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

research _ computed tomography dimensions. In this way, the results of the present study, in which discrepancies varied between 0.03 mm and 1.47 mm, coincide with the discrepancies observed by these authors. Acquiring a good CT scan is of primary im- portance for visualizing the different bony structures, and the quality and accuracy of the scan are influenced by various factors. The skill of the operator has a major in- fluence. Adequate positioning of the patient will minimize error, and the choice of the ap- propriate equipment settings is important for achieving good contrast. Discrepancies be- tween radiographic and real measurements can increase according to patient positioning for CT scanning.17,18 However, although many authors have observed discrepancies between radiographic measurements using CT and real bone mea- surements, these authors used a single axial reference plane, which in many cases was not specified.28-31 Currently, there are very few articles that examine the discrepancies obtained with var- ious axial reference planes. Cucchiarelli et al.’s comparison of the discrepancies between radiographic mea- surements with CT and measurements taken directly from 15 edentulous maxillae showed distortions with regard to the real bone mea- surements.19 It was found that the use of the horizontal plane showed 19.20% magnifica- tion, as opposed to the use of the occlusal plane, which showed 16.5% magnification. In this regard, Abrahams made a general study of mandibles using CT and concluded that the best axial reference plane is the occlusal plane.32 Although the present study found dis- crepancies when both the occlusal plane and the basal plane were taken as the axial ref- erence plane, the discrepancies were greater when the basal plane was used. _Conclusion The present study found that there are slight discrepancies between radiographic measurements taken using CT and real bone measurement. These must be taken into con- sideration in order to perform satisfactory implant treatments. With regard to patient positioning for the CT procedure, use of the occlusal plane as axial reference will produce the most accurate measurements. _Competing interests We wish to confirm that there are no known conflicts of interest associated with this publication and there has been no signif- icant financial support for this work that may have influenced its outcome. _Acknowledgments We wish to acknowledge the contribution of the radiology unit of Virgen de la Arrixaca Hospital, Murcia, Spain. tive validation of localisation of the mental foramen. Dentomaxillofac Radiol. 2002 Jan;31(1):39–43. dible: a comparison between CT-reformatted and conventional tomographic images. Clin Oral Implants Res. 2004 Apr;15(2):226–32. 17. Lindh C, Petersson A, Klinge B. Measurements of distances related to the mandibular canal in radiographs. Clin Oral Implants Res. 1995 Jun;6(2):96– 103. 18. Bolin A, Eliasson S, von Beetzen M, Jansson L. Radiographic evaluation of mandibular posterior implant sites: correlation between panoramic and to- mographic determinations. Clin Oral Implants Res. 1996 Dec;7(4):354–9. 19. Cucchiarelli D, Kitrilakis A, Pastori E. Tomographic distortion in toothless pa- tients. Acta Odontol Latinoam. 2008;21(1):35–41. 20. Abadi BJ, Okeson JP. Alteration of vertical dimension in the treatment of cra- niomandibular disorders. J Craniomandibular Pract. 1983 Sep-Nov;1(4):55–9. 21. Brånemark PI, Adell R, Breine U, Hansson BO, Lindström J, Ohlsson A. Intra- osseous anchorage of dental prostheses. I. Experimental studies. Scand J Plast Reconstr Surg. 1969;3(2):81–100. 22. Monsour PA, Dudhia R. Implant radiography and radiology. Aust Dent J. 2008 Jun;53 Suppl 1:S11–25. 23. Klinge B, Petersson A, Maly P. Location of the mandibular canal: comparison of macroscopic findings, conventional radiography, and computed tomo- graphy. Int J Oral Maxillofac Implants. 1989 Winter;4(4):327–32. 24. Frederiksen NL. Diagnostic imaging in dental implantology. Oral Surg Oral Med Oral Pathol Oral Radiol Endod. 1995 Nov;80(5):540–54. 26. Greenstein G, Tarnow D. The mental foramen and nerve: clinical and anato- mical factors to dental implant placement: a literature review. J Periodontol. 2006 Dec;77(12):1933–43. 27. Valente F, Schiroli G, Sbrenna A. Accuracy of computer-aided oral implant surgery: a clinical and radiographic study. Int J Oral Maxillofac Implants. 2009 Mar-Apr;24(2):234–42. 28. Seoares MM, Harari ND, Cardoso ES, Manso MC, Conz MB, Vidigal GM Jr. An in vitro model to evaluate the accuracy of guided surgery systems. Int J Oral Maxillofac Implants. 2012 Jul-Aug;27(4):824–31. 29. Patcas R, Müller L, Ullrich O, Peltomäki T. Accuracy of cone-beam compu- ted tomography at different resolutions assessed on the bony covering of the mandibular anterior teeth. Am J Orthod Dentofacial Orthop. 2012 Jan;141(1):41–50. 30. Takahashi A, Watanabe H, Kamivama Y, Honda E, Sumi Y, Kurabavashi T. Loca- lizing the mandibular canal on dental CT reformatted images: usefulness of panoramic views. Surg Radiol Anat. 2013 Nov;35(9):803–9. 31. Ozan O, Turkyilmaz I, Ersoy AE, McGlumphy EA, Rosenstiel SF. Clinical ac- curacy of 3 different types of computed tomographyderived stereolitho- graphic surgical guides in implant placement. J Oral Maxillofac Surg. 2009 Feb;67(2):394–401. 32. Abrahams JJ. Dental CT imaging: a look at the jaw. Radiology. 2001 25. Hanazawa T, Sano T, Seki K, Okano T. Radiologic measurements of the man- May;219(2):334–45. 1_2017 23