The impact of Cone Beam CT on financial costs and orthodontists’ treatment decisions in the management of maxillary canines with eruption disturbance

The impact of Cone Beam CT on financial costs and orthodontists’ treatment decisions in the... Summary Background Examination with Cone Beam CT (CBCT) is common for localizing maxillary canines with eruption disturbance. The benefits and costs of these examinations are unclear. Objectives To measure: 1. the proportion of orthodontists’ treatment decisions that were different based on intraoral and panoramic radiography (M1) compared with CBCT and panoramic radiography (M2); and 2. the costs of producing different treatment plans, regarding patients with maxillary canines with eruption disturbance. Subjects and methods Orthodontists participated in a web-based survey and were randomly assigned to denote treatment decisions and the level of confidence in this decision for four patient cases presented with M1 or M2 at two occasions for the same patient case. Results One hundred and twelve orthodontists made 445 assessments based on M1 and M2, respectively. Twenty-four per cent of the treatment decisions were different depending on which method the raters had access to, whereof one case differed significantly from all other cases. The mean total cost per examination was €99.84 using M1 and €134.37 using M2, resulting in an incremental cost per examination of €34.53 for M2. Limitations Benefits in terms of number of different treatment decisions must be considered as an intermediate outcome for the effectiveness of a diagnostic method and should be interpreted with caution. Conclusions For the patient cases presented in this study, most treatment decisions were the same irrespective of radiological method. Accordingly, this study does not support routine use of CBCT regarding patients with maxillary canine with eruption disturbance. Introduction After the third molar, the maxillary canine is the tooth most often affected by eruption disturbance impaction, with a prevalence of between 0.9 and 3.0 per cent (1–3). If left untreated, maxillary canines with eruption disturbance can cause root resorption on neighbouring teeth, notably lateral incisors, with a prevalence of between 7.7 and 67.6 per cent (4–6). Root resorption occurs when the predentin or precementum becomes mineralized or, in case of the precementum, is mechanically damaged or scraped off (7), which can be the case when an ectopically erupting or retained maxillary canine is present (8). Consequently, patients with this condition frequently receive orthodontic treatment with a range of treatment options being available. The decision on management for these patients requires adequate understanding of the position of the canine and its relation to the rest of the dentition. Such information can only be comprehensively obtained by radiographic imaging. Maxillary canines with eruption disturbance is mostly detected and treated in younger individuals and, as risk from radiation exposure is higher in this age group, it is particularly important that the radiographic examination is justified (9). Localisation of maxillary canines with eruption disturbance and detection of root resorption of teeth adjacent to the canine is a common indication for examination with Cone Beam Computed Tomography (CBCT) (10,11). This imaging method is, however, associated with a higher cost (12,13) and involves a higher radiation dose than conventional imaging techniques (14,15), which may include panoramic, cephalometric, occlusal, and periapical radiographs. These imaging methods have limitations due to two-dimensionality, superimposition of anatomy, and image distortion. Many of these problems were overcome with the introduction of CBCT. Regarding maxillary canines with eruption disturbance some previous studies found that the use of CBCT led to significantly different treatment plans (16,17) whereas other studies showed no such significant differences (18,19), compared with conventional radiography. In the SEDENTEXCT guidelines for evidence based use of CBCT, it was concluded that there was no strong evidence to support using CBCT as the ‘first line’ imaging method in the context of root resorption diagnosis (14). Currently, there is no available evidence on cost-effectiveness of CBCT imaging of patients with maxillary canines with eruption disturbance. With increasing demands on decision makers to allocate resources efficiently in ways that produce most health gain for available health care technologies (20), this knowledge gap is problematic. Hence, there is a need for well-designed comprehensive studies on the possible benefits of CBCT examinations and their relation to the associated costs. Therefore, the aim of this study was to measure: 1. the proportion of orthodontists who denoted a different treatment decision based on intraoral and panoramic radiography compared with CBCT and panoramic radiography and 2. the costs of producing different treatment plans, regarding patients with maxillary canines with eruption disturbance. Subjects and methods A web-based survey for specialists in orthodontics was constructed in association with a web developer. Invitations to participate were sent by e-mail to all members of the Swedish Orthodontic Society (n = 314) according to the society’s membership directory, with the intention to reach specialists in orthodontics who had at minimum of 1 year experience in treating orthodontic patients. Patient cases Twelve different patient cases, describing patients with unilateral eruption disturbance of the maxillary canine with otherwise no, or minor, need for orthodontic treatment, were constructed and included in the survey (Table 1). Each case was based on the following characteristics: A subjective treatment need One maxillary canine with eruption disturbance and no likelihood for spontaneous eruption A complete permanent dentition including the second molars Normal sagittal molar relation (Class I) Normal skeletal relations between the maxilla and the mandible Cephalometric analysis showed normal maxillary incisor inclination No subjective need for correction of the maxillary dental midline Good oral hygiene Table 1. Characteristics of the 12 patient cases included in the survey. Case  Age  Gender  Canine  Space deficiency in the maxilla  Centre line displacement in the maxilla  Angulation of the canine to the midline  Overlap of the canine with adjacent incisor/ -s  1  14  M  13  Small <4mm  1–2 mm to the right  40°  Lateral  2  13  M  13  Severe >8mm  2 mm to the right  40°  ½ central  3  13  F  23  No  —  40°  Lateral  4  13  F  23  No  —  53°  Lateral  5  13  M  13  No  —  42°  Central  6  14  M  23  No  —  62°  Central  7  14  M  23  Small <4mm  1 mm to the left  11°  No  8  13  F  13  No  —  30°  ½ central  9  13  F  23  No  —  56°  ½ lateral  10  13  F  23  Severe >8mm  —  38°  ½ central  11  14  F  23  Small <4mm  1–2 mm to the right  21°  ½ lateral  12  14  F  23  Small <4mm  —  38°  Lateral  Case  Age  Gender  Canine  Space deficiency in the maxilla  Centre line displacement in the maxilla  Angulation of the canine to the midline  Overlap of the canine with adjacent incisor/ -s  1  14  M  13  Small <4mm  1–2 mm to the right  40°  Lateral  2  13  M  13  Severe >8mm  2 mm to the right  40°  ½ central  3  13  F  23  No  —  40°  Lateral  4  13  F  23  No  —  53°  Lateral  5  13  M  13  No  —  42°  Central  6  14  M  23  No  —  62°  Central  7  14  M  23  Small <4mm  1 mm to the left  11°  No  8  13  F  13  No  —  30°  ½ central  9  13  F  23  No  —  56°  ½ lateral  10  13  F  23  Severe >8mm  —  38°  ½ central  11  14  F  23  Small <4mm  1–2 mm to the right  21°  ½ lateral  12  14  F  23  Small <4mm  —  38°  Lateral  Assessment of space deficiency in the maxilla, centre line displacement, angulation of the canine to the midline and the overlap of the canine in relation to the adjacent incisor(s) was based on the panoramic radiographs. M, male; F, female. View Large Individual parameters that varied between the cases: age, gender, left or right maxillary canine with eruption disturbance, and any maxillary centreline displacement, are presented in Table 1. In 10 of the cases, the space deficiency was less than 4 mm in the maxilla indicating no need for tooth extractions. For two cases, the space deficiency was at least 8 mm expressing an obvious need for tooth extractions. The assessment of space deficiency and centre line displacement was based on the panoramic radiographs. To do these assessments based on panoramic radiographs is not normal practice but was considered to have small impact on the exercise of this study. The cases were presented with two intraoral periapical radiographs obtained at different horizontal angles, panoramic radiographs, and CBCT images (see examples in Figure 1) as well as a written report describing the position of the maxillary canine, the distance of the canine crown in relation to the marginal bone, root morphology and any resorption of teeth neighbouring the maxillary canine. Intraoral and panoramic radiographs as well as CBCT-images from patients already examined in a previous study (12) were reviewed, and images from all patients with unilateral eruption disturbance of the maxillary canine with otherwise no, or minor, need for orthodontic treatment were included in present study. One of the authors (CL) a specialist in oral- and maxillofacial radiology assessed the radiographs and wrote the reports. The reports for intraoral and panoramic radiographs were written at one occasion and 1–2 weeks after, the reports on panoramic and CBCT images were written, without knowledge of the first report (Table 2). Figure 1. View largeDownload slide Examples of the radiographs presented in the survey for two of the 12 patient cases. Figure 1. View largeDownload slide Examples of the radiographs presented in the survey for two of the 12 patient cases. Table 2. Report based on images from the 12 patient cases using intraoral and panoramic radiography (M1) or CBCT and panoramic radiography (M2). Case  Horizontal position of the canine  Bucco-palatal position of the canine  Vertical level of the canine crown-tip - distance from the bone crest  Dilaceration of the canine root  Resorption of teeth adjacent to the canine  M1  M2  M1  M2  M1  M2  M1  M2  M1  M2  1  Mesioangular  Mesioangular  Palatal  Palatal  Broken through marginal bone  Broken through marginal bone  No  No  No  No  2  Mesioangular  Mesioangular  Palatal  Palatal  In level with marginal bone  In level with marginal bone  No  No  No  Slight  3  Mesioangular  Mesioangular  Palatal  Palatal  3 mm  1 mm  No  No  No  Slight  4  Mesioangular  Mesioangular  Palatal  Palatal  3 mm  1 mm  No  Mesially in the apical part  No  Slight  5  Mesioangular  Mesioangular  Palatal  Palatal  2 mm  Broken through marginal bone  No  No  No  No  6  Mesioangular  Mesioangular  Palatal  Palatal  10 mm  8 mm  Superiorly in the apical part  Superiorly in the apical part  No  Slight  7  Vertical  Vertical  Central  Central  In level with marginal bone  In level with marginal bone  No  No  No  Slight  8  Mesioangular  Mesioangular  Palatal  Palatal  3 mm  1 mm  No  No  No  No  9  Mesioangular  Mesioangular  Palatal  Palatal  5 mm  3 mm  No  No  Probably severe  Severe  10  Mesioangular  Mesioangular  Palatal  Palatal  5 mm  2 mm  No  No  No  Moderate  11  Vertical  Vertical  Central  Central  3 mm  1 mm  Mesial direction in the apical part  Buccal direction in the apical part  No  No  12  Mesioangular  Mesioangular  Palatal  Palatal  1 mm  Broken through marginal bone  Mesially along the entire root  Mesially along the entire root  No  No  Case  Horizontal position of the canine  Bucco-palatal position of the canine  Vertical level of the canine crown-tip - distance from the bone crest  Dilaceration of the canine root  Resorption of teeth adjacent to the canine  M1  M2  M1  M2  M1  M2  M1  M2  M1  M2  1  Mesioangular  Mesioangular  Palatal  Palatal  Broken through marginal bone  Broken through marginal bone  No  No  No  No  2  Mesioangular  Mesioangular  Palatal  Palatal  In level with marginal bone  In level with marginal bone  No  No  No  Slight  3  Mesioangular  Mesioangular  Palatal  Palatal  3 mm  1 mm  No  No  No  Slight  4  Mesioangular  Mesioangular  Palatal  Palatal  3 mm  1 mm  No  Mesially in the apical part  No  Slight  5  Mesioangular  Mesioangular  Palatal  Palatal  2 mm  Broken through marginal bone  No  No  No  No  6  Mesioangular  Mesioangular  Palatal  Palatal  10 mm  8 mm  Superiorly in the apical part  Superiorly