• Imaging Science in Dentistry
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• 제45권3호
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• pp.141-145
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• 2015

Purpose: This study evaluated the diagnostic accuracy of the reverse contrast mode in intraoral digital radiography for the detection of proximal dentinal caries, in comparison with the original digital radiographs. Materials and Methods: Eighty extracted premolars with no clinically apparent caries were selected, and digital radiographs of them were taken separately in standard conditions. Four observers examined the original radiographs and the same radiographs in the reverse contrast mode with the goal of identifying proximal dentinal caries. Microscopic sections $5{\mu}m$ in thickness were prepared from the teeth in the mesiodistal direction. Four slides prepared from each sample used as the diagnostic gold standard. The data were analyzed using SPSS (${\alpha}=0.05$). Results: Our results showed that the original radiographs in order to identify proximal dentinal caries had the following values for sensitivity, specificity, positive predictive value, negative predictive value, and accuracy, respectively: 72.5%, 90%, 87.2%, 76.5%, and 80.9%. For the reverse contrast mode, however, the corresponding values were 63.1%, 89.4%, 87.1%, 73.5%, and 78.8%, respectively. The sensitivity of original digital radiograph for detecting proximal dentinal caries was significantly higher than that of reverse contrast mode (p<0.05). However, no statistically significant differences were found regarding specificity, positive predictive value, negative predictive value, or accuracy (p>0.05). Conclusion: The sensitivity of the original digital radiograph for detecting proximal dentinal caries was significantly higher than that of the reversed contrast images. However, no statistically significant differences were found between these techniques regarding specificity, positive predictive value, negative predictive value, or accuracy.

• Imaging Science in Dentistry
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• 제51권3호
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• pp.237-242
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• 2021

Purpose: The aim of this study was to analyse and review deep learning convolutional neural networks for detecting and diagnosing early-stage dental caries on periapical radiographs. Materials and Methods: In order to conduct this review, the Preferred Reporting Items for Systematic Reviews and Meta-Analyses(PRISMA) guidelines were followed. Studies published from 2015 to 2021 under the keywords(deep convolutional neural network) AND (caries), (deep learning caries) AND (convolutional neural network) AND (caries) were systematically reviewed. Results: When dental caries is improperly diagnosed, the lesion may eventually invade the enamel, dentin, and pulp tissue, leading to loss of tooth function. Rapid and precise detection and diagnosis are vital for implementing appropriate prevention and treatment of dental caries. Radiography and intraoral images are considered to play a vital role in detecting dental caries; nevertheless, studies have shown that 20% of suspicious areas are mistakenly diagnosed as dental caries using this technique; hence, diagnosis via radiography alone without an objective assessment is inaccurate. Identifying caries with a deep convolutional neural network-based detector enables the operator to distinguish changes in the location and morphological features of dental caries lesions. Deep learning algorithms have broader and more profound layers and are continually being developed, remarkably enhancing their precision in detecting and segmenting objects. Conclusion: Clinical applications of deep learning convolutional neural networks in the dental field have shown significant accuracy in detecting and diagnosing dental caries, and these models hold promise in supporting dental practitioners to improve patient outcomes.

• Imaging Science in Dentistry
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• 제53권2호
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• pp.117-126
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• 2023

