Scholarly article on topic 'Agreement between cone beam computed tomography images and panoramic radiographs for initial orthodontic evaluation'

Agreement between cone beam computed tomography images and panoramic radiographs for initial orthodontic evaluation Academic research paper on "Veterinary science"

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Abstract of research paper on Veterinary science, author of scientific article — Pisha Pittayapat, Guy Willems, Ali Alqerban, Wim Coucke, Rejane Faria Ribeiro-Rotta, et al.

Objective The aim of this study was to compare the agreement between cone beam computed tomography (CBCT) and panoramic radiographs for initial orthodontic evaluation. This study was not meant to test differences between imaging modalities or to indicate superiority of one technique. Study Design Thirty-eight subjects with both panoramic and CBCT images were retrospectively collected. Eight observers answered 14 observational questions. The observation was repeated after 4 weeks. Results CBCT images yielded better agreement between 2 observer groups (orthodontic residents and radiologists) and better inter- and intraobserver agreement. The agreement between panoramic radiographs and CBCT scans was moderate. Conclusions If CBCT is a priori present in a case with justified indications, it has the potential to provide valuable diagnostic information for initial orthodontic evaluation and extra information for treatment planning. The moderate agreement between panoramic and CBCT images may indicate that the nature and amount of information gained from both imaging sources is deviant.

Academic research paper on topic "Agreement between cone beam computed tomography images and panoramic radiographs for initial orthodontic evaluation"

Accepted Manuscript

Agreement between cone-beam CT images and panoramic radiographs for initial orthodontic evaluation

Pisha Pittayapat, DDS, MSc Guy Willems, PhD Ali Alqerban, DDS, MSc Wim Coucke; PhD Rejane Faria Ribeiro-Rotta, PhD Paulo Couto Souza, PhD Fernando Henrique Westphalen, PhD Reinhilde Jacobs, PhD

PII: S2212-4403(13)00631-7

DOI: 10.1016/j.oooo.2013.10.016

Reference: OOOO 774

To appear in: Oral Surgery, Oral Medicine, Oral Pathology and Oral Radiology

Received Date: 7 August 2013

Revised Date: 21 October 2013

Accepted Date: 25 October 2013

Please cite this article as: Pittayapat P, Willems G, Alqerban A, Coucke W, Ribeiro-Rotta RF, Souza PC, Westphalen FH, Jacobs R, Agreement between cone-beam CT images and panoramic radiographs for initial orthodontic evaluation, Oral Surgery, Oral Medicine, Oral Pathology and Oral Radiology (2013), doi: 10.1016/j.oooo.2013.10.016.

This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

Agreement between cone-beam CT images and panoramic radiographs for

initial orthodontic evaluation

Pisha Pittayapat1'2, DDS, MSc

Guy Willems3, PhD

Ali Alqerban3, DDS, MSc

Wim Coucke4, PhD

Rejane Faria Ribeiro-Rotta5, PhD

Paulo Couto Souza6, PhD

Fernando Henrique Westphalen6, PhD

Reinhilde Jacobs1, PhD

*Oral Imaging Center, OMFS-IMPATH research group, Dept Imaging & Pathology, Faculty of Medicine, University of Leuven, Leuven, Belgium

2Radiology Department, Faculty of Dentistry, Chulalongkorn University, Bangkok, Thailand

3Orthodontics, Department of Oral Health Sciences, KU Leuven & Dentistry, University Hospitals Leuven, Leuven, Belgium

4Department of Clinical Biology, Scientific Institute of Public Health, Brussels, Belgium

5Department of Oral Medicine, School of Dentistry, Federal University of Goiás, Goiás, Brazil

6School of Dentistry, Pontifical Catholic University of Paraná, Curitiba, Brazil

Running title: CBCT vs Panoramic radiography in orthodontics

This manuscript, or any part of it, has not been submitted or published and will not be submitted elsewhere for publication while being considered by the journal OOOO. This study was presented as an oral presentation at the 13th Congress of European Academy of Dento-Maxillo-Facial Radiology, Leipzig, Germany in the research award section. The abstract was included in congress proceedings.

Funding

This work was supported by a doctoral scholarship in the framework of the Interfaculty Council for Development Co-operation (IRO).

Conflict of interest

The authors declare that they have no conflict of interest.

Abstract: 150 words Manuscript: 4597 words Table: 2 tables Figure: 3 figures

Correspondence to:

Pisha Pittayapat

Oral Imaging Center, OMFS-IMPATH research group

Dept Imaging & Pathology, Faculty of Medicine, University of Leuven

Kapucijnenvoer 33

3000 Leuven, Belgium

E-mail: p.pittayapat@gmail.com

Abstract

Objectives. The aim of this study was to compare the agreement between cone-beam computed tomography (CBCT) and panoramic radiographs for initial orthodontic evaluation. This study was not meant to test differences between imaging modalities or indicate superiority of one technique.

Study Design. Thirty-eight subjects with both panoramic and CBCT images were retrospectively collected. Eight observers answered 14 observational questions. The observation was repeated after 4 weeks.

