Sjollema, S.M. (2014) Het effect van veranderde exposure instellingen bij CBCT-opnames van het orofaciale deel van ongeprepareerde diepgevroren menselijke kadavers op de verkregen beeldkwaliteit. thesis, Dentistry.
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Abstract
Aim: Exploratory study to look at the effect of a changing mA and exposure time and the associated quality of Cone Beam Computered Tomography (CBCT) images on the interpretation of the X-ray image for three different dento-alveolar indication areas of human cadavers: implant planning in the posterior upper jaw, implant planning in the posterior lower jaw and endodontic diagnosis. Design: Screenshots of the CBCT-scans were made from two human cadavers obtained with 1, 2, 3, 5 and 7 mA and 9.0 or 17.5 sec exposure time. 10 dentists with experience in CBCT diagnosis evaluated in four ways: (1) A forced choice for best picture between two X-rays on the ability to assess the full cortical bone of the maxilla, quality of the chosen image by a grade and indicating whether there’s a difference in the interpretation of the compared images. (2) and (3) the threshold for mA for the visibility of the Mandibular canalis at 9.0 and 17.5 sec exposure time. (4) The threshold for mA for the visibility of a second root canal in a tooth at 17.5 sec exposure time. Use was made of descriptive statistics. Results: At varying mA with similar exposure time, the higher the comparison in mA, the less observers chose the highest mA: for 1-3mA chose 96.7% 3 mA, for 3-5mA 5mA chose 85% (9.0 seconds); for 1-2 mA chose 100% 2mA, for 3-5mA chose 60% 5mA (17.5 sec). The average quality of 3-5mA(9.0 sec) was 'sufficient', the average quality of 3-5mA(17.5 sec) was 'good'. At varying exposure time with equal mA: higher exposure was found to be superior (90-100%). The preference for X-ray images with an exposure time of 17.5 sec is higher at higher mA (50% at 1mA, 86.7% at 5mA). Threshold for CBCT of the mandible: 7 mA(9.0 sec) and 5mA(17.5 sec). Threshold for CBCT of root canal anatomy: ≥ 7 mA(17.5 sec) Conclusions: The interpretation of the X-ray image of different observers differ more at higher mA and longer exposure time than at lower settings. At an exposure time of 17.5 seconds more difference was seen in the quality of the picture at higher mA than at lower mA. Possible perception plays a role in the interpretation of X-ray images. Threshold values depend on the structure to be imaged.
| Item Type: | Thesis (Thesis) |
|---|---|
| Supervisor name: | Krol, drs A.A.B. |
| Faculty: | Medical Sciences |
| Date Deposited: | 25 Jun 2020 10:43 |
| Last Modified: | 25 Jun 2020 10:43 |
| URI: | https://umcg.studenttheses.ub.rug.nl/id/eprint/490 |
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