| 1. |
- Ahlqvist, Jan, et al.
(författare)
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A technique for the accurate administration of corticosteroids in the temporomandibular joint.
- 1993
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Ingår i: Dento-Maxillo-Facial Radiology. - 0250-832X .- 1476-542X. ; 22:4, s. 211-3
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Tidskriftsartikel (refereegranskat)abstract
- A new technique for intra-articular injection of a corticosteroid in the temporomandibular joint (TMJ) is presented. The corticosteroid is mixed with contrast medium and the administration visualized and controlled using fluoroscopy. When superior and inferior joint spaces have been filled and the soft tissues of the joint have been identified in the fluoroscopic image, additional corticosteroid can be administered to selected sites within the TMJ.
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| 2. |
- Ahlqvist, Jan, et al.
(författare)
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Sources of radiographic distortion in conventional and computed tomography of the temporal bone.
- 1998
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Ingår i: Dento-Maxillo-Facial Radiology. - 0250-832X .- 1476-542X. ; 27:6, s. 351-7
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVES: To identify those bony regions of the glenoid fossa where, due to the inclination, there is an increased risk of radiographic distortion in conventional and computed tomography (CT).METHODS: The inclination of the roof and posterior wall of the glenoid fossa was determined relative to established imaging planes. Measurements were performed on 50 corrected coronal MR and 50 axial CT images and 200 sagittal cryosections of 50 temporomandibular joints (TMJs). The location of regions with unfavourable bone wall inclination was identified using the condyle as a reference.RESULTS: The inclination of parts of the fossa roof exceeded the limit for reliable depiction in corrected sagittal and coronal planes in 40% and 8% of the joints respectively. The inclination of parts of the posterior wall of the fossa exceeded the limit for reliable depiction in corrected sagittal and in true sagittal planes in 100% and 84% of the joints respectively. In 84% of the joints the inclination exceeded the limit for reliable depiction in the axial plane. For both bone walls the regions with unfavourable inclination were in the medial part of the joint.CONCLUSIONS: The angulation of parts of the roof and posterior wall of the glenoid fossa in relation to established imaging planes makes them highly susceptible to distortion. The oblique coronal projection is well suited for depiction of the roof of the fossa and preferable to a sagittal projection. An oblique axial projection is required for the posterior wall.
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| 3. |
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| 4. |
- Ahlqvist, Jan, et al.
(författare)
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Validity of computed tomography in imaging thin walls of the temporal bone
- 1999
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Ingår i: Dento-Maxillo-Facial Radiology. - : British Institute of Radiology. - 0250-832X .- 1476-542X. ; 28:1, s. 13-19
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVES: To evaluate the validity of computed tomography (CT) for reproduction of the bone margins of the temporomandibular joint (TMJ).METHODS: Seven TMJ specimens were examined with a CT and then cryosectioned. The bone separating the TMJ from the middle cranial fossa, middle ear and external auditory canal was measured as the full width at half maximum (FWHM). Measurements were compared with the true thickness of the bone wall.RESULTS: There was good agreement when the bone walls were thicker than 1 mm: accuracy was influenced only by the angle of the bone wall to the scanning plane. Conversely, bone walls thinner than 1 mm were reproduced with a magnification that increased with decreasing bone thickness. The difference increased further as the inclination of the bone wall became greater.CONCLUSION: Measurements performed at FWHM are reliable within +/- 10% for bone walls more than approximately 1 mm thick which form an angle of less than 35 degrees to the perpendicular of the scanning plane. For bone walls thinner than 1 mm and for those thicker than 1 mm with an inclination exceeding approximately 35 degrees, partial volume effects result in a progressively increasing magnification of bone thickness.
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| 5. |
- Al-Okshi, Ayman, et al.
(författare)
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Dose optimization for assessment of periodontal structures in cone beam CT examinations
- 2016
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Ingår i: Dento-Maxillo-Facial Radiology. - : British institute of radiology. - 0250-832X .- 1476-542X. ; 46:3
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVES: To investigate the relationship between dose and image quality for a dedicated dental CBCT scanner using different scanning protocols and to set up an optimal imaging protocol for assessment of periodontal structures. METHODS: Radiation dose and image quality measurements were made using 3D Accuitomo 170 (J. Morita, Kyoto, Japan) dental CBCT scanner. The SedentexCT IQ phantom was used to investigate the relationship between contrast-to-noise ratio (CNR) and dose-area product. Subjective image quality assessment was achieved using a small adult skull phantom for the same range of exposure settings. Five independent observers assessed the images for three anatomical landmarks using a three-point visual grade analysis. RESULTS: When correlating the CNR of each scanning protocol to the exposure parameters used to obtain it, CNR decreased as these parameters decreased, especially current-exposure time product. When correlating to subjective image quality, the CNR level remained acceptable when 5 mA and 17.5 s or greater was selected and 80 kV could be used without compromising the CNR. CONCLUSIONS: For a dedicated CBCT unit, changing the rotation angle from 360 degrees to 180 degrees degrades image quality. By altering tube potential and current for the 360 degrees rotation protocol, assessment of periodontal structures can be performed with a smaller dose without substantially affecting visualization.
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| 6. |
- Al-Okshi, Ayman, et al.
