| 1. |
- Brown, J, et al.
(författare)
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Basic training requirements for the use of dental CBCT by dentists : a position paper prepared by the European Academy of DentoMaxilloFacial Radiology
- 2014
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Ingår i: Dento-Maxillo-Facial Radiology. - : British Institute of Radiology. - 0250-832X .- 1476-542X. ; 43:1
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Tidskriftsartikel (refereegranskat)abstract
- Cone beam CT (CBCT) is a relatively new imaging modality, which is now widely available to dentists for examining hard tissues in the dental and maxillofacial regions. CBCT gives a three-dimensional depiction of anatomy and pathology, which is similar to medical CT and uses doses generally higher than those used in conventional dental imaging. The European Academy of DentoMaxilloFacial Radiology recognizes that dentists receive training in two-dimensional dental imaging as undergraduates, but most of them have received little or no training in the application and interpretation of cross-sectional three-dimensional imaging. This document identifies the roles of dentists involved in the use of CBCT, examines the training requirements for the justification, acquisition and interpretation of CBCT imaging and makes recommendations for further training of dentists in Europe who intend to be involved in any aspect of CBCT imaging. Two levels of training are recognized. Level 1 is intended to train dentists who prescribe CBCT imaging, such that they may request appropriately and understand the resultant reported images. Level 2 is intended to train to a more advanced level and covers the understanding and skills needed to justify, carry out and interpret a CBCT examination. These recommendations are not intended to create specialists in CBCT imaging but to offer guidance on the training of all dentists to enable the safe use of CBCT in the dentoalveolar region.
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| 2. |
- Bryndahl, Fredrik, et al.
(författare)
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Cartilage changes link retrognathic mandibular growth to TMJ disc displacement in a rabbit model
- 2011
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Ingår i: International Journal of Oral and Maxillofacial Surgery. - : Elsevier. - 0901-5027 .- 1399-0020. ; 40:6, s. 621-627
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Tidskriftsartikel (refereegranskat)abstract
- Recent experimental research demonstrated that non-reducing temporomandibular joint (TMJ) disc displacement in growing rabbits impaired mandibular growth. TMJ disc displacement is also shown to induce histological changes of the condylar cartilage. The authors hypothesized that the severity of these changes would correlate to the magnitude of mandibular growth. Bilateral non-reducing TMJ disc displacement was surgically created in 10 growing New Zealand White rabbits. Ten additional rabbits constituted a sham operated control group. Aided by tantalum implants, growth was cephalometrically determined for each mandibular side during a period equivalent to childhood and adolescence in man. At the end of the growth period, histologically classified cartilage features were correlated with the assessed ipsilateral mandibular growth. Non-reducing displacement of the TMJ disc during the growth period induced histological reactions of the condylar cartilage in the rabbit model. The severity of cartilage changes was inversely correlated to the magnitude and the direction of mandibular growth, which resulted in a retrognathic growth pattern.
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| 3. |
- Cederhag, Josefine, et al.
(författare)
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Comparison of absorbed doses and organ doses measured with thermoluminescent dosimeters and Gafchromic film for cone beam computed tomography examination of the posterior mandibular region in a head phantom
- 2023
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Ingår i: Oral Surgery, Oral Medicine, Oral Pathology and Oral Radiology. - : Elsevier. - 2212-4403 .- 2212-4411. ; 136:6, s. 769-776
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Tidskriftsartikel (refereegranskat)abstract
- Objectives: We aimed to map the correlation between thermoluminescent dosimeters (TLDs) and Gafchromic film for measuring absorbed doses and to compare minimum, maximum, and mean absorbed doses over larger regions of interest and at various craniofacial organs and tissues during cone beam computed tomography (CBCT) exposure of the mandibular third molar region. Study Design: We positioned TLDs at 75 measurement points in a head phantom. Gafchromic film was cut to the same shape as the 5 levels of the phantom and was placed on top of the TLDs. Both dosimetry methods thus included the surface of each level simultaneously. CBCT scans were made using a 5 × 5 cm field of view and a rotation angle of 200°. Measurements included absorbed dose distributions, doses at all 75 points, and minimum, maximum, and mean doses within organs and tissues. Results: The correlation of point-dose measurements at all TLD sites with doses measured on film was strong (R2 = 0.9687), with greatest correlation at lower doses (<2 mGy). Large deviations between TLD and film measurements of minimum and maximum doses and absorbed doses to the organs occurred at all 5 levels. TLD positioning failed to cover several organ sites; for these, only absorbed dose measurements from the film were available. Conclusions: TLDs were unable to sample dose distributions and gradients accurately. The characteristics of Gafchromic LD-V1 film make it a favorable alternative in dental CBCT dosimetry.
