• Imaging Science in Dentistry
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• 제53권3호
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• pp.217-220
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• 2023

Purpose: This pilot study was conducted to evaluate half-value layer (HVL) measurements obtained using a semiconductor dosimeter for intraoral radiography. Materials and Methods: This study included 8 aluminum plates, 4 of which were low-purity (less than 99.9%) and 4 high-purity (greater than 99.9%). Intraoral radiography was performed using an intraoral X-ray unit in accordance with the dental protocol at the authors' affiliated hospital: tube voltage, 60 kVp and 70 kVp; tube current, 7 mA; and exposure time, 0.10 s. The accuracy of HVL measurements for intraoral radiography was assessed using a semiconductor dosimeter. A simple regression analysis was performed to compare the aluminum plate thickness and HVL in relation to the tube voltage (60 kVp and 70 kVp) and aluminum purity (low and high). Results: For the low-purity aluminum plates, the HVL at 60 kVp (Y) and 70 kVp (Y) was significantly correlated with the thickness of the aluminum plate (X), with Y=1.708+0.415X (r=0.999, P<0.05) and Y=1.980+0.484X (r=0.999, P<0.05), respectively. Similarly, for the high-purity aluminum plates, the HVL at 60 kVp (Y) and 70 kVp (Y) was significantly correlated with the plate thickness(X), with Y=1.696+0.454X (r=0.999, P<0.05) and Y=1.968+0.515X (r=0.998, P<0.05), respectively. Conclusion: This pilot study examined the relationship between aluminum plate thickness and HVL measurements using a semiconductor dosimeter for intraoral radiography. Semiconductor dosimeters may prove useful in HVL measurement for purposes such as quality assurance in dental X-ray imaging.

• 한국방사선학회논문지
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• 제15권4호
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• pp.491-498
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• 2021

본 연구에서는 국가에서 권고하고 있는 구강 내 촬영의 진단참고 준위 설정에 사용된 조건을 조사하여 PCXMC v2.0 프로그램을 이용하여 유효선량을 측정하고 Al 부가 필터의 효과를 확인하였다. 구내 촬영에서 11개 측정 장기들 중에서 대부분 연구대상에서 구강 점막에서 가장 큰 유효선량이 계산되었다. Al 부가 필터의 효과는 1mm보다 2mm에서 탁월한 방사선 피폭선량 저감효과를 보였다. 소아 5세의 경우 성인에 비하여 방사선 감수성이 크기 때문에 전반적으로 유효선량이 11개의 장기들 모두에서 높게 계산되었다. 그리고 구강 내 촬영 시 부가 필터 사용에 따른 영상 품질 평가를 실시한 결과 SNR 및 CNR의 변화가 부가 필터를 사용하기 전과 별다른 차이가 없었다. 본 연구를 바탕으로 구강 내 촬영 시 부가 필터 설정을 권고할 수 있을 것이라 사료 된다.

• Imaging Science in Dentistry
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• 제31권3호
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• pp.129-133
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• 2001

Purpose: To compare the copper equivalent values measured at premolar and molar areas in the copper equivalent images of panoramic and intraoral radiographs and to evaluate the possibility of the copper equivalent images of panorama for the assessment the bone density. Materials and Methods : Intraoral radiograms at mandibular premolar and molar area and panoramas of 6 human dry skulls were taken with copper-step wedge by Heliodent MD (Siemens Co., Germany) and by Planmeca (PM 2002 CC, Planmeca, Helsinki, Finland) were used for experiment. The copper equivalent values measured at premolar and molar areas in the copper equivalent im ages of panorama and intraoral film were compared. Results: The copper equivalent values were ranged 0.20 mmCu-0.44 mmCu at the molar areas, 0.05 mmCu-0.31 mmCu at the premolar areas on panoramic images. There were no significant differences (p>0.5) between the copper equivalent values on intraoral images and those on panoramic images measured at premolar areas and molar areas respectively. The correlation coefficient between the copper equivalent values on intraoral images and those on panoramic images was respectively 0.8495 at molar areas and 0.6184 at premolar areas. Conclusions : The copper equivalent images of panorama for the assessment the bone density appeared to be significant at molar area compared with the one of intraoral radiograph.

