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DTME1010

Practice Matters DENTALTRIBUNE Middle East & Africa Edition8 in detecting occlusal caries, since the dose is much higher than conventional radiographs with no additional information gained. However, it proved to be useful in assessing proximal caries and its depth.20 Table II shows examples of typical doses of various dental radiological procedures in dental practice. Forensic dentistry Many dental age estimation methods, which are a key ele- ment in forensic science, are de- scribed in the literature. CBCT was established as a non-inva- sivemethodtoestimatetheageof a person based on the pulp–tooth ratio.128 _Discussion CBCT scanners represent a great advance in dento-maxillo- facial (DMF) imaging. This tech- nology, introduced into dental use in the late 1990s,129 has ad- vanced dentistry significantly. The number of CBCT-related pa- pers published each year has in- creased tremendously in the last years. The above systematic re- view of the lite - rature related to CBCT-imaging applications in dental practice was undertaken in order to summarise concisely the indications of this new image techniqueindifferentdentalspe- cialties. Cone-beam computed to- mographyindentis-trywasused as key phrase in this systemic re- view.Otherterminologyencoun- tered in the literature, such as cone-beam volumetric scan- ning, volumetric computed to- mography, dental CT, dental 3-D CT and cone-beam volumetric imaging, did not result in addi- tional relevant papers.130 The clinical applications for CBCT imaging in dentistry are increasing. The results of this re- view demonstrate that 134 pa- pers were clinically relevant and that the most common clinical applications are in the field of oral and maxillofacial surgery, implant dentistry, and endodon- tics. CBCT has limited use in op- erative dentistry owing to the high radiation dose required in relation to its diagnostic value. The literature on CBCT is promising and needs further re- search, especially with regard to its use in forensic dentistry, in or- der to explore more potentially beneficial indications in that area. No literature concerning direct CBCT indications in prosthodontics was found. How- ever, several overlapping indica- tions were found in other dental specialties attributing to the final standardofcareinprosthodontic treatment. These indications in- clude but are not limited to bone grafting, soft-tissue grafting, prosthetically driven implant placement, maxillofacial prosthodontics and temporo- mandibular joint disorder. CBCT images can also be of great value in special cases in which multi- ple teeth have to be assessed for restorability (Figs. 7a–e). The latest CBCT units have a higher resolution, lower expo- sure, are less expensive and de- signed for use in dentistry. Addi- tionally, the flat-panel detectors appear to be less prone to beam- hardening artefacts. There are, however, several important dis- advantages as well, such as sus- ceptibility to movement arte- facts, low contrast resolution, limited capability to visualise in- ternal soft tissues and, owing to distortion of Hounsfield Units, CBCTcannotbeusedfortheesti- mation of bone density. It is crucial that the ALARA principle (As Low As Reasonably Achievable) is respected during treatment, as far as the radiation dose of CBCT imaging is con- cerned. CBCT imaging will im- prove patient care, but users havetobetrainedtobeabletoin- terpret the scanned data thor- oughly. Dentists should ask themselves whether these imag- ing modalities actually add to their diagnostic knowledge and raise the standard of dental care or whether they only place the patient at a higher risk. Continu- ous training, education and thor- ough research are thus ab- solutely essential. Oneofthemostclinicallyuse- ful aspects of CBCT imaging is thehighlysophisticatedsoftware that allows the huge volume of datacollectedtobebrokendown, processed or reconstructed. 131 This makes data interpretation much more user friendly, if the appropriate technical and edu- cational knowledge is available. The increasing popularity of CBCT resulted in numerous CBCT-unit manufacturers, fre- quent presentations at confer- ences and an increase in pub- lished papers. This resulted in an uncontrolled and non-evidence basedexchangeofradiationdose values and attributed to the lim- ited technical knowledge about medical imaging devices for new-user groups. As a result, the European Academy of Den- toMaxilloFacial Radiology has developed the following basic principles on the use of CBCT in dentistry:132 1. CBCT examinations must not becarriedoutunlessahistory and clinical examination have been performed. 2. CBCT examinations must be justified for each patient to demonstrate that the benefits outweigh the risks. 3. CBCT examinations should potentially add new informa- tion to aid the patient’s man- agement. 4. CBCT should not be repeated on a patient ‘routinely’ with- out a new risk/benefit assess- ment having been per- formed. 5.Whenacceptingreferralsfrom other dentists for CBCT ex- aminations, the referring dentist must supply sufficient clinical information (results of a history and examination) to allow the CBCT practi- tioner to perform the justifi- cation process. 