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Accuracy of virtual models in the assessment of maxillary defects.

Kamburoğlu K, Kurşun Ş, Kılıç C, Özen T - Imaging Sci Dent (2015)

Bottom Line: Virtual models obtained using VRMesh Design were compared with impressions obtained by scanning silicon models.Gold standard volumes of the impression models were then compared with CBCT and 3D scanner measurements.Further, the 3D scanner measurements were closer to the gold standard measurements when compared to the CBCT measurements.

View Article: PubMed Central - PubMed

Affiliation: Department of Dentomaxillofacial Radiology, Faculty of Dentistry, Ankara University, Ankara, Turkey.

ABSTRACT

Purpose: This study aimed to assess the reliability of measurements performed on three-dimensional (3D) virtual models of maxillary defects obtained using cone-beam computed tomography (CBCT) and 3D optical scanning.

Materials and methods: Mechanical cavities simulating maxillary defects were prepared on the hard palate of nine cadavers. Images were obtained using a CBCT unit at three different fields-of-views (FOVs) and voxel sizes: 1) 60×60 mm FOV, 0.125 mm(3) (FOV60); 2) 80×80 mm FOV, 0.160 mm(3) (FOV80); and 3) 100×100 mm FOV, 0.250 mm(3) (FOV100). Superimposition of the images was performed using software called VRMesh Design. Automated volume measurements were conducted, and differences between surfaces were demonstrated. Silicon impressions obtained from the defects were also scanned with a 3D optical scanner. Virtual models obtained using VRMesh Design were compared with impressions obtained by scanning silicon models. Gold standard volumes of the impression models were then compared with CBCT and 3D scanner measurements. Further, the general linear model was used, and the significance was set to p=0.05.

Results: A comparison of the results obtained by the observers and methods revealed the p values to be smaller than 0.05, suggesting that the measurement variations were caused by both methods and observers along with the different cadaver specimens used. Further, the 3D scanner measurements were closer to the gold standard measurements when compared to the CBCT measurements.

Conclusion: In the assessment of artificially created maxillary defects, the 3D scanner measurements were more accurate than the CBCT measurements.

No MeSH data available.


Related in: MedlinePlus

Measurement of differences using standardized FOV images
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Figure 3: Measurement of differences using standardized FOV images

Mentions: For a comparison of CBCT images taken with different FOVs, axial CBCT scans taken at each acquisition parameter of nine defects were exported as DICOM files and then imported into volumetric rendering software capable of measurements of a vector-based segmentation technology (3D Doctor, Able Software Corp., Lexington, MA, USA). This software allows defect segmentation on consecutive axial slices, enabling defect visualization at each level. This ensured manual, detailed slice-by-slice segmentation of the defect borders by using a mouse with color delineation (turquoise green). The maxillary cadaver images in which defects were identified were outlined with the mouse by using a tool called "Free" to remark at the region of interest. Figure 1 shows the segmentation process with 3D Doctor. After reconstruction with 3D Doctor, superimposition of the maxilla images obtained at different FOVs was performed by using VRMesh Design (Virtual Grid, Bellevue City, WA, USA). Then, virtual models obtained at each FOV were cut from the common intersection points in order to obtain identical borders of the maxillas. Thereafter, automated volume measurements were conducted, and differences between surfaces were demonstrated. Figure 2 shows the alignment of standardized FOV images, and Figure 3 shows the measurement of differences using standardized FOV images.


Accuracy of virtual models in the assessment of maxillary defects.

Kamburoğlu K, Kurşun Ş, Kılıç C, Özen T - Imaging Sci Dent (2015)

Measurement of differences using standardized FOV images
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4362988&req=5

Figure 3: Measurement of differences using standardized FOV images
Mentions: For a comparison of CBCT images taken with different FOVs, axial CBCT scans taken at each acquisition parameter of nine defects were exported as DICOM files and then imported into volumetric rendering software capable of measurements of a vector-based segmentation technology (3D Doctor, Able Software Corp., Lexington, MA, USA). This software allows defect segmentation on consecutive axial slices, enabling defect visualization at each level. This ensured manual, detailed slice-by-slice segmentation of the defect borders by using a mouse with color delineation (turquoise green). The maxillary cadaver images in which defects were identified were outlined with the mouse by using a tool called "Free" to remark at the region of interest. Figure 1 shows the segmentation process with 3D Doctor. After reconstruction with 3D Doctor, superimposition of the maxilla images obtained at different FOVs was performed by using VRMesh Design (Virtual Grid, Bellevue City, WA, USA). Then, virtual models obtained at each FOV were cut from the common intersection points in order to obtain identical borders of the maxillas. Thereafter, automated volume measurements were conducted, and differences between surfaces were demonstrated. Figure 2 shows the alignment of standardized FOV images, and Figure 3 shows the measurement of differences using standardized FOV images.

Bottom Line: Virtual models obtained using VRMesh Design were compared with impressions obtained by scanning silicon models.Gold standard volumes of the impression models were then compared with CBCT and 3D scanner measurements.Further, the 3D scanner measurements were closer to the gold standard measurements when compared to the CBCT measurements.

View Article: PubMed Central - PubMed

Affiliation: Department of Dentomaxillofacial Radiology, Faculty of Dentistry, Ankara University, Ankara, Turkey.

ABSTRACT

Purpose: This study aimed to assess the reliability of measurements performed on three-dimensional (3D) virtual models of maxillary defects obtained using cone-beam computed tomography (CBCT) and 3D optical scanning.

Materials and methods: Mechanical cavities simulating maxillary defects were prepared on the hard palate of nine cadavers. Images were obtained using a CBCT unit at three different fields-of-views (FOVs) and voxel sizes: 1) 60×60 mm FOV, 0.125 mm(3) (FOV60); 2) 80×80 mm FOV, 0.160 mm(3) (FOV80); and 3) 100×100 mm FOV, 0.250 mm(3) (FOV100). Superimposition of the images was performed using software called VRMesh Design. Automated volume measurements were conducted, and differences between surfaces were demonstrated. Silicon impressions obtained from the defects were also scanned with a 3D optical scanner. Virtual models obtained using VRMesh Design were compared with impressions obtained by scanning silicon models. Gold standard volumes of the impression models were then compared with CBCT and 3D scanner measurements. Further, the general linear model was used, and the significance was set to p=0.05.

Results: A comparison of the results obtained by the observers and methods revealed the p values to be smaller than 0.05, suggesting that the measurement variations were caused by both methods and observers along with the different cadaver specimens used. Further, the 3D scanner measurements were closer to the gold standard measurements when compared to the CBCT measurements.

Conclusion: In the assessment of artificially created maxillary defects, the 3D scanner measurements were more accurate than the CBCT measurements.

No MeSH data available.


Related in: MedlinePlus