• Restorative Dentistry and Endodontics
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• 제27권2호
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• pp.113-121
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• 2002

Conventional intraoral radiography continues to be the most widely used image modality for the diagnosis of dental caries. But, conventional intraoral radiography has several shortcomings, including the difficulty of exposing and processing intraoral film of consistently acceptable quality. In addition, radiographic retaking that was the result of processing errors, may result in increased discomfort and radiation dose to the patient. Recently, various digital radiographies substitute for conventional intraoral radiography to overcome these disadvantages. The advantages of digital radiography are numerous. One of advantages Is the elimination of processing errors. In addition, the radiation dose for digital system is approximately 20% to 25% of that required for conventional intraoral radiography Another potential advantage of digital imaging is the ability to perform image quality enhancements such as contrast and density modulation, which may increase diagnostic accuracy. The purpose of this study was to compare the diagnostic ability of artificial proximal defects to conventional intraoral radiography, direct digital image(CDX2000HQ$^{\circledR}$) and indirect digital image(Digora$^{\circledR}$). Artificial defects were made in proximal surfaces of 60 extracted human molars using #1/2, #1, #2 round bur. Five dentists assessed proximal defects on conventional intraoral radiography, direct digital image(CDX2000HQ$^{\circledR}$) and indirect digital image(Digora$^{\circledR}$). ROC(Receiver Operating Characteristic) analysis and Two-way ANOVA test were used for the evaluation of detectability, and following results were acquired. 1. The mean ROC area of conventional intraoral radiography, direct digital image(CDX2000HQ$^{\circledR}$) and indirect digital Image(Digora$^{\circledR}$) were 0.6766, 0.7538, 0.6791(Grade I), 0.7176, 0.7594, 0.7361(Grade II), and 0.7449, 0.7608, 0.7414(Grade III), respectively. 2. Diagnostic ability of direct digital image was higher than other image modalities. But, there was no statistically significant difference among other imaging modalities for Grade I, II, III lesion(p>0.05). In conclusion, when direct and indirect digital system are comparable with conventional intraoral radiography. these systems may be considered an alternative of conventional intraoral radiography for the diagnosis of proximal surface caries.

• Imaging Science in Dentistry
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• 제30권3호
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• pp.183-188
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• 2000

Purpose: This study was to evaluate the beam quality of intraoral X-ray equipments used at Yonsei University Dental Hospital (YUDH) using the half value layer (HVL) and the characteristic curve of intraoral standard X-ray film. Materials and Methods : The study was done using the intraoral X -ray equipments used at each clinical department at YUDH. Aluminum filter was used to determine the HVL. Intraoral standard film was used to get the characteristic curve of each intraoral X-ray equipment. Results: Most of the HVLs of intraoral X-ray equipments were higher than the least recommended thickness, but the REX 601 model used at the operative dentistry department and the X-707 model used at the pediatric dentistry department had HVLs lower than the recommended thickness. The slopes of the characteristic curves of films taken using the PANP AS 601 model and REX 601 model at operative dentistry department, the X-70S model of prosthodontic dentistry department, and the REX 601 model at the student clinic were relatively low. Conclusion: HVL and the characteristic curve of X-ray film can be used to evaluate the beam quality of intraoral X-ray equipment. In order to get the best X-ray films with the least radiation exposure to patients and best diagnostic information in clinical dentistry, X -ray equipment should be managed in the planned and organized fashion.

• Imaging Science in Dentistry
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• 제37권3호
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• pp.149-156
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• 2007

Purpose: The purpose of this study was to measure the absorbed dose and to calculate the effective dose for periapical radiography done by portable intraoral x-ray machines. Materials and Methods: 14 full mouth, upper posterior and lower posterior periapical radiographs were taken by wall-type 1 and portable type 3 intraoral x-ray machines. Thermoluminescent dosemeters were placed at 23 sites at the layers of the tissue-equivalent ART woman phantom for dosimetry. Average tissue absorbed dose and radiation weighted dose were calculated for each major anatomical site. Effective dose was calculated using 2005 ICRP tissue weighted factors. Results: On 14 full mouth periapical radiographs, the effective dose for wall-type x-ray machine was 30 Sv; for portable x-ray machines were 30 Sv, 22 Sv, 36 Sv. On upper posterior radiograph, the effective dose for wall-type x-ray machine was 4 Sv; for portable x-ray machines doses were 4 Sv, 3 Sv, 5 Sv. On lower posterior radiograph, the effective dose for wall type x-ray machine was 5 Sv; for portable x-ray machines doses were 4 Sv, 4 Sv, 5 Sv. Conclusion: Effective doses for periapical radiographs performed by portable intraoral x-ray machines were similar to doses for periapical radiographs taken by wall type intraoral x-ray machines.

