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Yadegari A, Safi Y, Shahbazi S, Yaghoutiazar S, Ghazizadeh Ahsaie M. Assessment of CBCT gray value in different regions-of-interest and fields-of-view compared to Hounsfield unit. Dentomaxillofac Radiol 2023; 52:20230187. [PMID: 37874074 DOI: 10.1259/dmfr.20230187] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2023] Open
Abstract
OBJECTIVES Different factors can affect the discrepancy between the gray value (GV) measurements obtained from CBCT and the Hounsfield unit (HU) derived from multidetector CT (MDCT), which is considered the gold-standard density scale. This study aimed to explore the impact of region of interest (ROI) location and field of view (FOV) size on the difference between these two scales as a potential source of error. METHODS Three phantoms, each consisting of a water-filled plastic bin containing a dry dentate human skull, were prepared. CBCT scans were conducted using the NewTom VGi evo system, while MDCT scans were performed using Philips system. Three different FOV sizes (8 × 8 cm, 8 × 12 cm, and 12 × 15 cm) were used, and the GVs obtained from eight distinct ROIs were compared with the HUs from the MDCT scans. The ROIs included dental and bony regions within the anterior and posterior areas of both jaws. Statistical analyses were performed using SPSS v. 26. RESULTS The GVs derived from CBCT images were significantly influenced by both ROI location and FOV size (p < 0.05 for both factors). Following the comparison between GVs and HUs, the anterior mandibular bone ROI represented the minimum error, while the posterior mandibular teeth exhibited the maximum error. Moreover, the 8 × 8 cm and 12 × 15 cm FOVs resulted in the lowest and highest degrees of GV error, respectively. CONCLUSIONS The ROI location and the FOV size can significantly affect the GVs obtained from CBCT images. It is not recommended to use the GV scale within the posterior mandibular teeth region due to the potential for error. Additionally, selecting smaller FOV sizes, such as 8 × 8 cm, can provide GVs closer to the gold-standard numbers.
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Affiliation(s)
- Atiye Yadegari
- Department of Pediatric Dentistry, School of Dentistry, Hamadan University of Medical Sciences, Hamadan, Iran
| | - Yaser Safi
- Department of Oral and Maxillofacial Radiology, School of Dentistry, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Soheil Shahbazi
- Dental Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Sahar Yaghoutiazar
- Department of Pediatric Dentistry, School of Dentistry, Hamadan University of Medical Sciences, Hamadan, Iran
| | - Mitra Ghazizadeh Ahsaie
- Department of Oral and Maxillofacial Radiology, School of Dentistry, Shahid Beheshti University of Medical Sciences, Tehran, Iran
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Safi Y, Ghazizadeh Ahsaie M, Jafarian Amiri M, Khalaf K. Effect of the Field of View Size on CBCT Artifacts Caused by the Presence of Metal Objects in the Exomass. Int J Dent 2022; 2022:1-10. [PMID: 36117513 PMCID: PMC9481401 DOI: 10.1155/2022/2071108] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2022] [Revised: 08/08/2022] [Accepted: 08/26/2022] [Indexed: 11/29/2022] Open
Abstract
Materials and Methods In this in vitro experimental study, titanium implants, teeth with cobalt-chromium (Co-Cr) intracanal posts, and teeth with mesio-occluso-distal (MOD) amalgam restorations were placed in an empty socket of the extracted third molar of a human mandible. These metallic materials were differently arranged in the exomass (zone outside of the FOV). A polypropylene tube containing dipotassium phosphate was placed in the empty socket of the right canine tooth in a dry human mandible. CBCT scans were taken with a NewTom VGI (Verona, Italy) scanner using a 6 × 6 cm and an 8 × 8 cm FOV. The histogram tool of OnDemand software (Cybermed, Seoul, Korea) was used to select circles with a 1.5 mm diameter as the (ROI) at the center of the homogenous solution of dipotassium phosphate tube on the axial plane. The mean gray value (GV) and its standard deviation (SD) in the region of interest (ROI) were calculated (P > 0.05). The data were analyzed by SPSS 26. Results The reduction in the size of the FOV significantly decreased the mean GV (P < 0.001). Metal objects in the exomass significantly decreased the mean GV (P < 0.001), and minimum mean GV and maximum SD were recorded for amalgam, followed by Co-Cr intracanal posts, and titanium implants. The unilateral presence of a metal object was associated with a higher mean GV and lower SD (P < 0.001). Conclusion Using a smaller FOV increases the size of the exomass, which may negatively affect the image quality. Metal objects in the exomass decrease the GV of CBCT scans and adversely affect the image quality.
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Eguren M, Holguin A, Diaz K, Vidalon J, Linan C, Pacheco-Pereira C, Lagravere Vich MO. Can gray values be converted to Hounsfield units? A systematic review. Dentomaxillofac Radiol 2022; 51:20210140. [PMID: 34148350 PMCID: PMC8693322 DOI: 10.1259/dmfr.20210140] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
OBJECTIVES The purpose of this systematic review was to answer the focus question: "Could the gray values (GVs) from CBCT (cone beam computed tomography) be converted to Hounsfield units (HUs) in multidetector computed tomography (MDCT)?" METHODS The included studies try to answer the research question according to the PICO strategy. Studies were gathered by searching several electronic databases and partial grey literature up to January 2021 without language or time restrictions. The methodological assessment of the studies was performed using The Oral Health Assessment Tool (OHAT) for in vitro studies and the Quality Assessment of Diagnostic Accuracy Studies (QUADAS-2) for in vivo studies. The Grading of Recommendations Assessment, Development and Evaluation (GRADE system) instrument was applied to assess the level of evidence across the studies. RESULTS 2710 articles were obtained in Phase 1, and 623 citations remained after removing duplicates. Only three studies were included in this review using a two-phase selection process and after applying the eligibility criteria. All studies were methodologically acceptable, although in general terms with low risks of bias. There are some included studies with quite low and limited evidence estimations and recommendation forces; evidencing the need for clinical studies with diagnostic capacity to support its use. CONCLUSIONS This systematic review demonstrated that the GVs from CBCT cannot be converted to HUs due to the lack of clinical studies with diagnostic capacity to support its use. However, it is evidenced that three conversion steps (equipment calibration, prediction equation models, and a standard formula (converting GVs to HUs)) are needed to obtain pseudo Hounsfield values instead of only obtaining them from a regression or directly from the software.
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Affiliation(s)
- Marjorie Eguren
- Master in Orthodontic Graduate Program, Faculty of Stomatology, Universidad Peruana Cayetano Heredia, Lima, Perú
| | - Anderson Holguin
- Program of Orthodontics, Faculty of Stomatology, Universidad Peruana Cayetano Heredia, Lima, Perú
| | - Karla Diaz
- Stomatology Second Specialty, Universidad Privada San Juan Bautista, Lima, Perú
| | - Jose Vidalon
- Department of Stomatology, Faculty of Stomatology, Universidad Peruana Cayetano Heredia, Lima, Perú
| | - Carlos Linan
- Department of Orthodontics, Faculty of Stomatology, Universidad Peruana Cayetano Heredia, Lima, Perú
| | - Camila Pacheco-Pereira
- University of Alberta, Faculty of Medicine and Dentistry, School of Dentistry, Dental Radiology, 11405-87 Ave, Edmonton, Canada
| | - Manuel Oscar Lagravere Vich
- University of Alberta, Faculty of Medicine and Dentistry, School of Dentistry, Orthodontic Graduate Program, ECHA 5-524, 11405-87 Ave, Edmonton, Canada
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Deng F, Touska P, Reinshagen KL, Curtin HD, Juliano AF. Diagnostic Performance of Conebeam CT Pixel Values in Active Fenestral Otosclerosis. AJNR Am J Neuroradiol 2021; 42:1667-1670. [PMID: 34140277 DOI: 10.3174/ajnr.a7192] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2021] [Accepted: 04/16/2021] [Indexed: 11/07/2022]
Abstract
BACKGROUND AND PURPOSE Quantitative bone densitometry on multidetector CT of the temporal bone is a diagnostic adjunct for otosclerosis in its active (spongiotic) phase, but translating this technique to conebeam CT is limited by the technical variability of conebeam CT pixel values. The purpose of this study was to evaluate the performance of internally calibrated conebeam CT pixel value measurements that can enable the determination of active fenestral otosclerosis (otospongiosis). MATERIALS AND METHODS This study included 37 ears in 22 patients with a clinical diagnosis of otospongiosis in those ears and 35 ears in 22 control patients without the diagnosis. Temporal bone conebeam CT was performed. ROIs were set anterior to the oval window, in the lateral semicircular canal bone island, and in a nearby aerated space. Mean conebeam CT pixel values in these regions determined the relative attenuation ratio of the area anterior to the oval window normalized to normal otic capsule bone and air. RESULTS The relative attenuation ratio for cases of otospongiosis was significantly lower than that for controls (P < .001). Based on receiver operating characteristic analysis, the optimal cutoff relative attenuation ratio was 0.876, which had an accuracy of 97.2% for the diagnosis of otospongiosis. CONCLUSIONS Internally calibrated pixel value ratios in temporal bone conebeam CT can feasibly help diagnose active/spongiotic-phase fenestral otosclerosis in an objective manner.
