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CAD/CAM - international magazine of digital dentistry, Italian Edition, No.1, 2017

research _ computed tomography Table 3_Distribution of discrepancies in millimeters observed in each of the 18 sagittal tomographic slices in relation to the axial reference plane used (Pearson’s chi-squared test). Basal plane (n = 18) Occlusal plane (n = 18) n (%) n (%) Discrepancies ≤ 0.5 mm > 0.5 mm 10 (55.56) 1 (5.56) 8 (44.44) 17 (94.44) p-value 0.001 nificant errors would occur, but if the slices were less than 1.5 mm, even if the CT pro- cedure were performed erroneously to some extent, the results would not show much variation and would be more precise. In 2004, Hanazawa et al. compared data obtained by means of a modified CT system and a conventional CT device with real mea- surements taken directly from cadaver man- dibles, finding discrepancies in 90% of the measurements taken with the modified CT system compared with the direct measure- ments and in 87.5% of those taken with the conventional CT device, the discrepancies be- ing approximately 1 mm.25 These radiographic discrepancies can lead to iatrogenic lesions during implant treat- ment, which are of particular concern in pos- terior mandibular regions, where they can produce lesions of the mandibular canal. In this regard, Klinge et al., who studied sensitivity and accuracy in locating the man- dibular canal using cadaverous mandibles, observed that when the accuracy in deter- mining mandibular canal position was evalu- ated, comparing the extent of error with the true value, the error was up to 1 mm in 94% of the CT measurements, but 39% with to- mography, 17% with panoramic radiography and 53% using intra-oral radiography.23 Similar discrepancies between mandibular canal positions determined radiographically using CT and measurements taken directly from the bone have been observed by other authors.15,16,26 Similarly, numerous authors have ob- served small variations between the precision of three-dimensional preoperative imaging and the final surgical positions of the den- tal implants, with variations ranging between 0.7 mm and 1.0 mm,2,27 due to the discrepan- cies between CT measurements and the real _references 1. Ostman PO. Immediate/early loading of dental implants. Clinical documen- tation and presentation of a treatment concept. Periodontol 2000. 2008 Jun;47(1):90–112. 9. Katakami K, Shimoda S, Kobayashi K, Kawasaki K. Histological investigation of osseous changes of mandibular condyles with backscattered electron images. Dentomaxillofac Radiol. 2008 Sep;37(6):330–9. 2. Brief J, Edinger D, Hassfeld S, Eggers G. Accuracy of image-guided implanto- logy. Clin Oral Implants Res. 2005 Aug;16(4):495–501. 3. Barnea E, Alt I, Kolerman R, Nissan J. Accuracy of a laboratory-based compu- ter implant guiding system. Oral Surg Oral Med Oral Pathol Oral Radiol Endod. 2010 May;109(5):e6–10. 4. Bou Serhal C, van Steenberghe D, Quirynen M, Jacobs R. Localisation of the mandibular canal using conventional spiral tomography: a human cadaver study. Clin Oral Implants Res. 2001 Jun;12(3):230–6. 5. Ulm CW, Solar P, Blahout R, Matejka M, Watzek G, Gruber H. Location of the mandibular canal within the atrophic mandible. Br J Oral Maxillofac Surg. 1993 Dec;31(6):370–5. 6. Cotton TP, Geisler TM, Holden DT, Schwartz SA, Schindler WG. Endodon- tic applications of cone-beam volumetric tomography. J Endod. 2007 Sep;33(9):1121–32. 7. Estrela C, Bueno MR, Azevedo BC, Azevedo JR, Pécora JD. A new periapi- cal index based on cone beam computed tomography. J Endod. 2008 Nov;34(11):1325–31. 8. Hamada Y, Kondoh T, Noguchi K, Iino M, Isono H, Ishii H, Mishima A, Ko- bayashi K, Seto K. Application of limited cone beam computed tomography to clinical assessment of alveolar bone grafting: a preliminary report. Cleft Palate Craniofac J. 2005 Mar;42(2):128–37. 10. Jacobs R, Lambrichts I, Liang X, Martens W, Mraiwa N, Adriaensens P, Gelan J. Neovascularization of the anterior jaw bones revised using high-resolution magnetic resonance imaging. Oral Surg Oral Med Oral Pathol Oral Radiol En- dod. 2007 May;103(5):683–93. 11. Trikeriotis D, Paravalou E, Diamantopoulos P, Nikolau D. Anterior mandible canal communications: a potential portal of entry for tumour spread. Dento- maxillofac Radiol. 2008 Mar;37(3):125–9. 12. Vandewalle G, Liang X, Jacobs R, Lambrichts I. Macroanatomic and radiologic characteristics of the superior genial spinal foramen and its bony canal. Int J Oral Maxillofac Implants. 2006 Jul-Aug;21(4):581–6. 13. Fuakami K, Shiozaki K, Mishima A, Shimoda S, Hamada Y, Kobayashi K. De- tection of buccal perimandibular neurovascularisation associated with ac- cessory foramina using limited cone-beam computed tomography and gross anatomy. Surg Radiol Anat. 2011 Mar;33(2):141–6. 14. Covino SW, Mitnick RJ, Shprintzen RJ, Cisneros GJ. The accuracy of measu- rements of three-dimensional computed tomography reconstructions. J Oral Maxillofac Surg. 1996 Aug;54(8):982–90. 15. Kamburoglu K, Kiliç C, Ozen T, Yüksel SP. Measurements of mandibular ca- nal region obtained by cone-beam computed tomography: a cadaveric study. Oral Surg Oral Med Oral Pathol Oral Radiol Endod. 2009 Feb;107(2):e34–42. 16. Bou Serhal C, Jacobs R, Flygare L, Quirynen M, van Steenberghe D. Periopera- 22 1_2017

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