in the apical part  No  Slight  7  Vertical  Vertical  Central  Central  In level with marginal bone  In level with marginal bone  No  No  No  Slight  8  Mesioangular  Mesioangular  Palatal  Palatal  3 mm  1 mm  No  No  No  No  9  Mesioangular  Mesioangular  Palatal  Palatal  5 mm  3 mm  No  No  Probably severe  Severe  10  Mesioangular  Mesioangular  Palatal  Palatal  5 mm  2 mm  No  No  No  Moderate  11  Vertical  Vertical  Central  Central  3 mm  1 mm  Mesial direction in the apical part  Buccal direction in the apical part  No  No  12  Mesioangular  Mesioangular  Palatal  Palatal  1 mm  Broken through marginal bone  Mesially along the entire root  Mesially along the entire root  No  No  Estimation of the amount of resorption was based on the index suggested by Ericson and Kurol (21). View Large Web-based survey Informed consent to participate in the study was obtained from all orthodontists. Those that agreed to participate received an e-mail with a link to the first part of the online survey. After a further 2 weeks, they received another e-mail with a link to the second part of the survey. Each orthodontist was randomly assigned to four of the 12 patient cases by the use of digital random function allocating randomized combinations of sequences of four cases with either intraoral and panoramic radiographs or CBCT and panoramic radiographs. Each orthodontist was presented with only four of the 12 cases as this strategy was believed to increase the response-rate. In the first part of the survey, two patient cases were presented with intraoral and panoramic radiographs (Method 1 = M1) and two patient cases were presented with CBCT images and panoramic radiographs (Method 2 = M2). In the second part of the survey, there was a switch in the presentation of images which meant that the same patient case was presented with the other imaging methods. To estimate intrarater agreement, 30 of the 112 orthodontists were randomly assigned to answer the survey a third time with the same imaging methods as the first occasion for the same patient case. The orthodontists were asked about their age, gender, and years of experience. They were also asked to make a treatment decision for the four cases they were assigned by selecting one of following alternatives: 1. no treatment, 2. nonextraction orthodontic treatment, 3. orthodontic treatment including extraction of the first premolar, 4. orthodontic treatment including extraction of the maxillary lateral incisor, and 5. orthodontic treatment including extraction of the maxillary canine with eruption disturbance. In addition, the orthodontists had to denote the level of confidence in their decision on a five-point scale: 1. very confident, 2. fairly confident, 3. neither confident—nor unconfident, 4. fairly unconfident, or 5. very unconfident. The viewer program for the CBCT images (i-Dixel One Data Viewer Plus software, J. Morita®, Kyoto, Japan) was available in the online survey enabling the orthodontists to view all CBCT images in all planes (the axial, coronal, and sagittal) dynamically by scrolling through the consecutive orthogonal image stack (Figure 2). The CBCT images and the viewer program as well as the responses of the orthodontists were stored on a remote server. The responses were downloaded onto a personal computer for analysis. Figure 2. View largeDownload slide Image of the viewer program for the CBCT images (i-Dixel One Data Viewer Plus software, J. Morita®, Kyoto, Japan) available in the survey enabling the orthodontists to view all CBCT images in three planes dynamically by scrolling through the consecutive orthogonal image stack. Figure 2. View largeDownload slide Image of the viewer program for the CBCT images (i-Dixel One Data Viewer Plus software, J. Morita®, Kyoto, Japan) available in the survey enabling the orthodontists to view all CBCT images in three planes dynamically by scrolling through the consecutive orthogonal image stack. The survey started in May 2016 and continued until November 2016. The original e-mail invitation to participate was followed by four reminder e-mails sent via MailChimp® (The Rocket Science Group, Atlanta, US). Some respondents informed us that the e-mails were classified as having low priority, therefore an additional one to four ordinary e-mails were sent (not using MailChimp®). Finally, an attempt was made to contact all non-responders by telephone. Prior to full implementation of the study, an evaluation group of three orthodontists, one specialist in periodontology, one trainee in dental and maxillofacial radiology and one external web-developer evaluated the online survey and the associated survey procedures with respect to entering the survey via a link, filling in and saving the answers as well as down-loading and viewing the CBCT-images. The orthodontists in the evaluation group also evaluated the relevance of the cases and were not included as subjects in the study. Cost-analysis Costing for the radiological methods M1 and M2 was based on the framework for cost-analysis as previously reported (12) with unit costs updated to 2014 (Table 3). Table 3. Distribution of direct costs per examination based on CBCT and panoramic radiography (M2) compared with intraoral and panoramic radiography (M1). Identified direct costs  Cost per examination  M2  M1  Incremental cost for M2  Provider-related costs   Capital costs  Equipment  24.42  6.48  17.94  Maintenance  4.96  0.83  4.13   Rental costs  Accommodation  10.78  6.28  4.50  Image archive patient record  4.01  2.90  1.11   Labour costs  Specialist  7.31  5.17  2.14  Dental nurse  26.75  23.18  3.57   Total provider-related costs  78.23  44.84  33.39  Patient-related costs   Cost for time spent on:  Transport  28.98  28.98  —  Waiting  7.63  7.63  —  Examination  9.02  7.88  1.14   ‘Out of pocket’ cost  Cost per km, parking  10.51  10.51  —   Total patient-related costs  56.14  55.00  1.14   Total costs from a societal view  134.37  99.83  34.54   Total cost including opportunity cost and cost for equipment depreciation using 3% rate  138.74  101.41  37.33   Total cost including opportunity cost and cost for equipment depreciation using 5% rate  141.86  102.57  39.29  Identified direct costs  Cost per examination  M2  M1  Incremental cost for M2  Provider-related costs   Capital costs  Equipment  24.42  6.48  17.94  Maintenance  4.96  0.83  4.13   Rental costs  Accommodation  10.78  6.28  4.50  Image archive patient record  4.01  2.90  1.11   Labour costs  Specialist  7.31  5.17  2.14  Dental nurse  26.75  23.18  3.57   Total provider-related costs  78.23  44.84  33.39  Patient-related costs   Cost for time spent on:  Transport  28.98  28.98  —  Waiting  7.63  7.63  —  Examination  9.02  7.88  1.14   ‘Out of pocket’ cost  Cost per km, parking  10.51  10.51  —   Total patient-related costs  56.14  55.00  1.14   Total costs from a societal view  134.37  99.83  34.54   Total cost including opportunity cost and cost for equipment depreciation using 3% rate  138.74  101.41  37.33   Total cost including opportunity cost and cost for equipment depreciation using 5% rate  141.86  102.57  39.29  Cost to the provider is presented with no opportunity cost or cost for depreciation as well as with opportunity cost and cost for equipment depreciation using 3 and 5% rate. Costs were estimated using 2014 prices (Euro). View Large Radiography The radiographic equipment used for CBCT was 3D Accuitomo (Morita®, Kyoto, Japan) (90 kV, 5–6.5 mA, 1/ 2PI, 9/ 17.5 second, 4 × 4 cm field of view (FOV)) and Verawiew epocs (Morita®, Kyoto, Japan) (80 kv, 5 mA, IPI, 9.4 second, 4 × 4 cm FOV), for panoramic radiography Planmeca Pro Max (Planmeca® Helsinki, Finland) (72 kV, 16 mA, 17 second, MAG 1.2) and Verawiew epocs (Morita®, Kyoto, Japan) (65 kv, 5 mA, IPI, 6.5 second, MAG 1.2), and for intraoral radiography Planmeca Intra (Planmeca®, Helsinki, Finland) (60 kV, 8 mA, 0.10–0.20 second). Statistical analyses Intrarater agreement for treatment decisions based on observations of the same patient case using the same imaging methods was estimated in terms of percent agreement per patient case. Kappa statistics (κ) (22) and percent agreement was used to analyse the treatment decision under the different imaging methods. Fisher’s Exact Test was used to compare treatment decisions and associated confidence levels when using the different imaging methods. IBM SPSS Statistics (Version 23, Chicago, Illinois, USA) was used for all calculations. Statistical significance was set at a P value less than 0.01. Radiographs and CBCT scans included in the survey were anonymised and the responses from orthodontists were recorded anonymously, using a study code number for each orthodontist. The study was conducted in accordance with the ethical principles of the World Medical Association Declaration of Helsinki (2008 version) and approved by the Regional Ethical Review Board, Lund, Sweden (H15606/2008). Results Three hundred and fourteen members of the Swedish Orthodontic society were invited to participate in the study. Ninety-three orthodontists were excluded due to following reasons: not active as orthodontist (n = 30) orthodontic resident (n = 20) not working in Sweden (n = 17) insufficient contact information (n = 10) on parental or sick leave (n = 9) not working with this patient group (n = 7) Of the remaining 221 orthodontists, participation was accepted by 154. Responses from 42 orthodontists could not be used due to the following reasons: 1. only answered one part of the survey (n = 17), 2. no response after four reminders (n = 12), 3. could not open the CBCT files/survey (n = 7), 4. could not save the answers (n = 3), 5. did not approve of the study design (n = 2), and 6. other reasons (n = 1). Downloading and opening the CBCT images, save the answers or open the survey were problematic for some of the orthodontists and this was according to the web-developer due to local factors like the internet connection and virus programmes. Some of the orthodontists that had these problems received the CBCT-images on a USB-memory and a Word-document to fill in their questions. When the survey closed, 112 orthodontists had answered both parts of the survey with altogether 445 assessments based on M1 and M2, respectively, for the same patient case. Of the 112 participants, 64 (57.1 per cent) were women and 48 (42.9 per cent) were men, 88 (78.6 per cent) worked in a public dental clinic, 22 (19.6 per cent) in private practice, and 2 (1.8 per cent) were university employees. The highest number of participants were found in the age group 36–45, as well as among participants having 1–10 years of experience (Table 4). Table 4. Characteristics of orthodontists (n = 112) that answered the survey at two occasions. Gender   Women  64 (57.1%)   Men  48 (42.9%)  Working place   Public dental clinic  88 (78.6%)   Private practice  22 (19.6%)   University  2 (1.8%)  Age (years)   25–35  7 (6.3%)   36–45  39 (34.8%)   46–55  23 (20.5%)   56–65  33 (29.5%)   >65  10 (8.9%)  Years of practice   1–10  49 (43.8%)   11–20  38 (33.9%)   21–30  13 (11.6%)   31–40  10 (8.9%)   >40  2 (1.8%)  Gender   Women  64 (57.1%)   Men  48 (42.9%)  Working place   Public dental clinic  88 (78.6%)   Private practice  22 (19.6%)   University  2 (1.8%)  Age (years)   25–35  7 (6.3%)   36–45  39 (34.8%)   46–55  23 (20.5%)   56–65  33 (29.5%)   >65  10 (8.9%)  Years of practice   1–10  49 (43.8%)   11–20  38 (33.9%)   21–30  13 (11.6%)   31–40  10 (8.9%)   >40  2 (1.8%)  View Large Intrarater agreement based on 30 orthodontist’s assessments regarding the choice of treatment varied from 50 to 100 per cent using M1 with the lowest level of agreement being for case 10. Full agreement was observed for eight cases (case 2, 3, 4, 5, 8, 9, 11, and 12). Based on M2, the agreement varied between 0 per cent (case 11) and 100 per cent for seven cases (case 1, 2, 3, 4, 5, 8, and 12). The number of assessments varied from 3 to 7 per case with 60 assessments per radiographic method. Comparison between imaging methods The number of assessments per case varied between 31 and 44 (Table 5). Treatment decisions showed a variability in agreement from 100 per cent (case 1) to 12.8 per cent (case 10) (Table 5). κ-values also varied from 1.0 (case 1) to −0.053 (case 4). For two cases (case 3 and 8), no κ-value could be calculated as the same treatment alternatives were chosen by all raters but one (Table 5). The most frequent treatment decision was orthodontic treatment not including extraction of any of the teeth, chosen in 66 per cent of the assessments based on M1, and