(författare)
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Measurability and reliability of assessments of root length and marginal bone level in cone beam CT and intraoral radiography : a study of adolescents
- 2019
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Ingår i: Dento-Maxillo-Facial Radiology. - : British Institute of Radiology. - 0250-832X .- 1476-542X. ; 48:5, s. 1-9
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Tidskriftsartikel (refereegranskat)abstract
- Objectives: To evaluate measurability and reliability of measurements of root length and marginal bone level in CBCT, periapical (PA) and bitewing (BW) radiographs. Methods: CBCT of both jaws, PA of maxillary incisors and posterior BW radiographs of 10 adolescents (mean age 13.4) were selected. The radiographs comprised part of the baseline examinations of a trial of orthodontic treatment. Six raters assessed measurability and measured root length and marginal bone level. Three raters repeated their assessments. Measurability was expressed as frequency of interpretable sites and reliability as intraclass correlation coefficient (ICC). Results: Measurability was 100 % in CBCT and 95 % in PA of maxillary incisors for root length measurements. For marginal bone level, measurability was 100 % in CBCT, 76 % in PA and 86 % in posterior BW. Mean ICC for interrater reliability for root length measurements in CBCT was 0.88 (range 0.27-0.96 among different teeth) and 0.69 in PA of maxillary incisors. For marginal bone level measurements, mean ICC was 0.4 in CBCT, 0.38 in PA of maxillary incisors and 0.4 in posterior BW. Intrarater reliability varied among methods, root length or marginal bone level and among raters, except for root length measurements in CBCT, which presented high reliability (above 0.8) for all raters. Conclusions: As measurability and reliability were high for root length measurements in CBCT, this may be the method of choice for scientific analyses in orthodontics. For clinical praxis, we recommend PA following the "as low as diagnostically acceptable" principle, as clinical decisions seem to be influenced only when severe root resorption occurs.
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| 7. |
- Al-Okshi, Ayman, et al.
(författare)
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Using GafChromic film to estimate the effective dose from dental cone beam CT and panoramic radiography
- 2013
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Ingår i: Dento-Maxillo-Facial Radiology. - : British Institute of Radiology. - 0250-832X .- 1476-542X. ; 42:7
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Tidskriftsartikel (refereegranskat)abstract
- Objectives: To demonstrate the feasibility of GafChromic(®) XR-QA2 (ISP Corp., Wayne, NJ) as a dosemeter when performing measurements of the effective dose from three cone beam CT (CBCT) units and to compare the doses from examinations of three common dental clinical situations. A second aim was to compare the radiation doses for three digital panoramic units with the doses for the CBCT units. METHODS: The CBCT units used were Veraviewepocs 3De(®) (J Morita MFG Corp., Kyoto, Japan), ProMax(®) 3D (Planmeca, Helsinki, Finland) and NewTom VGi(®) (Quantitative Radiology, Verona, Italy). GafChromic XR-QA2 films were placed between the selected layers of the head and neck of a tissue-equivalent human skull (RANDO(®) phantom; The Phantom Laboratory, Salem, NY). The exposure parameters were set using the automatic exposure control function of the units. Depending on the availability, medium and smaller field of view (FOV) scanning modes were used. The effective dose was estimated using the 2007 International Commission on Radiological Protection formalism. RESULTS: The lowest effective dose of a CBCT unit was observed for ProMax 3D, FOV 4 × 5 cm (10 μSv), the highest for NewTom VGi, FOV 8 × 8 cm-high resolution (129 μSv). The range of effective doses for digital panoramic machines measured was 8-14 μSv. CONCLUSIONS: This study demonstrates the feasibility of using radiochromic films for dental CBCT and panoramic dosimetry.
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| 8. |
- Andresen, Amanda K H, et al.
(författare)
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Radiographic features in 2D imaging as predictors for justified CBCT examinations of canine-induced root resorption.
- 2021
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Ingår i: Dento-Maxillo-Facial Radiology. - : British Institute of Radiology. - 0250-832X .- 1476-542X. ; 51:1
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVES: This retrospective observational study aimed to evaluate the diagnostic accuracy of two-dimensional radiographs on canine-induced root resorption (CIRR) in lateral incisors and identify predictors of CIRR in patients with impacted maxillary canines (IMC).METHODS: Ninety-nine patients aged 9-17 years, with 156 IMCs, were included in the study. All had CBCT-volumes and two-dimensional radiographs consisting of at least one panoramic radiograph. Two radiologists jointly viewed all cases twice. First, radiographic features related to the IMC and possible CIRR were recorded from two-dimensional radiographs. Then, CIRR was determined from CBCT and according to position and extension classified as mild, moderate and severe.RESULTS: CIRRs was detected in 80% of lateral incisors (mild: 45%; moderate: 44%; severe: 11%). The sensitivity was generally low at mild and moderate cut-offs (29 and 29%), and somewhat higher for severe (50%). Corresponding specificities were 48%, 63% and 68%. Canine cusp-tip superimposing the lateral incisor's middle third and root/crown ratio >1 was positively associated with mild CIRR, with an odds ratio (OR) of 3.8 and 6.7, respectively. In addition, the root development stage was positively associated with moderate/severe CIRR when the canine root was nearly or fully developed (OR = 3.1).CONCLUSIONS: The diagnostic accuracy of two-dimensional radiographs was inadequate for detecting CIRR amongst patients referred for CBCT examinations. Based on our results, none of the suggested two-dimensional radiographic features could predict moderate/severe CIRR except for root development stage. IMC in a later stage of root development seems to be associated with a higher risk of moderate/severe CIRR.
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