1.Application of a newly developed software program for image quality assessment in cone-beam computed tomography.
Marcus Vinicius Linhares DE OLIVEIRA ; António Carvalho SANTOS ; Graciano PAULO ; Paulo Sergio Flores CAMPOS ; Joana SANTOS
Imaging Science in Dentistry 2017;47(2):75-86
PURPOSE: The purpose of this study was to apply a newly developed free software program, at low cost and with minimal time, to evaluate the quality of dental and maxillofacial cone-beam computed tomography (CBCT) images. MATERIALS AND METHODS: A polymethyl methacrylate (PMMA) phantom, CQP-IFBA, was scanned in 3 CBCT units with 7 protocols. A macro program was developed, using the free software ImageJ, to automatically evaluate the image quality parameters. The image quality evaluation was based on 8 parameters: uniformity, the signal-to-noise ratio (SNR), noise, the contrast-to-noise ratio (CNR), spatial resolution, the artifact index, geometric accuracy, and low-contrast resolution. RESULTS: The image uniformity and noise depended on the protocol that was applied. Regarding the CNR, high-density structures were more sensitive to the effect of scanning parameters. There were no significant differences between SNR and CNR in centered and peripheral objects. The geometric accuracy assessment showed that all the distance measurements were lower than the real values. Low-contrast resolution was influenced by the scanning parameters, and the 1-mm rod present in the phantom was not depicted in any of the 3 CBCT units. Smaller voxel sizes presented higher spatial resolution. There were no significant differences among the protocols regarding artifact presence. CONCLUSION: This software package provided a fast, low-cost, and feasible method for the evaluation of image quality parameters in CBCT.
Artifacts
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Cone-Beam Computed Tomography*
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Methods
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Noise
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Polymethyl Methacrylate
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Quality Control
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Signal-To-Noise Ratio
2.Cone-beam computed tomography findings of impacted upper canines.
Ludmilla Mota DA SILVA SANTOS ; Luana Costa BASTOS ; Christiano OLIVEIRA-SANTOS ; Silvio Jose Albergaria DA SILVA ; Frederico Sampaio NEVES ; Paulo Sergio Flores CAMPOS
Imaging Science in Dentistry 2014;44(4):287-292
PURPOSE: To describe the features of impacted upper canines and their relationship with adjacent structures through three-dimensional cone-beam computed tomography (CBCT) images. MATERIALS AND METHODS: Using the CBCT scans of 79 upper impacted canines, we evaluated the following parameters: gender, unilateral/bilateral occurrence, location, presence and degree of root resorption of adjacent teeth (mild, moderate, or severe), root dilaceration, dental follicle width, and presence of other associated local conditions. RESULTS: Most of the impacted canines were observed in females (56 cases), unilaterally (51 cases), and at a palatine location (53 cases). Root resorption in adjacent teeth and root dilaceration were observed in 55 and 47 impacted canines, respectively. In most of the cases, the width of the dental follicle of the canine was normal; it was abnormally wide in 20 cases. A statistically significant association was observed for all variables, except for root dilaceration (p=0.115) and the side of impaction (p=0.260). CONCLUSION: Root resorption of adjacent teeth was present in most cases of canine impaction, mostly affecting adjacent lateral incisors to a mild degree. A wide dental follicle of impacted canines was not associated with a higher incidence of external root resorption of adjacent teeth.
Cone-Beam Computed Tomography*
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Cuspid
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Dental Sac
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Female
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Humans
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Incidence
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Incisor
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Root Resorption
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Tooth
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Tooth, Impacted