Results. CBCT images yielded better agreement between 2 observer groups (orthodontic residents and radiologists) and better inter- and intra-observer agreement. The agreement between panoramic radiographs and CBCTs was moderate. Conclusions. If CBCT is a priori present in case of justified indications, it has the potential to provide valuable diagnostic information for initial orthodontic evaluation and extra information for treatment planning. The moderate agreement between panoramic and CBCT images may indicate that the nature and amount of information gained from both imaging sources is deviant.

Keywords: Cone-beam computed tomography, Diagnostic imaging, Orthodontics, Panoramic radiography

Introduction

Panoramic radiography has been used as an essential diagnostic tool in dentistry for more than half a century.1-3 Although with several limitations such as geometric distortion and superimposition of anatomical structures4-7, panoramic radiographs are still generally used in orthodontic treatment planning, oral surgery and in almost all dental specialties for overall screening.

Three-dimensional computed tomography (CT) images have been introduced to dentistry in the 1990s but in view of the high radiation dose, the use has been rather controversial and not widely accepted. However, since the introduction of the first cone-beam computed tomography (CBCT)8, 3D-imaging has started to play an increasingly important role in oral health care diagnostics. The technology of this device has been continuously developing, offering dentists spatial visibility of anatomic structures and pathology with a better image quality and also with a relatively lower radiation dose than the multi-slice CT (MSCT).9

Although different guidelines and selection criteria may exist in various countries, orthodontists often seem to request a panoramic radiograph and a lateral cephalogram for initial treatment planning. Additional information about tooth eruption state, angulation of the teeth, overall dental, periodontal, and condylar condition is often added to the clinical evaluation based on analysis of the panoramic radiograph. This type of radiograph is also used to follow up orthodontic treatment progress as well as to visualize treatment outcome and prognosis of wisdom teeth if present.10 In particular indications, conventional radiographs seem to offer insufficient information to make a diagnosis, illustrating the need for a low dose CBCT for specific orthodontic comprehensive care such as cases of canine impaction, root resorption, supernumerary teeth, and airway-related problems.11'12 The radiation

burden by CBCT remains however a major concern, surely in children. Studies have been conducted on different CBCT devices and different protocols to evaluate radiation dose to the patients. Dosimetric studies showed that the amount of radiation dose is strongly related to the size of field of view (FOV) and imaging parameters (e.g. resolution, rotation, mA).13,14 The latter information is crucial to apply ALARA (as low as reasonably achievable) concept in children.

Several studies have tested the reliability of panoramic radiographs for orthodontic related issues and some have contrasted its reliability with that of CBCTs. Results show that panoramic radiographs are often unreliable in diagnosing canine impaction, third molar impaction, mesial angulation of the roots, root contact, root resorption, and diagnosis of supernumerary teeth. In contrast, CBCTs could offer more reliable information and may lead to a different diagnosis and treatment plan for these specific conditions.15-24

In a previous study, the ability of panoramic views generated from CBCTs was compared to conventional digital panoramic radiographs. The results suggested that the reformatted panoramic views from some CBCTs may be able to offer as equal diagnostic quality as the digital panoramic images, commonly used in dental practices.25 The next step would be to examine whether the full CBCT dataset has equal diagnostic quality compared to conventional digital panoramic radiographs or not. If the patient's pre-existing CBCT data can provide orthodontists all necessary information for orthodontic treatment, then extra conventional 2D radiographs will not be required anymore and making an additional panoramic radiograph abundant. Patients' datasets will be more compact and the radiation dose to them can be reduced.

There is only little evidence from literature that proves whether CBCT data can offer better diagnostic potential, lead to an improved orthodontic treatment planning and are capable of offering orthodontists the same amount of information as they usually require from conventional panoramic radiographs.26

The aim of this study is to compare the agreement between observers for cone-beam computed tomography (CBCT) and digital panoramic radiographs related to initial orthodontic evaluation in the situation where CBCT images are a priori requested by the orthodontist for justified indications. This study was not meant to test differences or indicate superiority of 3D imaging in general or CBCT imaging more specifically. This study was aimed to evaluate the suitability of CBCT for initial orthodontic evaluation, when a CBCT scan was indicated and a priori taken for some specific indication.

Materials and methods

Samples

Thirty-eight patients (13 males and 25 females, age range 8-25 years, mean age 13.2, SD 4.2 years) were retrospectively selected from the hospital orthodontic database (Oral Imaging Center, Katholieke Universiteit Leuven, Leuven, Belgium). The selection criteria were: (1) Patients with a panoramic radiograph and additional CBCT images after a panoramic radiograph had been taken (The CBCT was specifically indicated for patients with root resorption cases and for treatment planning when dealing with impacted canines); (2) Both types of images were taken within an average time interval of 3 months (range 0-11.5 months; SD 3.7 months); (3) No significant pathology of the maxillofacial region (benign or malignant tumor, cleft lip or cleft palate, trauma) was present; (4) No significant asymmetry of the face

was observed. The study protocol (reference number: ML6960) was approved by UZ Leuven Medical Ethics Committee. The authors have read the Helsinki Declaration and have followed the guidelines in this investigation.