6. CBCT should only be used when the question for which imagingisrequiredcannotbe answered adequately by lower dose conventional (tra- ditional) radiography. 7. CBCT images must undergo a thorough clin - ical evalua- tion (radiological report) of the entire image dataset. 8. Where it is likely that evalua- tion of soft tissues will be re- quired as part of the patient’s radiological assessment, the appropriate imaging should be conventional medical CT or MR, rather than CBCT. 9. CBCT equipment should offer a choice of volume sizes, and examinations must use the smallest that is compatible with the clinical situation, if this provides a lower radia- tion dose to the patient. 10. Where CBCT equipment of- fersachoiceofresolution,the resolution compatible with an adequate diagnosis and the lowest achievable dose should be used. 11. A quality assurance pro- gramme must be established and implemented for each CBCT facility, including equipment, techniques and quality-control procedures. 12. Aids to accurate positioning (light-beam markers) must always be used. 13. All new installations of CBCT equipment should undergo a critical examination and de- tailed acceptance tests before use to ensure that radiation protection for staff, members of the public and patient are optimal. 14. CBCT equipment should un- dergo regular routine tests to ensure that radiation protec- tion, for both practice/facility users and patients, has not significantly deteriorated. 15. For staff protection from CBCT equipment, the guide- lines detailed in Section 6 of the European Commission document Radiation protec- tion 136: European guide- linesonra-diationprotection in dental radiology should be followed. 16. All those involved with CBCT must have received adequate theoretical and practical training for the purpose of ra- diological practices and rele- vant competence in radiation protection. 17. Continuing education and training after qualification are required, particularly when new CBCT equipment or techniques are adopted. 18. Dentists responsible for CBCT facilities, who have not previously received ‘ade- quate theoretical and practi- cal training’, should undergo aperiodofadditionaltheoret- ical and practical training that has been validated by an academic institution (univer- sityorequivalent).Wherena- tional specialist qualifica- tions in dento-maxillofacial radiology exist, the design anddeliveryofCBCTtraining programmesshouldinvolvea DMF radiologist. 19. For dento-alveolar CBCT im- ages of the teeth, their sup- porting structures, the mandible and the maxilla up to the floor of the nose (for ex- ample, 8 cm x 8 cm or smaller fields of view), clinical evalu- ation (radiological report) should be done by a specially trained DMF radiologist or, where this is impracticable, an adequately trained gen- eral dental practitioner. 20. For non-dento-alveolar small fields of view (for example, temporal bone) and all cran- iofacial CBCT images (fields of view extending beyond the teeth, their supporting struc- tures, the mandible, includ- ing the TMJ, and the maxilla up to the floor of the nose), clinical evaluation (radiolog- ical report) should be done by a specially trained DMF radi- ologist or by a clinical radiol- ogist (medical radiologist). _Conclusion CBCT is most frequently ap- plied in oral and maxillofacial surgery, endodontics, implant dentistry and orthodontics. CBCT examination must not be carriedoutunlessitsmedicalne- cessity is proven and the benefits outweigh the risks. Furthermore, CBCT images mustundergoathoroughclinical evaluation (radiological report) of the entire image dataset in or- der to maximise the benefits. Fu- tureresearchshouldfocusonac- curate data with regard to the ra- diation dose of these units. CBCT units have small detector sizes and the field of view and scanned volumes are limited, which is the reason that CBCT units specific to orthodontic and orthognathic surgery are not yet available. Ad- ditional publications on CBCT indications in forensic dentistry and prosthodontics are also de- sirable._ Dr Mohammed A. Alshehri is a Consultant for Restorative and Implant Dentistry at the Riyadh Military Hospital, Department of Dentistry and Assistant Clinical Professor at the King Saud Uni- versity, College of Dentistry, De- partment of Restorative Dental Sciences. He can be contacted at dr_mzs@hotmail.com. Dr Hadi M. Alamri and Dr Mazen A. Alshalhoob are in- terns at Riyadh Colleges of Den- tistry and Pharmacy. About the authors Fig. 7a Fig. 7b Fig. 7c Fig. 7d_Extractions done for teeth #7, 8, 9 and 10 were atraumatic and bone grafting was performed. Fig. 7e_Temporisation done and healing of the grafted sites for future implant placement is awaited.Fig. 7eFig. 7d Fig. 7a_Multiple endodontically treated teeth with a history of peri-apical surgery. Fig. 7b_Peri-apical image showing a compromised crown-to-root ratio. Fig. 7c_CBCT image showing the absence of the buccal plate and a compromised palatal plate, indicating that the teeth need to be extracted and site grafting performed before implant placement.