Cone beam

1. DentalRadiography Shanon Patel Shalini Kanagasingam and Francesco Mannocci Cone Beam Computed Tomography (CBCT) in Endodontics Abstract: Cone beam computed tomography (CBCT) is an extra-oral imaging system which produces 3-dimensional scans of the maxillofacial skeleton. It is useful in overcoming the limitations of conventional radiography. CBCT is a valuable aid in providing additional information for diagnosis and enabling more predictable management of complex endodontic problems compared to using intra-oral radiographs alone. Clinical Relevance: There are potential indications for the use of CBCT in diagnosis and treatment planning. Dent Update 2010; 37: 373–379 One of the most important stages in diagnosis and management of endodontic problems is radiographic examination. The periapical radiograph is widely used in the field of endodontics to detect the presence, location and size of periapical lesions.1-3 It also reveals information about root canal anatomy and proximity of neighbouring anatomical structures. In most endodontic cases, the periapical radiograph is the image of choice as it provides a high definition image at a low dose. However, conventional radiographic techniques have certain limitations. This paper will review cone beam computed tomography (CBCT) technology and how this technology can be applied to overcome some of the shortcomings of conventional radiography in the management of complex endodontic problems. assessed. The spatial relationship of the root(s) to their surrounding anatomical structures and associated periapical lesions cannot always be truly assessed with conventional radiographs.6,7 In addition, the location, nature and shape of structures within the root under investigation (eg root resorption) may be difficult to gauge.3,8,9 Limitations of conventional radiography Conventional intra-oral radiography has limitations which may reduce the amount of useful information gained. Geometric distortion Radiographs should be taken with a beam aiming device as this produces more geometrically accurate images as compared to the bisecting technique.10 However, it is not always easy to position the radiographic film parallel to the long axis of the tooth, for example, patients with a shallow palatal vault or gag reflex. The inability to do this will affect the accuracy of the image produced as some degree of geometric distortion will be present. S Patel, BDS, MSc, MClinDent, MFDS MRD, Endodontic Postgraduate Unit, King’s College London Dental Institute, Guy’s Tower, Guy’s Hospital, St Thomas’ Street, London, SE1 9RT and 45 Wimpole Street, London, S Kanagasingam, BDS MFDS, Endodontic Postgraduate Unit, King’s College London Dental Institute, Guy’s Tower, Guy’s Hospital, St Thomas’ Street, London, SE1 9RT andUniversiti Kebangsaan Malaysia, Kuala Lumpur, Malaysia and F Mannocci, MD DDS, PhD, Endodontic Postgraduate Unit, King’s College London Dental Institute, Guy’s Tower, Guy’s Hospital, St Thomas’ Street, London, SE1 9RT, UK. Compression of 3-dimensional anatomy The amount of information gained from intra-oral radiographs is limited by the fact that the 3-dimensional anatomy of the area being radiographed is compressed into a 2-dimensional image, which limits their diagnostic value.3-5 Data are obtained in the mesio-distal (proximal) plane only, as the bucco-lingual view (ie the third dimension) cannot be fully Anatomical superimposition Certain anatomical features may mask or overlap the area of interest, resulting in difficulty in interpreting radiographic images.11 These anatomical DentalUpdate 373 July/August 2010

2. DentalRadiography of the patient is acquired in a single revolution of the x-ray source and detector.2,15 The X-ray source and the detector rotate between 180° to 360° around the patient’s head, depending on the CBCT scanner used. This results in a cylindrical or spherical volume of data, described as the field of view (Figure 1). Limited volume CBCT scanners capture small volumes of data that can include just two or three individual teeth, for example, the 3D Accuitomo (J Morita Corporation, Osaka, Japan) can capture a 40mm height by 40mm diameter volume of data which is similar in overall height and width to a periapical radiograph. The majority of CBCT systems scan the patient in a seated position. Scan times typically take between 10–40 seconds, depending on the scanner used and the exposure parameters selected. The actual exposure time is a fraction of this, only about 2–5 