Imaging modalities

Panoramic radiographs were acquired from a standard digital panoramic device with CCD sensor (Veraviewepocs 2D®, J. Morita, Kyoto, Japan). The panoramic settings were selected depending on each patient (64 kVp 8.9 mA 7.4 sec with pixel size 0.144 mm, image size size 30 x 15 cm). The images were collected from the hospital picture archiving and communication system (PACS) by exporting as TIFF files.

The CBCT scans of each patient were taken with 3D Accuitomo® 170 (J. Morita, Kyoto, Japan) with field of view (FOV): 140 x 100 mm (High-Fidelity (Hi-Fi) mode: 90 kVp, 5 mA, scan time 30.8 sec, voxel size 0.25 mm.) All datasets were exported as DICOM files.

Image evaluation

Eight observers (five 2nd year orthodontic residents and three dentomaxillofacial radiologists with more than 5 years experience) were initially introduced to an instruction and calibration session. Detailed instructions and definitions of all questions were given to all observers. The observers made an observation of 3 cases. Then the answers were checked and calibrated by the main author. All of them participated at the first observation session and five observers (orthodontic residents) repeated the evaluation after a 4-week interval. Both observation sessions were performed under standardized conditions: dimmed ambient

light, with 20-inch, 2 Megapixel clinical review display (MDRC-2120, Barco N.V., Kortrijk, Belgium).

During the observation, images from the patients were divided in 2 groups and then randomized within the group and also re-randomized for the second session. Group 1: panoramic radiographs were shown to observers on the ImageJ® software, version 1.45s (National Institutes of Health, Bethesda, USA) (Figure 1). Group 2: The entire volumes of CBCT images were shown on the OnDemand3D® software, version 1.0.8.0408 (Cybermed, Seoul, Republic of South Korea) (Figure 2).

In both groups, the observers had the possibility to use all tools available in the software, including panoramic curve tool in the OnDemand3D®.

Questionnaire

Observers answered 14 questions related to initial orthodontic evaluation. The detailed questions and answer options are shown in Table I. The tooth numbering system used in the questionnaire was the FDI World Dental Federation notation, e.g. #13 is a maxillary right canine.

Statistical analysis

Statistical analysis was performed with R 2.14 software© for Windows (R Development Core Team, ©R Foundation for Statistical Computing, Vienna, Austria). Agreements were assessed using Fleiss' kappa statistics. Data were assessed on the following aspects:

• Agreement between radiologist group and the orthodontic resident group

• Agreement between digital panoramic radiographs and CBCT images

• Inter-observer agreement

• Intra-observer agreement Results

Agreement between observer groups

A high agreement was found between the orthodontic resident and the radiologist group. The agreement was higher in the CBCT image group than in the panoramic group with Fleiss' kappa being 1.0 and 0.9 (P < 0.0001), respectively.

Agreement between two imaging modalities

A moderate agreement for all observers (Fleiss' kappa 0.5, P < 0.0001) was observed when comparing the two image modalities (group 1 panoramic and group 2 CBCT).31 The Fleiss' kappa was slightly higher in the orthodontic resident group (0.54) than in the radiologist group (0.45) (P < 0.0001).

More detailed results of the questionnaire per question and the frequency of all answers given to all questions were shown in Table II. It was found that for question 10 (localization of the upper right canine), the agreement between 2D and 3D modality was only slight (Fleiss' kappa = 0.2, P < 0.0001).31 Other questions that received fair agreement (Fleiss' kappa 0.2-0.4) are question 4, 5, 6 (apical area of frontal, middle and posterior region), 11 (angulation of the upper right canine), 12 (root resorption of the upper right lateral incisor) and 14 (impaction risk of third molars).

Intra- and Inter-observer agreement

The intra-observer agreement was substantial and was slightly better for the CBCT than the panoramic images, Fleiss' kappa 0.71 and 0.65 (P < 0.0001),

respectively. Moderate agreement was found in the inter-observer agreement. The Fleiss' kappa tended to be higher for the CBCT (0.5) than the panoramic images (0.4), (P < 0.0001).

Discussion

The present study demonstrated only a moderate agreement between CBCT images and digital panoramic radiographs when questions related to the initial orthodontic evaluation have to be answered.

In this study, panoramic and CBCT images of the patients were collected retrospectively. The patients were selected from the database of patients who had images from both modalities taken. The patients included in this study had CBCTs, acquired in the clinic according to the treating doctor's specified exposure parameters. The patients were not intentionally overexposed for this study. The patients often had problems with impacted canines or third molars, thus the population of this study was not distributed to people with normal oral condition. Although patients with oral and maxillofacial tumor, cleft lip and cleft palate and trauma were discarded, still there might have been some potential bias to this study.