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| 4. |
- Hellén-Halme, Kristina, et al.
(författare)
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Comparison of the performance of intraoral X-ray sensors using objective image quality assessment
- 2016
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Ingår i: Oral surgery, oral medicine, oral pathology and oral radiology. - : Elsevier. - 2212-4403 .- 2212-4411. ; 121:5, s. e129-e137
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Tidskriftsartikel (refereegranskat)abstract
- Objectives. The main aim of this study was to evaluate the performance of 10 individual sensors of the same make, using objective measures of key image quality parameters. A further aim was to compare 8 brands of sensors. Study Design. Ten new sensors of 8 different models from 6 manufacturers (i.e., 80 sensors) were included in the study. All sensors were exposed in a standardized way using an X-ray tube voltage of 60 kVp and different exposure times. Sensor response, noise, low-contrast resolution, spatial resolution and uniformity were measured Results. Individual differences between sensors of the same brand were surprisingly large in some cases. There were clear differences in the characteristics of the different brands of sensors. The largest variations were found for individual sensor response for some of the brands studied. Also, noise level and low contrast resolution showed large variations between brands Conclusions. Sensors, even of the same brand, vary significantly in their quality. It is thus valuable to establish action levels for the acceptance of newly delivered sensors and to use objective image quality control for commissioning purposes and periodic checks to ensure high performance of individual digital sensors.
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| 5. |
- Mota de Almeida, Fernando José, et al.
(författare)
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The effect of cone beam CT (CBCT) on therapeutic decision-making in endodontics
- 2014
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Ingår i: Dento-Maxillo-Facial Radiology. - : British Institute of Radiology. - 0250-832X .- 1476-542X. ; 43:4
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Tidskriftsartikel (refereegranskat)abstract
- Objectives: The aim was to assess to what extent cone beam CT (CBCT) used in accordance with current European Commission guidelines in a normal clinical setting has an impact on therapeutic decisions in a population referred for endodontic problems.Methods: The study includes data of consecutively examined patients collected from October 2011 to December 2012. From 2 different endodontic specialist clinics, 57 patients were referred for a CBCT examination using criteria in accordance with current European guidelines. The CBCT examinations were performed using similar equipment and standardized among clinics. After a thorough clinical examination, but before CBCT, the examiner made a preliminary therapy plan which was recorded. After the CBCT examination, the same examiner made a new therapy plan. Therapy plans both before and after the CBCT examination were plotted for 53 patients and 81 teeth. As four patients had incomplete protocols, they were not included in the final analysis.Results: 4% of the patients referred to endodontic clinics during the study period were examined with CBCT. The most frequent reason for referral to CBCT examination was to differentiate pathology from normal anatomy, this was the case in 24 patients (45% of the cases). The primary outcome was therapy plan changes that could be attributed to CBCT examination. There were changes in 28 patients (53%).Conclusions: CBCT has a significant impact on therapeutic decision efficacy in endodontics when used in concordance with the current European Commission guidelines.
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| 6. |
- Olsson, Lars, et al.
(författare)
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The effect of anatomical noise on perception of low contrast in intra-oral radiographs : an in vitro study
- 2016
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Ingår i: Dento-Maxillo-Facial Radiology. - London, United Kingdom : British Institute of Radiology. - 0250-832X .- 1476-542X. ; 45:4
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Tidskriftsartikel (refereegranskat)abstract
- Objectives: Radiographic images suffer from varying amounts of noise. The most studied and discussed of these is random noise. However, recent research has shown that the projected anatomy contributes substantially to noise, especially when detecting low-contrast objects in the images. Our aim, therefore, was to evaluate the extent to which overprojected anatomical noise affects the detection of low-contrast objects in intra-oral images.Methods: Our study used four common sensor models. With each sensor, we took four series of images, three series with and one series without an anatomical phantom present. In each series, we exposed a low-contrast phantom at 18 different exposure times using a standardized method. 4 observers evaluated all 288 images.Results: The low-contrast characteristics differed substantially when imaging low contrast on a homogeneous background compared with imaging low contrast when an anatomical phantom was present. For three of the sensors, optimal exposure times for low-contrast imaging were found, while the fourth sensor displayed a completely different behaviour.Conclusions: Calibrating the low-contrast properties of an imaging system using low-contrast objects on a homogeneous background is not recommended. On an anatomical background, low-contrast properties are completely different, and these will mimic the clinical situation much more closely, directing the operator how to best use the system. There is a clear demand for further research on this subject.
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| 7. |
- Sonesson, Mikael, et al.