Purpose: Odontomas represent a common clinical entity among odontogenic tumors, but are not well-addressed in the Vietnamese population. The present study aimed to determine the clinical and preclinical characteristics of odontomas and associated factors in the Vietnamese population. Materials and Methods: This retrospective study retrieved data from histopathological diagnoses from 2 central hospitals of Odonto-Stomatology in Ho Chi Minh City, Vietnam during 2004-2017. The odontomas were classified as complex (CxOD) or compound (CpOD) subtypes. The epidemiological, clinical, and radiological characteristics of the odontomas, stratified by subtype and sex, were obtained and analyzed. Results: Ninety cases, consisting of 46 CxODs and 44 CpODs, were included. The average age of patients was 32.4 (±20.2) years. The patients with CxOD were older than those with CpOD (P<0.05). Clinically, 67% of patients showed an intraoral bone expansion. Approximately 60% of patients with CxOD exhibited a painful symptom, about 3-fold more than those with CpOD (P<0.05), whereas almost all patients with CpOD exhibited perturbations of dentition, unlike those with CxOD (P<0.05). Radiologically, CxOD was characterized by a larger dimension than CpOD in both sexes (P<0.05), and CpOD induced complications in adjacent teeth more often than CxOD (P<0.05). The development of odontoma with advancing age differed significantly in odontoma subtypes related to their pathological origins, and between the sexes, resulting from different physiological states. Conclusion: The findings of this study highlight the value of clinical and radiological features of odontomas and their associated factors for the early diagnosis and adequate treatment of younger patients.

• Imaging Science in Dentistry
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• 제53권4호
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• pp.365-373
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• 2023

Purpose: In the context of COVID-19, studies evaluating the adherence of dentists and dental students to infection control are relevant due to their high occupational exposure and risk, as well as their responsibility for disseminating information and good practices. This study evaluated the adherence of dentists and dental students to infection control in the oral radiology field in the setting of the COVID-19 pandemic on different continents. Materials and Methods: This cross-sectional observational study involved individuals who performed intraoral radiographic examinations during the COVID-19 pandemic. The Questionnaire on Infection Control in Oral Radiology was administered virtually using a Google Form. Participants from different continents(the Americas, Africa, Europe, Asia, and Oceania) were recruited. Data were subjected to descriptive analysis and simple and multiple binary regression (5%). Results: There were 582 valid answers, and 68.73% of the participants were from the Americas, 18.90% from Europe, and 12.37% from Asia. The median score for infection control protocols was 94 points for dental students and 104 points for dentists, and participants below the median were considered to have low adherence to infection control in oral radiology. Low access to infection control was found for 53.0% of dentists in the Americas, 34.0% from Europe, and 26.9% from Asia. Conclusion: The adherence to infection control protocols in oral radiology was low even in the face of the COVID-19 pandemic. The results may help improve the awareness of students and professionals, since oral radiology routines have the potential for transmitting COVID-19.

• Journal of Periodontal and Implant Science
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• 제53권5호
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• pp.388-401
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• 2023

Purpose: This study investigated the accuracy of free-hand implant surgery performed by an experienced operator compared to static guided implant surgery performed by an inexperienced operator on an anterior maxillary dental model arch. Methods: A maxillary dental model with missing teeth (No. 11, 22, and 23) was used for this in vitro study. An intraoral scan was performed on the model, with the resulting digital impression exported as a stereolithography file. Next, a cone-beam computed tomography (CBCT) scan was performed, with the resulting image exported as a Digital Imaging and Communications in Medicine file. Both files were imported into the RealGUIDE 5.0 dental implant planning software. Active Bio implants were selected to place into the model. A single stereolithographic 3-dimensional surgical guide was printed for all cases. Ten clinicians, divided into 2 groups, placed a total of 60 implants in 20 acrylic resin maxillary models. Due to the small sample size, the Mann-Whitney test was used to analyze mean values in the 2 groups. Statistical analyses were performed using SAS version 9.4. Results: The accuracy of implant placement using a surgical guide was significantly higher than that of free-hand implantation. The mean difference between the planned and actual implant positions at the apex was 0.68 mm for the experienced group using the free-hand technique and 0.14 mm for the non-experienced group using the surgical guide technique (P=0.019). At the top of the implant, the mean difference was 1.04 mm for the experienced group using the free-hand technique and 0.52 mm for the non-experienced group using the surgical guide technique (P=0.044). Conclusions: The data from this study will provide valuable insights for future studies, since in vitro studies should be conducted extensively in advance of retrospective or prospective studies to avoid burdening patients unnecessarily.

• Imaging Science in Dentistry
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• 제40권3호
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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.

