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1.
Objectives The preferred reference point to describe the force–moment system exerted upon a tooth is its center of resistance (CR). Morphological data on the dentoalveolar complex can be used to locate this point either three-dimensionally (3D) with the finite element (FE) method, or two-dimensionally (2D) with a mathematical method calculating the centroid of the projected dental root. This study aimed to compare and appraise these two methods with regard to their accuracy and time requirements. Methods Three radiological datasets with permanent teeth were included. Each single 3D dataset was used in each of these patients to derive both a 3D and 2D morphological model of the upper right central incisor. CR levels were evaluated in percent, indicating the relative height as measured from the (averaged levels of the mesial and distal) bony ridge margin to the tooth’s apex. Results Mean CR levels of 42.8% for distalization and 56.5% for lingual movement were obtained from the 3D FE simulations of initial tooth movement. The 2D mathematical model yielded a mean CR level of 44.5%. Compared to this mathematical approach, the 3D FE simulations were around 15 times more time-consuming, with an interactive requirement of around 15 h. Conclusion Because they contain so much more morphological information, 3D FE simulations should offer superior predictability. In addition, they are the only method offering detailed CR identification for specific directions of tooth movement. Before this method can be used in clinical practice, however, there is still a major need to reduce time requirements via further automation of process steps and to investigate how it should be applied to different tooth types. 相似文献
2.
PurposeThe prevalence of the middle distal (MD) canal in the mandibular molar is significantly low among countries including the USA, Spain, Turkey, and Jordan; however, analysis of its prevalence and configuration has not been performed in Saudi Arabia. Therefore, we aimed to assess the prevalence and configuration of the MD canal in Saudi Arabia. MethodsA retrospective analysis of 132 cone-beam computed tomography (CBCT) images was performed to evaluate the presence of the MD canal in patients visiting the Radiology Department of The College of Dentistry in King Saud University between July 2018 and July 2019. The canal was examined if it was confluent with the distobuccal (DB) or distolingual (DL) canals, fin, or independent. Moreover, the distances from the MD canal to the DL and DB canals and cementoenamel junction (CEJ) were recorded. ResultsOne MD canal (0.7%) was observed in 145 teeth. It was confluent with the DL canal. No statistical significance was observed among sex and age. The distances from the MD canal to the DL canal, DB canal, and CEJ were 1.4 mm, 1.9 mm, and 3.1 mm, respectively. ConclusionsThe prevalence of the MD canal was significantly low in a Saudi subpopulation (0.7%). Careful evaluation of CBCT images and the pulpal floor is significantly important to detect the MD canal to ensure a good prognosis. 相似文献
3.
IntroductionLocalization of impacted maxillary canine (IMC) position is essential in orthodontic treatment for accurate orthodontic treatment as well as prognosis. ObjectivesThis study aimed to: 1- investigate the relationship between the locations of IMC in panoramic radiograph (PR) using sectors in relation to their labio-palatal position in cone beam computed tomography (CBCT): 2- report the incisor root resorption in CBCT in relation to its sector location of IMC in PR. Material and MethodsThe study is a retrospective imaging assessment of 60 IMCs in multiple centers in Riyadh, Saudi Arabia. Sector location of IMC was determined on the PR and correlated with each of their labio-palatal positions and resorption of the root of permanent incisors using CBCT. ResultsThere is a significant correlation between sector location and impaction location of IMC. No statistical correlation was found between IMC sector location and lateral incisor root resorption, whereas a significant correlation was found between sector location and central incisor root resorption. ConclusionsFor Sectors I and II, IMC tended to be in either the mid-alveolus or labial location, whereas Sectors III and IV tended to show palatal impaction. Therefore, sector could be a good tool for localization of IMC and to predict the possibility of incisor root resorption. 相似文献
4.