As the results have shown, a high agreement was found between the two observer groups and the agreement was higher when visualizing the CBCT images compared to the panoramic images. This was not unforeseen because the CBCT images should offer more precise and realistic volume data when comparing to the panoramic images that are actually 2D shadows of the jaws. Evaluation of the dentomaxillofacial region on CBCT images should give more reliable answers to the questions. This supports the fact that both inter- and intra-observer agreement were higher in the CBCT group.

Questions were raised when comparing the two image modalities as only a moderate agreement was observed. The Fleiss' kappa was slightly higher in the orthodontic resident group. This implied that there were some points for which panoramic and CBCT images actually resulted in different answers to the questions, or otherwise spoken, they provided different information. The agreement was then inspected closely to see which questions had less agreement and the results are shown in Table II.

Some questions showed low or slight agreement (Q10: Fleiss' kappa = 0.2, P < 0.0001) (Table II). In question 10, the observers were asked to localize the upper right canine. In all cases, the canine could be localized in the CBCT images but in the panoramic radiographs, the observers could only localize 72.3% of the cases, which in reality may not always be the true location because the panoramic radiographs only provide 2-dimensional aspects but do not show the real bucco-palatal dimension (Table II). The present results of this study are compliant with previous evidence on

19 20 28

managing canine impaction.

Studies showed that 3D imaging was advantageous in the management of impacted canines28 and that the CBCT was more sensitive than conventional radiography for canine localization.19 The findings from Botticelli et al.20 demonstrated that CBCT increased precision in the localization of the canines and improved the estimation of the space conditions in the arch. The latter resulted in a difference in diagnosis and treatment planning from the 2D imaging approach.20

Some questions showed fair agreement (Fleiss' kappa 0.2-0.4).31 These were questions about apical area (Q4, 5, 6), angulation of the upper right canine (Q11), root resorption of the upper right lateral incisor (Q12) and the impaction risk of third molars (Q14). Some questions (especially Q4, 5, 6) are indeed rather subjective and

cannot be truly objectified. Therefore, they probably had a large influence on the level of agreement. On the other hand, the authors decided to include these questions since they are often asked by orthodontists during the initial evaluation.

Question 4-6 asked the observers to evaluate the space at the apical areas. As

mentioned, the nature of these questions are rather subjective and in this study true

distance measurements could not be performed as a gold standard; therefore, it was impossible to justify whether which answers were correct for each case. It is expected that 3D CBCTs will give the answer that is closer to the real situation than panoramic radiographs, which have more distortion from their image geometry. However, in this study only the agreement between the 2 imaging modalities could be tested.

To be able to answer Q11, the observers had to use the angular measuring tools, both in the ImageJ® and OnDemand3D® software (Figure 3), and then selected the angle categories from 1 to 4 (Table II). However, the image geometry of the panoramic radiograph might influence the angular measurements. Patient positioning in the panoramic radiographic machine can influence the occlusal plane or the smile curve of the panoramic radiographs and therefore can result in only a fair agreement between the 2 imaging modalities.21,32 Results of this present study were also supported by the results from Alqerban et al.19 in 2011 who reported a significant difference in upper canine angulation to the midline between a digital panoramic radiograph and a medium field of view CBCT.19

In Q12, the observers were asked to report any pathological root resorption on the upper right lateral incisor. Fair agreement was found (Fleiss' kappa = 0.3). In the panoramic group, 24.0% of all the answers were categorized as "unidentified", in contrast to only 7.2% in CBCT group (Table II). This may be explained by the fact that in panoramic radiographs, the observers can only visualize the teeth in 2

dimensions. Superimposition of anatomical structures and teeth might camouflage any root resorption in panoramic images, contrary to CBCT images where the observers can look for the presence of root resorption on every side of the tooth. This result should be read with some caution. When root resorption was severe, it was obvious in both panoramic radiography and CBCT. In contrast, when it came to mild resorption cases, studies showed that CBCT is more sensitive than panoramic radiography.15,16

So far, several articles related to root resorption and 3D imaging, were

-Iff *I/T 1 Q OO oc

published. , , , - Before the introduction of CBCT, studies compared conventional panoramic radiography with computed tomography (CT). Results showed lower reliability of panoramic radiography for diagnosing incisor root resorption associated with impacted canines.33, 34 When looking at the CBCT devices, studies also found that CBCTs were more accurate than panoramic radiographs for detecting root resorption.15,16,19 In the study by Dudic et al.16, it was found that 'no resorption' was observed more in panoramic radiographs than in CBCT but mild resorption cases were observed more in CBCT, in agreement with the results of the present study.16

Results from another study by Alqerban et al.35 demonstrated that high image quality was important for detecting root resorption and the CBCT systems showed high accuracy in the detection of the severity of root resorption.35

The question related to the impaction risk of third molars (Q14) showed fair agreement (Fleiss' kappa 0.4, P < 0.0001). The reason might be the nature of the question that was rather subjective. Another reason might be the age of the patients included in this study. The mean age was approximately 13 years old, neither the jaws nor the third molars were fully developed, and for this reason, it was difficult to answer whether there was an impaction risk of the third molars. As a prediction, this resulted in fair agreement.