in 64 per cent of the assessments based on M2 (Figure 3). Overall, 107 of 445 (24 per cent) treatment decisions were different when based on M2 instead of M1 and case 10 differed statistically significant from all other cases (Figure 4). For case 10, 87.2 per cent (34 of 39) treatment decisions were different depending on which imaging method the orthodontists had access to (Table 5). Table 5. Agreement between imaging methods, intraoral and panoramic radiography (M1) and CBCT and panoramic radiography (M2), regarding treatment alternatives chosen when having access to either M1 or M2 at two different occasions for the same patient case, presented as κ-values and percent agreement (%) for the number of assessments per case (n). Patient case  κ-value  Agreement between M1 and M2 (%)  Number of assessment per patent case (n)  1  1  100  35  2  0.323  64.7  34  3  —  97.0  33  4  −0.053  86.1  36  5  0.479  94.6  37  6  0.632  83.9  31  7  0.253  63.4  41  8  —  97.7  44  9  0.273  69.8  43  10  0.018  12.8  39  11  0.314  66.7  36  12  0.339  80.6  36  Patient case  κ-value  Agreement between M1 and M2 (%)  Number of assessment per patent case (n)  1  1  100  35  2  0.323  64.7  34  3  —  97.0  33  4  −0.053  86.1  36  5  0.479  94.6  37  6  0.632  83.9  31  7  0.253  63.4  41  8  —  97.7  44  9  0.273  69.8  43  10  0.018  12.8  39  11  0.314  66.7  36  12  0.339  80.6  36  View Large Figure 3. View largeDownload slide Number of treatment decisions (%) per patient case based on altogether 445 assessments using either intraoral and panoramic radiography (M1) or CBCT and panoramic radiography (M2) at two occasions for the same patient cases, distributed per case (1 to 12). Figure 3. View largeDownload slide Number of treatment decisions (%) per patient case based on altogether 445 assessments using either intraoral and panoramic radiography (M1) or CBCT and panoramic radiography (M2) at two occasions for the same patient cases, distributed per case (1 to 12). Figure 4. View largeDownload slide Number of treatment decisions (%) per patient case by 112 orthodontists based on either intraoral and panoramic radiography (M1) or CBCT and panoramic radiography (M2) at two occasions for the same patient cases. The difference between case 10 and all other cases was significant (P < 0.01). Figure 4. View largeDownload slide Number of treatment decisions (%) per patient case by 112 orthodontists based on either intraoral and panoramic radiography (M1) or CBCT and panoramic radiography (M2) at two occasions for the same patient cases. The difference between case 10 and all other cases was significant (P < 0.01). The treatment alternatives chosen for case 10 based on M1 were to do orthodontic treatment and to extract the permanent canine in 51 per cent (20 of 39) of the assessments, the first premolar 38 per cent, the lateral incisor in 5 per cent, and non-extraction in 5 per cent. In comparison, based on M2 the majority (79 per cent) chose to do orthodontic treatment and extract the lateral incisor with root resorption. In four cases (1, 3, 5, and 8), no or at most two of the treatment decisions were different irrespective of radiological method and these cases had no space deficiency for the teeth or a space deficiency less than 4 mm and no root resorption of any tooth adjacent to the maxillary canine. In six of 445 (1 per cent) assessments based on M1 and in 14 of 445 (3 per cent) assessments based on M2, the orthodontists stated that they lacked information such as clinical photographs, dental casts, or examining the patient clinically. In five (1 per cent) assessments based on M1, they stated that they lacked information from CBCT and in eight (2 per cent) assessments that they were uncertain of the presence of any root resorption. Two (0.4 per cent) orthodontists stated that they were unfamiliar with interpretation of the CBTC-images. The confidence level in the treatment decisions specified according to the five-point scale for the different cases comparing the two radiological methods is illustrated in Figure 5. Pairwise comparisons between cases showed no significant difference regarding confidence level, except for case 2 compared with case 3 and for case 10 compared with case 11. Figure 5. View largeDownload slide Number of treatment decisions (%) per patient case with a different level of confidence rated on a five-point scale. Based on 112 orthodontists′ assessments using intraoral and panoramic radiography (M1) or CBCT and panoramic radiography (M2) at two occasions for the same patient cases. In most (62 of 66) pairwise comparisons between cases, no significant differences were seen (P < 0.01). Figure 5. View largeDownload slide Number of treatment decisions (%) per patient case with a different level of confidence rated on a five-point scale. Based on 112 orthodontists′ assessments using intraoral and panoramic radiography (M1) or CBCT and panoramic radiography (M2) at two occasions for the same patient cases. In most (62 of 66) pairwise comparisons between cases, no significant differences were seen (P < 0.01). Cost analysis The mean total cost per examination was €99.84 using M1 and €134.37 using M2, resulting in an incremental diagnostic cost per examination of €34.53 using M2 (Table 3). Taking into account opportunity cost and depreciation for the radiographic equipment the incremental cost was higher. Using a rate of 3 per cent for both equipment depreciation and opportunity cost of funds increased the incremental cost per examination by €2.79 (7 per cent) whereas a rate of 5 per cent resulted in an increase of €4.75 (12 per cent). Part of the treatment decisions was different (24 per cent) when based on M2 instead of M1. This can be considered a potential benefit for CBCT provided that the additional information is worthwhile for some of the patients and thus, leading to an improved treatment decision. The choice of using M2 implies a probability of 0.24 that the treatment decision will be different compared with using M1. This can be expressed in terms of an incremental cost-effectiveness ratio (ICER) which is a measure of the average additional cost per treatment decision that is different as a result of using CBCT imaging, i.e. €143.88. Discussion For most of the patient cases, the orthodontists chose the same treatment alternative irrespective of imaging method. For one case (number 10) however, a majority of the treatment decisions were different depending on the radiological method that was a significant difference compared with all other cases. This case was the only one exhibiting severe space deficiency in the maxilla and had root resorption on the lateral incisor adjacent to the canine that was visible only on the CBCT images. This indicates that examination with CBCT and panoramic radiography may be more beneficial than that of intraoral and panoramic radiography and influence treatment decision to a higher degree for patients with characteristics like those in case 10. For the majority of the cases however, CBCT examination does not seem to be beneficial in terms of influencing the treatment decision. Furthermore, for most pairwise comparisons between cases the confidence in the treatment decision was the same irrespective of imaging method. The choice of an imaging method should be based on a complete understanding of its efficacy, which can be defined as the probability of a test benefiting patients, applied under ideal conditions of use. Diagnostic efficacy can be described as a six-level hierarchy where an acceptable level of efficacy must exist at lower levels to assure efficacy at higher levels (23). Recently, two studies evaluated costs and effects regarding radiographic examinations prior to removal of wisdom teeth (13,24). According to our knowledge, this study is the first to assess efficacy related to the costs of radiographic examination of maxillary canines with eruption disturbance. Therapeutic thinking efficacy can be assessed in terms of number of different treatment decisions when comparing different diagnostic methods. This measure must, however, be considered as an intermediate outcome for the benefits of an imaging method and should be interpreted with caution (25). Diagnostic methods often tend to focus on the specific impact of the intervention as opposed to the broader health of the patient. Achieving intermediate outcome may, however, lead to cost-effectiveness in the long run and these results could be helpful for decision-makers choosing between methods for the same condition (25). The radiographic methods frequently used for localisation of maxillary canines with eruption disturbance are intraoral and panoramic radiography using the principle of horizontal or vertical parallax (26). The accuracy of detection of root resorption has been shown to be superior using CBCT compared with intraoral radiography (27,28). A higher diagnostic accuracy in detecting resorption may, however, not be of clinical interest as the long-term prognosis even for severe root resorption is relatively good (29). Furthermore, root resorption of different degrees of severity was found in up to 68 per cent of teeth adjacent to maxillary canines with eruption disturbance, but also on teeth adjacent to normally erupting canines, with a prevalence of over 30 per cent (6). This raises the question whether it is necessary or justified to use imaging methods to identify all teeth with root resorption considering the radiation exposure and financial cost. Radiological decision-making is a complex process affected by several factors like the properties of the diagnostic method, the diagnostic information, clinicians’ perception and experience as well as the anamnesis (30). In this study, patient cases representing typical patients frequently encountered in clinical orthodontic practice were constructed containing information relevant to make a treatment decision. In order to have few variables that would have impact on the treatment decision, only patients with unilateral maxillary canines with otherwise no or minor malocclusion were selected. The assumption was that the information supplied for each case, other than that of the imaging methods, would have little impact on the treatment decision. This approach was supported by the orthodontists with only two dropping out of the study because they did not understand or approve of the cases. In this study, the management chosen by the orthodontists differed markedly for several of the cases when the orthodontists had access to different imaging methods but this did not result in an overall change in the frequency of different types of treatment. Only two cases (2 and 10) showed a profound difference in management with dramatically increased number of extractions of the lateral incisor. For both of these cases the lateral incisor had root resorption only visible on CBCT-images and they were the only cases with severe space deficiency. A study by Bjerklin and Bondemark (31), showed that a substantial proportion of the orthodontists suggested the first premolar or the permanent canine to be extracted regarding a case with severe space deficiency, even though computed tomography showed root resorption half way to the pulp on the maxillary lateral incisor. In this study however, when receiving information from CBCT about root resorption on the lateral incisor, most orthodontists chose to extract this tooth instead of another healthy or undamaged tooth. Early management of patients with maxillary canines with suspected eruption disturbance has been shown to have better prognosis compared with that of adult patients (32). The patients included in this study were 13–14 years old with unilateral maxillary canine with eruption disturbance whereas previous studies also included adult patients with a mixture of uni- and bilateral maxillary canines with eruption disturbance (16–19). Present study used a small FOV (4 × 4 cm) but this was reported by only one other study (18). Furthermore, only two other studies used intraoral radiographs as part of their conventional imaging (16,17). Due to these differences, the results of the present study is difficult to compare with that of previous studies. Previous studies have shown significantly higher confidence level in the treatment planning based on CBCT compared with panoramic radiography (19,33,34). This study, with considerably more raters, showed no clear evidence that the confidence was improved by CBCT. A reason for that could be that all orthodontists were well-trained and confident in their decisions irrespective