seconds. Sophisticated software processes the collected data into a format which closely resembles that produced by medical CT scanners. Reconstructed images are generated within minutes (Figure 2). The data acquired by CBCT are captured in terms of volume, which are made up of voxels. With digital imaging, the picture is composed of pixels. In the case of CBCT, voxels are basically 3-dimensional versions of pixels. CBCT voxels are isotropic, which means that they are equal in all 3 dimensions. Objects captured within the volume can be accurately measured in various directions. Images can be displayed in a number of different ways. For example, images can be displayed in the 3 orthogonal planes, axial, sagittal and coronal, simultaneously. Selecting and moving the cursor on one image simultaneously alters the other reconstructed slices. This allows an area to be investigated 3-dimensionally in ‘real time’. Surface rendering, which is a technique for visualizing a geometric representation of a surface from a 3-dimensional Imaging technique Effective doses (micro Sieverts) Panoramic radiograph 13 Cephalometric radiograph 1−3 Periapical radiograph 1−8 Occlusal radiograph 8 CBCT (6 cm field of view of standard mandible) 75.3 CBCT (6 cm field of view of standard maxilla) 36.5 Conventional CT scan of head 2000 Table 1. Comparison of effective doses of various imaging techniques.22 Figure 1. The X-ray source and detector rotate once around the patient’s head. This results in a cylindrical volume of data being captured. Sophisticated software reconstructs the data, which may then be displayed in axial, sagittal and coronal planes. features may be radio-opaque (eg the zygomatic buttress) or radiolucent (eg the maxillary sinus). The effect of this anatomical superimpostion is dependent on the degree of bone demineralization, size of the endodontic lesion and the nature of the anatomical structures (ie its thickness, shape and density of the overyling anatomy). Some of these problems may be resolved by the use of CBCT. volume tomography (DVT) is an extra-oral imaging system which can produce 3-dimensional scans of the maxillofacial skeleton.12 The technology has existed since the 1980s in the medical field13 and has more recently been developed for use in dentistry. It has evolved into a practical and relevant imaging apparatus which is fast gaining importance in dentistry.14 How does it work? CBCT employs a pyramid or cone-shaped X-ray beam. The entire 3-dimensional volume of data What is CBCT? Cone beam computed tomography (CBCT) or digital 374 DentalUpdate July/August 2010

3. DentalRadiography a b e c d Figure 2. (a–d) CBCT produces high resolution multiplanar images (b): green plane (sagittal slice-d); blue plane (coronal slice-c); red plane (axial slice-a). (a) Axial CBCT slice clearly shows 2 canals in an upper central incisor in a case of dens in dente (red arrows) as compared to a periapical radiograph (e). volume data set, makes it possible to produce 3-dimensional images. expensive. This has resulted in an increase in its uptake in dental practices,14,17 although these scanners are more costly than conventional radiographic equipment. CBCT scans offer a significant radiation dose reduction as compared to medical CT. Previous studies suggest that it can be almost as low as a dental panoramic radiograph.18–21 Limited volume CBCT scanners are best suited for endodontic imaging of only one tooth or two neighbouring teeth, as there is a smaller field of view, which is similar in size to a conventional periapical radiograph. A more recent study agreed that the doses from CBCT were much lower compared to medical CT. However, the authors stated that the effective dose was significantly higher than conventional radiographic techniques.22 Table 1 compares the effective radiological dose from conventional imaging techniques to CBCT, as quoted from the abovementioned article.22 With this in mind, the use of CBCT should be justified over conventional radiography, especially when treating paediatric patients. Several studies appear to show the 3-dimensional geometric accuracy of CBCT.23–26 Why would you use CBCT? CBCT may be useful in complex endodontic cases where conventional radiography has not provided sufficient information. It can provide additional information via 3-dimensional views in order to manage a case predictably. CBCT permits the clinician to view areas of interest in any plane rather than being restricted to the limited views available with conventional