ObjectivesThe purpose of this study is to assess the stages of skeletal maturity in cone beam computed tomography (CBCT), hand–wrist radiography (HWR) and cephalometric radiography (CR) techniques of orthodontic patients, and associate skeletal maturity stages with chronological age, in a Turkish subpopulation. MethodsHand–wrist radiographs, cephalometric radiographs and CBCT of 105 patients were evaluated. For evaluation of HWR, the “Hand Bone Age A Digital Atlas of Skeletal Maturity” of Vicente Gilsanz and Osman Ratib (2005) was used. Skeletal maturation in the cephalometric radiographs and sagittal sections of cervical vertebrae obtained by CBCT were evaluated with Hassel and Farman’s method (1995). All results were re-evaluated 3 weeks later to assess intra-observer reliability. ResultsIntra-observer reliability coefficients of the skeletal maturity stages in HWR, CR, and CBCT were 0.912, 0.595, 0.756 respectively (p?<?0.05). Spearman’s correlation coefficient value between skeletal developmental stages in in HWR, CR, and CBCT was found to be 0.785, 0.875, and 0.791, respectively (p?<?0.05). ConclusionResults of this study reveal that the determination of the skeletal development status with analysis of cervical vertebrae using cephalometric radiographs and CBCT is as reliable method as the evaluation of the hand–wrist radiographs and is compatible with chronological age in a subgroup of the Turkish population. When assessing the skeletal development stages of patients, both CBCT and CR can be used validly, so no extra hand–wrist radiography is required. This information is important for the prevention of increased radiation doses in patients. 相似文献
5.
Objective:To determine the usefulness of panoramic radiographs in determining the labio-palatal position of maxillary impacted canines (MICs) and root resorption of permanent incisors on cone-beam computed tomography (CBCT) in correlation with the mesiodistal position of MICs on panoramic radiographs. Materials and Methods:This retrospective radiographic study reviewed 64 patients with 86 MICs. Subjects were divided into two groups: group I (<15 years old) and group II (>15 years old). The mesiodistal position of the MICs'' cusp tips was classified into five sectors on panoramic radiographs. The labio-palatal position of the MICs and root resorption of permanent incisors were evaluated on CBCT. The statistical correlation between panoramic radiograph and CBCT results was examined using the chi-square test and the Fisher exact test. Results:Most of the positions of MICs were palatal (67%), followed by labial (28%) and mid-alveolus (5%; P < .05). Labial positioned MICs on CBCT were more frequent in panoramic sector 1, mid-alveolus MICs were more common in sector 2, and palatally positioned MICs were more frequent in sectors 3, 4, and 5. The association between sectors of the MICs on panoramic images and the labio-palatal position of the MICs on CBCT was statistically significant ( P < .001). Root resorption of adjacent incisors showed a significant difference according to sector location ( P < .01) and was mainly found in sectors 4 and 5. Conclusions:This study showed that the labio-palatal position of MICs and resorption of permanent incisors might be predicted using sector location on panoramic radiographs. 相似文献
6.
Background and objectiveIn surgical dentistry, shape, location, position, and extent of the anterior loop of mental foramen plays a deliberately imperative landmark during an osteotomy procedure. To evade any neurological disturbance during implant surgery radiological assessment is compulsory. Therefore, the aim of the study was to assess the position and level of mental nerve for placement of implants using Cone-beam computed tomography & Panoramic radiography in the Saudi population. Materials and methodsA total of 150 CBCT and Panoramic radiographs were taken from the patients who visited the Department of Oral Medicine and Radiology. The data collection was done by using the same radiographic pieces of equipment for both CBCT and Panoramic radiographs. CBCT images taken from Kodak 9000 3D, Carestream Health, Inc., New York, USA, and Panoramic Radiographs taken from Panoramic Planmeca ProMax, Helsinki, Finland ( Vujanovic-Eskenazi et al., 2015). The Chi-square test student test was used for statistical analysis. ResultsThe most frequent shape and location of mental foramen in both CBCT and Panoramic radiographs were oval and in between the first and second premolar, both in CBCT & PR views. The visibility of mental loop on CBCT & PR view showed that; visibility of mental loop in CBCT was higher with 42(56%) as compared with PR view 26(34.66%) with statistically significant p-value 0.014. The mean length of the mental loop on CBCT was statistically significant (p = 0.001). But the mean distance from the lower point of the mental foramen to the lower border of the mandible was not statistically significant. ConclusionBased on the results of the present study; the visibility of the mental loop and its extension is more in CBCT as compared with PR views. Therefore, we recommended CBCT, during of implant surgery. 相似文献
7.