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Affiliation(s)
- F Deng
- From the Department of Radiology (F.D.), Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts
| | - P Touska
- Department of Radiology (P.T), Guy's Hospital, Guy's and St. Thomas' Hospitals National Health Service Foundation Trust, London, UK
| | - K L Reinshagen
- Department of Radiology (K.L.R, H.D.C., A.F.J.), Massachusetts Eye and Ear, Harvard Medical School, Boston, Massachusetts
| | - H D Curtin
- Department of Radiology (K.L.R, H.D.C., A.F.J.), Massachusetts Eye and Ear, Harvard Medical School, Boston, Massachusetts
| | - A F Juliano
- Department of Radiology (K.L.R, H.D.C., A.F.J.), Massachusetts Eye and Ear, Harvard Medical School, Boston, Massachusetts.
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Akmal JS, Salmi M, Hemming B, Teir L, Suomalainen A, Kortesniemi M, Partanen J, Lassila A. Cumulative Inaccuracies in Implementation of Additive Manufacturing Through Medical Imaging, 3D Thresholding, and 3D Modeling: A Case Study for an End-Use Implant. Applied Sciences 2020; 10:2968. [DOI: 10.3390/app10082968] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
In craniomaxillofacial surgical procedures, an emerging practice adopts the preoperative virtual planning that uses medical imaging (computed tomography), 3D thresholding (segmentation), 3D modeling (digital design), and additive manufacturing (3D printing) for the procurement of an end-use implant. The objective of this case study was to evaluate the cumulative spatial inaccuracies arising from each step of the process chain when various computed tomography protocols and thresholding values were independently changed. A custom-made quality assurance instrument (Phantom) was used to evaluate the medical imaging error. A sus domesticus (domestic pig) head was analyzed to determine the 3D thresholding error. The 3D modeling error was estimated from the computer-aided design software. Finally, the end-use implant was used to evaluate the additive manufacturing error. The results were verified using accurate measurement instruments and techniques. A worst-case cumulative error of 1.7 mm (3.0%) was estimated for one boundary condition and 2.3 mm (4.1%) for two boundary conditions considering the maximum length (56.9 mm) of the end-use implant. Uncertainty from the clinical imaging to the end-use implant was 0.8 mm (1.4%). This study helps practitioners establish and corroborate surgical practices that are within the bounds of an appropriate accuracy for clinical treatment and restoration.
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Candemil AP, Salmon B, Freitas DQ, Haiter-Neto F, Oliveira ML. Distribution of metal artifacts arising from the exomass in small field-of-view cone beam computed tomography scans. Oral Surg Oral Med Oral Pathol Oral Radiol 2020; 130:116-125. [PMID: 32057753 DOI: 10.1016/j.oooo.2020.01.002] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2019] [Revised: 12/11/2019] [Accepted: 01/10/2020] [Indexed: 12/19/2022]
Abstract
OBJECTIVES To evaluate the distribution of metal artifacts from the exomass in small field-of-view (FOV) cone beam computed tomography (CBCT) scans. STUDY DESIGN An image phantom was scanned by using 3 CBCT units. Metal objects were positioned in the exomass, and additional CBCT scans were obtained. Mean gray values were obtained from 16 homogeneous areas and the standard deviation was calculated to quantify gray level inhomogeneity according to distinct zones of the FOV: total area and outer, inner, right, left, and mid-zones. The discrepancy between each zone and the total area was calculated to compare different CBCT units. Mean gray, gray level inhomogeneity, and discrepancy values were separately assessed by using analysis of variance (ANOVA) and Tukey's test (α = 0.05). RESULTS Overall, the mean gray values were significantly lower in the inner zone, and the gray level inhomogeneity values were significantly higher in the inner and mid-zones irrespective of the presence of metal objects in the exomass. The 3 CBCT units presented significantly different discrepancy values in most conditions. CONCLUSIONS The distribution of metal artifacts from the exomass follows the inherent gray value dispersion of CBCT images, with greater inhomogeneity in the inner zone of the FOV. This is exacerbated when metal objects are in the exomass.
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Affiliation(s)
- Amanda P Candemil
- Division of Oral Radiology, Department of Oral Diagnosis, Piracicaba Dental School, University of Campinas, Piracicaba (São Paulo), Brazil.
| | - Benjamin Salmon
- Université de Paris, Orofacial Pathologies, Imaging and Biotherapies EA2496 Lab, Montrouge, France; Dental Medicine Department, AP-HP, Bretonneau Hospital, Paris, France
| | - Deborah Queiroz Freitas
- Division of Oral Radiology, Department of Oral Diagnosis, Piracicaba Dental School, University of Campinas, Piracicaba (São Paulo), Brazil
| | - Francisco Haiter-Neto
- Division of Oral Radiology, Department of Oral Diagnosis, Piracicaba Dental School, University of Campinas, Piracicaba (São Paulo), Brazil
| | - Matheus Lima Oliveira
- Division of Oral Radiology, Department of Oral Diagnosis, Piracicaba Dental School, University of Campinas, Piracicaba (São Paulo), Brazil
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Mehralizadeh S, Talaipour AR, Olyaee P, Amiri siavoshani M. Correlation Between Tissue Densities in Computed Tomography and Three Different Cone-Beam Computed Tomography Units (In Vitro). J Res Dentomaxillofac Sci 2020. [DOI: 10.29252/jrdms.5.1.13] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
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Fang R, Mazur T, Mutic S, Khan R. The impact of mass density variations on an electron Monte Carlo algorithm for radiotherapy dose calculations. Phys Imaging Radiat Oncol 2018; 8:1-7. [PMID: 33458409 PMCID: PMC7807677 DOI: 10.1016/j.phro.2018.10.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/08/2018] [Revised: 10/19/2018] [Accepted: 10/23/2018] [Indexed: 01/21/2023]
Abstract
Background and Purpose A key step in electron Monte Carlo dose calculation requires converting Computed Tomography (CT) numbers from a tomographic acquisition to a mass density. This study investigates the dosimetric consequences of perturbations applied to a calibration table between CT number and mass density. Materials and Methods A literature search was performed to define lower and upper bounds for physically reasonable perturbations to a reference CT number to mass density calibration table. Electron beam dose was calculated for ten patients using these variations and the results were compared to clinical plans originally derived with a reference calibration table. Dose differences both globally and in the Planning Target Volume (PTV) were assessed using dose- and volume-based metrics and 3- dimensional gamma analysis for each patient. Results Small but statistically significant differences were observed between perturbations and reference data for certain metrics including volume of the 50% prescription isodose. Upper and lower variations in CT number to mass density calibration yielded mean values of V50% that were 4.4% larger and 2.1% smaller than reference values respectively. Gamma analysis using 3%/3mm criteria indicated >99% passing rate for the PTV for all patients. Global gamma analysis for some patients showed larger discrepancies possibly due to large electron path lengths through inhomogeneities. Conclusions In most patients, physically reasonable perturbations in CT number to mass density curves will not induce clinically significant impact on calculated target dose distributions. Strong dependence of electron transport on voxel material may produce dose speckle throughout the volume. Care should be taken in evaluating critical structures at depths beyond the target volume in highly heterogeneous regions.
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Affiliation(s)
- Raymond Fang
- Department of Radiation Oncology, Washington University School of Medicine, St. Louis, MO, USA
| | - Thomas Mazur
- Department of Radiation Oncology, Washington University School of Medicine, St. Louis, MO, USA
| | - Sasa Mutic
- Department of Radiation Oncology, Washington University School of Medicine, St. Louis, MO, USA
| | - Rao Khan
- Department of Radiation Oncology, Washington University School of Medicine, St. Louis, MO, USA
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Genisa M, Shuib S, Rajion ZA, Arief EM, Hermana M. Density estimation based on the Hounsfield unit value of cone beam computed tomography imaging of the jawbone system. Proc Inst Mech Eng H 2018; 232:954411918806333. [PMID: 30309283 DOI: 10.1177/0954411918806333] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
The aim of this study is to investigate the estimation of density from the Hounsfield unit of cone beam computed tomography data in dental imaging, especially for dental implant application. A jaw phantom with various known densities of anatomical parts (e.g. soft tissue, cortical bone, trabecular bone, tooth enamel, tooth dentin, sinus cavity, spinal cord and spinal disc) has been used to test the accuracy of the Hounsfield unit of cone beam computed tomography in estimating the mechanical density (true density). The Hounsfield unit of cone beam computed tomography data was evaluated via the MIMICS software using both two-dimensional and three-dimensional methods, and the results showed correlation with the true density of the object. In addition, the results revealed that the Hounsfield unit of cone beam computed tomography and bone density had a logarithmic relation, rather than a linear one. To this end, the correlation coefficient of logarithmic correlation (R2 = 0.95) is higher than the linear one (R2 = 0.77).