radiography. Most CBCT scanners are the size of a panoramic machine and can therefore be easily installed in dental practices. As previously mentioned, scans are quick (only 10–40 seconds) and can be done with the patient sitting comfortably. CBCT scanners use simpler, and therefore less expensive, hardware (X-ray source and detector) than CT scanners and powerful low cost computers,2,16 which means that the cost of CBCT scanners is not prohibitively When would you use it? CBCT should be used in cases where conventional radiography has not provided sufficient information. The following are some indications for the use of CBCT. Detection of apical periodontitis A CBCT scan may be helpful in investigating the presence or absence of periapical lesions in cases whereby information from conventional radiographs has been inconclusive. CBCT enables radiolucent endodontic lesions to be detected before radiolucent lesions are diagnosed on conventional radiographs (Figure 3). Lofthag-Hansen et al 27 demonstrated that CBCT scans resulted in 62% more periapical lesions being detected as compared to two angled periapical DentalUpdate 375 July/August 2010

4. DentalRadiography a This could help exclude cases of non- odontogenic orofacial pain (eg atypical facial pain). with dental trauma as compared to multiple intra-oral radiographs taken using a paralleling device. CBCT scans are also useful for detecting cortical bone fractures.5 Pre-surgical assessment Three dimensional imaging allows the anatomical relationship of the root apices to important neighbouring anatomical structures, such as the inferior dental canal, mental foramen and maxillary sinus, to be clearly identified in any plane.3 Rigolone et al32 concluded that CBCT may play an important role in periapical microsurgery of palatal roots of maxillary first molars. The presence or absence of the maxillary sinus between the roots can be assessed by measuring the distance between the cortical plate and the palatal root apex. By selecting relevant views, the thickness of the cortical plate, the cancellous bone pattern, fenestrations, as well as the inclination of the roots of teeth planned for periapical surgery, can be accurately determined pre- operatively.31 Root morphology, bony topography and the number of root canals can be assessed. Unidentified (and untreated) root canals in root- treated teeth may be identified using axial slices which may not be readily identifiable with periapical radiographs.33 The size, location and extent of the periapical lesion can also be gauged, while the actual root to which the lesion is associated can be identified. This additional information will prove useful in surgical planning. a b b Figure 3. (a) Periapical radiograph shows lower left first molar with no obvious periapical lesion. (b) Sagittal CBCT slice shows periapical lesions associated with mesial and distal roots (red arrows) of the same lower left first molar. radiographs. Patel et al28 found CBCT to be more sensitive than conventional radiographic films in detecting simulated periapical lesions in dried human jaws. Ozen et al29 assessed the diagnostic potential of two different CBCT units and compared this with intra-oral digital and conventional film in the detection of periapical lesions. They concluded that the two CBCT units performed similarly and both performed better than intra-oral digital and film radiography in detecting periapical lesions. Earlier detection of periradicular radiolucent changes with CBCT should result in earlier identification and management of endodontic disease. This could lead to a better outcome from endodontic treatment as teeth could be treated sooner.30 CBCT may reveal the presence of previously undiagnosed periapical disease, especially in cases where patients have poorly localized symptoms and periapical radiographs seem to show no evidence of disease.2,3,31 c Assessment of dental trauma Case reports and expert opinion suggest that CBCT is likely to be useful in diagnosis and management of dento-alveolar trauma.2,3,5 The nature and severity of alveolar and luxation injuries can be assessed from just one scan, from which multiplanar views can be selected and assessed with no geometric distortion or anatomical noise. A recent study has shown that CBCT can be used to detect horizontal root fractures and that it performed better than the 2-dimensional intra-oral, conventional as well as digital radiographic methods.34 As an extra-oral technique, CBCT is much more comfortable for patients Figure 4. (a) Periapical radiograph of lower right first molar with deep carious lesion, showing mesial and distal roots. (b) Coronal and (c) axial CBCT slices confirmed the presence of an additional distobuccal root (red arrows). 376 DentalUpdate July/August 2010