Although several studies have proven the additional values of the CBCT, a systematic review on the use of cone-beam computed tomography in orthodontics published in 2012 showed interesting findings.26 It was found that there is still limited evidence that CBCT offers better diagnostic potential or leads to an improved treatment planning and a more predictable or superior treatment outcome than conventional imaging modalities. Only some specific studies on airway diagnostics provide sound scientific data suggesting that CBCT use can have an added value.26 There is little evidence to support a role of CBCT in the initial orthodontic evaluation.

The present study did not aim to compare the superiority of any imaging modalities but was instead trying to evaluate whether both imaging modalities offer the essential information needed for an initial orthodontic diagnostic evaluation. The study did not aim to compare the observers' reply to the real case findings (clinical standard). Even though this could be regarded as a limitation, this study has demonstrated that the cone-beam computed tomography showed its ability to give all necessary information for initial orthodontic evaluation. With moderate agreement between 2D and 3D imaging modality, it suggested that the information gained from CBCTs might not be similar to the information usually gained from panoramic radiographs. When observing the detailed results, CBCT actually offered more in depth information of the patient's condition. Further studies should be performed on the accuracy of the radiographic findings, by comparing CBCT and panoramic radiography with a gold standard and to evaluate whether the differential findings using 2D vs 3D imaging modalities could influence treatment planning and treatment outcome in orthodontics. Radiation to the patients

The present study is a retrospective study and all images were acquired prior

to data collection. Both CBCT and panoramic images were referred by orthodontists with justified indications. As the radiation dose, received from the CBCTs, is strongly related to FOV size and also dependent on the exposure.13, 14 for children it is crucial that dental CBCT examinations should be fully justified over conventional X-ray imaging. New guidelines and recommendations on CBCT for dental and maxillofacial radiology are now available and should be followed.36 One recent published recommendations by the American Academy of Oral and Maxillofacial Radiology (AAOMR)37 stated that CBCT in orthodontic treatment should be justified on an individual basis, based on clinical presentation and the position statement should be periodically revised to reflect new evidence. A proper radiation regimen is highly recommended and it is emphasized to be able to keep the radiation dose to the patient as low as reasonably achievable (ALARA).

Conclusions

In this questionnaire-based study, moderate agreement on initial orthodontic evaluation was shown between CBCT images and panoramic radiographs. This does not mean that the information received from CBCT images is either incorrect or unreliable, but rather deviating from the information gained from panoramic radiographs. If a priori present, CBCT imaging has the potential to provide valuable diagnostic information for initial orthodontic evaluation and also add extra information for orthodontic treatment planning. Yet proper justification and ALARA should be meticulously followed.

Acknowledgments

The authors would like to thank Karoline Dreesen, Ellen Ghijselings, Sophie Carpentier, and Simon Poelmans for their hard work and contribution in the observation.

References

1. Numata H. Consideration of the parabolic radiography of the dental arch. J

Shimazu Stud. 1933;10:13.

2. Paatero Y. The use of a mobile source of light in radiography. Acta Radiol. 1948;29:221.

3. Paatero Y. A new tomographic method for radiographing curved outer surfaces. Acta Radiol. 1949;32:177.

4. Tronje G, Welander U, McDavid WD, Morris CR. Image distortion in rotational panoramic radiography. I. General considerations. Acta Radiol Diagn (Stockh). 1981;22:295-9.

5. Tronje G, Eliasson S, Julin P, Welander U. Image distortion in rotational panoramic radiography. II. Vertical distances. Acta Radiol Diagn (Stockh). 1981;22:449-55.

6. Tronje G, Welander U, McDavid WD, Morris CR. Image distortion in rotational panoramic radiography. III. Inclined objects. Acta Radiol Diagn (Stockh). 1981;22:585-92.

7 Wyatt DL, Farman AG, Orbell GM, Silveira AM, Scarfe WC. Accuracy of dimensional and angular measurements from panoramic and lateral oblique radiographs. Dentomaxillofac Radiol. 1995;24:225-31.

8. Mozzo P, Procacci C, Tacconi A, Martini PT, Andreis IA. A new volumetric CT machine for dental imaging based on the cone-beam technique: preliminary results. Eur Radiol. 1998;8:1558-64.

9. Loubele M, Bogaerts R, Van Dijck E, Pauwels R, Vanheusden S, Suetens P, et al. Comparison between effective radiation dose of CBCT and MSCT scanners for dentomaxillofacial applications. Eur J Radiol. 2009;71:461-8.

10. Proffit WR, Fields HW, Jr. , Sarver DM. Contemporary Orthodontics. 4th ed. St.Lois, MO: Mosby Elsevier: 2007.

11. Kau CH, Richmond S, Palomo JM, Hans MG. Three-dimensional cone beam computerized tomography in orthodontics. J Orthod. 2005;32:282-93.

12. Mah JK, Huang JC, Choo H. Practical applications of cone-beam computed tomography in orthodontics. Journal of the American Dental Association. 2010;141:7S-13S.