of imaging method. Hodges et al. (34) found that there was a greater increase in confidence when the observers already used CBCT frequently in practice and it could be that the orthodontists in this study did not frequently use CBCT. Only two orthodontists however, stated that they were unfamiliar with interpreting CBCT-images. Another study on endodontic diagnosis found no clear evidence that confidence was improved by CBCT (35) but these results may be due to the observers being general dentists rather than specialists. Clinicians often place great value on results of a diagnostic method that does nothing more than reassure them (23) but it is questionable whether this should be an indication for radiographic examination of young patients with maxillary canines with eruption disturbance. Indeed, the definition of ‘justification’ in radiation protection explicitly requires benefits to the patient or society in general, but does not include benefits to the clinician (36). Cost-analysis The mean incremental cost per examination of €34.53 for M2 in the present cost-analysis was lower than the €46.58 reported in the cost-analysis from 2012 (12). The main reasons for that is the 12 per cent reduction of the purchase price of the CBCT machine and the 30 per cent increase in the number of CBCT examinations, thus spreading the capital costs of the machine’s purchase among a higher number of examinations. The increase in number of CBCT examinations may be due to an increase in the catchment area and/ or to increased capacity of clinical staff to operate the technology, as well as an increased demand from referring clinicians. The cost-analysis included opportunity cost of funds and cost for depreciation of capital equipment which involved an increase of the incremental cost compared with that obtained in the previous cost analysis (12). This adjustment to the incremental cost per examination was however, more than offset by the reductions arising from the lower purchase price and increased volume of patients. Provided that the information from CBCT is worthwhile, hence leading to improved treatment decisions, this could be interpreted as a potential benefit to some of the patients. Few treatment decisions however, were different when the orthodontists had access to CBCT and panoramic radiography which makes this method relatively costly. Conclusions Only a proportion of patients might benefit from CBCT in terms of a changed treatment plan. It remains to be determined whether for this sub-group the change in treatment plan would lead to better outcomes. Furthermore, the study presented here raises the possibility of identifying high yield selection criteria for CBCT in the context of patients with maxillary canines with eruption disturbance. Accordingly, this study does not support routine use of CBCT regarding patients with maxillary canine with eruption disturbance. Funding The European Atomic Energy Community’s Seventh Framework Programme FP7/2007–2011 under grant agreement no 212246 (SEDENTEXCT: Safety and Efficacy of a New and Emerging Dental X-ray Modality). Acknowledgements The authors gratefully acknowledge all orthodontists that participated in the study as well as the persons who were part of the evaluation group. References 1. Dachi, S.F. and Howell, F.V. ( 1961) A survey of 3,874 routine full-month radiographs. II. A study of impacted teeth. Oral Surgery, Oral Medicine, and Oral Pathology , 14, 1165– 1169. Google Scholar CrossRef Search ADS PubMed  2. Thilander, B. and Myrberg, N. ( 1973) The prevalence of malocclusion in Swedish schoolchildren. Scandinavian Journal of Dental Research , 81, 12– 21. Google Scholar PubMed  3. Ericson, S. and Kurol, J. ( 1986) Longitudinal study and analysis of clinical supervision of maxillary canine eruption. Community Dentistry and Oral Epidemiology , 14, 172– 176. Google Scholar CrossRef Search ADS PubMed  4. Liu, D.G., Zhang, W.L., Zhang, Z.Y., Wu, Y.T. and Ma, X.C. ( 2008) Localization of impacted maxillary canines and observation of adjacent incisor resorption with cone-beam computed tomography. Oral Surgery, Oral Medicine, Oral Pathology, Oral Radiology, and Endodontics , 105, 91– 98. Google Scholar CrossRef Search ADS PubMed  5. Strbac, G.D., Foltin, A., Gahleitner, A., Bantleon, H.P., Watzek, G. and Bernhart, T. ( 2013) The prevalence of root resorption of maxillary incisors caused by impacted maxillary canines. Clinical Oral Investigations , 17, 553– 564. Google Scholar CrossRef Search ADS PubMed  6. Hadler-Olsen, S.,et al.  ( 2015) Root resorptions related to ectopic and normal eruption of maxillary canine teeth - A 3D study. Acta Odontologica Scandinavica , 73, 609– 615. Google Scholar CrossRef Search ADS PubMed  7. Tronstad, L. ( 1988) Root resorption–etiology, terminology and clinical manifestations. Endodontics & Dental Traumatology , 4, 241– 252. Google Scholar CrossRef Search ADS PubMed  8. Ericson, S. and Kurol, J. ( 1987) Radiographic examination of ectopically erupting maxillary canines. American Journal of Orthodontics and Dentofacial Orthopedics , 91, 483– 492. Google Scholar CrossRef Search ADS PubMed  9. UNSCEAR. Sources, Effects and Risks of Ionizing Radiation. Scientific Annex B. Effects of Radiation Exposure of Children. United Nations, Vol II (2013) http://www.unscear.org/docs/reports/2013/13-85418_Report_2013_Annex_A.pdf. (11 May 2017, date last accessed). 10. Hidalgo-Rivas, J.A., Theodorakou, C., Carmichael, F., Murray, B., Payne, M. and Horner, K. ( 2014) Use of cone beam CT in children and young people in three United Kingdom dental hospitals. International Journal of Paediatric Dentistry , 24, 336– 348. Google Scholar CrossRef Search ADS PubMed  11. Hol, C., Hellén-Halme, K., Torgersen, G., Nilsson, M. and Møystad, A. ( 2015) How do dentists use CBCT in dental clinics? A Norwegian nationwide survey. Acta Odontologica Scandinavica , 73, 195– 201. Google Scholar CrossRef Search ADS PubMed  12. Christell, H., Birch, S., Horner, K., Rohlin, M. and Lindh, C.; The SEDENTEXCT Project Consortium.( 2012) A framework for costing diagnostic methods in oral health care: an application comparing a new imaging technology with intraoral and panoramic radiography for maxillary canines with eruption disturbance. Community Dentistry and Oral Epidemiology , 40, 351–35 7. Google Scholar CrossRef Search ADS PubMed  13. Petersen, L.B., Olsen, K.R., Christensen, J. and Wenzel, A. ( 2014) Image and surgery-related costs comparing cone beam CT and panoramic imaging before removal of impacted mandibular third molars. Dento Maxillo Facial Radiology , 43, 20140001. Google Scholar CrossRef Search ADS PubMed  14. European Commission. ( 2012) Cone Beam CT for Dental and Maxillofacial Radiology: Evidence Based Guidelines, Radiation Protection Publication 172 . European Commission. http://www.sedentexct.eu/files/radiation_protection_172.pdf. (1 May 2017, date last accessed). 15. Al-Okshi, A., Lindh, C., Salé, H., Gunnarsson, M. and Rohlin, M. ( 2015) Effective dose of cone beam CT (CBCT) of the facial skeleton: a systematic review. British Journal of Radiology , 88, 20140658. Google Scholar CrossRef Search ADS PubMed  16. Haney, E., Gansky, S.A., Lee, J.S., Johnson, E., Maki, K. and Miller, A.J.( 2010) Comparative analysis of traditional radiographs and cone-beam computed tomography volumetric images in the diagnosis and treatment planning of maxillary impacted canines. American Journal of Orthodontics and Dentofacial Orthopedics , 137, 590– 597. Google Scholar CrossRef Search ADS PubMed  17. Botticelli, S., Verna, C., Cattaneo, P.M., Heidmann, J. and Melsen, B. ( 2011) Two- versus three-dimensional imaging in subjects with unerupted maxillary canines. European Journal of Orthodontics , 33, 344– 349. Google Scholar CrossRef Search ADS PubMed  18. Wriedt, S., Jaklin, J., Al-Nawas, B. and Wehrbein, H. ( 2012) Impacted upper canines: examination and treatment proposal based on 3D versus 2D diagnosis. Journal of Orofacial Orthopedics = Fortschritte Der Kieferorthopadie , 73, 28– 40. Google Scholar CrossRef Search ADS PubMed  19. Alqerban, A., Willems, G., Bernaerts, C., Vangastel, J., Politis, C. and Jacobs, R. ( 2014) Orthodontic treatment planning for impacted maxillary canines using conventional records versus 3D CBCT. European Journal of Orthodontics , 36, 698– 707. Google Scholar CrossRef Search ADS PubMed  20. Sorenson, C. and Chalkidou, K. ( 2012) Reflections on the evolution of health technology assessment in Europe. Health Economics, Policy, and Law , 7, 25– 45. Google Scholar CrossRef Search ADS PubMed  21. Ericson, S. and Kurol, J. ( 2000) Incisor root resorptions due to ectopic maxillary canines imaged by computerized tomography: a comparative study in extracted teeth. Angle Orthodontist , 70, 276– 283. Google Scholar PubMed  22. Altman, D.G. ( 1990) Practical statistics for medical research . Chapman and Hall/CRC Texts in Statistical Science, London, UK. 23. Fryback, D.G. and Thornbury, J.R. ( 1991) The efficacy of diagnostic imaging. Medical Decision Making , 11, 88– 94. Google Scholar CrossRef Search ADS PubMed  24. Petersen, L.B., Olsen, K.R., Matzen, L.H., Vaeth, M. and Wenzel, A. ( 2015) Economic and health implications of routine CBCT examination before surgical removal of the mandibular third molar in the Danish population. Dento Maxillo Facial Radiology , 44, 20140406. Google Scholar CrossRef Search ADS PubMed  25. Drummond, M.F., Sculpher, M.J., Claxton, K., Stoddart, G.L. and Torrance, G.W. ( 2015) Methods for the Economic Evaluation of Health Care Programmes . 4th ed. Oxford Medical Publications, Oxford. 26. Husain, J., Burden, D., McSherry, P., Morris, D. and Allen, M; Clinical Standards Committee of the Faculty of Dental Surgery, Royal College of Surgeons of England. ( 2012) National clinical guidelines for management of the palatally ectopic maxillary canine. British Dental Journal , 213, 171– 176. Google Scholar CrossRef Search ADS PubMed  27. Shokri, A., Mortazavi, H., Salemi, F., Javadian, A., Bakhtiari, H. and Matlabi, H. ( 2013) Diagnosis of simulated external root resorption using conventional intraoral film radiography, CCD, PSP, and CBCT: a comparison study. Biomedical Journal , 36, 18– 22. Google Scholar CrossRef Search ADS PubMed  28. Creanga, A.G., Geha, H., Sankar, V., Teixeira, F.B., McMahan, C.A. and Noujeim, M. ( 2015) Accuracy of digital periapical radiography and cone-beam computed tomography in detecting external root resorption. Imaging Science In Dentistry , 45, 153– 158. Google Scholar CrossRef Search ADS PubMed  29. Bjerklin, K. and Guitirokh, C.H. ( 2011) Maxillary incisor root resorption induced by ectopic canines. A follow-up study 13 to 28 years post treatment. Angle Orthodontist , 81, 800– 806. Google Scholar CrossRef Search ADS PubMed  30. Blesser, B. and Ozonoff, D. ( 1972) A model for the radiologic process. Radiology , 103, 515– 521. Google Scholar CrossRef Search ADS PubMed  31. Bjerklin, K. and Bondemark, L. ( 2008) Management of ectopic maxillary canines: variations among orthodontists. Angle Orthodontist , 78, 852– 859. Google Scholar CrossRef Search ADS PubMed  32. Ericson, S. and Kurol, J. ( 1988) Early treatment of palatally erupting maxillary canines by extraction of the primary canines. European Journal of Orthodontics , 10, 283– 295. Google Scholar CrossRef Search ADS PubMed  33. Alqerban, A.et al.   SedentexCT Consortium. ( 2013) Pre-surgical treatment planning of maxillary canine impactions using panoramic vs cone beam CT imaging. Dento Maxillo Facial Radiology , 42, 20130157. Google Scholar CrossRef Search ADS PubMed  34. Hodges, R.J., Atchison, K.A. and White, S.C. ( 2013) Impact of cone-beam computed tomography on orthodontic diagnosis and treatment planning. American Journal of Orthodontics and Dentofacial Orthopedics , 143, 665– 674. Google Scholar CrossRef Search ADS PubMed  35. Al-Salehi, S.K. and Horner, K. ( 2016) Impact of cone beam computed tomography (CBCT) on diagnostic thinking in endodontics of posterior teeth: A before- after study. Journal of Dentistry , 53, 57– 63. Google Scholar CrossRef Search ADS PubMed  36. The 2007 Recommendations of the International Commission on Radiological Protection Annals of the ICRP Vol 37 ( 2007) http://www.icrp.org/publication.asp?id=ICRP Publication 103. (11 May 2017, date last accessed). © The Author(s) 2017. Published by Oxford University Press on behalf of the European Orthodontic Society. All rights reserved. For permissions, please email: journals.permissions@oup.com http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png The European Journal of Orthodontics Oxford University Press