5. DentalRadiography a c paper have found CBCT reconstructed scans invaluable for assessing teeth with unusual anatomy, such as teeth with an unusual number of roots, dilacerated teeth and dens in dente (Figure 2). In these situations, the exact location and anatomy of the root canal can be assessed, allowing successful management of the case. Previously, even with the aid of magnification, the anatomy of such a tooth may not be truly appreciated. What are the limitations of CBCT? Currently, the images produced with CBCT technology do not have the resolution (ie detail) of conventional radiographs. The spatial resolution of conventional direct-action packet film and digital sensors is in the order of 15–20 line pairs/mm.38 CBCT images only have a spatial resolution of 2 line pairs/mm.39 However, CBCT technology is improving, and resolution is improving. A significant problem which can affect the image quality and diagnostic efficacy of CBCT images is the scatter and beam hardening caused by high density neighbouring structures, such as metal posts and crowns.40 If this scattering and beam hardening is within or close to the tooth being assessed, the resulting CBCT images will be of minimal diagnostic use27,41 (Figure 6). The potential presence of artefacts also poses a problem in this respect. As shown in Table 1, the significantly higher radiation dose of CBCT as compared to conventional radiographic techniques should be kept in mind so as to limit its usage to very specific situations. d b Figure 5. (a) Periapical radiograph of lower left central incisor showing an internal resorptive lesion. (b-d) Series of CBCT slices which show the extent of the internal resorptive lesion, perforating the lingual surface of the tooth (red arrow). CBCT reconstructed images are indispensable in the diagnosis and management of resorption lesions.36 It is able to disclose the extent and exact location of the lesion, determine the ‘portal of entry’ of the resorptive lesion and also reveal previously undetected resorptive lesions.8,37 With this additional information, decision-making on treatment strategies may be more predictable, eg CBCT slices may reveal if an external cervical resorptive lesion has perforated the root canal, or if an internal resorptive lesion has perforated into the adjacent periodontium (Figure 5). The authors of this review Assessment of root canal anatomy Conventional radiographs do not always reveal the actual number of canals present in a tooth (Figure 4). Matherne et al35 conducted an in vitro study which evaluated digital radiography systems with CBCT for comparing the number of root canals in 72 extracted teeth. They found that, with digital intra- oral radiography, endodontists failed to identify at least one root canal in 40% of teeth, despite taking parallax radiographs. Though it must be noted that the teeth were not subsequently sectioned to confirm the true number of root canals compared with the ‘gold standard’ CBCT data. Discussion CBCT technology is constantly being developed and advanced. Scanners are becoming more affordable, thus making CBCT technology a viable option in dental practices. However, it must be stressed that users of CBCT must be adequately trained in CBCT radiology, as well as interpretation of these images, as they are completely different from DentalUpdate 377 July/August 2010

6. DentalRadiography a is proving to be an indispensable supplementary diagnostic tool. It must always be kept in mind that patient radiation exposure should be as low as reasonably practicable (ALARP). After all, CBCT uses ionizing radiation and is therefore not without risk. As previously mentioned, the effective dose of CBCT is considerably higher than conventional imaging techniques. Evidence-based selection criteria for CBCT use would be essential for guiding clinicians. imaging modalities. Oral Surg Oral Med Oral Path Oral Radiol Endod 1999; 88: 239–247. Cohenca N, Simon JH, Roges R, Morag Y, Malfaz JM. Clinical indications for digital imaging in dento-alveolar trauma. Part 1: Traumatic injuries. Dent Traumatol 2007; 23: 95–104. Cotti E, Vargiu P, Dettori C, Mallarini G. Computerized tomography in the management and follow-up of extensive periapical lesion. Endod Dent Traumatol 1999; 15: 186–189. Cotti E, Campisi G. Advanced radiographic techniques for the detection of lesions in bone. Endodontic Topics 2004; 7: 52–72. Cohenca N, Simon JH, Marhtur A, Malfaz JM. Clinical indications for digital imaging in dento-alveolar trauma. Part 2: Root resorption. Dent Traumatol 2007; 23: 105–113. Whaites E. Essentials of Dental Radiology and Radiography 4th edn. Philadelphia: Elsevier, 2007. 