13. Pauwels R, Beinsberger J, Collaert B, Theodorakou C, Rogers J, Walker A, et al. Effective dose range for dental cone beam computed tomography scanners. Eur J Radiol. 2012;81:267-71.

14. Theodorakou C, Walker A, Horner K, Pauwels R, Bogaerts R, Jacobs R. Estimation of paediatric organ and effective doses from dental cone beam CT using anthropomorphic phantoms. Br J Radiol. 2012;85:153-60.

15. Alqerban A, Jacobs R, Souza PC, Willems G. In-vitro comparison of 2 cone-beam computed tomography systems and panoramic imaging for detecting simulated canine impaction-induced external root resorption in maxillary lateral incisors. Am J OrthodDentofacial Orthop. 2009;136:764 e1-11.

16. Dudic A, Giannopoulou C, Leuzinger M, Kiliaridis S. Detection of apical root resorption after orthodontic treatment by using panoramic radiography and cone-beam computed tomography of super-high resolution. Am J Orthod Dentofacial Orthop. 2009;135:434-7.

17. Haney E, Gansky SA, Lee JS, Johnson E, Maki K, Miller AJ, et al. Comparative analysis of traditional radiographs and cone-beam computed tomography volumetric images in the diagnosis and treatment planning of maxillary impacted canines. Am J Orthod Dentofacial Orthop. 2010;137:590-7.

18. Leuzinger M, Dudic A, Giannopoulou C, Kiliaridis S. Root-contact evaluation by panoramic radiography and cone-beam computed tomography of super-high resolution. Am J OrthodDentofacial Orthop. 2010;137:389-92.

19. Alqerban A, Jacobs R, Fieuws S, Willems G. Comparison of two cone beam computed tomographic systems versus panoramic imaging for localization of impacted maxillary canines and detection of root resorption. Eur J Orthod. 2011;33:93-102.

20. Botticelli S, Verna C, Cattaneo PM, Heidmann J, Melsen B. Two- versus three-dimensional imaging in subjects with unerupted maxillary canines. Eur J Orthod. 2011;33:344-9.

21. Bouwens DG, Cevidanes L, Ludlow JB, Phillips C. Comparison of mesiodistal root angulation with posttreatment panoramic radiographs and cone-beam computed tomography. Am J Orthod Dentofacial Orthop. 2011;139:126-32.

22. Ghaeminia H, Meijer GJ, Soehardi A, Borstlap WA, Mulder J, Vlijmen OJ, et al. The use of cone beam CT for the removal of wisdom teeth changes the surgical approach compared with panoramic radiography: a pilot study. Int J Oral Maxillofac Surg. 2011;40:834-9.

23. Anthonappa RP, King NM, Rabie AB, Mallineni SK. Reliability of panoramic radiographs for identifying supernumerary teeth in children. Int J Paediatr Dent. 2012;22:37-43.

24. Neves FS, Souza TC, Almeida SM, Haiter-Neto F, Freitas DQ, Boscolo FN. Correlation of panoramic radiography and cone beam CT findings in the assessment of the relationship between impacted mandibular third molars and the mandibular canal. Dentomaxillofac Radiol. 2012;41:553-7.

25. Pittayapat P, Galiti D, Huang Y, Dreesen K, Schreurs M, Souza PC, et al. An in vitro comparison of subjective image quality of panoramic views acquired via 2D or 3D imaging. Clin Oral Investig. 2013;17:293-300.

26. van Vlijmen OJ, Kuijpers MA, Berge SJ, Schols JG, Maal TJ, Breuning H, et al. Evidence supporting the use of cone-beam computed tomography in orthodontics. J Am Dent Assoc. 2012;143:241-52.

27. Liu DG, Zhang WL, Zhang ZY, Wu YT, Ma XC. Localization of impacted maxillary canines and observation of adjacent incisor resorption with cone-beam computed tomography. Oral Surg Oral Med Oral Pathol Oral Radiol Endod. 2008;105:91-8.

28. Walker L, Enciso R, Mah J. Three-dimensional localization of maxillary canines with cone-beam computed tomography. Am J Orthod Dentofacial Orthop. 2005;128:418-23.

29. Ericson S, Kurol J. Resorption of maxillary lateral incisors caused by ectopic eruption of the canines. A clinical and radiographic analysis of predisposing factors. Am J Orthod Dentofacial Orthop. 1988;94:503-13.

30. Ericson S, Kurol J. Radiographic examination of ectopically erupting maxillary canines. Am J Orthod Dentofacial Orthop. 1987;91:483-92.

31. Landis JR, Koch GG. The measurement of observer agreement for categorical data. Biometrics. 1977;33:159-74.

32. Peck JL, Sameshima GT, Miller A, Worth P, Hatcher DC. Mesiodistal root angulation using panoramic and cone beam CT. Angle Orthod. 2007;77:206-13.

33. Schmuth GP, Freisfeld M, Köster O, Schüller H. The application of computerized tomography (CT) in cases of impacted maxillary canines. Eur J Orthod. 1992;14:296-301.

