi M. Alamri and Dr Mazen A. Alshalhoob the maxilla up to the floor of the nose), clin- are interns at Riyadh Colleges of Dentistry ical evaluation (radiological report) should and Pharmacy. be done by a specially trained DMF radio-38 I roots 4_ 2010