10. Forsberg J, Halse A. Radiographic simulation of a periapical lesion comparing the paralleling and the bisecting-angle techniques. Int Endod J 1994; 27: 133–138. 11. Gröndahl H-G, Huumonen S. Radiographic manifestations of periapical inflammatory lesions. Endodontic Topics 2004; 8: 55–67. 12. Arai Y, Tammisalo E, Iwai K, Hashimoto K, Shinoda K. Development of a compact computed tomographic apparatus for dental use. Dent Radiol 1999; 28: 245–248. 13. Robb RA, Sinak LJ, Hoffman EA, Kinsey JH, Harris LD, Ritman EI. Dynamic volume imaging of moving organs. J Med Syst 1982; 6: 539–554. 14. Arnheiter C, Scarfe WC, Farman AG. Trends in maxillofacial cone-beam computed tomography usage. Oral Radiol 2006; 22: 80–85. 15. Danforth RA, Clarke DE. Effective doses from radiation absorbed during a panoramic examination with a new generation machine. Oral Surg Oral Med Oral Path Oral Radiol Endod 2000; 89: 236–243. 16. Baba R, Ueda K, Okabe M. Using a 5. 6. b Conclusion 7. Finally, the benefits of a CBCT investigation must outweigh any potential risks.43,44 Consequently, endodontic cases should be judged individually, until further evidence is available. CBCT should not be used routinely. It should only be considered for the management of complex endodontic cases, after conventional radiographic views have been taken and found to be inadequate. 8. 9. Figure 6. (a, b) Lower CBCT slices of lower central incisors which had undergone apicectomies and had retrograde amalgam fillings placed, which have caused beam scattering and hardening. Acknowledgements We thank Cavendish Imaging, London, UK and the Radiology Department, Guy’s and St Thomas’ NHS Trust for their help and advice in preparation of this article. conventional radiography systems. CBCT captures a considerable amount of data. All the data on the scan (not just the area of interest) must be reviewed and any anomalies must be reported and acted upon by the dental surgeon requesting the scan, or by a specialist radiologist.17,42 Three-dimensional CBCT scans may complement conventional two-dimensional radiographic techniques which, at present, have higher resolution than CBCT images, therefore making the most of both systems.43 This should result in more accurate diagnosis and therefore improved decision-making for the management of complex endodontic problems. Ideally, its use should be incorporated into endodontic postgraduate programmes, as it References 1. Cohen S, Hargreaves KM. Pathways of the Pulp 7th edn. Philadelphia: Mosby Elsevier, 2006. 2. Cotton TP, Geisler TM, Holden DT, Schwartz SA, Schindler WG. Endodontic applications of cone- beam volumetric tomography. J Endod 2007; 33: 1121–1132. 3. Patel S, Dawood A, Whaites E, Pitt Ford T. The potential applications of cone beam computed tomography in the management of endodontic problems. Int Endod J 2007; 40: 818– 830. 4. Webber RL, Messura JK. An in vivo comparison of digital information obtained from tuned-aperture computed tomography and conventional dental radiographic 378 DentalUpdate July/August 2010

7. DentalRadiography flat-panel detector in high resolution cone beam CT for dental imaging. Dent Radiol 2004; 33: 285–290. 17. Scarfe WC, Farman AG, Sukovic P. Clinical applications of cone-beam computed tomography in dental practice. J Can Dent Assoc 2005; 72: 75–80. 18. Ngan DCS, Kharbanda OP, Geenty JP, Darendeliler MA. Comparison of radiation levels from computed tomography and conventional dental radiographs. Aus Dent J 2003; 19: 67–75. 19. Mah J, Danforth RA, Bumann A, Hatcher D. Radiation absorbed in maxillofacial imaging with a new dental computed tomography device. Oral Surg Oral Med Oral Path Oral Radiol Endod 2003; 96: 508–513. 20. Ludlow JB, Davies-Ludlow LE, Brooks SL, Howerton WB. Dosimetry of 3 CBCT devices for oral and maxillofacial radiology: CB Mercuray, NewTom 3G and i-CAT. Dent Radiol 2005; 35: 219–226. 21. Lofthag-Hansen S, Thilander-Klang A, Ekestubbe A, Helmrot E, Gröndahl K. Calculating effective dose on a cone beam computed tomography device: 3D Accuitimo and 3D Accuitomo FPD. Dent Radiol 2008; 37: 72–79. 