34. Freisfeld M, Dahl IA, Jäger A, Drescher D, Schüller H. X-ray diagnosis of impacted upper canines in panoramic radiographs and computed tomographs. J Orofac Orthop. 1999;60:177-84.

35. Alqerban A, Jacobs R, Fieuws S, Nackaerts O; SEDENTEXCT Project Consortium, Willems G. Comparison of 6 cone-beam computed tomography systems for image quality and detection of simulated canine impaction-induced external root resorption in maxillary lateral incisors. Am J Orthod Dentofacial Orthop. 2011;140:e129-39.

36. European, Commission. Guidelines on CBCT for Dental and Maxillofacial Radiology: Evidence Based Guidelines. Radiation Protection Publication 2012

37. American Academy of Oral and Maxillofacial Radiology. Clinical recommendations regarding use of cone beam computed tomography in orthodontics. Position statement by the American Academy of Oral and Maxillofacial Radiology. Oral Surg Oral Med Oral Pathol Oral Radiol. 2013;116: 238-57.

Figures and tables legends

Table I. Questions related to the initial orthodontic evaluation, answered by the observers

Table II. Agreement between group 1 panoramic and group 2 CBCT per question for all observers and frequency of all answers in percentage with standard error (SE)

*M midline

Fig. 1. Panoramic radiograph of a 10-year-old male subject from group 1, displayed as TIFF file

Fig. 2. The CBCT image of the same patient as in Figure 1, viewed on the OnDemand3D® software. During the observation, the observers could view the entire CBCT volume in axial, coronal and sagittal slices and could potentially draw a panoramic curve to create a reformatted panoramic view as shown in this figure. The thickness of reformatted panoramic views could be adjusted. This figure is showing a reformatted panoramic view with 20 mm thickness.

Fig. 3. The angular measurement performed in Question 11 (Q11) on a panoramic radiograph (A) and on a CBCT image (B). The angle was formed by a line on the midline bisecting the jaw in two and a line through the cusp and the apex bisecting the canine along its long axis.

Statement of Clinical relevance

Although CBCTs still cannot replace panoramic radiographs, the present study might suggest eliminating the need for a further panoramic image, if a recent CBCT scan of both jaws is already available.

Table I. Questions related to the initial orthodontic evaluation, answered by the observers

Questions Description Answers

Q1 Are all permanent teeth present? All permanent teeth including both teeth and tooth buds. 1 Yes/ 2 No/ 3 Unidentified

Q2 Is the sequence of eruption in upper The same sequence of eruption applied for both left and 1 Yes/ 2 No/ 3 Unidentified

left and upper right side symmetrical? right side of the upper jaw or not. Q3 Is the sequence of eruption in lower The same sequence of eruption is applied for both left 1 Yes/ 2 No/ 3 Unidentified

left and lower right side symmetrical? and right side of the lower jaw or not. Q4 Is the anterior apical area (root The space in the area between the mesial surface of the 1 Yes/ 2 Reduced/

spacing) optimal? upper right and left canines is adequate for normal 3 Severe/ 4 Unidentified

eruption or not.

Yes - The space is optimal and adequate. Reduced - The space is slightly reduced. This will determine the treatment plan to gain more space. Severe - The space is severely reduced. This will determine the treatment plan to gain more space and whether there is a need for tooth extraction. Q5 Is the middle apical area (root The space in the area from the mesial surface of the 1 Yes/ 2 Reduced/

spacing) optimal?

Q6 Is the posterior apical area (root spacing) optimal?

Q7 Is the path of eruption of #13 optimal?

Q8 Is the path of eruption of #23 optimal?

Q9 Is there impaction risk of #13 and

upper canine to the mesial surface of the first molar is 3 Severe/ 4 Unidentified adequate for normal eruption or not. The answers are as in Q4.

The space in the area from the mesial surface of the 1 Yes/ 2 Reduced/ upper first molar to the distal surface of the upper third 3 Severe/ 4 Unidentified molar is adequate for normal eruption or not. The answers are as in Q4.

The optimal path of eruption is when the upper canine 1 Yes/ 2 No/ 3 Unidentified replaces the primary canine vertically without deviating to the mesial or distal side.

The optimal path of eruption is when the upper canine 1 Yes/ 2 No/ 3 Unidentified replaces the primary canine vertically without deviating to the mesial or distal side.

Impaction is defined as a suboptimal path of eruption, 1 Yes/ 2 No/ 3 Unidentified the canine has not erupted when the dental age is more than 13 years old, complete canine root formation without eruption, or insufficient mesio-distal space.

Q10 Can the upper right canine (#13) be Localization of the upper right canine in relation to the 1 Buccal/ 2 Middle/

localized? dental arch. 3 Palatal/ 4 Unidentified

Q11 What is the angulation of upper right The angle is formed by a line on the midline bisecting 1 Category A: 0-22.5° to canine (#13) to the midline? the jaw in two and a line through the cusp and the apex the midline

bisecting the canine along its long axis (Figure 3).19,27-30 2 Category B: 22.6-45.0°

to the midline

3 Category C: 45.1-67.5° to the midline

4 Category D: 67.6-90.0° to the midline

Q12 Is there pathological root resorption Detection of a resorption defect on the upper right 1 Yes/ 2 No/ 3 Unidentified at the upper right lateral incisor lateral incisor root. (#12)?