The impact of Cone Beam CT on financial costs and orthodontists’ treatment decisions in the management of maxillary canines with eruption disturbance

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Abstract

Summary Background Examination with Cone Beam CT (CBCT) is common for localizing maxillary canines with eruption disturbance. The benefits and costs of these examinations are unclear. Objectives To measure: 1. the proportion of orthodontists’ treatment decisions that were different based on intraoral and panoramic radiography (M1) compared with CBCT and panoramic radiography (M2); and 2. the costs of producing different treatment plans, regarding patients with maxillary canines with eruption disturbance. Subjects and methods Orthodontists participated in a web-based survey and were randomly assigned to denote treatment decisions and the level of confidence in this decision for four patient cases presented with M1 or M2 at two occasions for the same patient case. Results One hundred and twelve orthodontists made 445 assessments based on M1 and M2, respectively. Twenty-four per cent of the treatment decisions were different depending on which method the raters had access to, whereof one case differed significantly from all other cases. The mean total cost per examination was €99.84 using M1 and €134.37 using M2, resulting in an incremental cost per examination of €34.53 for M2. Limitations Benefits in terms of number of different treatment decisions must be considered as an intermediate outcome for the effectiveness of a diagnostic method and should be interpreted with caution. Conclusions For the patient cases presented in this study, most treatment decisions were the same irrespective of radiological method. Accordingly, this study does not support routine use of CBCT regarding patients with maxillary canine with eruption disturbance. Introduction After the third molar, the maxillary canine is the tooth most often affected by eruption disturbance impaction, with a prevalence of between 0.9 and 3.0 per cent (1–3). If left untreated, maxillary canines with eruption disturbance can cause root resorption on neighbouring teeth, notably lateral incisors, with a prevalence of between 7.7 and 67.6 per cent (4–6). Root resorption occurs when the predentin or precementum becomes mineralized or, in case of the precementum, is mechanically damaged or scraped off (7), which can be the case when an ectopically erupting or retained maxillary canine is present (8). Consequently, patients with this condition frequently receive orthodontic treatment with a range of treatment options being available. The decision on management for these patients requires adequate understanding of the position of the canine and its relation to the rest of the dentition. Such information can only be comprehensively obtained by radiographic imaging. Maxillary canines with eruption disturbance is mostly detected and treated in younger individuals and, as risk from radiation exposure is higher in this age group, it is particularly important that the radiographic examination is justified (9). Localisation of maxillary canines with eruption disturbance and detection of root resorption of teeth adjacent to the canine is a common indication for examination with Cone Beam Computed Tomography (CBCT) (10,11). This imaging method is, however, associated with a higher cost (12,13) and involves a higher radiation dose than conventional imaging techniques (14,15), which may include panoramic, cephalometric, occlusal, and periapical radiographs. These imaging methods have limitations due to two-dimensionality, superimposition of anatomy, and image distortion. Many of these problems were overcome with the introduction of CBCT. Regarding maxillary canines with eruption disturbance some previous studies found that the use of CBCT led to significantly different treatment plans (16,17) whereas other studies showed no such significant differences (18,19), compared with conventional radiography. In the SEDENTEXCT guidelines for evidence based use of CBCT, it was concluded that there was no strong evidence to support using CBCT as the ‘first line’ imaging method in the context of root resorption diagnosis (14). Currently, there is no available evidence on cost-effectiveness of CBCT imaging of patients with maxillary canines with eruption disturbance. With increasing demands on decision makers to allocate resources efficiently in ways that produce most health gain for available health care technologies (20), this knowledge gap is problematic. Hence, there is a need for well-designed comprehensive studies on the possible benefits of CBCT examinations and their relation to the associated costs. Therefore, the aim of this study was to measure: 1. the proportion of orthodontists who denoted a different treatment decision based on intraoral and panoramic radiography compared with CBCT and panoramic radiography and 2. the costs of producing different treatment plans, regarding patients with maxillary canines with eruption disturbance. Subjects and methods A web-based survey for specialists in orthodontics was constructed in association with a web developer. Invitations to participate were sent by e-mail to all members of the Swedish Orthodontic Society (n = 314) according to the society’s membership directory, with the intention to reach specialists in orthodontics who had at minimum of 1 year experience in treating orthodontic patients. Patient cases Twelve different patient cases, describing patients with unilateral eruption disturbance of the maxillary canine with otherwise no, or minor, need for orthodontic treatment, were constructed and included in the survey (Table 1). Each case was based on the following characteristics: A subjective treatment need One maxillary canine with eruption disturbance and no likelihood for spontaneous eruption A complete permanent dentition including the second molars Normal sagittal molar relation (Class I) Normal skeletal relations between the maxilla and the mandible Cephalometric analysis showed normal maxillary incisor inclination No subjective need for correction of the maxillary dental midline Good oral hygiene Table 1. Characteristics of the 12 patient cases included in the survey. Case  Age  Gender  Canine  Space deficiency in the maxilla  Centre line displacement in the maxilla  Angulation of the canine to the midline  Overlap of the canine with adjacent incisor/ -s  1  14  M  13  Small <4mm  1–2 mm to the right  40°  Lateral  2  13  M  13  Severe >8mm  2 mm to the right  40°  ½ central  3  13  F  23  No  —  40°  Lateral  4  13  F  23  No  —  53°  Lateral  5  13  M  13  No  —  42°  Central  6  14  M  23  No  —  62°  Central  7  14  M  23  Small <4mm  1 mm to the left  11°  No  8  13  F  13  No  —  30°  ½ central  9  13  F  23  No  —  56°  ½ lateral  10  13  F  23  Severe >8mm  —  38°  ½ central  11  14  F  23  Small <4mm  1–2 mm to the right  21°  ½ lateral  12  14  F  23  Small <4mm  —  38°  Lateral  Case  Age  Gender  Canine  Space deficiency in the maxilla  Centre line displacement in the maxilla  Angulation of the canine to the midline  Overlap of the canine with adjacent incisor/ -s  1  14  M  13  Small <4mm  1–2 mm to the right  40°  Lateral  2  13  M  13  Severe >8mm  2 mm to the right  40°  ½ central  3  13  F  23  No  —  40°  Lateral  4  13  F  23  No  —  53°  Lateral  5  13  M  13  No  —  42°  Central  6  14  M  23  No  —  62°  Central  7  14  M  23  Small <4mm  1 mm to the left  11°  No  8  13  F  13  No  —  30°  ½ central  9  13  F  23  No  —  56°  ½ lateral  10  13  F  23  Severe >8mm  —  38°  ½ central  11  14  F  23  Small <4mm  1–2 mm to the right  21°  ½ lateral  12  14  F  23  Small <4mm  —  38°  Lateral  Assessment of space deficiency in the maxilla, centre line displacement, angulation of the canine to the midline and the overlap of the canine in relation to the adjacent incisor(s) was based on the panoramic radiographs. M, male; F, female. View Large Individual parameters that varied between the cases: age, gender, left or right maxillary canine with eruption disturbance, and any maxillary centreline displacement, are presented in Table 1. In 10 of the cases, the space deficiency was less than 4 mm in the maxilla indicating no need for tooth extractions. For two cases, the space deficiency was at least 8 mm expressing an obvious need for tooth extractions. The assessment of space deficiency and centre line displacement was based on the panoramic radiographs. To do these assessments based on panoramic radiographs is not normal practice but was considered to have small impact on the exercise of this study. The cases were presented with two intraoral periapical radiographs obtained at different horizontal angles, panoramic radiographs, and CBCT images (see examples in Figure 1) as well as a written report describing the position of the maxillary canine, the distance of the canine crown in relation to the marginal bone, root morphology and any resorption of teeth neighbouring the maxillary canine. Intraoral and panoramic radiographs as well as CBCT-images from patients already examined in a previous study (12) were reviewed, and images from all patients with unilateral eruption disturbance of the maxillary canine with otherwise no, or minor, need for orthodontic treatment were included in present study. One of the authors (CL) a specialist in oral- and maxillofacial radiology assessed the radiographs and wrote the reports. The reports for intraoral and panoramic radiographs were written at one occasion and 1–2 weeks after, the reports on panoramic and CBCT images were written, without knowledge of the first report (Table 2). Figure 1. View largeDownload slide Examples of the radiographs presented in the survey for two of the 12 patient cases. Figure 1. View largeDownload slide Examples of the radiographs presented in the survey for two of the 12 patient cases. Table 2. Report based on images from the 12 patient cases using intraoral and panoramic radiography (M1) or CBCT and panoramic radiography (M2). Case  Horizontal position of the canine  Bucco-palatal position of the canine  Vertical level of the canine crown-tip - distance from the bone crest  Dilaceration of the canine root  Resorption of teeth adjacent to the canine  M1  M2  M1  M2  M1  M2  M1  M2  M1  M2  1  Mesioangular  Mesioangular  Palatal  Palatal  Broken through marginal bone  Broken through marginal bone  No  No  No  No  2  Mesioangular  Mesioangular  Palatal  Palatal  In level with marginal bone  In level with marginal bone  No  No  No  Slight  3  Mesioangular  Mesioangular  Palatal  Palatal  3 mm  1 mm  No  No  No  Slight  4  Mesioangular  Mesioangular  Palatal  Palatal  3 mm  1 mm  No  Mesially in the apical part  No  Slight  5  Mesioangular  Mesioangular  Palatal  Palatal  2 mm  Broken through marginal bone  No  No  No  No  6  Mesioangular  Mesioangular  Palatal  Palatal  10 mm  8 mm  Superiorly in the apical part  Superiorly in the apical part  No  Slight  7  Vertical  Vertical  Central  Central  In level with marginal bone  In level with marginal bone  No  No  No  Slight  8  Mesioangular  Mesioangular  Palatal  Palatal  3 mm  1 mm  No  No  No  No  9  Mesioangular  Mesioangular  Palatal  Palatal  5 mm  3 mm  No  No  Probably severe  Severe  10  Mesioangular  Mesioangular  Palatal  Palatal  5 mm  2 mm  No  No  No  Moderate  11  Vertical  Vertical  Central  Central  3 mm  1 mm  Mesial direction in the apical part  Buccal direction in the apical part  No  No  12  Mesioangular  Mesioangular  Palatal  Palatal  1 mm  Broken through marginal bone  Mesially along the entire root  Mesially along the entire root  No  No  Case  Horizontal position of the canine  Bucco-palatal position of the canine  Vertical level of the canine crown-tip - distance from the bone crest  Dilaceration of the canine root  Resorption of teeth adjacent to the canine  M1  M2  M1  M2  M1  M2  M1  M2  M1  M2  1  Mesioangular  Mesioangular  Palatal  Palatal  Broken through marginal bone  Broken through marginal bone  No  No  No  No  2  Mesioangular  Mesioangular  Palatal  Palatal  In level with marginal bone  In level with marginal bone  No  No  No  Slight  3  Mesioangular  Mesioangular  Palatal  Palatal  3 mm  1 mm  No  No  No  Slight  4  Mesioangular  Mesioangular  Palatal  Palatal  3 mm  1 mm  No  Mesially in the apical part  No  Slight  5  Mesioangular  Mesioangular  Palatal  Palatal  2 mm  Broken through marginal bone  No  No  No  No  6  Mesioangular  Mesioangular  Palatal  Palatal  10 mm  8 mm  Superiorly in the apical