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Affiliation(s)
- Maya Genisa
- 1 Medical Faculty of YARSI University, Jakarta, Indonesia
| | - Solehuddin Shuib
- 2 Faculty of Mechanical Engineering, Universiti Teknologi MARA, Shah Alam, Malaysia
| | - Zainul Ahmad Rajion
- 3 School of Dental Sciences, Health Campus, Universiti Sains Malaysia, Kota Bharu, Malaysia
| | - Erry Mochamad Arief
- 3 School of Dental Sciences, Health Campus, Universiti Sains Malaysia, Kota Bharu, Malaysia
| | - Maman Hermana
- 4 Universiti Teknologi PETRONAS, Seri Iskandar, Malaysia
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Stokbro K, Thygesen T. A 3-Dimensional Approach for Analysis in Orthognathic Surgery—Using Free Software for Voxel-Based Alignment and Semiautomatic Measurement. J Oral Maxillofac Surg 2018; 76:1316-1326. [DOI: 10.1016/j.joms.2017.11.010] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2017] [Revised: 10/04/2017] [Accepted: 11/04/2017] [Indexed: 10/18/2022]
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Abstract
OBJECTIVE Rapid maxillary expansion (RME) is usually used for expanding the maxillary bony segments. Many studies have assessed the dental and skeletal effects of the expansion treatment but few studies evaluated soft tissue changes using cone beam computed tomography (CBCT) images. This study aims to compare soft tissue changes after RME in prepubertal and postpubertal subjects using CBCT images. The null hypothesis of this study is there is no difference between prepubertal and postpubertal patients in soft tissue changes after RME treatment. MATERIALS AND METHODS A total of 28 patients (10 males, 18 females) with a bonded type of rapid maxillary expander were included in this study. The patients were divided into two subgroups according to cervical vertebral maturation stage. Prepubertal and postpubertal groups were obtained. Following the selection of CBCT images from the archive, pretreatment (T0) and postretention measurements (T1) were performed. Nine linear and one angular measurement for a total of 10 measurements were evaluated on each CBCT image. The mean differences between T0 and T1 measurements were compared by using the paired-samples t test and significance was set at P < 0.05. RESULTS The largest median increase was found in cheek projection of the prepubertal group. Changes in soft tissue nasal base, philtrum width, upper lip length, columella width, columella height, and cheek projection were statistically significant (P < 0.001) in both groups. No significant differences were observed in soft tissue alar base, nostril width, nostril height, and nasolabial angle. CONCLUSION Some significant changes in facial soft tissues were observed after RME treatment but there were no significant differences between prepubertal and postpubertal subjects. The null hypothesis is accepted because there were no significant differences between the groups.
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Affiliation(s)
- Gülşilay Sayar Torun
- Department of Orthodontics, School of Dentistry, Istanbul Medipol University, Atatürk Bulvarı No:27, Unkapanı-Fatih, 34083, Istanbul, Turkey.
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Aimetti M, Manavella V, Corano L, Ercoli E, Bignardi C, Romano F. Three-dimensional analysis of bone remodeling following ridge augmentation of compromised extraction sockets in periodontitis patients: A randomized controlled study. Clin Oral Implants Res 2017; 29:202-214. [PMID: 29148597 DOI: 10.1111/clr.13099] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/13/2017] [Indexed: 11/27/2022]
Abstract
OBJECTIVES The aim of this study was to analyze linear and volumetric hard tissue changes in severely resorbed alveolar sockets after ridge augmentation procedure and to compare them with spontaneous healing using three-dimensional cone beam computed tomography (CBCT). MATERIAL AND METHODS Thirty patients (mean age 53.2 ± 6.3 years) requiring tooth extraction for advanced periodontitis were randomly allocated to test and control groups. The test sites were grafted using a collagenated bovine-derived bone (DBBM-C) covered with a collagen membrane, while control sites had spontaneous healing. Both groups healed by secondary intention. Linear and volumetric measurements were taken on superimposed CBCT images obtained after tooth extraction and 12 months later. RESULTS Greater horizontal shrinkage, localized mainly in the crestal zone, was observed in the control group (4.92 ± 2.45 mm) compared to the test group (2.60 ± 1.24 mm). While both groups presented a rebuilding of the buccal wall, it was most pronounced in the grafted sockets (2.50 ± 2.12 mm vs. 0.51 ± 1.02 mm). A significant difference was also registered in the percentage of volume loss between grafted and non-grafted sites (9.14% vs. 35.16%, p-value <.0001). CONCLUSION Alveolar sockets with extensive buccal bone deficiencies undergo significant three-dimensional volumetric alterations following natural healing. The immediate application of a slow-resorbing xenograft with a covering collagen membrane seems to be effective in improving alveolar ridge shape and dimensions, thus potentially reducing the need for adjunctive regenerative procedures at the time of implant placement.
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Affiliation(s)
- Mario Aimetti
- Department of Surgical Sciences, C.I.R. Dental School, University of Turin, Turin, Italy
| | - Valeria Manavella
- Department of Surgical Sciences, C.I.R. Dental School, University of Turin, Turin, Italy
| | | | - Elena Ercoli
- Department of Surgical Sciences, C.I.R. Dental School, University of Turin, Turin, Italy
| | - Cristina Bignardi
- Department of Mechanical and Aerospace Engineering, Politecnico of Torino, Turin, Italy
| | - Federica Romano
- Department of Surgical Sciences, C.I.R. Dental School, University of Turin, Turin, Italy
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Feng B, Jiang M, Xu X, Li J. A new method of volumetric assessment of alveolar bone grafting for cleft patients using cone beam computed tomography. Oral Surg Oral Med Oral Pathol Oral Radiol 2017; 124:e171-e182. [PMID: 28606827 DOI: 10.1016/j.oooo.2017.04.003] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2016] [Revised: 12/01/2016] [Accepted: 04/05/2017] [Indexed: 11/24/2022]
Abstract
OBJECTIVE The aims of this study were to propose a new method for volumetric assessment of alveolar bone grafting and to quantitatively assess alveolar bone grafting based on this method. STUDY DESIGN Cone beam computed tomography images of 18 patients with unilateral cleft alveolus were selected. Volume of the alveolar cleft before grafting operation (VOLcleft), graft bone filled into cleft immediately after operation (VOLgraft), and bony bridge formed 1 year after operation (VOLbridge) were obtained. The grafting fill rate (VOLgraft/VOLcleft × 100%), bony bridge formation rate (VOLbridge/VOLcleft × 100%), and grafting resorption rate [(VOLgraft - VOLbridge)/VOLgraft × 100%] were calculated. Correlations between these parameters were investigated. Intraobserver and interobserver reliability of this method was assessed. RESULTS Intraobserver and interobserver reliability was good as no statistically significant difference was seen, and the Pearson correlation coefficient was significant (intraobserver R ≥ .953; interobserver, R ≥ .859). A positive linear correlation (R2 = .808; P < .001) between grafting fill rate and bony bridge formation rate and a negative linear correlation (R2 = .458, P = .002) between grafting fill rate and grafting resorption rate were found. CONCLUSIONS This method was practical and valuable for quantitative assessment of alveolar bone grafting.
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Affiliation(s)
- Bin Feng
- Department of Oral Radiology, Stomatology Hospital affiliated with Zhejiang University of Medicine, Zhejiang University, Hangzhou, China.
| | - Meng Jiang
- State Key Laboratory of Oral Diseases and Department of Oral Radiology, West China School of Stomatology, Sichuan University, Chengdu, China
| | - Xue Xu
- State Key Laboratory of Oral Diseases and Department of Cleft Lip and Palate Surgery, West China School of Stomatology, Sichuan University, Chengdu, China
| | - Jingtao Li
- State Key Laboratory of Oral Diseases and Department of Cleft Lip and Palate Surgery, West China School of Stomatology, Sichuan University, Chengdu, China
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Abstract
A patient's position changes in every CBCT scan despite patient alignment protocols. However, there have been studies to determine image quality differences when an object is located at the center of the field of view (FOV). To evaluate changes in the image quality of the CBCT scan according to different object positions, the image quality indexes of the Alphard 3030 (Alphard Roentgen Ind., Ltd., Kyoto, Japan) and the Rayscan Symphony (RAY Ind., Ltd., Suwon, Korea) were measured using the Quart DVT_AP phantom at the center of the FOV and 6 peripheral positions under four types of exposure conditions. Anterior, posterior, right, left, upper, and lower positions 1 cm offset from the center of the FOV were used for the peripheral positions. We evaluated and compared the voxel size, homogeneity, contrast to noise ratio (CNR), and the 10% point of the modulation transfer function (MTF10%) of the center and periphery. Because the voxel size, which is determined by the Nyquist frequency, was within tolerance, other image quality indexes were not influenced by the voxel size. For the CNR, homogeneity, and MTF10%, there were peripheral positions which showed considerable differences with statistical significance. The average difference between the center and periphery was up to 31.27% (CNR), 70.49% (homogeneity), and 13.64% (MTF10%). Homogeneity was under tolerance at some of the peripheral locations. Because the CNR, homogeneity, and MTF10% were significantly affected by positional changes of the phantom, an object's position can influence the interpretation of follow up CBCT images. Therefore, efforts to locate the object in the same position are important.