Q13 Is there impaction risk of premolar The impaction risk is classified when: the path of 1 Yes/ 2 No/ 3 Unidentified and molars? eruption is not optimal, complete root formation without

eruption, insufficient mesio-distal space.

Q14 Is there impaction risk of third The impaction risk is classified when: the path of 1 Yes/ 2 No/ 3 Unidentified

molars? eruption is not optimal, complete root formation without

eruption, insufficient mesio-distal space.

Table II. Agreement between group 1 panoramic and group 2 CBCT per question for all observers and frequency of all answers in percentage with standard error (SE)

Fleiss' Image % Answer 1, % Answer 2, % Answer 3, % Answer 4,

P-value

kappa modality (SE) (SE) (SE) (SE)

Q1 Are all permanent teeth present?

0.6 <0.0001 Panoramic 55.6, (1.2)

54.3, (1.3)

No 39.1, (1.0)

44.7, (1.1)

Unidentified 5.3, (0.4)

1.0, (0.2)

Q2 Is the sequence of eruption of upper Left and 0.6 <0.0001 Panoramic 46.7, (1.2)

upper Right side symmetrical?

39.8, (1.3)

32.9, (1.0) 43.8,(1.2)

20.4, (0.8) 16.4, (0.8)

Q3 Is the sequence of eruption of lower Left and 0.6 <0.0001 Panoramic

lower Right side symmetrical?

53.0, (1.2) 48.7, (1.3)

16.4, (0.8) 19.7, (0.9)

30.6, (1.0) 31.6, (1.0)

Q4 Is the anterior apical area of the upper jaw 0.3 <0.0001 Panoramic 58.5, (2.8)

optimal?

71.1, (2.6)

Reduced 31.9, (3.4)

23.0, (3.3)

Severe 8.9, (2.6)

4.9, (2.0)

Unidentified 0.7, (0.8)

1.0, (1.0)

Q5 Is the middle apical area of the upper jaw optimal?

0.2 <0.0001 Panoramic 48.4, (2.9)

74.7, (2.5)

36.8, (3.4) 24.0, (3.5)

11.8, (2.8) 1.0, (1.0)

3.0, (1.7) 0.3, (0.6)

Q6 Is the posterior apical area of the upper jaw 0.4 <0.0001 Panoramic 31.2, (2.7)

45.7, (3.2)

16.5, (3.1)

6.6, (2.3)

optimal?

37.5, (2.8)

49.7, (3.3)

9.9, (2.7)

2.9, (1.7)

Q7 Is the path of eruption of #13 optimal?

Q8 Is the path of eruption of #23 optimal?

Q9 Is there impaction risk of #13 and #23?

0.4 <0.0001 Panoramic CBCT

Yes 56.9, (1.2)

43.4, (1.3)

0.6 <0.0001 Panoramic 40.8, (1.2)

47.0, (1.3)

0.5 <0.0001 Panoramic 76.0, (1.0)

72.7, (1.1)

34.2, (1.0)

48.0, (1.2)

52.3, (1.1)

46.4, (1.2)

20.7, (0.8) 25.0,(1.0)

Unidentified 8.9, (0.6)

8.6, (0.6)

6.9, (0.5) 6.6, (0.5)

3.3, (0.4) 2.3, (0.3)

Q10 Can #13 be localized?

0.2 <0.0001 Panoramic CBCT

Buccal 4.9, (1.2)

15.8, (2.1)

Middle 51.3, (2.9)

59.5, (3.0)

Palatal 16.1, (2.7)

24.7, (3.5)

Unidentified 27.7, (3.6)

0.0, (0.0)

Q11 What is the angulation of #13 to the midline? 0.3 <0.0001 Panoramic

0-22.5° to M 22.6-45.0° to M 45.1-67.5° to M 67.6-90.0° to M*

79.0, (2.3)

68.1, (2.7)

17.4, (3.2) 25.3, (3.4)

3.6, (1.8) 6.3, (2.3)

0.0, (0.0) 0.3, (0.6)

Q12 Is there any pathological root resorption at

0.3 <0.0001 Panoramic

Yes 10.5, (1.8)

No 65.5, (2.8)

Unidentified 24.0, (3.5)

Q13 Is there impaction risk of premolar and 0.5 molars?

Q14 Is there impaction risk of third molars? 0.4

*M midline

<0.0001

<0.0001

Panoramic CBCT

Panoramic CBCT

10.9, (1.8)

28.6, (1.1) 20.4, (1.0)

67.8. (2.7)

61.9, (2.8)

81.9, (2.3)

67.8, (1.0) 76.3, (1.0)

9.8. (2.3) 12.8, (2.5)

7.2, (2.4)

3.6, (0.4)

3.3, (0.4)

22.4. (3.5) 25.3,(3.5)