part  Superiorly in the apical part  No  Slight  7  Vertical  Vertical  Central  Central  In level with marginal bone  In level with marginal bone  No  No  No  Slight  8  Mesioangular  Mesioangular  Palatal  Palatal  3 mm  1 mm  No  No  No  No  9  Mesioangular  Mesioangular  Palatal  Palatal  5 mm  3 mm  No  No  Probably severe  Severe  10  Mesioangular  Mesioangular  Palatal  Palatal  5 mm  2 mm  No  No  No  Moderate  11  Vertical  Vertical  Central  Central  3 mm  1 mm  Mesial direction in the apical part  Buccal direction in the apical part  No  No  12  Mesioangular  Mesioangular  Palatal  Palatal  1 mm  Broken through marginal bone  Mesially along the entire root  Mesially along the entire root  No  No  Estimation of the amount of resorption was based on the index suggested by Ericson and Kurol (21). View Large Web-based survey Informed consent to participate in the study was obtained from all orthodontists. Those that agreed to participate received an e-mail with a link to the first part of the online survey. After a further 2 weeks, they received another e-mail with a link to the second part of the survey. Each orthodontist was randomly assigned to four of the 12 patient cases by the use of digital random function allocating randomized combinations of sequences of four cases with either intraoral and panoramic radiographs or CBCT and panoramic radiographs. Each orthodontist was presented with only four of the 12 cases as this strategy was believed to increase the response-rate. In the first part of the survey, two patient cases were presented with intraoral and panoramic radiographs (Method 1 = M1) and two patient cases were presented with CBCT images and panoramic radiographs (Method 2 = M2). In the second part of the survey, there was a switch in the presentation of images which meant that the same patient case was presented with the other imaging methods. To estimate intrarater agreement, 30 of the 112 orthodontists were randomly assigned to answer the survey a third time with the same imaging methods as the first occasion for the same patient case. The orthodontists were asked about their age, gender, and years of experience. They were also asked to make a treatment decision for the four cases they were assigned by selecting one of following alternatives: 1. no treatment, 2. nonextraction orthodontic treatment, 3. orthodontic treatment including extraction of the first premolar, 4. orthodontic treatment including extraction of the maxillary lateral incisor, and 5. orthodontic treatment including extraction of the maxillary canine with eruption disturbance. In addition, the orthodontists had to denote the level of confidence in their decision on a five-point scale: 1. very confident, 2. fairly confident, 3. neither confident—nor unconfident, 4. fairly unconfident, or 5. very unconfident. The viewer program for the CBCT images (i-Dixel One Data Viewer Plus software, J. Morita®, Kyoto, Japan) was available in the online survey enabling the orthodontists to view all CBCT images in all planes (the axial, coronal, and sagittal) dynamically by scrolling through the consecutive orthogonal image stack (Figure 2). The CBCT images and the viewer program as well as the responses of the orthodontists were stored on a remote server. The responses were downloaded onto a personal computer for analysis. Figure 2. View largeDownload slide Image of the viewer program for the CBCT images (i-Dixel One Data Viewer Plus software, J. Morita®, Kyoto, Japan) available in the survey enabling the orthodontists to view all CBCT images in three planes dynamically by scrolling through the consecutive orthogonal image stack. Figure 2. View largeDownload slide Image of the viewer program for the CBCT images (i-Dixel One Data Viewer Plus software, J. Morita®, Kyoto, Japan) available in the survey enabling the orthodontists to view all CBCT images in three planes dynamically by scrolling through the consecutive orthogonal image stack. The survey started in May 2016 and continued until November 2016. The original e-mail invitation to participate was followed by four reminder e-mails sent via MailChimp® (The Rocket Science Group, Atlanta, US). Some respondents informed us that the e-mails were classified as having low priority, therefore an additional one to four ordinary e-mails were sent (not using MailChimp®). Finally, an attempt was made to contact all non-responders by telephone. Prior to full implementation of the study, an evaluation group of three orthodontists, one specialist in periodontology, one trainee in dental and maxillofacial radiology and one external web-developer evaluated the online survey and the associated survey procedures with respect to entering the survey via a link, filling in and saving the answers as well as down-loading and viewing the CBCT-images. The orthodontists in the evaluation group also evaluated the relevance of the cases and were not included as subjects in the study. Cost-analysis Costing for the radiological methods M1 and M2 was based on the framework for cost-analysis as previously reported (12) with unit costs updated to 2014 (Table 3). Table 3. Distribution of direct costs per examination based on CBCT and panoramic radiography (M2) compared with intraoral and panoramic radiography (M1). Identified direct costs  Cost per examination  M2  M1  Incremental cost for M2  Provider-related costs   Capital costs  Equipment  24.42  6.48  17.94  Maintenance  4.96  0.83  4.13   Rental costs  Accommodation  10.78  6.28  4.50  Image archive patient record  4.01  2.90  1.11   Labour costs  Specialist  7.31  5.17  2.14  Dental nurse  26.75  23.18  3.57   Total provider-related costs  78.23  44.84  33.39  Patient-related costs   Cost for time spent on:  Transport  28.98  28.98  —  Waiting  7.63  7.63  —  Examination  9.02  7.88  1.14   ‘Out of pocket’ cost  Cost per km, parking  10.51  10.51  —   Total patient-related costs  56.14  55.00  1.14   Total costs from a societal view  134.37  99.83  34.54   Total cost including opportunity cost and cost for equipment depreciation using 3% rate  138.74  101.41  37.33   Total cost including opportunity cost and cost for equipment depreciation using 5% rate  141.86  102.57  39.29  Identified direct costs  Cost per examination  M2  M1  Incremental cost for M2  Provider-related costs   Capital costs  Equipment  24.42  6.48  17.94  Maintenance  4.96  0.83  4.13   Rental costs  Accommodation  10.78  6.28  4.50  Image archive patient record  4.01  2.90  1.11   Labour costs  Specialist  7.31  5.17  2.14  Dental nurse  26.75  23.18  3.57   Total provider-related costs  78.23  44.84  33.39  Patient-related costs   Cost for time spent on:  Transport  28.98  28.98  —  Waiting  7.63  7.63  —  Examination  9.02  7.88  1.14   ‘Out of pocket’ cost  Cost per km, parking  10.51  10.51  —   Total patient-related costs  56.14  55.00  1.14   Total costs from a societal view  134.37  99.83  34.54   Total cost including opportunity cost and cost for equipment depreciation using 3% rate  138.74  101.41  37.33   Total cost including opportunity cost and cost for equipment depreciation using 5% rate  141.86  102.57  39.29  Cost to the provider is presented with no opportunity cost or cost for depreciation as well as with opportunity cost and cost for equipment depreciation using 3 and 5% rate. Costs were estimated using 2014 prices (Euro). View Large Radiography The radiographic equipment used for CBCT was 3D Accuitomo (Morita®, Kyoto, Japan) (90 kV, 5–6.5 mA, 1/ 2PI, 9/ 17.5 second, 4 × 4 cm field of view (FOV)) and Verawiew epocs (Morita®, Kyoto, Japan) (80 kv, 5 mA, IPI, 9.4 second, 4 × 4 cm FOV), for panoramic radiography Planmeca Pro Max (Planmeca® Helsinki, Finland) (72 kV, 16 mA, 17 second, MAG 1.2) and Verawiew epocs (Morita®, Kyoto, Japan) (65 kv, 5 mA, IPI, 6.5 second, MAG 1.2), and for intraoral radiography Planmeca Intra (Planmeca®, Helsinki, Finland) (60 kV, 8 mA, 0.10–0.20 second). Statistical analyses Intrarater agreement for treatment decisions based on observations of the same patient case using the same imaging methods was estimated in terms of percent agreement per patient case. Kappa statistics (κ) (22) and percent agreement was used to analyse the treatment decision under the different imaging methods. Fisher’s Exact Test was used to compare treatment decisions and associated confidence levels when using the different imaging methods. IBM SPSS Statistics (Version 23, Chicago, Illinois, USA) was used for all calculations. Statistical significance was set at a P value less than 0.01. Radiographs and CBCT scans included in the survey were anonymised and the responses from orthodontists were recorded anonymously, using a study code number for each orthodontist. The study was conducted in accordance with the ethical principles of the World Medical Association Declaration of Helsinki (2008 version) and approved by the Regional Ethical Review Board, Lund, Sweden (H15606/2008). Results Three hundred and fourteen members of the Swedish Orthodontic society were invited to participate in the study. Ninety-three orthodontists were excluded due to following reasons: not active as orthodontist (n = 30) orthodontic resident (n = 20) not working in Sweden (n = 17) insufficient contact information (n = 10) on parental or sick leave (n = 9) not working with this patient group (n = 7) Of the remaining 221 orthodontists, participation was accepted by 154. Responses from 42 orthodontists could not be used due to the following reasons: 1. only answered one part of the survey (n = 17), 2. no response after four reminders (n = 12), 3. could not open the CBCT files/survey (n = 7), 4. could not save the answers (n = 3), 5. did not approve of the study design (n = 2), and 6. other reasons (n = 1). Downloading and opening the CBCT images, save the answers or open the survey were problematic for some of the orthodontists and this was according to the web-developer due to local factors like the internet connection and virus programmes. Some of the orthodontists that had these problems received the CBCT-images on a USB-memory and a Word-document to fill in their questions. When the survey closed, 112 orthodontists had answered both parts of the survey with altogether 445 assessments based on M1 and M2, respectively, for the same patient case. Of the 112 participants, 64 (57.1 per cent) were women and 48 (42.9 per cent) were men, 88 (78.6 per cent) worked in a public dental clinic, 22 (19.6 per cent) in private practice, and 2 (1.8 per cent) were university employees. The highest number of participants were found in the age group 36–45, as well as among participants having 1–10 years of experience (Table 4). Table 4. Characteristics of orthodontists (n = 112) that answered the survey at two occasions. Gender   Women  64 (57.1%)   Men  48 (42.9%)  Working place   Public dental clinic  88 (78.6%)   Private practice  22 (19.6%)   University  2 (1.8%)  Age (years)   25–35  7 (6.3%)   36–45  39 (34.8%)   46–55  23 (20.5%)   56–65  33 (29.5%)   >65  10 (8.9%)  Years of practice   1–10  49 (43.8%)   11–20  38 (33.9%)   21–30  13 (11.6%)   31–40  10 (8.9%)   >40  2 (1.8%)  Gender   Women  64 (57.1%)   Men  48 (42.9%)  Working place   Public dental clinic  88 (78.6%)   Private practice  22 (19.6%)   University  2 (1.8%)  Age (years)   25–35  7 (6.3%)   36–45  39 (34.8%)   46–55  23 (20.5%)   56–65  33 (29.5%)   >65  10 (8.9%)  Years of practice   1–10  49 (43.8%)   11–20  38 (33.9%)   21–30  13 (11.6%)   31–40  10 (8.9%)   >40  2 (1.8%)  View Large Intrarater agreement based on 30 orthodontist’s assessments regarding the choice of treatment varied from 50 to 100 per cent using M1 with the lowest level of agreement being for case 10. Full agreement was observed for eight cases (case 2, 3, 4, 5, 8, 9, 11, and 12). Based on M2, the agreement varied between 0 per cent (case 11) and 100 per cent for seven cases (case 1, 2, 3, 4, 5, 8, and 12). The number of assessments varied from 3 to 7 per case with 60 assessments per radiographic method. Comparison between imaging methods The number of assessments per case varied between 31 and 44 (Table 5). Treatment decisions showed a variability in agreement from 100 per cent (case 1) to 12.8 per cent (case 10) (Table 5). κ-values also varied from 1.0 (case 1) to −0.053 (case 4). For two cases (case 3 and 8), no κ-value could be calculated as the same treatment alternatives were chosen by all raters but one (Table 5). The most frequent treatment decision was orthodontic treatment not including extraction of any of the teeth, chosen in 66 per cent of the assessments based