• Imaging Science in Dentistry
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• 제33권2호
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• pp.113-119
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• 2003

Purpose : To evaluate the relationship between morphometric analysis of bone microstructure from digital radiographic image and trabecular bone strength. Materials and Methods : One hundred eleven bone specimens with 5 mm thickness were obtained from the mandibles of 5 pigs. Digital images of specimens were taken using a direct digital intraoral radiographic system. After selection of ROI (100 × 100 pixel) within the trabecular bone, mean gray level and standard deviation were obtained. Fractal dimension and the variants of morphometric analysis (trabecular area, periphery, length of skeletonized trabeculae, number of terminal point, number of branch point) were obtained from ROI. Punch sheer strength analysis was performed using Instron (model 4465, Instron Corp., USA). The loading force (loading speed 1 mm/min) was applied to ROI of bone specimen by a 2 mm diameter punch. Stress-deformation curve was obtained from the punch sheer strength analysis and maximum stress, yield stress, Young's modulus were measured. Results: Maximum stress had a negative linear correlation with mean gray level and fractal dimension significantly (p<0.05). Yield stress had a negative linear correlation with mean gray level, periphery, fractal dimension and the length of skeletonized trabeculae significantly (p < 0.05). Young's modulus had a negative linear correlation with mean gray level and fractal dimension significantly (p < 0.05). Conclusions : The strength of cancellous bone exhibited a significantly linear relationship between mean gray level, fractal dimension and morphometric analysis. The methods described above can be easily used to evaluate bone quality clinically.

• 대한소아치과학회지
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• 제31권4호
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• pp.587-597
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• 2004

치아 우식증의 발생과 관련된 분야에 대한 연구는 지난 20년간 활발히 진행되어 괄목할만한 발전을 이루었다. 그러나 치아 우식증의 원천적인 예방을 이루기 위해서는 보다 새로운 실험 장비와 기구를 이용한 다각적인 연구가 요구되며, 이러한 흐름에 부응하여 미국의 인디아나 치과대학을 중심으로 초기 법랑질 우식증에 관한 재조명이 집중적으로 이루어지고 있다. 또한 세계적으로 치과계의 지속적인 대민 교육과 홍보 및 불소화사업 등의 우식 예방에 대한 노력과 구강 보건에 대한 대중의 인식 향상을 통해 치아 우식증이 감소하는 추세에 있으며, 이로 인해 치아 우식증이 기존의 교합면보다 인접면에서 더 많이 발견되는 추세로 변화되고 있다. 치아 우식증의 조기 진단을 목적으로 새로운 진단 장비들이 속속 개발되고 있으며 이미 성능의 우수성이 실험실 연구를 통해 입증된 바 있다. 본 연구의 목적은 초기 인접면 우식증의 진단에 있어 새로 개발된 $DIFOTI^{TM}$ 시스템의 효능을 기존의 방법인 시진 및 교익방사선사진과 비교 평가하고, 임상 적용시의 문제점을 파악하여 차후 $DIFOTI^{TM}$ 시스템 개발에 필요한 개선안을 제시함과 아울러 치아 우식증의 예방 및 불소를 이용한 초기 우식증 재광화 방법에 대한 기초 연구 자료를 마련하고자하였다. 학동기 연령에 있는 유치 탈락 시기에 근접한 것으로 기대되는 23명의 아동을 대상으로 구강 검진 2회, 구치부 교익 방사선 필름 판독 2회 그리고 전치부 및 구치부 $DIFOTI^{TM}$ 이미지 판독 2회를 실시하고 각 방법에 대한 신뢰도 평가를 시행한 결과 다음과 같은 결론을 얻었다. 1. 구강 검진시 검사자간 신뢰도는 교합면에서 평균 0.8470으로 가장 높았으며, 근심면 평균 0.6430, 원심면 평균 0.5727, 설면 평균 0.2807 그리고 협면 평균 0.2339순으로 나타났다. 구치부에 국한시킨 경우 교합면에서는 평균 0.8577이었으며, 원심면 평균 0.8211, 설면 평균 0.7728, 협면 평균 0.7152, 근심면 평균 0.6782 순으로 나타났다. 2. 구치부 교익 방사선 사진 판독 결과에 대한 검사자간 신뢰도는 교합면 평균 0.8346, 근심면 평균 0.8675, 원심면 평균 0.8482 순으로 나타났다. 3. $DIFOTI^{TM}$ 이미지 판독 결과에 대한 검사자간 신뢰도는 교합면 평균 0.8437, 협면 평균 8379, 근심면 평균 0.8223, 설면 평균 0.7766, 원심면 평균 0.6781 순으로 나타났다. 4. 치아 우식증 진단율을 비교한 결과 교합면, 협면, 설면에서는 $DIFOTI^{TM}$ 이미지 판독이 가장 우수한 것으로 나타났으며(p<0.05), 근심면과 원심면에서는 방사선 판독이 가장 우수한 것으로 나타났다(p<0.05).