Background and objectiveIn surgical dentistry, shape, location, position, and extent of the anterior loop of mental foramen plays a deliberately imperative landmark during an osteotomy procedure. To evade any neurological disturbance during implant surgery radiological assessment is compulsory. Therefore, the aim of the study was to assess the position and level of mental nerve for placement of implants using Cone-beam computed tomography & Panoramic radiography in the Saudi population. Materials and methodsA total of 150 CBCT and Panoramic radiographs were taken from the patients who visited the Department of Oral Medicine and Radiology. The data collection was done by using the same radiographic pieces of equipment for both CBCT and Panoramic radiographs. CBCT images taken from Kodak 9000 3D, Carestream Health, Inc., New York, USA, and Panoramic Radiographs taken from Panoramic Planmeca ProMax, Helsinki, Finland (Vujanovic-Eskenazi et al., 2015). The Chi-square test student test was used for statistical analysis. ResultsThe most frequent shape and location of mental foramen in both CBCT and Panoramic radiographs were oval and in between the first and second premolar, both in CBCT & PR views. The visibility of mental loop on CBCT & PR view showed that; visibility of mental loop in CBCT was higher with 42(56%) as compared with PR view 26(34.66%) with statistically significant p-value 0.014. The mean length of the mental loop on CBCT was statistically significant (p = 0.001). But the mean distance from the lower point of the mental foramen to the lower border of the mandible was not statistically significant. ConclusionBased on the results of the present study; the visibility of the mental loop and its extension is more in CBCT as compared with PR views. Therefore, we recommended CBCT, during of implant surgery. 相似文献
8.
Objective: This study aimed to investigate the prevalence of pre-eruptive intracoronal resorption (PIR) using cone beam computed tomography (CBCT) and panoramic radiography and to compare the findings of these imaging techniques. Methods: This retrospective study consisted of 733 patients who had at least one unerupted tooth and had undergoneimaging with both three-dimensional (3D) CBCT and two-dimensional (2D) panoramic radiography. In all the images, the number of teeth with intracoronal resorption, affected tooth type and number, and size and location of the PIR defects were recorded. The McNemar test was used to compare the prevalence of PIR in the CBCT and panoramic images. Results: Fewer PIR defects were detected in the panoramic images (3.1% of the patients) than in the CBCT images (9.5% of the patients) ( p.001). According to the CBCT images, the distribution of PIR defects was as follows: third molars (59.5%), canine teeth (11.4%), second molars and premolars (7.6% for both), supernumerary teeth (5.1%), second molars (3.8%), central incisors (2.5%), and first premolar and primary second molar teeth (1.5% for both). According to the scoring classification system for PIR defects, PIR 1 defects were the most common (65.8%), followed by PIR 3 (24.1%) and PIR 2 (10.1%). Of these defects, 69.6% were located in the central aspect of the crown. Ectopically positioned teeth showing intracoronal resorption accounted for 51.9% of the cases of PIR. Conclusions: CBCT detected more cases of PIR than panoramic radiography. The mandibular third permanent molar was the most commonly affected tooth. 相似文献
9.
Objective:To identify anatomic structures in three dimensions and examine their reliability to be used as landmarks in a three-dimensional coordinate cephalometric analysis, using cone-beam computerized tomography (CBCT). Materials and Methods:Thirty CBCT images were randomly selected for landmark location. Forty-two anatomic landmarks, which are not included in the traditional cephalometric landmarks, were chosen based on radiographic characteristics that make them pragmatic to mark in the CBCT image slices. The principal investigator marked the full set of landmarks on the software by navigating in the X, Y, and Z axes for every image three times, with each measurement trial being at least 1 week apart. One other investigator also located the landmarks once for each image for reliability purposes. Intraclass correlation coefficients (ICCs) were used to analyze the mean differences in landmark location in all axes. Results:Intra- and interexaminer reliability for x, y, and z coordinates for all landmarks had ICC greater than 0.95 with confidence interval of 0.88–0.99. Mean measurement differences found were <1.4 mm for all landmarks in all three coordinates. Mean measurement error differences obtained in the principal investigator''s trials were primarily <0.5 mm. Conclusion:The most reliable and reproducible landmarks tested for use in CBCT are mental foramina, infraorbital foramina, inferior hamulus, dens axis, foramina transversarium of atlas, medial and lateral condyles of the mandible, superior clinoid processes, and mid-clinoid. 相似文献
10.