on M1, and in 64 per cent of the assessments based on M2 (Figure 3). Overall, 107 of 445 (24 per cent) treatment decisions were different when based on M2 instead of M1 and case 10 differed statistically significant from all other cases (Figure 4). For case 10, 87.2 per cent (34 of 39) treatment decisions were different depending on which imaging method the orthodontists had access to (Table 5). Table 5. Agreement between imaging methods, intraoral and panoramic radiography (M1) and CBCT and panoramic radiography (M2), regarding treatment alternatives chosen when having access to either M1 or M2 at two different occasions for the same patient case, presented as κ-values and percent agreement (%) for the number of assessments per case (n). Patient case  κ-value  Agreement between M1 and M2 (%)  Number of assessment per patent case (n)  1  1  100  35  2  0.323  64.7  34  3  —  97.0  33  4  −0.053  86.1  36  5  0.479  94.6  37  6  0.632  83.9  31  7  0.253  63.4  41  8  —  97.7  44  9  0.273  69.8  43  10  0.018  12.8  39  11  0.314  66.7  36  12  0.339  80.6  36  Patient case  κ-value  Agreement between M1 and M2 (%)  Number of assessment per patent case (n)  1  1  100  35  2  0.323  64.7  34  3  —  97.0  33  4  −0.053  86.1  36  5  0.479  94.6  37  6  0.632  83.9  31  7  0.253  63.4  41  8  —  97.7  44  9  0.273  69.8  43  10  0.018  12.8  39  11  0.314  66.7  36  12  0.339  80.6  36  View Large Figure 3. View largeDownload slide Number of treatment decisions (%) per patient case based on altogether 445 assessments using either intraoral and panoramic radiography (M1) or CBCT and panoramic radiography (M2) at two occasions for the same patient cases, distributed per case (1 to 12). Figure 3. View largeDownload slide Number of treatment decisions (%) per patient case based on altogether 445 assessments using either intraoral and panoramic radiography (M1) or CBCT and panoramic radiography (M2) at two occasions for the same patient cases, distributed per case (1 to 12). Figure 4. View largeDownload slide Number of treatment decisions (%) per patient case by 112 orthodontists based on either intraoral and panoramic radiography (M1) or CBCT and panoramic radiography (M2) at two occasions for the same patient cases. The difference between case 10 and all other cases was significant (P < 0.01). Figure 4. View largeDownload slide Number of treatment decisions (%) per patient case by 112 orthodontists based on either intraoral and panoramic radiography (M1) or CBCT and panoramic radiography (M2) at two occasions for the same patient cases. The difference between case 10 and all other cases was significant (P < 0.01). The treatment alternatives chosen for case 10 based on M1 were to do orthodontic treatment and to extract the permanent canine in 51 per cent (20 of 39) of the assessments, the first premolar 38 per cent, the lateral incisor in 5 per cent, and non-extraction in 5 per cent. In comparison, based on M2 the majority (79 per cent) chose to do orthodontic treatment and extract the lateral incisor with root resorption. In four cases (1, 3, 5, and 8), no or at most two of the treatment decisions were different irrespective of radiological method and these cases had no space deficiency for the teeth or a space deficiency less than 4 mm and no root resorption of any tooth adjacent to the maxillary canine. In six of 445 (1 per cent) assessments based on M1 and in 14 of 445 (3 per cent) assessments based on M2, the orthodontists stated that they lacked information such as clinical photographs, dental casts, or examining the patient clinically. In five (1 per cent) assessments based on M1, they stated that they lacked information from CBCT and in eight (2 per cent) assessments that they were uncertain of the presence of any root resorption. Two (0.4 per cent) orthodontists stated that they were unfamiliar with interpretation of the CBTC-images. The confidence level in the treatment decisions specified according to the five-point scale for the different cases comparing the two radiological methods is illustrated in Figure 5. Pairwise comparisons between cases showed no significant difference regarding confidence level, except for case 2 compared with case 3 and for case 10 compared with case 11. Figure 5. View largeDownload slide Number of treatment decisions (%) per patient case with a different level of confidence rated on a five-point scale. Based on 112 orthodontists′ assessments using intraoral and panoramic radiography (M1) or CBCT and panoramic radiography (M2) at two occasions for the same patient cases. In most (62 of 66) pairwise comparisons between cases, no significant differences were seen (P < 0.01). Figure 5. View largeDownload slide Number of treatment decisions (%) per patient case with a different level of confidence rated on a five-point scale. Based on 112 orthodontists′ assessments using intraoral and panoramic radiography (M1) or CBCT and panoramic radiography (M2) at two occasions for the same patient cases. In most (62 of 66) pairwise comparisons between cases, no significant differences were seen (P < 0.01). Cost analysis The mean total cost per examination was €99.84 using M1 and €134.37 using M2, resulting in an incremental diagnostic cost per examination of €34.53 using M2 (Table 3). Taking into account opportunity cost and depreciation for the radiographic equipment the incremental cost was higher. Using a rate of 3 per cent for both equipment depreciation and opportunity cost of funds increased the incremental cost per examination by €2.79 (7 per cent) whereas a rate of 5 per cent resulted in an increase of €4.75 (12 per cent). Part of the treatment decisions was different (24 per cent) when based on M2 instead of M1. This can be considered a potential benefit for CBCT provided that the additional information is worthwhile for some of the patients and thus, leading to an improved treatment decision. The choice of using M2 implies a probability of 0.24 that the treatment decision will be different compared with using M1. This can be expressed in terms of an incremental cost-effectiveness ratio (ICER) which is a measure of the average additional cost per treatment decision that is different as a result of using CBCT imaging, i.e. €143.88. Discussion For most of the patient cases, the orthodontists chose the same treatment alternative irrespective of imaging method. For one case (number 10) however, a majority of the treatment decisions were different depending on the radiological method that was a significant difference compared with all other cases. This case was the only one exhibiting severe space deficiency in the maxilla and had root resorption on the lateral incisor adjacent to the canine that was visible only on the CBCT images. This indicates that examination with CBCT and panoramic radiography may be more beneficial than that of intraoral and panoramic radiography and influence treatment decision to a higher degree for patients with characteristics like those in case 10. For the majority of the cases however, CBCT examination does not seem to be beneficial in terms of influencing the treatment decision. Furthermore, for most pairwise comparisons between cases the confidence in the treatment decision was the same irrespective of imaging method. The choice of an imaging method should be based on a complete understanding of its efficacy, which can be defined as the probability of a test benefiting patients, applied under ideal conditions of use. Diagnostic efficacy can be described as a six-level hierarchy where an acceptable level of efficacy must exist at lower levels to assure efficacy at higher levels (23). Recently, two studies evaluated costs and effects regarding radiographic examinations prior to removal of wisdom teeth (13,24). According to our knowledge, this study is the first to assess efficacy related to the costs of radiographic examination of maxillary canines with eruption disturbance. Therapeutic thinking efficacy can be assessed in terms of number of different treatment decisions when comparing different diagnostic methods. This measure must, however, be considered as an intermediate outcome for the benefits of an imaging method and should be interpreted with caution (25). Diagnostic methods often tend to focus on the specific impact of the intervention as opposed to the broader health of the patient. Achieving intermediate outcome may, however, lead to cost-effectiveness in the long run and these results could be helpful for decision-makers choosing between methods for the same condition (25). The radiographic methods frequently used for localisation of maxillary canines with eruption disturbance are intraoral and panoramic radiography using the principle of horizontal or vertical parallax (26). The accuracy of detection of root resorption has been shown to be superior using CBCT compared with intraoral radiography (27,28). A higher diagnostic accuracy in detecting resorption may, however, not be of clinical interest as the long-term prognosis even for severe root resorption is relatively good (29). Furthermore, root resorption of different degrees of severity was found in up to 68 per cent of teeth adjacent to maxillary canines with eruption disturbance, but also on teeth adjacent to normally erupting canines, with a prevalence of over 30 per cent (6). This raises the question whether it is necessary or justified to use imaging methods to identify all teeth with root resorption considering the radiation exposure and financial cost. Radiological decision-making is a complex process affected by several factors like the properties of the diagnostic method, the diagnostic information, clinicians’ perception and experience as well as the anamnesis (30). In this study, patient cases representing typical patients frequently encountered in clinical orthodontic practice were constructed containing information relevant to make a treatment decision. In order to have few variables that would have impact on the treatment decision, only patients with unilateral maxillary canines with otherwise no or minor malocclusion were selected. The assumption was that the information supplied for each case, other than that of the imaging methods, would have little impact on the treatment decision. This approach was supported by the orthodontists with only two dropping out of the study because they did not understand or approve of the cases. In this study, the management chosen by the orthodontists differed markedly for several of the cases when the orthodontists had access to different imaging methods but this did not result in an overall change in the frequency of different types of treatment. Only two cases (2 and 10) showed a profound difference in management with dramatically increased number of extractions of the lateral incisor. For both of these cases the lateral incisor had root resorption only visible on CBCT-images and they were the only cases with severe space deficiency. A study by Bjerklin and Bondemark (31), showed that a substantial proportion of the orthodontists suggested the first premolar or the permanent canine to be extracted regarding a case with severe space deficiency, even though computed tomography showed root resorption half way to the pulp on the maxillary lateral incisor. In this study however, when receiving information from CBCT about root resorption on the lateral incisor, most orthodontists chose to extract this tooth instead of another healthy or undamaged tooth. Early management of patients with maxillary canines with suspected eruption disturbance has been shown to have better prognosis compared with that of adult patients (32). The patients included in this study were 13–14 years old with unilateral maxillary canine with eruption disturbance whereas previous studies also included adult patients with a mixture of uni- and bilateral maxillary canines with eruption disturbance (16–19). Present study used a small FOV (4 × 4 cm) but this was reported by only one other study (18). Furthermore, only two other studies used intraoral radiographs as part of their conventional imaging (16,17). Due to these differences, the results of the present study is difficult to compare with that of previous studies. Previous studies have shown significantly higher confidence level in the treatment planning based on CBCT compared with panoramic radiography (19,33,34). This study, with considerably more raters, showed no clear evidence that the confidence was improved by CBCT. A reason for that could be that all orthodontists were well-trained and confident in their decisions