• Imaging Science in Dentistry
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• 제48권1호
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• pp.45-49
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• 2018

Purpose: The aim of this study was to evaluate the quantitative strain elastography of tongue carcinoma using intraoral ultrasonography. Materials and Methods: Two patients with squamous cell carcinoma (SCC) who underwent quantitative strain elastography for the diagnosis of tongue lesions using intraoral ultrasonography were included in this prospective study. Strain elastography was performed using a linear 14 MHz transducer (Aplio 300; Canon Medical Systems, Otawara, Japan). Manual light compression and decompression of the tongue by the transducer was performed to achieve optimal and consistent color coding. The variation in tissue strain over time caused by the compression exerted using the probe was displayed as a strain graph. The integrated strain elastography software allowed the operator to place circular regions of interest (ROIs) of various diameters within the elastography window, and automatically displayed quantitative strain (%) for each ROI. Quantitative indices of the strain (%) were measured for normal tissues and lesions in the tongue. Results: The average strain of normal tissue and tongue SCC in a 50-year-old man was 1.468% and 0.000%, respectively. The average strain of normal tissue and tongue SCC in a 59-year-old man was 1.007% and 0.000%, respectively. Conclusion: We investigated the quantitative strain elastography of tongue carcinoma using intraoral ultrasonography. Strain elastography using intraoral ultrasonography is a promising technique for characterizing and differentiating normal tissues and SCC in the tongue.

• Imaging Science in Dentistry
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• 제53권3호
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• pp.209-216
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• 2023

Purpose: This study was conducted to compare dental plaque scores obtained through clinical examinations and various imaging techniques, as well as to assess the effectiveness of herbal and conventional toothpastes for plaque removal. Materials and Methods: Thirty volunteers were divided into 3 groups. Each group was given a different toothpaste (from 2 herbal toothpastes and a conventional toothpaste) with which to brush their teeth for 21 days. Both initially and after brushing, dental plaque samples were collected, and plaque on the buccal surfaces of anterior teeth was scored using several imaging systems after staining with a disclosing agent. Specifically, digital dental photography, intraoral digital scanning, and FluoreCam imaging were employed to capture intraoral images. The Turesky Modified Quigley-Hein Plaque Index was used for clinical examination and image analysis. Quantitative polymerase chain reaction analyses and correlational assessments between clinical examination and imaging scores were conducted before and after toothpaste use. The Shapiro-Wilk test and Pearson correlations were utilized. Results: The lowest mean value was observed in the clinical examination without staining, while the highest was obtained using the FluoreCam method. No significant change was found in the level of any microorganism assessed following toothpaste use (P<0.05), with the exception of a decrease in S. mutans levels after using conventional toothpaste (P<0.05). Conclusion: Herbal toothpaste demonstrated plaque-removal effectiveness comparable to that of conventional toothpaste. The use of imaging methods for measuring plaque index has been suggested as a means to educate patients about plaque control and promote ongoing oral care.

• 한국의학물리학회지:의학물리
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• 제31권1호
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• pp.8-8
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• 2020

• Imaging Science in Dentistry
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• 제51권4호
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• pp.399-406
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• 2021

Purpose: This in vitro study measured and compared 3 intraoral scanners' accuracy (trueness and precision) with different span lengths. Materials and Methods: Three master casts were prepared to simulate 3 different span lengths (fixed partial dentures with 3, 4, and 5 units). Each master cast was scanned once with an E3 lab scanner and 10 times with each of the 3 intraoral scanners (Trios 3, Planmeca Emerald, and Primescan AC). Data were stored as Standard Tessellation Language (STL) files. The differences between measurements were compared 3-dimensionally using metrology software. Data were analyzed using 1-way analysis of variance with post hoc analysis by the Tukey honest significant difference test for trueness and precision. Statistical significance was set at P<0.05. Results: A statistically significant difference was found between the 3 intraoral scanners in trueness and precision (P<0.05). Primescan AC showed the lowest trueness and precision values(36.8 ㎛ and 42.0 ㎛;(39.4 ㎛ and 51.2 ㎛; and 54.9 ㎛ and 52.7 ㎛) followed by Trios 3 (38.9 ㎛ and 53.5 ㎛; 49.9 ㎛ and 59.1 ㎛; and 58.1 ㎛ and 64.5 ㎛) and Planmeca Emerald (60.4 ㎛ and 63.6 ㎛; 61.3 ㎛ and 69.0 ㎛; and 70.8 ㎛ and 74.3 ㎛) for the 3-unit, 4-unit, and 5-unit fixed partial dentures, respectively. Conclusion: Primescan AC had the best trueness and precision, followed by Trios 3 and Planmeca Emerald. Increasing span length reduced the trueness and precession of the 3 scanners; however, their values were within the accepted successful ranges.