AbstractObjectives. Cone beam computed tomography (CBCT) was introduced to Norwegian dental clinics in 2007. The aim of the study was to investigate how dental clinics use this imaging modality, including factors related to workflow and image quality, and to evaluate dentists’ opinions on and experiences of using it. Materials and methods. A web-based 59-item questionnaire regarding the clinical use of CBCT was sent to all 39 CBCT clinics in Norway. Results. Twenty-nine clinics (74%) responded. Most respondents (93%) were from clinics with more than one dentist and 83% had at least one specialist. All clinics had digital intraoral x-ray receptors and all but one had panoramic imaging. The most common indications for CBCT were implant treatment planning (34% of all clinics) and localization of impacted teeth (43% of specialist clinics). Seventy-two per cent of clinics reported an average of four or fewer CBCT examinations each week and 83% of respondents were subjectively satisfied with the image quality. The most commonly used enhancement functions were contrast (97%), brightness (90%) and zoom (86%). Conclusions. The Norwegian CBCT clinics surveyed were fully digitized and had multiple dentists. Periodontists and oral and maxillofacial surgeons were the most frequent specialties represented in the clinics. Clinics with only dental specialists performed more CBCT examinations/week than clinics with general practitioners or both general practitioners and specialists. The most common indications for CBCT examinations were related to treatment planning. This study found some challenges related to image quality and communication within the radiological team. 相似文献
11.
IntroductionThe aim of this study was to evaluate the accuracy of two imaging methods in diagnosing apical periodontitis (AP) using histopathological findings as a gold standard. MethodsThe periapex of 83 treated or untreated roots of dogs' teeth was examined using periapical radiography (PR), cone-beam computed tomography (CBCT) scans, and histology. Sensitivity, specificity, predictive values, and accuracy of PR and CBCT diagnosis were calculated. ResultsPR detected AP in 71% of roots, a CBCT scan detected AP in 84%, and AP was histologically diagnosed in 93% (p = 0.001). Overall, sensitivity was 0.77 and 0.91 for PR and CBCT, respectively. Specificity was 1 for both. Negative predictive value was 0.25 and 0.46 for PR and CBCT, respectively. Positive predictive value was 1 for both. Diagnostic accuracy (true positives + true negatives) was 0.78 and 0.92 for PR and CBCT (p = 0.028), respectively. ConclusionA CBCT scan was more sensitive in detecting AP compared with PR, which was more likely to miss AP when it was still present. 相似文献
12.
IntroductionCone-beam computed tomographic (CBCT) imaging is useful in detecting apical periodontitis, which is often missed in periapical (PA) radiographs. This study aimed to identify preoperative predictors correlated with the presence of apical periodontitis visible only in CBCT images and to investigate the important characteristics of such lesions. MethodsIn total, 332 consecutive patients with both PA radiographs and CBCT images were enrolled in this study. The patients’ clinical charts were reviewed retrospectively to collect information regarding their symptoms and diagnoses. Periapical lesions were assessed using a modified CBCT PA index by 2 endodontists. Patient-related factors (age, sex, and symptoms) and tooth-related factors (tooth type, location, pulp status, and pulpal diagnosis) were assessed to determine their relationships with the presence of apical periodontitis visible only in CBCT images. ResultsApical periodontitis was detected in 24.6% and 35.5% of untreated teeth by PA radiographs and CBCT images, respectively. In a multivariate logistic regression analysis, pulp necrosis was significantly correlated with the presence of apical periodontitis visible only in CBCT images (odds ratio = 5.401; 95% confidence interval, 1.911–15.265; P = .001); the involvement of molars showed borderline nonsignificant correlation (odds ratio = 2.843; 95% confidence interval, 0.990–8.164; P = .052). Lesion sizes smaller than 2 mm in diameter and the involvement of molars were significant factors of lesions visible only in CBCT images ( P < .05). ConclusionsPulp necrosis was a preoperative predictor of apical periodontitis visible only in CBCT images. This research could provide a proper indication for CBCT imaging at diagnostic stages. 相似文献
13.