irrespective of imaging method. Hodges et al. (34) found that there was a greater increase in confidence when the observers already used CBCT frequently in practice and it could be that the orthodontists in this study did not frequently use CBCT. Only two orthodontists however, stated that they were unfamiliar with interpreting CBCT-images. Another study on endodontic diagnosis found no clear evidence that confidence was improved by CBCT (35) but these results may be due to the observers being general dentists rather than specialists. Clinicians often place great value on results of a diagnostic method that does nothing more than reassure them (23) but it is questionable whether this should be an indication for radiographic examination of young patients with maxillary canines with eruption disturbance. Indeed, the definition of ‘justification’ in radiation protection explicitly requires benefits to the patient or society in general, but does not include benefits to the clinician (36). Cost-analysis The mean incremental cost per examination of €34.53 for M2 in the present cost-analysis was lower than the €46.58 reported in the cost-analysis from 2012 (12). The main reasons for that is the 12 per cent reduction of the purchase price of the CBCT machine and the 30 per cent increase in the number of CBCT examinations, thus spreading the capital costs of the machine’s purchase among a higher number of examinations. The increase in number of CBCT examinations may be due to an increase in the catchment area and/ or to increased capacity of clinical staff to operate the technology, as well as an increased demand from referring clinicians. The cost-analysis included opportunity cost of funds and cost for depreciation of capital equipment which involved an increase of the incremental cost compared with that obtained in the previous cost analysis (12). This adjustment to the incremental cost per examination was however, more than offset by the reductions arising from the lower purchase price and increased volume of patients. Provided that the information from CBCT is worthwhile, hence leading to improved treatment decisions, this could be interpreted as a potential benefit to some of the patients. Few treatment decisions however, were different when the orthodontists had access to CBCT and panoramic radiography which makes this method relatively costly. Conclusions Only a proportion of patients might benefit from CBCT in terms of a changed treatment plan. It remains to be determined whether for this sub-group the change in treatment plan would lead to better outcomes. Furthermore, the study presented here raises the possibility of identifying high yield selection criteria for CBCT in the context of patients with maxillary canines with eruption disturbance. Accordingly, this study does not support routine use of CBCT regarding patients with maxillary canine with eruption disturbance. Funding The European Atomic Energy Community’s Seventh Framework Programme FP7/2007–2011 under grant agreement no 212246 (SEDENTEXCT: Safety and Efficacy of a New and Emerging Dental X-ray Modality). Acknowledgements The authors gratefully acknowledge all orthodontists that participated in the study as well as the persons who were part of the evaluation group. References 1. Dachi, S.F. and Howell, F.V. ( 1961) A survey of 3,874 routine full-month radiographs. II. A study of impacted teeth. Oral Surgery, Oral Medicine, and Oral Pathology , 14, 1165– 1169. Google Scholar CrossRef Search ADS PubMed  2. Thilander, B. and Myrberg, N. ( 1973) The prevalence of malocclusion in Swedish schoolchildren. Scandinavian Journal of Dental Research , 81, 12– 21. Google Scholar PubMed  3. Ericson, S. and Kurol, J. ( 1986) Longitudinal study and analysis of clinical supervision of maxillary canine eruption. Community Dentistry and Oral Epidemiology , 14, 172– 176. Google Scholar CrossRef Search ADS PubMed  4. Liu, D.G., Zhang, W.L., Zhang, Z.Y., Wu, Y.T. and Ma, X.C. ( 2008) Localization of impacted maxillary canines and observation of adjacent incisor resorption with cone-beam computed tomography. Oral Surgery, Oral Medicine, Oral Pathology, Oral Radiology, and Endodontics , 105, 91– 98. Google Scholar CrossRef Search ADS PubMed  5. Strbac, G.D., Foltin, A., Gahleitner, A., Bantleon, H.P., Watzek, G. and Bernhart, T. ( 2013) The prevalence of root resorption of maxillary incisors caused by impacted maxillary canines. Clinical Oral Investigations , 17, 553– 564. Google Scholar CrossRef Search ADS PubMed  6. Hadler-Olsen, S.,et al.  ( 2015) Root resorptions related to ectopic and normal eruption of maxillary canine teeth - A 3D study. Acta Odontologica Scandinavica , 73, 609– 615. Google Scholar CrossRef Search ADS PubMed  7. Tronstad, L. ( 1988) Root resorption–etiology, terminology and clinical manifestations. Endodontics & Dental Traumatology , 4, 241– 252. Google Scholar CrossRef Search ADS PubMed  8. Ericson, S. and Kurol, J. ( 1987) Radiographic examination of ectopically erupting maxillary canines. American Journal of Orthodontics and Dentofacial Orthopedics , 91, 483– 492. Google Scholar CrossRef Search ADS PubMed  9. UNSCEAR. Sources, Effects and Risks of Ionizing Radiation. Scientific Annex B. Effects of Radiation Exposure of Children. United Nations, Vol II (2013) http://www.unscear.org/docs/reports/2013/13-85418_Report_2013_Annex_A.pdf. (11 May 2017, date last accessed). 10. Hidalgo-Rivas, J.A., Theodorakou, C., Carmichael, F., Murray, B., Payne, M. and Horner, K. ( 2014) Use of cone beam CT in children and young people in three United Kingdom dental hospitals. International Journal of Paediatric Dentistry , 24, 336– 348. Google Scholar CrossRef Search ADS PubMed  11. Hol, C., Hellén-Halme, K., Torgersen, G., Nilsson, M. and Møystad, A. ( 2015) How do dentists use CBCT in dental clinics? A Norwegian nationwide survey. Acta Odontologica Scandinavica , 73, 195– 201. Google Scholar CrossRef Search ADS PubMed  12. Christell, H., Birch, S., Horner, K., Rohlin, M. and Lindh, C.; The SEDENTEXCT Project Consortium.( 2012) A framework for costing diagnostic methods in oral health care: an application comparing a new imaging technology with intraoral and panoramic radiography for maxillary canines with eruption disturbance. Community Dentistry and Oral Epidemiology , 40, 351–35 7. Google Scholar CrossRef Search ADS PubMed  13. Petersen, L.B., Olsen, K.R., Christensen, J. and Wenzel, A. ( 2014) Image and surgery-related costs comparing cone beam CT and panoramic imaging before removal of impacted mandibular third molars. Dento Maxillo Facial Radiology , 43, 20140001. Google Scholar CrossRef Search ADS PubMed  14. European Commission. ( 2012) Cone Beam CT for Dental and Maxillofacial Radiology: Evidence Based Guidelines, Radiation Protection Publication 172 . European Commission. http://www.sedentexct.eu/files/radiation_protection_172.pdf. (1 May 2017, date last accessed). 15. Al-Okshi, A., Lindh, C., Salé, H., Gunnarsson, M. and Rohlin, M. ( 2015) Effective dose of cone beam CT (CBCT) of the facial skeleton: a systematic review. British Journal of Radiology , 88, 20140658. Google Scholar CrossRef Search ADS PubMed  16. Haney, E., Gansky, S.A., Lee, J.S., Johnson, E., Maki, K. and Miller, A.J.( 2010) Comparative analysis of traditional radiographs and cone-beam computed tomography volumetric images in the diagnosis and treatment planning of maxillary impacted canines. American Journal of Orthodontics and Dentofacial Orthopedics , 137, 590– 597. Google Scholar CrossRef Search ADS PubMed  17. Botticelli, S., Verna, C., Cattaneo, P.M., Heidmann, J. and Melsen, B. ( 2011) Two- versus three-dimensional imaging in subjects with unerupted maxillary canines. European Journal of Orthodontics , 33, 344– 349. Google Scholar CrossRef Search ADS PubMed  18. Wriedt, S., Jaklin, J., Al-Nawas, B. and Wehrbein, H. ( 2012) Impacted upper canines: examination and treatment proposal based on 3D versus 2D diagnosis. Journal of Orofacial Orthopedics = Fortschritte Der Kieferorthopadie , 73, 28– 40. Google Scholar CrossRef Search ADS PubMed  19. Alqerban, A., Willems, G., Bernaerts, C., Vangastel, J., Politis, C. and Jacobs, R. ( 2014) Orthodontic treatment planning for impacted maxillary canines using conventional records versus 3D CBCT. European Journal of Orthodontics , 36, 698– 707. Google Scholar CrossRef Search ADS PubMed  20. Sorenson, C. and Chalkidou, K. ( 2012) Reflections on the evolution of health technology assessment in Europe. Health Economics, Policy, and Law , 7, 25– 45. Google Scholar CrossRef Search ADS PubMed  21. Ericson, S. and Kurol, J. ( 2000) Incisor root resorptions due to ectopic maxillary canines imaged by computerized tomography: a comparative study in extracted teeth. Angle Orthodontist , 70, 276– 283. Google Scholar PubMed  22. Altman, D.G. ( 1990) Practical statistics for medical research . Chapman and Hall/CRC Texts in Statistical Science, London, UK. 23. Fryback, D.G. and Thornbury, J.R. ( 1991) The efficacy of diagnostic imaging. Medical Decision Making , 11, 88– 94. Google Scholar CrossRef Search ADS PubMed  24. Petersen, L.B., Olsen, K.R., Matzen, L.H., Vaeth, M. and Wenzel, A. ( 2015) Economic and health implications of routine CBCT examination before surgical removal of the mandibular third molar in the Danish population. Dento Maxillo Facial Radiology , 44, 20140406. Google Scholar CrossRef Search ADS PubMed  25. Drummond, M.F., Sculpher, M.J., Claxton, K., Stoddart, G.L. and Torrance, G.W. ( 2015) Methods for the Economic Evaluation of Health Care Programmes . 4th ed. Oxford Medical Publications, Oxford. 26. Husain, J., Burden, D., McSherry, P., Morris, D. and Allen, M; Clinical Standards Committee of the Faculty of Dental Surgery, Royal College of Surgeons of England. ( 2012) National clinical guidelines for management of the palatally ectopic maxillary canine. British Dental Journal , 213, 171– 176. Google Scholar CrossRef Search ADS PubMed  27. Shokri, A., Mortazavi, H., Salemi, F., Javadian, A., Bakhtiari, H. and Matlabi, H. ( 2013) Diagnosis of simulated external root resorption using conventional intraoral film radiography, CCD, PSP, and CBCT: a comparison study. Biomedical Journal , 36, 18– 22. Google Scholar CrossRef Search ADS PubMed  28. Creanga, A.G., Geha, H., Sankar, V., Teixeira, F.B., McMahan, C.A. and Noujeim, M. ( 2015) Accuracy of digital periapical radiography and cone-beam computed tomography in detecting external root resorption. Imaging Science In Dentistry , 45, 153– 158. Google Scholar CrossRef Search ADS PubMed  29. Bjerklin, K. and Guitirokh, C.H. ( 2011) Maxillary incisor root resorption induced by ectopic canines. A follow-up study 13 to 28 years post treatment. Angle Orthodontist , 81, 800– 806. Google Scholar CrossRef Search ADS PubMed  30. Blesser, B. and Ozonoff, D. ( 1972) A model for the radiologic process. Radiology , 103, 515– 521. Google Scholar CrossRef Search ADS PubMed  31. Bjerklin, K. and Bondemark, L. ( 2008) Management of ectopic maxillary canines: variations among orthodontists. Angle Orthodontist , 78, 852– 859. Google Scholar CrossRef Search ADS PubMed  32. Ericson, S. and Kurol, J. ( 1988) Early treatment of palatally erupting maxillary canines by extraction of the primary canines. European Journal of Orthodontics , 10, 283– 295. Google Scholar CrossRef Search ADS PubMed  33. Alqerban, A.et al.   SedentexCT Consortium. ( 2013) Pre-surgical treatment planning of maxillary canine impactions using panoramic vs cone beam CT imaging. Dento Maxillo Facial Radiology , 42, 20130157. Google Scholar CrossRef Search ADS PubMed  34. Hodges, R.J., Atchison, K.A. and White, S.C. ( 2013) Impact of cone-beam computed tomography on orthodontic diagnosis and treatment planning. American Journal of Orthodontics and Dentofacial Orthopedics , 143, 665– 674. Google Scholar CrossRef Search ADS PubMed  35. Al-Salehi, S.K. and Horner, K. ( 2016) Impact of cone beam computed tomography (CBCT) on diagnostic thinking in endodontics of posterior teeth: A before- after study. Journal of Dentistry , 53, 57– 63. Google Scholar CrossRef Search ADS PubMed  36. The 2007 Recommendations of the International Commission on Radiological Protection Annals of the ICRP Vol 37 ( 2007) http://www.icrp.org/publication.asp?id=ICRP Publication 103. (11 May 2017, date last accessed). © The Author(s) 2017. Published by Oxford University Press on behalf of the European Orthodontic Society. All rights reserved. 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Published: Feb 1, 2018

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