(författare)
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Orthodontic appliances and MR image artefacts : An exploratory in vitro and in vivo study using 1.5-T and 3-T scanners
- 2021
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Ingår i: Imaging Science in Dentistry. - : Korean Academy of Oral and Maxillofacial Radiology. - 2233-7822 .- 2233-7830. ; 51
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: The aim of this study was to assess the artefacts of 12 fixed orthodontic appliances in magnetic resonance images obtained using 1.5-T and 3-T scanners, and to evaluate different imaging sequences designed to suppress metal artefacts. Materials and Methods: In vitro, study casts of 1 adult with normal occlusion were used. Twelve orthodontic appliances were attached to the study casts and scanned. Turbo spin echo (TSE), TSE with high readout bandwidth, and TSE with view angle tilting and slice encoding for metal artefact correction were used to suppress metal artefacts. Artefacts were measured. In vivo, 6 appliances were scanned: 1) conventional stainless-steel brackets; 2) nickelfree brackets; 3) titanium brackets; 4) a Herbst appliance; 5) a fixed retainer; and 6) a rapid maxillary expander. The maxilla, mandible, nasopharynx, tongue, temporomandibular joints, and cranial base/eye globes were assessed. Scores of 0, 1, 2, and 3 indicated no artefacts and minor, moderate, and major artefacts, respectively. Results: In vitro, titanium brackets and the fixed retainer created minor artefacts. In vivo, titanium brackets caused minor artefacts. Conventional stainless-steel and nickel free brackets, the fixed retainer, and the rapid maxillary expander caused major artefacts in the maxilla and mandible. Conventional stainless-steel and nickel-free brackets caused major artefacts in the eye globe (3-T). TSE with high readout bandwidth reduced image artefacts in both scanners. Conclusion: Titanium brackets, the Herbst appliance, and the fixed retainer caused minor artefacts in images of neurocranial structures(1.5-T and 3-T) when using TSE with high readout bandwidth.(Imaging Sci Dent 20200199)
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| 8. |
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| 9. |
- Torgersen, Gerald R., et al.
(författare)
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A phantom for simplified image quality control of dental cone beam computed tomography units
- 2014
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Ingår i: Oral Surgery, Oral Medicine, Oral Pathology and Oral Radiology. - : Elsevier BV. - 2212-4403 .- 2212-4411. ; 118:5, s. 603-611
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Tidskriftsartikel (refereegranskat)abstract
- Objective. The purpose of this work was to develop an inexpensive phantom for simplified image quality assurance (IQA) together with algorithms for objective evaluation of image quality parameters and to integrate these components into an easy-to-use software package. This should help make quality control of dental cone beam computed tomography (CBCT) units accessible, easy, and affordable for any specialist or general practitioner. Study Design. Our study developed an inexpensive polymethyl methacrylate (Plexiglas) phantom containing objects and structures for objective quantification of the most important image-quality parameters in CBCT imaging. It also paired the phantom with a software package, based on open-source software, for automatic processing and analysis. Results. The software produces objectively measured IQA data for low-and high-contrast resolution, uniformity, noise characteristics, and geometric linearity. Conclusions. The authors consider the phantom and methods presented in this article to be a step toward helping clinical dental personnel perform regular quality assurance on CBCT units.
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| 10. |
- Larsson, Anna-Karin, et al.
(författare)
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Parents’ Worried State of Mind When Fetal Ultrasound Shows an Unexpected Finding
- 2009
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Ingår i: Journal of ultrasound in medicine. - 0278-4297 .- 1550-9613. ; 28:12, s. 1663-1670
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Tidskriftsartikel (refereegranskat)abstract
- Objective. Most parents yearn for a second-trimester ultrasound examination and feel excitement about it, but some also worry about what the examination will show. According to prior research, using only generic instruments or specific questionnaires, anxiety decreases when the ultrasound findings are normal. The aim of this study was to compare parents’ worry (Parents’ Expectations, Experiences, and Reactions to Ultrasound [PEER-U] State of Mind Index) and sense of coherence before and after a routine second-trimester ultrasound examination when it showed normal or abnormal findings. Methods. A 1-year cohort study was performed at a Swedish university hospital. A total of 2049 parents who had their second-trimester ultrasound examinations there filled in a questionnaire consisting of 2 parts before and after the examinations. Results. Parents with normal ultrasound findings were less worried than parents with abnormal findings. The group with normal findings also showed less worry after the examination than before. A sex analysis showed similar patterns. Conclusions. Parents with abnormal ultrasound findings are more worried and anxious. The new instrument, the PEER-U State of Mind Index, not only measures parents’ worry but can also expose what influences their ultrasound examination experience.
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