ObjectivesTo determine the different impact of moment-to-force ratio (M:F) variation for each tooth and spatial plane and to develop a mathematical model to predict the orthodontic movement for every tooth. Materials and MethodsTwo full sets of teeth were obtained combining cone-beam computed tomography (CBCT) and optical scans for two patients. Subsequently, a finite element analysis was performed for 510 different force systems for each tooth to evaluate the centers of rotation. ResultsThe center of C ROT locations were analyzed, showing that the M:F effect was related to the spatial plane on which the moment was applied, to the force direction, and to the tooth morphology. The tooth dimensions on each plane were mathematically used to derive their influence on the tooth movement. ConclusionThis study established the basis for an orthodontist to determine how the teeth move and their axes of resistance, depending on their morphology alone. The movement is controlled by a parameter (k), which depends on tooth dimensions and force system features. The k for a tooth can be calculated using a CBCT and a specific set of covariates. 相似文献
14.
BackgroundSinus lift procedures have become a routine and reliable way to gain bone volume in the posterior maxilla for implant placement. The presence of an antral septum in the maxillary sinus increases the risk of complications and subsequent implant failure. This study was designed to estimate the prevalence of maxillary sinus septa and its correlation with age, sex, dentition status and the risk of perforating the Schneiderian membrane using cone beam computed tomography (CBCT). MethodsThis retrospective, cross-sectional study consisted of a total of 178 CBCT images (100 male, 78 female), 63.0% were dentate, 36.0% partially dentate and 1.1% edentate subjects with a mean age of 35 ± 45 years was analyzed to determine the prevalence, height, location, and orientation of maxillary sinus septa. The septa were classified according to the modified Al-Faraje’s classification into VII septal patterns, and the risk of perforation of the Schneiderian membrane was estimated. The chi-square test was used to compare categorical variables, and Student’s t-test and the Kruskal-Wallis test were used to compare continuous variables. ResultsSepta were present in 25.6% of the sinus segments (37.64% of the subjects). The mean septum height was 5.22 mm ± 2.06 in males and 6.27 mm ± 3.55 in females. The majority of septa were located in the middle 76.92%, while 4.40% were anterior, and 18.68% were posterior; 76.92% were in a buccopalatal direction, whereas 23.08% were in an anteroposterior direction. Class III was the most prevalent type. Overall, 60.4% had a moderate risk of membrane perforation, 30.8% had a low risk, and only 8.8% had a high risk .ConclusionThree-dimensional CBCT image analyses can be used as a diagnostic tool to provide accurate information that can help avoid unnecessary intra- and postoperative complications during sinus augmentation procedures by identifying the anatomic structures inherent to the maxillary sinus. 相似文献
15.
BackgroundMandibular neurovascular canal contents may be vulnerable to damage during mandibular surgical procedures. Greater knowledge of the location and configuration of the mandibular canal can help in the safe performance of these procedures in the dental clinic. Cross-sectional CBCT imaging is a good modality for studying the course, location, configuration and accessory branches of the mandibular canal. The aim of this study was to observe the branching of the mandibular canal at different segments of the mandible and mandibular tooth groups. MethodsCBCT images of 116 mandibular halves were included in this study. The presence of secondary branching of the mandibular canal in the ramus, retromolar area, molar and premolar teeth as well as the length, diameter and angle of these branches were observed. Resultssixty nine mandibular halves (59.5%), had a main canal with no branching, There were 36 IAC (31%) with one, 8 (6.9%) with two, 2 (1.7%) with three and 1(0.9%) with 5 accessory branches. Of these secondary branches, 16 (25.4%) were in the ramus, 16(25.4%) in the retromolar, and 31(49.2%) in the molar regions. ConclusionAdvanced cross-sectional imaging modalities especially CBCT is a suitable tool for observing anatomic characteristics of mandibular canal to preserve this vital structure in surgical procedures. 相似文献
16.
AimThe aim of this is to evaluate the prevalence and location of the accessory mental foramen (AMF) in a Saudi population using cone-beam computed tomography (CBCT) .MethodologyCBCT data were retrieved from two dental facilities at two universities located in two different cities and filtered over a period of four years. The scans were aligned when the AMF was noticed, and then the size of both the AMF and mental foramen (MF), its location, and the distance from the AMF to the MF were recorded. The AMF measurements were compared between males and females and between the two sides of the mandible. ResultsIn total, 603 CBCT scans were investigated. The percentage of scans with an AMF was 9.95% (n = 60), and AMFs were almost equally distributed on both sides. Only four cases (0.66%) of a second AMF were detected among the scans. The MFs on both sides were significantly larger in males than in females (P > 0.05), but they showed no differences in the sizes of the AMFs. The AMFs were most commonly located inferior and posterior to the MF. The distance between the MF and AMF ranged from 2.32 to 5 mm. ConclusionsThe prevalence of the AMF in this Saudi population was 9.95%, and it was significantly more prevalent in males than in females. Its proximity to the MF makes it clinically important to conduct proper detailed planning prior to performing any procedure that might risk the vital structures. 相似文献
17.