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Affiliation(s)
- Jae Joon Hwang
- Department of Oral and Maxillofacial Radiology, College of Dentistry, Yonsei University, Seoul, Korea
| | - Hyok Park
- Department of Oral and Maxillofacial Radiology, College of Dentistry, Yonsei University, Seoul, Korea
| | - Ho-Gul Jeong
- Department of Oral and Maxillofacial Radiology, College of Dentistry, Yonsei University, Seoul, Korea
| | - Sang-Sun Han
- Department of Oral and Maxillofacial Radiology, College of Dentistry, Yonsei University, Seoul, Korea
- * E-mail:
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Rostetter C, Metzler P, Schenkel JS, Seifert B, Luebbers HT. Comparison of in vivo cone-beam and multidetector computed tomographic scans by three-dimensional merging software. Br J Oral Maxillofac Surg 2015; 53:1021-6. [DOI: 10.1016/j.bjoms.2015.09.030] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2014] [Accepted: 09/27/2015] [Indexed: 12/17/2022]
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Valizadeh S, Vasegh Z, Rezapanah S, Safi Y, Khaeazifard MJ. Effect of Object Position in Cone Beam Computed Tomography Field of View for Detection of Root Fractures in Teeth with Intra-Canal Posts. Iran J Radiol 2015; 12:e25272. [PMID: 26793289 PMCID: PMC4711188 DOI: 10.5812/iranjradiol.25272] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/11/2014] [Revised: 07/13/2015] [Accepted: 08/15/2015] [Indexed: 12/29/2022]
Abstract
Background: Vertical root fracture (VRF) is a common problem in endodontically treated teeth. Due to its poor prognosis, a reliable technique must be used to make an accurate diagnosis. Cone beam computed tomography (CBCT) has been recently introduced for maxillofacial imaging. Despite the high diagnostic value of this method, metal artifacts resulting from intra-canal posts still make the detection of VRFs challenging. Objectives: This study aimed to assess the effect of object position in the field of view (FOV) of CBCT on detection of VRFs in teeth with intra-canal posts. Materials and Methods: The crowns of 60 extracted premolar teeth were cut at the level of cementoenamel junction (CEJ). Root canals were filled with gutta-percha and filling of the coronal 2/3 of the root canals was subsequently removed to fabricate intra-canal cast posts. The teeth were randomly divided into two groups of 30. Fracture was induced in group one using an Instron machine. Group two was considered as the control group with no fracture. All teeth were then randomly positioned and scanned in five different positions starting at the center of the FOV as well as right, left anterior and posterior relative to the center (3, 9, 12, and 6 O’clock) via the New Tom VGI CBCT unit. Two observers evaluated images for VRFs. Sensitivity and specificity of fracture diagnosis in each position was calculated in comparison with the gold standard. Wilcoxon test was used for data analysis. Results: Considering deterministic and probabilistic diagnostic parameters, probabilistic sensitivity was similar in all positions; but probabilistic specificity of the center position (65.1%) was significantly higher than that of 6 and 12 O’clock positions. Considering the deterministic diagnostic parameters, the overall sensitivity and specificity values decreased in all positions in FOV, but sensitivity of the center position of FOV was significantly higher than that of other positions; specificity was significantly higher at the 3 O’clock position (58.5%). Conclusion: Concerning the positions in FOV, the center position is suitable for detection of VRF in teeth with intra-canal posts due to significantly higher sensitivity at this position. The 3 O’clock position would be suitable for assessment of intact teeth without fractures due to significantly higher specificity at this position.
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Affiliation(s)
- Solmaz Valizadeh
- Department of Oral and Maxillofacial Radiology, School of Dentistry, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Zahra Vasegh
- Department of Oral and Maxillofacial Radiology, School of Dentistry, Shahid Beheshti University of Medical Sciences, Tehran, Iran
- Corresponding author: Zahra Vasegh, Department of Oral and Maxillofacial Radiology, School of Dentistry, Shahid Beheshti University of Medical Sciences, Tehran, Iran. Tel: +98-2188773550, Fax: +98-2188773550, E-mail:
| | - Samin Rezapanah
- Department of Oral and Maxillofacial Radiology, School of Dentistry, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Yaser Safi
- Department of Oral and Maxillofacial Radiology, School of Dentistry, Shahid Beheshti University of Medical Sciences, Tehran, Iran
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Li H, Zhang H, Smales RJ, Zhang Y, Ni Y, Ma J, Wang L. Effect of 3 vertical facial patterns on alveolar bone quality at selected miniscrew implant sites. IMPLANT DENT 2014; 23:92-7. [PMID: 24398849 DOI: 10.1097/ID.0000000000000036] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
OBJECTIVE To evaluate dental alveolar bone quality among young healthy Chinese adults having 3 different vertical patterns. MATERIALS AND METHODS Three-dimensional cone-beam computed tomography images of 101 subjects (15 low-angle, 48 average-angle, and 38 high-angle) were reconstructed. Facial alveolar cortical bone thicknesses and cortical and cancellous bone densities at 4 selected miniscrew implant sites in both arches, together with cancellous bone densities of third cervical vertebrae, were measured. Bone qualities were compared among the 3 vertical pattern groups. RESULTS The cortical bone thicknesses at mandibular 5-6 and 6-7 and the cortical and cancellous bone densities at maxillary and mandibular 5-6 and 6-7 were generally greater in the low-angle than in the other 2 groups. There was no similar consistent vertical pattern apparent for bone quality at the 1-1 and 1-2 sites. No significant differences in bone densities for third cervical vertebrae were found among the 3 groups. CONCLUSION Careful selection of suitable implantation sites and sizes of the miniscrews used should be made to reduce the possible occurrence of implant loosening in patients with average-angle and high-angle vertical facial patterns in particular.
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Abstract
CBCT is a widely applied imaging modality in dentistry. It enables the visualization of high-contrast structures of the oral region (bone, teeth, air cavities) at a high resolution. CBCT is now commonly used for the assessment of bone quality, primarily for pre-operative implant planning. Traditionally, bone quality parameters and classifications were primarily based on bone density, which could be estimated through the use of Hounsfield units derived from multidetector CT (MDCT) data sets. However, there are crucial differences between MDCT and CBCT, which complicates the use of quantitative gray values (GVs) for the latter. From experimental as well as clinical research, it can be seen that great variability of GVs can exist on CBCT images owing to various reasons that are inherently associated with this technique (i.e. the limited field size, relatively high amount of scattered radiation and limitations of currently applied reconstruction algorithms). Although attempts have been made to correct for GV variability, it can be postulated that the quantitative use of GVs in CBCT should be generally avoided at this time. In addition, recent research and clinical findings have shifted the paradigm of bone quality from a density-based analysis to a structural evaluation of the bone. The ever-improving image quality of CBCT allows it to display trabecular bone patterns, indicating that it may be possible to apply structural analysis methods that are commonly used in micro-CT and histology.
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Affiliation(s)
- R Pauwels
- 1 Department of Radiology, Faculty of Dentistry, Chulalongkorn University, Bangkok, Thailand
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Linderup BW, Küseler A, Jensen J, Cattaneo PM. A Novel Semiautomatic Technique for Volumetric Assessment of the Alveolar Bone Defect Using Cone Beam Computed Tomography. Cleft Palate Craniofac J 2015; 52:e47-55. [DOI: 10.1597/13-287] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Objective The aims of this study were (1) to determine the three-dimensional anatomical boundaries of the alveolar bone defect in cleft lip and palate (CLP) patients, (2) to precisely translate these anatomical boundaries into reliable cephalometric landmarks and planes that can be used for cone beam computed tomography (CBCT) analysis, (3) to standardize image acquisition and reconstruction parameters, and (4) to test the reproducibility of the proposed protocol for measuring the predefined alveolar bone defect, using a third-party software. Methods The alveolar bone defect volume of 10 randomly selected patients with unilateral CLP (UCLP) aged 8 years and 6 months to 11 years and 2 months was evaluated on preoperative and 1-year postoperative CBCT scans using a semiautomatic, standardized protocol. The alveolar bone graft outcome was calculated as a percentage of the bone fill using the formula (VOLpre – VOLpost)/VOLpre) × 100. Intra- and interobserver reliability was assessed. Results Intra- and interobserver reproducibility was excellent for volumes and bone fill as no statistically significant difference ( P < .001) was seen between the different sets of measurements, and Pearson correlation coefficients were large (intraobserver: r > .9849, interobserver: r > .8784). The Bland-Altman plots indicated that the differences between the plots were not patterned. Conclusions Volume determination using CBCT, third-party medical image processing software, and the presently defined image acquisition and reconstruction parameters, including anatomical boundaries, is a reproducible and practical method for assessing the volumetric outcome of secondary alveolar bone grafting in patients with UCLP.
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Affiliation(s)
- Bo Werner Linderup
- Department of Orthodontics, School of Dentistry, Health, Aarhus University, Denmark
| | - Annelise Küseler
- Cleft Lip Palate Center, Aarhus, Denmark; Department of Orthodontics, Health, Aarhus University, Denmark
- Department of Oral and Maxillofacial Surgery, Aarhus University Hospital, Denmark
| | - John Jensen
- Department of Oral and Maxillofacial Surgery, Aarhus University Hospital, Denmark
| | - Paolo M. Cattaneo
- Department of Orthodontics, School of Dentistry, Health, Aarhus University, Denmark
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Rodrigues AF, da Silva Campos MJ, Chaoubah A, Fraga MR, Farinazzo Vitral RW. Use of Gray Values in CBCT and MSCT Images for Determination of Density: Influence of Variation of FOV Size. IMPLANT DENT 2015; Publish Ahead of Print. [DOI: 10.1097/id.0000000000000179] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
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González-Carbonell RA, Ortiz-Prado A, Jacobo-Armendáriz VH, Cisneros-Hidalgo YA, Alpízar-Aguirre A. 3D patient-specific model of the tibia from CT for orthopedic use. J Orthop 2015; 12:11-6. [PMID: 25829755 DOI: 10.1016/j.jor.2015.01.009] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/17/2014] [Accepted: 01/04/2015] [Indexed: 11/18/2022] Open
Abstract
OBJECTIVES 3D patient-specific model of the tibia is used to determine the torque needed to initialize the tibial torsion correction. METHODS The finite elements method is used in the biomechanical modeling of tibia. The geometric model of the tibia is obtained from CT images. The tibia is modeled as an anisotropic material with non-homogeneous mechanical properties. CONCLUSIONS The maximum stress is located in the shaft of tibia diaphysis. With both meshes are obtained similar results of stresses and displacements. For this patient-specific model, the torque must be greater than 30 Nm to initialize the correction of tibial torsion deformity.
