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CAD0210

I 27 research _ CBCT I CAD/CAM 2_2010 margins.56,122 The measurements proved to be as accurate as direct measurements with a peri- odontal probe.56,123 Furthermore, it also aids in assessing furcation involvements.20,56,116 CBCT can be used to detect buccal and lingual defects, which was previously not possible with conventional 2-D radiographs.56,124 Additionally, owing to the high accuracy of CBCT measure- ments, intra-bony defects can accurately be measured and dehiscence, fenestration defects and periodontal cysts assessed.56,125–127 CBCT has also proved its superiority in evaluating the outcome of regenerative periodontal therapy.124 General dentistry Based on the available literature, CBCT is not justifiedforuseindetectingocclusalcaries,since the dose is much higher than conventional radi- ographs with no additional information gained. However,itprovedtobeusefulinassessingprox- imal caries and its depth.20 Table II shows exam- ples of typical doses of various dental radiologi- cal procedures in dental practice. Forensic dentistry Many dental age estimation methods, which are a key element in forensic science, are de- scribed in the literature. CBCT was established as a non-invasive method to estimate the age of a person based on the pulp–tooth ratio.128 _Discussion CBCT scanners represent a great advance in dento-maxillofacial (DMF) imaging. This tech- nology, introduced into dental use in the late 1990s,129 has advanced dentistry significantly. The number of CBCT-related papers published each year has increased tremendously in the last years. The above systematic review 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 technique in different dental specialties. Cone-beam computed tomography in dentis- try wasusedaskeyphraseinthissystemicreview. Other terminology encountered in the literature, such as cone-beam volumetric scanning, volu- metric computed tomography, dental CT, dental 3-D CT and cone-beam volumetric imaging, did not result in additional relevant papers.130 The clinical applications for CBCT imaging in dentistryareincreasing.Theresultsofthisreview demonstrate that 134 papers were clinically rel- evant and that the most common clinical appli- cations are in the field of oral and maxillofacial surgery, implant dentistry, and endodontics. CBCThaslimiteduseinoperativedentistryowing to the high radiation dose required in relation to its diagnostic value. The literature on CBCT is promising and needs further research, especially with regard to its use in forensic dentistry, in order to explore more potentially beneficial indications in that area. No literature concerning direct CBCT indications in prosthodontics was found. However, several overlappingindicationswerefoundinotherden- tal specialties attributing to the final standard of care in prosthodontic treatment. These indica- tionsincludebutarenotlimitedtobonegrafting, soft-tissue grafting, prosthetically driven im- plant placement, maxillofacial prosthodontics and temporomandibular joint disorder. CBCT im- ages can also be of great value in special cases in which multiple teeth have to be assessed for restorability (Figs. 7a–e). The latest CBCT units have a higher resolution, lowerexposure,arelessexpensiveanddesignedfor use in dentistry. Additionally, the flat-panel detec- tors appear to be less prone to beam-hardening artefacts. There are, however, several important disadvantages as well, such as susceptibility to Fig. 5d_Total buccal plate destruction is evident in this CBCT image. Fig. 6_CBCT image to assess the bone density during treatment. Table II_Typical doses of various dental radiological procedures. Fig. 6Fig. 5d Intra-oral (F speed, rectangular collimator) 0.001 mSv Intra-oral (E speed, round collimator) 0.004 mSv Full-mouth set (E speed, round collimator) 0.080 mSv Lateral cephalogram (F speed, rare-earth screen) 0.002 mSv Dental panoramic technique (F speed, rare-earth screen) 0.015 mSv CBCT (both jaws) 0.068 mSv Hospital CT scan (both jaws) 0.6 mSv Table II