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How precise is dental volumetric tomography in the prediction of bone density?

Bilhan H, Arat S, Geckili O - Int J Dent (2012)

Bottom Line: The highest HU values were recorded in the interforaminal region, especially in the midline (408-742).Posterior regions showed lower HU values, especially the first molar regions (22-61 for the right; 14-66 for the left first molar regions).Conclusion.

View Article: PubMed Central - PubMed

Affiliation: Department of Prosthodontics, Faculty of Dentistry, Istanbul University, 34093 Çapa Istanbul, Turkey.

ABSTRACT
Objectives. The aim of this study was to review the bone density assessment techniques and evaluate the macroscopic structure of bone specimens scored by Hounsfield Units (HUs) and decide if they are always in congruence. Methods. The mandible of a formalin-fixed human cadaver was scanned by dental volumetric tomography (DVT) for planning of the specimen positions and fabrication of a surgical guide and a surgical stent was fabricated afterwards. Bone cylinders of 3.5 mm diameter and 5 mm length, were excised from the mandible using the surgical stent with a slow speed trephine drill. After removal of the cylinders two more scans were performed and the images of the first scan were used for the determination of the HU values. The removed bone cylinder was inspected macroscopically as well by micro-CT scan. Results. The highest HU values were recorded in the interforaminal region, especially in the midline (408-742). Posterior regions showed lower HU values, especially the first molar regions (22-61 for the right; 14-66 for the left first molar regions). Conclusion. Within the limitations of this pilot study, it can be concluded that HU values alone could be a misleading diagnostic tool for the determination of bone density.

No MeSH data available.


The photograph of the micro-CT scanner.
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fig5: The photograph of the micro-CT scanner.

Mentions: As a part of the pilot study, the bone cylinder on the left first premolar molar region of human cadaver bone was randomly chosen for micro-CT scanning. The bone cylinder was placed in a custom vessel wrapped in paper soaked with saline solution to prevent any desiccation, and isotropically scanned at 14 μm resolution with a model 1172 micro-CT scanner (Skyscan, Kontich, Belgium) using a CBCT scanning technique (Figure 5). CBCT is a novel CT image acquisition technique in which up to a several hundred CT images (as opposed to 1–3 images in normal CT) are reconstructed by one data acquisition as the data on the fluoroscopic image is handled as plane data. The total time required for scanning and reconstruction was approximately 30 minutes per sample, thus deterioration of the bone cylinder as a result of being exposed to ambient conditions was significantly reduced. To ensure a consistent CT image resolution among all the datasets, the scanner turntable location was fixed at a specific SOD and SID distance of 19.03 mm and 356.90 mm, respectively. The X-ray parameters were set at 51 kV and 200 μA and the CT images were processed at a scaling coefficient of 50 and averaged three times. With these parameters, together with a 0.5 mm aluminum plate placed at the X-ray detector, a good contrast was achieved in the resultant CT images between trabeculae. Resultant dataset had an isotropic resolution of 14.836 μm. Resultant CT images for each bone cylinder was evaluated for microarchitectural parameters [19] such as tissue volume, bone volume, percent bone volume, tissue surface, bone surface, intersection surface, bone specific surface, bone surface density, trabecular bone pattern factor, structure model index, trabecular thickness, trabecular number and trabecular separation (CT Analyzer, Skyscan, Belgium) (Figure 6).


How precise is dental volumetric tomography in the prediction of bone density?

Bilhan H, Arat S, Geckili O - Int J Dent (2012)

The photograph of the micro-CT scanner.
© Copyright Policy - open-access
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3369485&req=5

fig5: The photograph of the micro-CT scanner.
Mentions: As a part of the pilot study, the bone cylinder on the left first premolar molar region of human cadaver bone was randomly chosen for micro-CT scanning. The bone cylinder was placed in a custom vessel wrapped in paper soaked with saline solution to prevent any desiccation, and isotropically scanned at 14 μm resolution with a model 1172 micro-CT scanner (Skyscan, Kontich, Belgium) using a CBCT scanning technique (Figure 5). CBCT is a novel CT image acquisition technique in which up to a several hundred CT images (as opposed to 1–3 images in normal CT) are reconstructed by one data acquisition as the data on the fluoroscopic image is handled as plane data. The total time required for scanning and reconstruction was approximately 30 minutes per sample, thus deterioration of the bone cylinder as a result of being exposed to ambient conditions was significantly reduced. To ensure a consistent CT image resolution among all the datasets, the scanner turntable location was fixed at a specific SOD and SID distance of 19.03 mm and 356.90 mm, respectively. The X-ray parameters were set at 51 kV and 200 μA and the CT images were processed at a scaling coefficient of 50 and averaged three times. With these parameters, together with a 0.5 mm aluminum plate placed at the X-ray detector, a good contrast was achieved in the resultant CT images between trabeculae. Resultant dataset had an isotropic resolution of 14.836 μm. Resultant CT images for each bone cylinder was evaluated for microarchitectural parameters [19] such as tissue volume, bone volume, percent bone volume, tissue surface, bone surface, intersection surface, bone specific surface, bone surface density, trabecular bone pattern factor, structure model index, trabecular thickness, trabecular number and trabecular separation (CT Analyzer, Skyscan, Belgium) (Figure 6).

Bottom Line: The highest HU values were recorded in the interforaminal region, especially in the midline (408-742).Posterior regions showed lower HU values, especially the first molar regions (22-61 for the right; 14-66 for the left first molar regions).Conclusion.

View Article: PubMed Central - PubMed

Affiliation: Department of Prosthodontics, Faculty of Dentistry, Istanbul University, 34093 Çapa Istanbul, Turkey.

ABSTRACT
Objectives. The aim of this study was to review the bone density assessment techniques and evaluate the macroscopic structure of bone specimens scored by Hounsfield Units (HUs) and decide if they are always in congruence. Methods. The mandible of a formalin-fixed human cadaver was scanned by dental volumetric tomography (DVT) for planning of the specimen positions and fabrication of a surgical guide and a surgical stent was fabricated afterwards. Bone cylinders of 3.5 mm diameter and 5 mm length, were excised from the mandible using the surgical stent with a slow speed trephine drill. After removal of the cylinders two more scans were performed and the images of the first scan were used for the determination of the HU values. The removed bone cylinder was inspected macroscopically as well by micro-CT scan. Results. The highest HU values were recorded in the interforaminal region, especially in the midline (408-742). Posterior regions showed lower HU values, especially the first molar regions (22-61 for the right; 14-66 for the left first molar regions). Conclusion. Within the limitations of this pilot study, it can be concluded that HU values alone could be a misleading diagnostic tool for the determination of bone density.

No MeSH data available.