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Affiliation(s)
| | - Armando Ortiz-Prado
- Unidad de Investigación y Asistencia Técnica en Materiales, Universidad Nacional Autónoma de México, Coyoacán 04510, DF, México
| | - Victor H Jacobo-Armendáriz
- Unidad de Investigación y Asistencia Técnica en Materiales, Universidad Nacional Autónoma de México, Coyoacán 04510, DF, México
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Nishino K, Shimamoto H, Kakimoto N, Tsujimoto T, Chindasombatjaroen J, Murakami S, Furukawa S. Influence of an object's z-axis location and location on the axial plane on the voxel value representation and uniformity in cone beam computed tomography. Oral Surg Oral Med Oral Pathol Oral Radiol 2014; 118:619-24. [PMID: 25442500 DOI: 10.1016/j.oooo.2014.08.010] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2014] [Revised: 07/30/2014] [Accepted: 08/06/2014] [Indexed: 10/24/2022]
Abstract
OBJECTIVE This study aimed to determine the influence of an object's z-axis location and location on the axial plane on the voxel values in cone beam computed tomography. STUDY DESIGN The CTP401 and CTP486 of the Catphan 500 phantom were scanned with an Alphard-3030 at 6 locations in the z-axis. RESULTS In CTP401, the voxel values of 3 inserts showed the lowest values when the center of the radiation field corresponded to under 2 or 4 cm of the z-axis center of CTP401. In CTP486, the voxel values showed the lowest values when the center of the radiation field corresponded to under 2 or 4 cm of the z-axis center of CTP486. On the same axial plane, the voxel values at the center showed significantly lower values than the off-center locations (P = .002). CONCLUSIONS The voxel values in the Alphard-3030 changed based on the z-axis location of the radiation field and were nonuniform on the same axial plane.
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Affiliation(s)
- Kanako Nishino
- Department of Oral and Maxillofacial Radiology, Osaka University Graduate School of Dentistry, Osaka, Japan
| | - Hiroaki Shimamoto
- Department of Oral and Maxillofacial Radiology, Osaka University Graduate School of Dentistry, Osaka, Japan.
| | - Naoya Kakimoto
- Department of Oral and Maxillofacial Radiology, Osaka University Graduate School of Dentistry, Osaka, Japan
| | - Tomomi Tsujimoto
- Department of Oral and Maxillofacial Radiology, Osaka University Graduate School of Dentistry, Osaka, Japan
| | - Jira Chindasombatjaroen
- Department of Oral and Maxillofacial Radiology, Faculty of Dentistry, Mahidol University, Bangkok, Thailand
| | - Shumei Murakami
- Department of Oral and Maxillofacial Radiology, Osaka University Graduate School of Dentistry, Osaka, Japan
| | - Souhei Furukawa
- Department of Oral and Maxillofacial Radiology, Osaka University Graduate School of Dentistry, Osaka, Japan
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Oliveira ML, Tosoni GM, Lindsey DH, Mendoza K, Tetradis S, Mallya SM. Assessment of CT numbers in limited and medium field-of-view scans taken using Accuitomo 170 and Veraviewepocs 3De cone-beam computed tomography scanners. Imaging Sci Dent 2014; 44:279-85. [PMID: 25473635 PMCID: PMC4245469 DOI: 10.5624/isd.2014.44.4.279] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2014] [Revised: 08/30/2014] [Accepted: 09/13/2014] [Indexed: 11/21/2022] Open
Abstract
Purpose To assess the influence of anatomic location on the relationship between computed tomography (CT) number and X-ray attenuation in limited and medium field-of-view (FOV) scans. Materials and Methods Tubes containing solutions with different concentrations of K2HPO4 were placed in the tooth sockets of a human head phantom. Cone-beam computed tomography (CBCT) scans were acquired, and CT numbers of the K2HPO4 solutions were measured. The relationship between CT number and K2HPO4 concentration was examined by linear regression analyses. Then, the variation in CT number according to anatomic location was examined. Results The relationship between K2HPO4 concentration and CT number was strongly linear. The slopes of the linear regressions for the limited FOVs were almost 2-fold lower than those for the medium FOVs. The absolute CT number differed between imaging protocols and anatomic locations. Conclusion There is a strong linear relationship between X-ray attenuation and CT number. The specific imaging protocol and anatomic location of the object strongly influence this relationship.
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Affiliation(s)
- Matheus L Oliveira
- Department of Oral Diagnosis, Piracicaba Dental School, State University of Campinas, Campinas, SP, Brazil
| | - Guilherme M Tosoni
- Department of Oral Diagnosis and Surgery, Araraquara Dental School, São Paulo State University, Araraquara, SP, Brazil
| | - David H Lindsey
- Section of Oral and Maxillofacial Radiology, School of Dentistry, University of California, Los Angeles, CA, USA
| | - Kristopher Mendoza
- Section of Oral and Maxillofacial Radiology, School of Dentistry, University of California, Los Angeles, CA, USA
| | - Sotirios Tetradis
- Section of Oral and Maxillofacial Radiology, School of Dentistry, University of California, Los Angeles, CA, USA
| | - Sanjay M Mallya
- Section of Oral and Maxillofacial Radiology, School of Dentistry, University of California, Los Angeles, CA, USA
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Campos MJDS, de Souza TS, Mota Júnior SL, Fraga MR, Vitral RWF. Bone mineral density in cone beam computed tomography: Only a few shades of gray. World J Radiol 2014; 6:607-12. [PMID: 25170398 PMCID: PMC4147441 DOI: 10.4329/wjr.v6.i8.607] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/27/2013] [Revised: 03/11/2014] [Accepted: 04/25/2014] [Indexed: 02/06/2023] Open
Abstract
Cone beam computed tomography (CBCT) has often been used to determine the quality of craniofacial bone structures through the determination of mineral density, which is based on gray scales of the images obtained. However, there is no consensus regarding the accuracy of the determination of the gray scales in these exams. This study aims to provide a literature review concerning the reliability of CBCT to determine bone mineral density. The gray values obtained with CBCT show a linear relationship with the attenuation coefficients of the materials, Hounsfield Units values obtained with medical computed tomography, and density values from dual energy X-ray absorciometry. However, errors are expected when CBCT images are used to define the quality of the scanned structures because these images show inconsistencies and arbitrariness in the gray values, particularly when related to abrupt change in the density of the object, X-ray beam hardening effect, scattered radiation, projection data discontinuity-related effect, differences between CBCT devices, changes in the volume of the field of view (FOV), and changes in the relationships of size and position between the FOV and the object evaluated. A few methods of mathematical correction of the gray scales in CBCT have been proposed; however, they do not generate consistent values that are independent of the devices and their configurations or of the scanned objects. Thus, CBCT should not be considered the examination of choice for the determination of bone and soft tissue mineral density at the current stage, particularly when values obtained are to be compared to predetermined standard values. Comparisons between symmetrically positioned structures inside the FOV and in relation to the exomass of the object, as it occurs with the right and left sides of the skull, seem to be viable because the effects on the gray scale in the regions of interest are the same.
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Bujtár P, Simonovics J, Zombori G, Fejer Z, Szucs A, Bojtos A, Batista WO, Váradi K, Sándor GK. Internal or in-scan validation: a method to assess CBCT and MSCT gray scales using a human cadaver. Oral Surg Oral Med Oral Pathol Oral Radiol 2014; 117:768-79. [DOI: 10.1016/j.oooo.2014.02.012] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2013] [Revised: 01/29/2014] [Accepted: 02/04/2014] [Indexed: 11/25/2022]
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Plachtovics M, Bujtar P, Nagy K, Mommaerts M. High-quality image acquisition by double exposure overlap in dental cone beam computed tomography. Oral Surg Oral Med Oral Pathol Oral Radiol 2014; 117:760-7. [PMID: 24736110 DOI: 10.1016/j.oooo.2014.02.024] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2013] [Revised: 02/11/2014] [Accepted: 02/19/2014] [Indexed: 10/25/2022]
Abstract
OBJECTIVE With a double exposure overlapping cone beam computed tomography (CBCT) scan technique, using CBCT acquisition radiation dose, the objective was to obtain apparent density similar to that of multidetector computed tomography (MDCT). STUDY DESIGN Factory quality-assurance phantom and water phantom were used for the evaluation of apparent density fidelity of iCAT scans in different modes. Each scan's apparent density was analyzed for identical regions using ImageJ, version 1.42q. RESULTS The iCAT Classic extended height acquisition with 4-cm central overlap and reconstruction of 2 groups of 300 projections per rotation for the water and quality-assurance CBCT phantoms resulted in improved apparent density fidelity. This apparent density accuracy was superior to that of iCAT scan at high resolution (600 projections during 1 rotation). CONCLUSIONS Using double exposure overlapping CBCT scans allows the analysis quality to be comparable with that of MDCT.