• 대한방사선기술학회지:방사선기술과학
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• 제33권2호
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• pp.109-120
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• 2010

치과 X선 검사 시 환자선량의 권고량 가이드라인을 개발하기 위해서 우선 국내 치과방사 선의 현황 및 이용 실태를 설문조사하여 비교분석하였다. 응답을 받은 77곳의 치과병 의원 중에서 치과대학이 있는 치과대학병원을 A그룹(11곳), 치과대학이 없는 대학병원을 포함한 치과병원을 B그룹(30곳), 치과의원을 C그룹(36곳)으로 분류하였다. 그룹별로 분석한 결과는 다음과 같았다. 치과병 의원 한 곳당 평균 unit chairs수는 A그룹 140.2개, B그룹 15.3개, C그룹 5.8개, 평균치과의사수는 A그룹 112.6명, B그룹 7.3명, C그룹 1.7명, 평균방사선사수는 A그룹 3.1명, B그룹 0.5명, C그룹에는 한 명도 없었고, 평균치과위생사수는 A그룹 19.7명, B그룹 12.5명, C그룹 3.3명이었다. 설치된 치과용 X선장치의 평균보유수는 A그룹 14.64대, B그룹 3.21대, C그룹 2.19대로 나타났다. 이 중에서 구내촬영장치가 가장 많았고, 다음은 파노라마 장치, 세팔로 장치, CBCT 장치 순이었으며, 장치시스템의 비율은 세 그룹 모두 DR 시스템이 50% 이상으로 가장 많았다. 필름 시스템인 경우, 사용된 구내필름은 감광도가 높은 Insight 필름(Kodak, USA)이 대부분이었으며, 자동 현상기는 사용하는 곳이 적었으나, 필름유지기구는 사용하는 곳이 약간 많았다. PACS 이용률은 A그룹 90.9%, B그룹 83.3%, C그룹 16.7%이었고, 프로그램은 국내의 Infinitt에서 개발된 PiView STAR가 가장 많이 이용되고 있었다. 치과병 의원 한 곳당 2008년도의 연간 평균촬영건수는 A그룹이 B그룹보다 6.8배, C그룹보다 21.2배 더 많았으며, 구내 치근단 촬영과 파노라마 촬영이 대부분이었다. 구내 치근단 촬영 시 관전압과 관전류는 세 그룹 모두 비슷하였으나, 노출시간은 C그룹이 A그룹의 12배, B 그룹의 3.5배 정도 길었다. 즉, 대부분 치과위생사가 촬영하고 있는 C그룹에서는 방사선 노출량이 다른 그룹에 비해 훨씬 많았다. 그러나 파노라마촬영 시의 조건은 세 그룹에서 큰 차이가 없었다. 결론적으로, 촬영조건은 경험적 지식을 따르기보다는 권장량을 사용해야 하며, 필름시스템에서는 자동현상기와 필름유지기구를 사용하여 방사선의 노출량을 줄여준다. 또한 환자선량의 감소와 X선 영상의 질 향상을위해서 X선발생장치 및 관련기기의 체계적인 정도관리가 반드시 필요하다.