• Imaging Science in Dentistry
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• v.40 no.3
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• pp.103-107
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• 2010

Purpose : This study was performed to examine the effects of image filter on observer performance by counting the number of holes at each wedge step on a radiographic image. Materials and Methods : An aluminum step wedge with 11 steps ranged in thickness from 1.5 mm to 16.5 mm in 1.5 mm increments was fabricated for this study. Each step had 10 notched holes with 1.0 mm diameter on the bottom of the step wedge which were ranged in depths from 0.1 mm to 1.0 mm in 0.1 mm increments. Digital radiographic raw images of the aluminum step wedge were acquired by using CCD intraoral sensor. The images were processed using several types of noise reduction filters and kernel sizes. Three observers counted the number of holes which could be discriminated on each step. The data were analyzed by ANOVA. Results : The number of holes at each step was decreased as the thickness of step was increased. The number of holes at each step on the raw images was significantly higher than that on the processed images. The number of holes was different according to the types and kernel sizes of the image filters. Conclusions : The types and kernel sizes of image filters on observer performance were important, therefore, they should be standardized for commercial digital imaging systems.

• Journal of Korean Dental Science
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• v.4 no.1
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• pp.20-25
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• 2011

Purpose: To describe the newly developed Film image transfer system (FITS) for proper positioning of the orthodontic mini-implant in the narrow interdental space and considerations for better application. Materials and Methods: A patient who was planning to have orthodontic mini-implant treatment on the posterior maxilla was recruited to assess the feasibility of FITS. Dental radiographic film and bite record was taken. And then the film image was transferred on the photographic emulsion coated model using transfer light through film projector (enlarger). After exposing the photo emulsion coating on the model, the image was developed with a working solution for a paper developer and fixed. The surgical guide for the mini-implant was fabricated from the transported FITS data. Results: The completed surgical guide was easily placed intraorally, and allowed a simple and rapid placement of the mini-implant. The site of the implant placement was accurate as planned position. Conclusion: In the reported case, The FITS technique represents an effort to minimize risk to the patient and produce consistently good results based upon accurate information about the anatomy of the implant site.

• Journal of Korea Multimedia Society
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• v.17 no.10
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• pp.1205-1212
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• 2014

In this paper, we propose a high-quality stitching method of 3D multiple dental CT images. First, a weighted function is generated using the difference of two distance functions that calculate a distance from the nearest edge of an overlapped region to each position. And a blending ratio propagation function for two gradient vectors is parameterized by the difference and magnitude of gradient vectors that is also applied by the weighted function. When the blending ratio is propagated, an improved region growing scheme is proposed to decide the next position and calculate the blending intensity. The proposed method produces a high-quality stitching image. Our method removes the seam artifact caused by the mean intensity difference between images and vignetting effect. And it removes double edges caused by local misalignment. Experimental results showed that the proposed method produced high-quality stitching images for ten patients. Our stitching method could be usefully applied into the stitching of 3D or 2D multiple images.

• Journal of dental hygiene science
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• v.12 no.4
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• pp.392-403
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• 2012

This study aims at providing the basic data to help establish the right identity of dental hygienist and develop the work of dental hygienists, and thereby investigating the effect of patients' perception of dental hygienist on their social demand of dental hygienist, by conducting a survey of 300 patients visiting dentists around Busan-Gyeongnam region from April 7, 2012 to April 25, 2012. The collected data is statistically analyzed by SPSS (Statistical Packages for Social Science 14.0. SPSS Inc., Chicago, IL, USA). First, I analyzed the frequency by suggesting the demographic and descriptive characteristics of data, and conducted t-test and One-Way ANOVA at 5% of significance level to figure out the degree of perception and social demand of dental hygienists depending on customers' reason for visiting dentists, and also conducted regression analysis to find the effect of the perception of dental hygienist on patient's social demand of dental hygienist. The result suggests that as the perception of the dental hygienists' role, the social demand for dental hygienists' image increases, but as perception of dental hygienists' image increases, the social demand of dental hygienists' image decreases. Therefore, it suggests that as the knowledge about dental hygienists increases, patients demand their service more, while the perception of their image lowers the social demand for their image. It turns out that as the knowledge of dental hygienists increase, the social demand for the knowledge also increases.

• Journal of Digital Convergence
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• v.10 no.2
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• pp.243-247
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• 2012

Beam hardening artifact happens in the CT image. when a PET/CT is conducted while there is a metallic dental implant. The artifact appears in the CT image can affect the PET image. When the patient with head and neck cancer has a metallic dental implant, Beam hardening artifact which was taken in th CT image can change the PET image and SUV value. Therefore, by Quantitative measure of the SUV according to the change in HU by the metallic dental implant, the appropriacy in the clinical application was assessed. The records of 47 patients with PET/CT August 2011. For the analysis, 2 region of interest were defined in area where CT and PET image. As a result of the experiment, if there in an implant, the HU and the SUV increased and there existed a statistically significant difference(p<0.01). Although this level of increase was not large compared with that in the patient who have no metallic dental implant, when a person has head and neck cancer, it is even more likely to be overestimated when diagnosing the cancer. When conducting PET/CT for the patient who have head and neck cancer, the physical biological parts should be considered in order not to make an error in decoding.