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Affiliation(s)
- Mark Plachtovics
- Research Associate, University of Szeged, Faculty of Dentistry, Szeged, Hungary.
| | - Peter Bujtar
- Research Associate, Oral and Maxillo-Facial Surgery Department, University of Oulu, Oulu, Finland
| | - Katalin Nagy
- Professor, Department of Cranio-Maxillo-Facial Surgery, European Face Centre, Vrije Universiteit Brussel, Brussels, Belgium
| | - Maurice Mommaerts
- Professor, University of Szeged, Faculty of Dentistry, Szeged, Hungary
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Batista WO, Navarro MVT, Maia AF. Development and implementation of a low-cost phantom for quality control in cone beam computed tomography. Radiat Prot Dosimetry 2013; 157:552-560. [PMID: 23838096 DOI: 10.1093/rpd/nct177] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
A phantom for quality control in cone beam computed tomography (CBCT) scanners was designed and constructed, and a methodology for testing was developed. The phantom had a polymethyl methacrylate structure filled with water and plastic objects that allowed the assessment of parameters related to quality control. The phantom allowed the evaluation of essential parameters in CBCT as well as the evaluation of linear and angular dimensions. The plastics used in the phantom were chosen so that their density and linear attenuation coefficient were similar to those of human facial structures. Three types of CBCT equipment, with two different technological concepts, were evaluated. The results of the assessment of the accuracy of linear and angular dimensions agreed with the existing standards. However, other parameters such as computed tomography number accuracy, uniformity and high-contrast detail did not meet the tolerances established in current regulations or the manufacturer's specifications. The results demonstrate the importance of establishing specific protocols and phantoms, which meet the specificities of CBCT. The practicality of implementation, the quality control test results for the proposed phantom and the consistency of the results using different equipment demonstrate its adequacy.
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Affiliation(s)
- W O Batista
- Instituto Federal de Educação, Ciência e Tecnologia da Bahia, 40300-010, Rua Emídio Santos, SN, Barbalho, Salvador, Bahia, Brazil
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Parsa A, Ibrahim N, Hassan B, van der Stelt P, Wismeijer D. Influence of object location in cone beam computed tomography (NewTom 5G and 3D Accuitomo 170) on gray value measurements at an implant site. Oral Radiol 2013. [DOI: 10.1007/s11282-013-0157-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Azeredo F, de Menezes LM, Enciso R, Weissheimer A, de Oliveira RB. Computed gray levels in multislice and cone-beam computed tomography. Am J Orthod Dentofacial Orthop 2013; 144:147-55. [PMID: 23810056 DOI: 10.1016/j.ajodo.2013.03.013] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2012] [Revised: 03/01/2013] [Accepted: 03/01/2013] [Indexed: 12/13/2022]
Abstract
INTRODUCTION Gray level is the range of shades of gray in the pixels, representing the x-ray attenuation coefficient that allows for tissue density assessments in computed tomography (CT). An in-vitro study was performed to investigate the relationship between computed gray levels in 3 cone-beam CT (CBCT) scanners and 1 multislice spiral CT device using 5 software programs. METHODS Six materials (air, water, wax, acrylic, plaster, and gutta-percha) were scanned with the CBCT and CT scanners, and the computed gray levels for each material at predetermined points were measured with OsiriX Medical Imaging software (Geneva, Switzerland), OnDemand3D (CyberMed International, Seoul, Korea), E-Film (Merge Healthcare, Milwaukee, Wis), Dolphin Imaging (Dolphin Imaging & Management Solutions, Chatsworth, Calif), and InVivo Dental Software (Anatomage, San Jose, Calif). The repeatability of these measurements was calculated with intraclass correlation coefficients, and the gray levels were averaged to represent each material. Repeated analysis of variance tests were used to assess the differences in gray levels among scanners and materials. RESULTS There were no differences in mean gray levels with the different software programs. There were significant differences in gray levels between scanners for each material evaluated (P <0.001). CONCLUSIONS The software programs were reliable and had no influence on the CT and CBCT gray level measurements. However, the gray levels might have discrepancies when different CT and CBCT scanners are used. Therefore, caution is essential when interpreting or evaluating CBCT images because of the significant differences in gray levels between different CBCT scanners, and between CBCT and CT values.
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Affiliation(s)
- Fabiane Azeredo
- Department of Orthodontics, Pontifical Catholic University of Rio Grande do Sul, Porto Alegre, RS, Brazil
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Molteni R. Prospects and challenges of rendering tissue density in Hounsfield units for cone beam computed tomography. Oral Surg Oral Med Oral Pathol Oral Radiol 2013; 116:105-19. [DOI: 10.1016/j.oooo.2013.04.013] [Citation(s) in RCA: 91] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2012] [Revised: 03/11/2013] [Accepted: 04/19/2013] [Indexed: 11/30/2022]
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Abstract
Cone-beam computed tomography (CBCT) is an imaging technology that has revolutionised dental imaging in the last decade. Although of particular value to specialists performing implant treatment, it is increasingly being adopted by general dental practitioners. As the radiation dose is higher than that of conventional radiography, it is important to consider its diagnostic efficacy for the common tasks performed in general dental practice, such as caries diagnosis, endodontics and the detection of periapical pathosis. Any new imaging technique needs to have proven advantages over existing techniques before it is adopted, yet the evidence remains quite limited. Furthermore, image quality and radiation doses vary enormously between different manufacturers' equipment, so that extrapolating results of one piece of research from one CBCT machine to another is fraught with pitfalls. Radiation doses with CBCT are typically an order of magnitude higher than conventional radiography. There is scope, however, for reducing these doses by judicious adjustment of exposure factors and limiting the field of view to the smallest dimensions consistent with the clinical situation. There is still a long way to go before we understand the value of CBCT in dentistry. High quality research evidence is needed, particularly with regard to assessing whether using BCT improves patient outcomes.
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Campos MJDS, de Albuquerque EG, Pinto BCH, Húngaro HM, Gravina MA, Fraga MR, Vitral RWF. The role of orthodontic tooth movement in bone and root mineral density: a study of patients submitted and not submitted to orthodontic treatment. Med Sci Monit 2013. [PMID: 23197239 PMCID: PMC3560800 DOI: 10.12659/msm.883604] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
Background Orthodontic force application to the teeth is responsible for a series of biological responses in the bone and dentin, which lead to some alterations of the mineral density of the tissues. Our objective was determine, through cone-beam computed tomography (CBCT), the mineral density of the apical third of the roots of the upper central incisors and of the periapical bone portion surrounding these teeth, in patients submitted to orthodontic treated and untreated individuals. Material/Methods 30 untreated individuals and 15 treated ones (treatment cessation at least 1 year before the study) underwent CBCT. Mineral density was assessed in the apical third of the root of the upper central incisors and in the alveolar bone in the periapical region of these teeth. In order to reduce CBCT-related mineral density variability, we standardized the cone-beam tomography device, the image-acquisition settings and the field of view positioning and size. Student’s t test was used for the analyses. Results bone mineral density (BMD) and root mineral density (RMD), in Hounsfield Units, were 674.84 and 1282.26 for the untreated group and 630.28 and 1370.29 for the treated group, respectively. The differences between the group means were statistically significant for RMD (p<0.05). Conclusions untreated individuals had a significant lower mean RMD in comparison with those submitted to orthodontic treatment.
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Pauwels R, Nackaerts O, Bellaiche N, Stamatakis H, Tsiklakis K, Walker A, Bosmans H, Bogaerts R, Jacobs R, Horner K. Variability of dental cone beam CT grey values for density estimations. Br J Radiol 2013; 86:20120135. [PMID: 23255537 DOI: 10.1259/bjr.20120135] [Citation(s) in RCA: 91] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
OBJECTIVE The aim of this study was to investigate the use of dental cone beam CT (CBCT) grey values for density estimations by calculating the correlation with multislice CT (MSCT) values and the grey value error after recalibration. METHODS A polymethyl methacrylate (PMMA) phantom was developed containing inserts of different density: air, PMMA, hydroxyapatite (HA) 50 mg cm(-3), HA 100, HA 200 and aluminium. The phantom was scanned on 13 CBCT devices and 1 MSCT device. Correlation between CBCT grey values and CT numbers was calculated, and the average error of the CBCT values was estimated in the medium-density range after recalibration. RESULTS Pearson correlation coefficients ranged between 0.7014 and 0.9996 in the full-density range and between 0.5620 and 0.9991 in the medium-density range. The average error of CBCT voxel values in the medium-density range was between 35 and 1562. CONCLUSION Even though most CBCT devices showed a good overall correlation with CT numbers, large errors can be seen when using the grey values in a quantitative way. Although it could be possible to obtain pseudo-Hounsfield units from certain CBCTs, alternative methods of assessing bone tissue should be further investigated. ADVANCES IN KNOWLEDGE The suitability of dental CBCT for density estimations was assessed, involving a large number of devices and protocols. The possibility for grey value calibration was thoroughly investigated.
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Affiliation(s)
- R Pauwels
- Department of Oral Health Sciences, University of Leuven, Leuven, Belgium.
