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21Implant TribuneMay 17-23, 2010United Kingdom Edition els, improved digital radiographic sensors and software enhanced diagnostic acumen, and ultrason- ic units with a variety of tips de- signed specifically for use when performing both nonsurgical and surgical endodontic procedures minimised damage to coronal and radicular tooth structure in the effort to locate the pathways of the pulp. The treatment outcome of non-surgical root canal thera- py at this point in time is far more predictable than at any other pe- riod in our history. Diagnosis Of all the technologic innovations embraced by endodontics, digital radiography should have generat- ed the greatest impact; however, its value remains limited in diag- nosis, treatment planning, intra- operative control and outcome assessment. Flat field sensors still require three to four parallax im- ages of the area of interest to es- tablish better perception of depth and spatial orientation of osseous or dental pathology. These three- dimensional information defi- cits, geometric distortion and the masking of areas of interest by overlying anatomy or anatomic noise are of strategic relevance to treatment planning in general and in endodontics specifically (14) , (Fig 5a, 5b). Cone beam computed tom- ography (cbCT) produces up to 580 individual projection imag- es with isotropic submillimeter spatial resolution enhanced by advanced image receptor sen- sors; it is ideally suited for dedi- cated dento-maxillofacial CT scanning. When combined with application-specific software tools, cone beam computed tom- ography can provide a complete solution for performing specific diagnostic and surgical tasks. The images can be resliced at any angle, producing a new set of reconstructed orthogonal im- ages and studies have shown that the scans accurately reflect the volume of anatomic defects. The limited volume cbCT scanners best suited for endodontics re- quire an effective radiation dose comparable to two or three con- ventional periapical radiographs and as such are set to revolution- ise endodontics (15, 16) (Fig 6). Three dimensional pre-surgi- cal assessment of the approxima- tion of root apices to the inferior dental canal, mental foramen and maxillary sinus are essential to treatment planning. The ability of cbCT to diagnose and manage dento-alveolar trauma using mul- tiplanar views, the determination of the root canal anatomy and the number of canals, the detection of the true nature and exact loca- tion of resorptive lesions and the discovery of the existence of verti- cal and horisontal fractures out- weigh concerns about the degree of ionising radiation and the risks posed (17) . Provided cbCT is used in situations where the informa- tion from conventional imaging systems is inadequate, the ben- efits are essential for optimisation of the standard of care. Patel reported that periapical disease can be detected sooner and more accurately using cbCT compared with traditional peri- apical views and that the true sise, extent, nature and position of periapical and resorptive le- sions can be accurately assessed (18) . Using a new periapical index based on cone beam computed tomography for identification of apical periodontitis, periapical le- sions were identified in 39.5 per cent by radiography and 60.9 per cent of cases by cbCT respectively (P < .01). Simon et al compared the differential diagnosis of large periapical lesions with tradition- al biopsy. The results suggested that cbCT might provide a faster method to differentially diagnose a solid from a fluid-filled lesion or cavity, without invasive surgery (19, 20) . In spite of the presence of artifacts, the learning curve relat- ed to image manipulation and the cost, cone beam tomography will invariably be the accepted stand- ard of diagnostic care and treat- ment planning in endodontics in the very near future. Access An improperly designed access cavity will hamper facilitation of optimal root canal therapy. If the orientation, extension, angula- tions and depth are inaccurate, retention of the native anatomy of the root canal space becomes precarious. The requirements of access cavity design can be achieved by conceptual and technical regression of the exist- ing configuration to that which one would logically expect to have seen prior to the insults of restoration, function and aging. page 22DTà

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