22. Roberts JA, Drage NA, Davies J, Thomas DW. Effective dose from cone beam CT examinations in dentistry. Br J Radiol 2009; 82: 35–40. 23. Kobayashi K, Shimoda S, Nakagawa Y, Yamamoto A. Accuracy in measurement of distance using cone- beam computerized tomography. Int J Oral Maxillofac Surg 2004; 19: 228–231. 24. Murmulla R, Wörtche R, Mϋhling J, Hassfeld S. Geometric accuracy of the NewTom 9000 Cone Beam CT. Dent Radiol 2005; 34: 28–31. 25. Ludlow JB, Lester WS, See M, Bailey LJ, Hershey HG. Accuracy of measurements of mandibular anatomy in cone beam computed tomography images. Oral Surg Oral Med Oral Path Oral Radiol Endod 2007; 103: 534–542. 26. Mischkowski RA, Pulsfort R, Ritter L, Neugebauer J, Brochhagen HG, Keeve E, Zöller JE. Geometric accuracy of a newly developed cone-beam device for maxillofacial imaging. Oral Surg Oral Med Oral Path Oral Radiol Endod 2007; 104: 551–559. 27. Lofthag-Hansen S, Huumonen S, Gröndahl K, Gröndahl H-G. Limited cone-beam CT and intraoral radiography for the diagnosis of periapical pathology. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2007; 103: 114–119. 28. Patel S, Dawood A, Mannocci F, Wilson R, Pitt Ford T. Detection of periapical bone defects in human jaws using cone beam computed tomography and intraoral radiography. Int Endodont J 2009; 42: 507–515. 29. Ozen T, Kamburoglu K, Cebeci AR, Yuksel SP, Paksoy CS. Interpretation of chemically created periapical lesions using 2 different dental cone- beam computerized tomography units, an intraoral digital sensor and conventional film. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2008; Online 8 Nov: 1–7. 30. Friedman S. Prognosis of initial endodontic therapy. Endodontic Topics 2002; 2: 59–98. 31. Nakata K, Naitoh M, Izumi M, Inamoto K, Ariji E, Nakamura H. Effectiveness of dental computed tomography in diagnostic imaging of periradicular lesion of each root of a multirooted tooth: a case report. J Endod 2006; 32: 583–587. 32. Rigolone M, Pasqualini D, Bianchi L, Berutti E, Bianchi SD. Vestibular surgical access to the palatine root of the superior first molar: “Low- doses Cone-beam” CT analysis of the pathway and its anatomic variations. J Endod 2003; 29: 773–775. 33. Low MTL, Dula KD, Bürgin W, von Arx T. Comparison of periapical radiography and limited cone-beam tomography in posterior maxillary teeth referred for apical surgery. J Endod 2008; 34: 557–562. 34. Kamburoglu K, Cebeci ARI, Grondahl HG. Effectiveness of limited cone-beam computed tomography in the detection of horizontal root fracture. Dent Traumatol 2009; 25: 256–261. 35. Matherne RP, Angelopoulos C, Kulilid JC, Tira D. Use of Cone-Beam Computed Tomography to identify root canal systems in vitro. J Endod 2008; 34: 87–89. 36. Maini A, Durning P, Drage N. Resorption: within or without? The benefit of Cone-Beam Computed Tomography when diagnosing a case of an internal/external resorption defect. Br Dent J 2008; 204: 135–137. 37. Patel S, Dawood A. The use of cone beam computed tomography in the management of external cervical resorption lesions. Int Endod J 2007; 40: 818–830. 38. Farman AG, Farman TT. A comparison of 18 different x-ray detectors currently used in dentistry. Oral Surg Oral Med Oral Path Oral Radiol Endod 2005; 99: 485–489. 39. Yamamoto K, Ueno K, Seo K, Shinohara D. Development of dento-maxillofacial cone beam X-ray computed tomography system. Orthod Craniofac Res 2003; 6 (Suppl 1): 160–162. 40. Mora MA, Mol A, Tyndall DA, Rivera E. In vitro assessment of local tomography for the detection of longitudinal tooth fractures. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2007; 103: 825–829. 41. Estrela C, Bueno MR, Leles CR, Azevedo B, Azevedo JR. Accuracy of Cone Beam Computed Tomography and panoramic radiography for the detection of apical periodontitis. J Endod 2008; 34: 273–279. 42. Nair MK, Nair UP, Seyedain A, Gassner R, Piesco N, Mooney M, Ganta S, Agarwal S. Correlation of tuned aperture computed tomography with conventional computed tomography for evaluation of osseous healing in calvarial defects. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2007; 103: 267–273. 43. Vandenberghe B, Jacobs R, Yang J. Diagnostic validity (or acuity) of 2D CCD versus 3D CBCT images for assessing periodontal breakdown. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2007; 104: 395–401. 44. Farman AG. ALARA still applies – Editorial Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2005; 100: 395–397. DentalUpdate 379 July/August 2010