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Cavézian R, Pasquet G. [Cone Beam computerized tomography and implants]. Rev Stomatol Chir Maxillofac 2012; 113:245-258. [PMID: 22889565 DOI: 10.1016/j.stomax.2012.05.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/03/2012] [Accepted: 05/25/2012] [Indexed: 06/01/2023]
Abstract
The authors, both working as radiologist in private practice, have initiated the Cone Beam technique as soon as 1999 and report their own experience. Cone Beam Computerized Tomography (CBCT) is dedicated to hard tissues imaging thus specifically adapted to oral implantology and maxillofacial surgery. It has the advantage to deliver low dose radiation, compared to other techniques. CBCT permits anatomical volume acquisition. After data analysis on computer, distances and implants 3D simulation can be checked. CBCT differs from CT scan because it is more adapted to hard tissues, it has a better resolution than CT, and because it delivers lower doses. Its isotropic pixel particularity which gives exact linear measurements, and the fact that metallic artifacts are significatively diminished, gives CBCT its high interest in implantology. These advantages of CBCT and the small place needed for its installation explain its global wide spreading. CBCT is now considered to be the gold standard in dental and maxillofacial sectional imaging. Because of its biomeasuring capacity, its bi- and tridimensional reconstruction possibilities, its surgical navigation and simulation capacity, it is now widely used in implantology.
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Affiliation(s)
- R Cavézian
- Cabinet de radiologie dentaire, 179, rue Saint-Honoré, 75001 Paris, France.
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Scarfe WC, Li Z, Aboelmaaty W, Scott SA, Farman AG. Maxillofacial cone beam computed tomography: essence, elements and steps to interpretation. Aust Dent J 2012; 57 Suppl 1:46-60. [PMID: 22376097 DOI: 10.1111/j.1834-7819.2011.01657.x] [Citation(s) in RCA: 113] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Maxillofacial cone beam computed tomography (CBCT) is one of the most significant advances in dental imaging since rotational panoramic radiography. While the acquisition of CBCT data is technically simple, numerous parameters should be considered so that CBCT imaging is performed appropriately and 'task specific'. This involves an understanding of not only exposure (e.g. geometric and software parameters to minimize patient dose, while sustaining diagnostic image quality) but also image formatting options to maximize image display. CBCT images contain far more detailed information of the maxillofacial region than do panoramic or other 2-D images and necessitate a thorough knowledge of the 3-D anatomy of the region and considerations of variability in the range of the anatomically normal. These principles, procedures and protocols, together with the interpretation of CBCT images form the basis of best practices in maxillofacial CBCT imaging. This communication aims to provide: (1) an overview of the fundamental principles of operation of maxillofacial CBCT technology; (2) an understanding of 'task specific' equipment, image selection and image display modes; and (3) a systematic methodology for sequencing interpretation of CBCT images.
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Affiliation(s)
- William C Scarfe
- Radiology and Imaging Science Division, Department of Surgical and Hospital Dentistry, School of Dentistry, The University of Louisville, Kentucky 40292, USA.
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Lukáts O, Bujtár P, Sándor GK, Barabás J. Porous Hydroxyapatite and Aluminium-Oxide Ceramic Orbital Implant Evaluation Using CBCT Scanning: A Method for In Vivo Porous Structure Evaluation and Monitoring. Int J Biomater 2012; 2012:764749. [PMID: 22481940 DOI: 10.1155/2012/764749] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2011] [Revised: 11/15/2011] [Accepted: 11/29/2011] [Indexed: 01/12/2023] Open
Abstract
Objective. This study aimed to define CBCT as a technique for postimplantation in vivo examination of porous hydroxyapatite and aluminium-oxide orbital implant shape, volume and density changes. Methods and Materials. CBCT was used to evaluate 30 enucleated patients treated with spherical polyglactin 910 wrapped hydroxyapatite and aluminum-oxide orbital implants. The mean duration of patient
followup was 3.2 years or 1338 days with a range of 0.2 to 7.2 years or 79 to 2636 days in a population with an average age of 40.8 years. Results. The resolution of currently clinically used CBCT equipment allowed detailed structural observation of the orbital hydroxyapatite implants with some modifications. Volume and shape estimations were possible while density evaluation was more complicated compared to medical source computed tomography. The mean densities of the orbital implants were followed and a consistent gradual decrease identified from the beginning of implantation which was better defined after the applied correction procedure. Conclusion. CBCT with lower dosages of radiation exposure can be used to follow changes in implanted high-density porous structures. The density evaluation is possible with calibration modifications. Changes in orbital implant densities identified in this study may correspond to healing and maturation of soft tissues surrounding and penetrating the implants.
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Hsu JT, Chang HW, Huang HL, Yu JH, Li YF, Tu MG. Bone density changes around teeth during orthodontic treatment. Clin Oral Investig. 2011;15:511-519. [PMID: 20393863 DOI: 10.1007/s00784-010-0410-1] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2009] [Accepted: 03/22/2010] [Indexed: 01/16/2023]
Abstract
The objective of this study was to evaluate bone density changes around the teeth during orthodontic treatment by using cone beam computed tomography (CBCT). CBCT was used to measure the bone densities around six teeth (both maxilla central incisors, lateral incisors, and canines) before and after 7 months of orthodontic treatment in eight patients. In addition, each root was divided into three portions (cervical, intermediate, and apical) to determine whether the bone density change varied with tooth level. The mean reduction in bone density around the measured teeth was 24% after orthodontic treatment. The bone density reduction around teeth was largest for the upper-right and upper-left central incisor (29% and 26%, respectively) and ranged from 20% to 23% for the other four teeth. The mean bone density reduction did not differ significantly between the cervical, portion, and apical portions of the teeth (26%, 22%, and 24%, respectively). CBCT is useful for evaluating bone density changes around teeth during orthodontic treatment. The bone density around the teeth reduced significantly after the application of orthodontic forces for 7 months.
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Chindasombatjaroen J, Kakimoto N, Shimamoto H, Murakami S, Furukawa S. Correlation between pixel values in a cone-beam computed tomographic scanner and the computed tomographic values in a multidetector row computed tomographic scanner. J Comput Assist Tomogr 2011; 35:662-5. [PMID: 21926866 DOI: 10.1097/rct.0b013e31822d9725] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
OBJECTIVES The study's objectives were to investigate the correlation between pixel values obtained from a cone-beam computed tomographic (CBCT) scanner and the computed tomographic (CT) values from a multidetector row CT scanner and to determine whether they have a linear relationship at various tube voltages and tube currents. METHODS A phantom with different concentrations of contrast medium at the center of a multidetector row CT and a CBCT scanner was scanned at various imaging parameters. Computed tomographic values and pixel values were measured using ImageJ. Regression analysis was performed, as well as correlation tests with a Pearson correlation coefficient. RESULTS A significant correlation between pixel values and the CT values of the same specimen was observed (P < 0.0001), and a linear relationship was found between the values from the 2 scanners at each parameter. CONCLUSIONS A high correlation and linear relationship between the CT values and pixel values were found at each parameter. Therefore, linear functions can be used to convert a pixel value from the CBCT machine used in this study to the CT values.
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Affiliation(s)
- Jira Chindasombatjaroen
- Department of Oral and Maxillofacial Radiology, Osaka University Graduate School of Dentistry, Osaka, Japan
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Pauwels R, Stamatakis H, Manousaridis G, Walker A, Michielsen K, Bosmans H, Bogaerts R, Jacobs R, Horner K, Tsiklakis K. Development and applicability of a quality control phantom for dental cone-beam CT. J Appl Clin Med Phys 2011; 12:3478. [PMID: 22089004 PMCID: PMC5718749 DOI: 10.1120/jacmp.v12i4.3478] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2010] [Revised: 03/15/2011] [Accepted: 05/03/2011] [Indexed: 11/23/2022] Open
Abstract
Cone‐beam CT (CBCT) has shown to be a useful imaging modality for various dentomaxillofacial applications. However, optimization and quality control of dental CBCT devices is hampered due to the lack of an appropriate tool for image quality assessment. To investigate the application of different image quality parameters for CBCT, a prototype polymethyl methacrylate (PMMA) cylindrical phantom with inserts for image quality analysis was developed. Applicability and reproducibility of the phantom were assessed using seven CBCT devices with different scanning protocols. Image quality parameters evaluated were: CT number correlation, contrast resolution, image homogeneity and uniformity, point spread function, and metal artifacts. Deviations of repeated measurements were between 0.0% and 3.3%. Correlation coefficients of CBCT voxel values with CT numbers ranged between 0.68 and 1.00. Contrast‐to‐noise ratio (CNR) values were much lower for hydroxyapatite (0<CNR<7.7) than for air and aluminum (5.0<CNR<32.8). Noise values ranged between 35 and 419. The uniformity index was between 3.3% and 11.9%. Full width at half maximum (FWHM) measurements varied between 0.43 mm and 1.07 mm. The increase of mean voxel values surrounding metal objects ranged between 6.7% and 43.0%. Results from preliminary analyses of the prototype quality control phantom showed its potential for routine quality assurance on CBCT. Large differences in image quality performance were seen between CBCT devices. Based on the initial evaluations, the phantom can be optimized and validated. PACS numbers: 87.57.C‐, 87.57.N‐, 87.57.Q‐
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Affiliation(s)
- Ruben Pauwels
- Oral Imaging Center, Faculty of Medicine, Katholieke Universiteit Leuven, Leuven, Belgium.