• The Journal of the Korean dental association
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• v.50 no.4
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• pp.189-195
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• 2012

Various imaging modalities have been used for dental implant assessment in the different stages of implant treatment. Basic imaging, such as panoramic and periapical radiographs, are generally useful and cost-effective but do not provide the cross-sectional visualization or interactive image analysis that can be obtained with more sophisticated imaging techniques, such as Cone-Beam Computed Tomography(CBCT) imaging. This article includes the applications of CBCT imaging and their diagnostic contribution to presurgical evaluation, treatment planning, and postoperative assessment of dental implants.

• The korean journal of orthodontics
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• v.48 no.5
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• pp.346-346
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• 2018

• Imaging Science in Dentistry
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• v.42 no.4
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• pp.243-247
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• 2012

Purpose: This study was performed to compare the inverted digital images and film-based images of dry pig mandibles to measure the periodontal bone defect depth. Materials and Methods: Forty 2-wall bone defects were made in the proximal region of the premolar in the dry pig mandibles. The digital and conventional radiographs were taken using a Schick sensor and Kodak F-speed intraoral film. Image manipulation (inversion) was performed using Adobe Photoshop 7.0 software. Four trained examiners made all of the radiographic measurements in millimeters a total of three times from the cementoenamel junction to the most apical extension of the bone loss with both types of images: inverted digital and film. The measurements were also made in dry mandibles using a periodontal probe and digital caliper. The Student's t-test was used to compare the depth measurements obtained from the two types of images and direct visual measurement in the dry mandibles. A significance level of 0.05 for a 95% confidence interval was used for each comparison. Results: There was a significant difference between depth measurements in the inverted digital images and direct visual measurements (p>|t|=0.0039), with means of 6.29 mm ($IC_{95%}$:6.04-6.54) and 6.79 mm ($IC_{95%}$:6.45-7.11), respectively. There was a non-significant difference between the film-based radiographs and direct visual measurements (p>|t|=0.4950), with means of 6.64mm($IC_{95%}$:6.40-6.89) and 6.79mm($IC_{95%}$:6.45-7.11), respectively. Conclusion: The periodontal bone defect measurements in the inverted digital images were inferior to film-based radiographs, underestimating the amount of bone loss.

• Restorative Dentistry and Endodontics
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• v.48 no.2
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• pp.16.1-16.11
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• 2023

Objectives: The aim of this study was to evaluate the influence of peak kilovoltage (kVp) and a metal artifact reduction (MAR) tool on image quality and the diagnosis of vertical root fracture (VRF) in cone-beam computed tomography (CBCT). Materials and Methods: Twenty single-rooted human teeth filled with an intracanal metal post were divided into 2 groups: control (n = 10) and VRF (n = 10). Each tooth was placed into the socket of a dry mandible, and CBCT scans were acquired using a Picasso Trio varying the kVp (70, 80, 90, or 99), and the use of MAR (with or without). The examinations were assessed by 5 examiners for the diagnosis of VRF using a 5-point scale. A subjective evaluation of the expression of artifacts was done by comparing random axial images of the studied protocols. The results of the diagnoses were analyzed using 2-way analysis of variance and the Tukey post hoc test, the subjective evaluations were compared using the Friedman test, and intra-examiner reproducibility was evaluated using the weighted kappa test (α = 5%). Results: The kVp and MAR did not influence the diagnosis of VRF (p > 0.05). According to the subjective classification, the 99 kVp protocol with MAR demonstrated the least expression of artifacts, while the 70 kVp protocol without MAR led to the most artifacts. Conclusions: Protocols with higher kVp combined with MAR improved the image quality of CBCT examinations. However, those factors did not lead to an improvement in the diagnosis of VRF.

• Imaging Science in Dentistry
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• v.50 no.4
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• pp.339-346
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• 2020

Purpose: The purpose of this study was to evaluate the image quality, diagnostic efficacy, and radiation dose associated with the use of a cadmium telluride (CdTe) detector, compared to charge-coupled device (CCD) and complementary metal oxide semiconductor(CMOS) detectors. Materials and Methods: Lateral cephalographs of a phantom (type 1) composed of synthetic polymer filled with water and another phantom (type 2) composed of human skull macerated with polymer coating were obtained with CdTe, CCD, and CMOS detectors. Dosimeters placed on the type 2 phantom were used to measure radiation. Noise levels from each image were also measured. McNamara cephalometric analysis was conducted, the dentoskeletal configurations were assessed, and a subjective evaluation of image quality was conducted. Parametric data were compared via 1-way analysis of variance with the Tukey post-hoc test, with a significance level of 5%. Subjective image quality and dentoskeletal configuration were described qualitatively. Results: A statistically significant difference was found among the images obtained with the 3 detectors(P<0.05), with the lowest noise level observed among the images obtained with the CdTe detector and a higher subjective preference demonstrated for those images. For the cephalometric analyses, no significant difference (P>0.05) was observed, and perfect agreement was seen with regard to the classifications obtained from the images acquired using the 3 detectors. The radiation dose associated with the CMOS detector was higher than the doses associated with the CCD (P<0.05) and CdTe detectors(P<0.05). Conclusion: Considering the evaluated parameters, the CdTe detector is recommended for use in clinical practice.