IntroductionThis report of 2 cases describes the diagnostic procedures used to identify 2 Stafne's bone cavities (SBC) found in unusually anterior locations in the mandible, both mimicking periapical lesions of endodontic origin. MethodsIn the first patient, a 47-year-old man, an SBC was diagnosed in the area of teeth #27, 28, and 29. In the second patient, a 62-year-old man, the SBC was a fortuitous finding, because this patient was referred for dental implant therapy. ResultsIn both cases, the final diagnosis was achieved by using limited cone beam computed tomography (CBCT) and magnetic resonance imaging (MRI). In both patients, the lingual bone cavity was found to be occupied by accessory salivary gland tissue. ConclusionsThe combination of CBCT and MRI as noninvasive diagnostic techniques seems ideal to avoid surgical explorations, incisional biopsies, or enucleations of the lesion for diagnostic purposes. 相似文献
19.
Abstract Objective. The ‘retromolar’ nerve is a collateral branch of the inferior alveolar nerve. Cone-beam computed tomography (CBCT) provides higher resolution images. This CBCT study reports the frequency of the retromolar nerve. Materials and methods. From 2007–2010 the CBCT study of 233 hemi-mandibles have been examined. The CBCT study was obtained from an investigation of the posterior mandibular region in 187 patients suffering from different pathologies and it was aimed at detecting in patients the presence of a retromolar canal and foramen. Results. Thirty-four retromolar canals with a foramen were detected on 233 CBCT (14.6%) in 30 out of 187 patients (16%). In the 46 patients who underwent CBCT bilaterally, the retromolar canal was found in nine subjects (19.6%) and was present bilaterally in four subjects, for an incidence of 8.7%. Conclusions. The results suggest that the radiological frequency of the retromolar nerve is notable, with a possible relevance in the surgical approach of the mandibular retromolar area. The presence of a retromolar canal, well detected with CBCT, may warn clinicians about the possibility of inadequate pre-surgical anaesthesia, local intra-operative bleeding and post-operative alterations of the sensation in the third molar area. 相似文献
20.
ObjectivesThe lack of standardized X-ray imaging remains a challenge for comparative studies on spatial scans acquired from different clinic-specific X-ray scanners. The central objectives of this study are: 1) to delineate mineral density (MD) values, and 2) generate spatial MD maps of various physiologic and pathologic biominerals, and 3) propose a standardization protocol within the safe-operating zone of a CT scanner that underpins normalization of absorbed dose to shape and density of tissues. MethodsA systematic approach to propose a standardization protocol for CT imaging in vivo included: 1) estimation of pathologic MD ranges by performing a comparative meta-analysis on 2009–2019 data from the PubMed database; 2) calibration of cone-beam CT (CBCT) and micro-CT scanners with phantoms of known mineral densities (0, 250, 500, 750 and 3000 mg/cc) and shapes (cylinders and polyhedrons); 3) scanning craniofacial bones (N = 5) and dental tissues (N = 5), and ectopic minerals from humans (N = 3 each, pulp, salivary gland, kidney and prostrate stones, and penile and vascular plaques); 4) underscoring the effect of shape-factor (surface area-to-volume ratio) on MD of biominerals. ResultsHigher MDs of physiologic and pathologic cortical bones (504–1009 mg/cc) compared to trabecular bone (82–212 mg/cc) were observed. An increase in shape-factor increased the CBCT error in MD measurement and revealed that the scanner resolution is dependent on the absorbed dose and shape-factor of detectable features. SignificanceCT scanners should be calibrated with phantoms containing segments of known shape-factors and mineral densities to identify safe-operating zones. The calibrated approach will narrow the gap between length-scale dependent measurements, and will permit spatiotemporal quantitative and reliable detection of pathologies. 相似文献
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