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Volume 52 (2012)
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Volume 52, Issue 1
Displaying 1-3 of 3 articles from this issue
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Yoshihiko Hayakawa, Ken-ichiro Ejima, Kazuyuki Araki, Kaoru Kobayashi, ...2012 Volume 52 Issue 1 Pages 1-8
Published: 2012
Released on J-STAGE: May 11, 2012
JOURNAL FREE ACCESSPurpose: The Japanese Task Group of the Japanese Society for Oral and Maxillofacial Radiology (JSOMR) has worked on the project of “Dental Mapping and Query-Retrieve (Q-R)”. This is an approved work item of DICOM WG-22 (Dentistry). The project aims to utilize the coding of teeth to create x-ray charts for mapping and viewing intraoral radiographs. An interoperable solution is necessary for dental practice. Therefore, we carried out a survey of display mapping and viewing solutions for intraoral radiographs in university dental hospitals.
Methods: The Task Group sent questionnaires on display formats to 80 representatives of JSOMR using the mailing list, jsomr-daigiin@umin.ac.jp (JSOMR-daigiin-ML) on Dec.10, 2010. We sent the questionnaire to all 29 university dental hospitals. We indicated typical patterns and asked whether each affiliation uses these patterns or not. We asked the respondents to indicate exceptional patterns.
Results: The survey showed the display mapping and format patterns of intraoral radiographs that were used in dental school hospitals in Japan, in Dec. 2010. A finite number of templates were used in university dental hospitals in Japan.
Discussion & Conclusions: Our proposal to the DICOM Standards is to define specific examination codes (DICOM tags) for intraoral radiography techniques and to add tags for designation of specific displaying templates. This will provide a solution for the dental query-retrieve for intraoral radiographs on any given template by achieving a definition of the relationship between tooth/teeth groups and display disposition. A method to specify a finite number of display format templates is possible based on the survey result, which showed that only a finite number of templates are required.View full abstractDownload PDF (538K) -
Midori Yokoi, Akitoshi Katsumata, Munetaka Naitoh, Kenichi Goto, Akiko ...2012 Volume 52 Issue 1 Pages 9-14
Published: 2012
Released on J-STAGE: May 11, 2012
JOURNAL FREE ACCESSPanoramic radiography is one of the most frequently used radiological techniques in dentistry for the detection of dental caries and periodontal diseases. However, it is generally accepted that marked overlapping of the approximal surfaces of the teeth occurs frequently, making interpretation of caries and/or marginal bone loss difficult.
Several methods have been proposed to overcome this problem. One is the improved orthoradial panoramic projection program (Veraview series, Morita, Japan), another is panoramic layer reconstruction based on the tomosynthesis method (PanoACT 1000, Axion, Japan).
Therefore, we evaluated the deviation between the projection angle of the X-ray beam and the interproximal surfaces of the teeth in the dental arch by means of a special phantom.
The phantom represented the optimal direction of the beam of radiation that is perpendicular to the average dental arch.
As a result, in every panoramic image, the projection angle of the X-ray beam deviated medially from the optimal direction. In the conventional projection mode, the direction of the X-ray beam deviated from 25 degrees to 30 degrees in the premolars and the first molar region. The discrepancy in these regions was decreased from 10 degrees to 20 degrees in both improved panoramic projections.To achieve an ideal orthoradial projection for the dental arch, further improvements in imaging techniques are needed.View full abstractDownload PDF (753K) -
—Comparison with a Conventional-type Computed Radiography Photostimulable Phosphor Cephalometric System—Naoki Maeda, Midori Yoshida, Hidehiko Hosoki, Eiichi Honda2012 Volume 52 Issue 1 Pages 15-21
Published: 2012
Released on J-STAGE: May 11, 2012
JOURNAL FREE ACCESSObjective: Here we examine the distance measurement accuracy of a digital CCD sensor cephalometric system and we compare this to a conventional-type computed radiography photostimulable phosphor cephalometric system (CR cephalometric system).
Methods: A handmade phantom made of an acrylic resin plate and ball bearings was used for measurement. The phantom was exposed using a CCD sensor and a CR cephalometric system. The image obtained was converted to a dicom format image and printed out to film. The distance between each ball on the film was measured by a caliper with 0.01 μm accuracy. The measurement value was compared to the theoretical value.
Results: For the CR cephalometric system, errors of -0.28 to -0.56 mm (enlargement ratio 1.096 to 1.097) and 0.03 to 0.18 mm (enlargement ratio 1.098 to 1.099) were observed in the vertical and horizontal directions, respectively. For the CCD sensor system, errors of -3.25 to -3.37 mm (enlargement ratio 1.075 to 1.076) and -1.46 to -1.65 mm (enlargement ratio 1.086 to 1.088) were observed in the vertical and horizontal directions, respectively. The error of the CR cephalometric system was significantly lower than that of the CCD sensor cephalometric system (p < 0.001). Moreover, there was a significant difference in distance among the first, middle and last scanning in the horizontal direction for the CCD sensor system (p < 0.001).
Conclusion: The CCD sensor system had a certain level of distance error. It is unknown whether the error affects clinical treatment, but knowledge of the error is required before using the system. Further quality control and quality assurance measures by the manufacturer are required.View full abstractDownload PDF (507K)
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