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Sunku R, Roopesh R, Kancherla P, Perumalla KK, Yudhistar PV, Reddy VS. Quantitative digital subtraction radiography in the assessment of external apical root resorption induced by orthodontic therapy: a retrospective study. J Contemp Dent Pract 2011; 12:422-428. [PMID: 22269231 DOI: 10.5005/jp-journals-10024-1070] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
AIM The objective of this study was to evaluate density changes around the apices of teeth during orthodontic treatment by using digital subtraction radiography to measure the densities around six teeth (maxilla central incisors, lateral incisors, and canines) before and after orthodontic treatment in 36 patients and also assess treatment variables and their coorelation with root resorption. MATERIALS AND METHODS A total of 36 consecutive patient files were selected initially. The selected patients presented with a class I or II relationship and were treated with or without premolar extractions and fixed appliances. Some class II patients were treated additionally with extraoral forces or functional appliances. External apical root resorption (EARR) per tooth in millimeters was calculated and was also expressed as a percentage of the original root length. Image reconstruction and subtraction were performed using the software Regeemy Image Registration and Mosaicing (version 0.2.43-RCB, DPI-INPE, Sao Jose dos Campos, Sao Paulo, Brazil) by a single operator. A region of interest (ROI) was defined in the apical third of the root and density calibration was made in Image J® using enamel (gray value = 255) as reference in the same image. The mean gray values in the ROIs were reflective of the change in the density values between the two images. STATISTICAL ANALYSIS The root resorption of the tooth and the factors of malocclusion were analyzed with a one-way ANOVA. An independent t-test was performed to compare the mean amount of resorption between male and female, between extraction and nonextraction cases. The density changes after orthodontic treatment were analyzed using the Wilcoxon signedrank test. In addition, the density changes in different teeth were analyzed using the Kruskal-Wallis test. The cut-off for statistical significance was a p-value of 0.05. All the statistical analyses were carried out using SPSS (version 13.0 for Windows, Chicago, IL, USA). RESULTS Gender, the age at which treatment was started and Angle's classification was not statistically related with observed root resorption. The mean percentage density reduction as assessed by DSR was greatest in both central incisor: by 27.2 and 25.2% in the upper-right and upper-left central incisors, respectively, followed by the upper-right and upper-left canine teeth (23.5 and 21.0%) and then the upper-right and upper-left lateral incisors (19.1 and 17.4%). CONCLUSION Tooth extraction prior to treatment initiation and the duration of orthodontic treatment was positively correlated with the amount of root resorption. DSR is useful for evaluating density changes around teeth during orthodontic treatment. The density around the apices of teeth reduced significantly after the application of orthodontic forces during treatment. CLINICAL SIGNIFICANCE Assessment of density changes on treatment radiographs of patients undergoing orthodontic therapy may help in the monitoring of external apical root resorption during course of treatment.
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Affiliation(s)
- Raghavendra Sunku
- Department of Orthodontics and Dentofacial Orthodpedics, Dental College and Hospital, Sangareddy, Andhra Pradesh, India
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Abstract
Abstract
Objective:
To validate the use of three-dimensional (3-D) surface rendering (SR) images to quantify the height of alveolar dehiscences.
Materials and Methods:
Twenty-four dehiscences were created on 9 incisors, 9 canines, and 6 premolars on 4 cadaver skulls. i-CAT cone beam computed tomography scans (CBCTs) were taken of each skull at .2 mm voxel size. Each dehiscence was quantified by 21 orthodontic residents using 3-D SR. The principal investigator (PI) also quantified each dehiscence using the 2-D multiplanar (MP) image and the 3-D SR image.
Results:
Results of this study showed an average method error of the residents as a group to be 0.57 mm with an intraclass correlation (ICC) of 0.77%. Residents' method error ranged from 0.45 mm to 1.32 mm, and the ICC ranged from 0.201% to 0.857%. Systematic error was low at −0.01 mm for the direct measurement compared with the residents' average 3-D SR at 1365 density value (DV) measurement. The 3-D SR at 1365 DV images were compared with the MP and 3-D SR images at 1200 DV, and no significant differences in measurements and low systematic error were noted. The method error of the PI was 0.45 mm, 0.45 mm, and 0.41 mm for 3-D SR at 1365 DV, 3-D SR at 1200 DV, and 2-D MP, respectively.
Conclusions:
3-D SR and 2D MRP can be used to measure dehiscences of the periodontium with similar levels of accuracy.
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Affiliation(s)
| | - Ki Beom Kim
- Assistant Professor, Department of Orthodontics, St Louis University, St Louis, Mo
| | - Eustaquio Araujo
- Professor, Department of Orthodontics, St Louis University, St Louis, Mo
| | - Peter Buschang
- Adjunct Professor, Department of Orthodontics, St Louis University, St Louis, Mo; Professor, Department of Orthodontics, Baylor College of Dentistry, Dallas, Tex
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Lagravère MO, Gordon JM, Flores-Mir C, Carey J, Heo G, Major PW. Cranial base foramen location accuracy and reliability in cone-beam computerized tomography. Am J Orthod Dentofacial Orthop 2011; 139:e203-10. [PMID: 21392663 DOI: 10.1016/j.ajodo.2009.06.027] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2008] [Revised: 06/01/2009] [Accepted: 06/01/2009] [Indexed: 11/29/2022]
Abstract
INTRODUCTION The purpose of this study was to evaluate the reliability and accuracy in locating several different foramina in the cranial base by using cone-beam computerized tomography (CBCT) images for future use in establishing reference coordinate systems. METHODS CBCT images from 10 dry skulls were taken with and without the foramina ovale, spinosum, and rotundum, and the hypoglossal canals filled with radiopaque gutta-percha (gold standard). Three evaluators identified the foramen landmarks in the CBCT images without gutta-percha. Mean differences and main researcher intraexaminer and interexaminer reliability were measured by using intraclass correlation coefficients for all landmark coordinates. Descriptive statistics were calculated with respect to the landmark coordinates and distances to the reference points. RESULTS Intraexaminer and interexaminer reliability values for the x-, y-, and z-coordinates for all landmarks were greater than 0.9 with the exception of 4 (of 72) points that still had acceptable interexaminer reliability (>0.75). Mean measurement error differences obtained in the principal investigator's trials were primarily less than 0.5 mm. When comparing the mean distance differences of the same examiner and between the 3 examiners with the gold standard, the highest difference obtained was 1.3 mm. CONCLUSIONS Foramina spinosum, ovale, and rotundum, and the hypoglossal canal all provided high intraexaminer reliability and accuracy, and can be considered acceptable landmarks to use in establishing reference coordinate systems for future 3-dimensional superimposition analysis.
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Affiliation(s)
- Manuel O Lagravère
- Orthodontic Graduate Program, Department of Dentistry, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada.
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Chang HW, Huang HL, Yu JH, Hsu JT, Li YF, Wu YF. Effects of orthodontic tooth movement on alveolar bone density. Clin Oral Investig 2011; 16:679-88. [PMID: 21519883 DOI: 10.1007/s00784-011-0552-9] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2010] [Accepted: 04/11/2011] [Indexed: 01/28/2023]
Abstract
The object of this study was to evaluate the relationship between changes in the alveolar bone density around the teeth and the direction of tooth movement by using cone-beam computed tomography (CBCT). CBCT was used to measure the bone densities around six maxilla anterior teeth before and after 7 months of orthodontic treatment in eight patients. Each root was divided into three levels (cervical, intermediate, and apical) to determine whether the bone density change varied with the tooth level. Moreover, each level was divided into four regions (palatal, distal, mesial, and buccal sides). Three-dimensional computer models of the maxilla before and after orthodontic treatment were created to detect the direction of tooth movement. The percentage for all 144 samples [8 (patients) × 6 (teeth) × 3 (levels)] in which the side (palatal, distal, mesial, or buccal sides) of maximum bone density reduction (before and after orthodontic treatment) coincided with the direction of tooth movement was calculated; this was referred to as the "coincidence percentage". The bone density around the teeth reduced by 24.3 ± 9.5%. The average coincidence percentage for the eight patients was 59.0%. The coincidence percentages for the eight patients were 62.5%, 62.5%, and 52.1% at the cervical, intermediate, and apical levels, respectively. The obtained results demonstrate that the direction of tooth movement is associated with the side of maximum bone density reduction, and that CBCT is a useful approach for evaluating bone density changes around teeth induced by orthodontic treatment.
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Affiliation(s)
- Hsing-Wen Chang
- School of Dentistry, College of Medicine, China Medical University and Hospital, 91 Hsueh-Shih Road, Taichung 404, Taiwan, Republic of China
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Inglam S, Suebnukarn S, Tharanon W, Apatananon T, Sitthiseripratip K. Influence of graft quality and marginal bone loss on implants placed in maxillary grafted sinus: a finite element study. Med Biol Eng Comput 2010; 48:681-9. [DOI: 10.1007/s11517-010-0584-3] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2008] [Accepted: 01/30/2010] [Indexed: 11/25/2022]
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Eshima KI, Takemoto M, Inoue S, Higo T, Tada H, Sunagawa K. Coronary aneurysm associated with coronary perforation after sirolimus-eluting stents implantation: Close follow-up exceeding 2 years by coronary 3-dimensional computed tomography. J Cardiol 2009; 54:115-20. [DOI: 10.1016/j.jjcc.2008.09.013] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/01/2008] [Revised: 09/21/2008] [Accepted: 09/30/2008] [Indexed: 10/21/2022]
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