• Imaging Science in Dentistry
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• 제34권3호
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• pp.145-150
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• 2004

Purpose: To compare three digital radiographic imaging sensors by evaluating the visibility of endodontic file tips with interobserver reproducibility and assessing subjectively the clarity of images in comparison with the x-ray film images. Materials and Methods: Forty-five extracted sound premolars were used for this study. Fifteen plaster blocks were made with three premolars each and #8, 10, 15 K-flexofiles were inserted into the root canal of premolars. They were radiographically exposed using periapical x-ray films (Kodak Insight Dental film, Eastmann Kodak company, Rochester, USA), Digora imaging plates (Soredex-Orion Co., Helsinki, Finland), CDX 2000HQ sensors (Biomedisys Co., Seoul, Korea), and CDR sensors (Schick Inc., Long Island, USA). The visibility of endodontic files was evaluated with interobserver reproducibility, which was calculated as the standard deviations of X, Y coordinates of endodontic file tips measured on digital images by three oral and maxillofacial radiologists. The clarity of images was assessed subjectively using 3 grades, i.e. plus, equal, and minus in comparison with the conventional x-ray film images. Results: Interobserver reproducibility of endodontic file tips was the highest in CDR sensor (p < 0.05) only except at Y coordinates of #15 file. In the subjective assessment of the image clarity, the plus grade was the most frequent in CDR sensor at all size of endodontic file (p < 0.05). Conclusion : CDR sensor was the most superior to the other sensors, CDX 2000HQ sensor and Digora imaging plate in the evaluation of interobserver reproducibility of endodontic file tip and subjective assessment of image clarity.

• Journal of Korean Dental Science
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• 제3권2호
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• pp.12-19
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• 2010

Despite the latest advancement made in its techniques and devices/apparatuses and the resulting rising expectation in the field of dental surgery, apicoectomy performed in the molar teeth remains a technical challenge and lacks evidence substantiated by long-term follow-up studies. This study sought to investigate the treatment outcomes and post-operative success rate in the root-end resected molar teeth accompanied by a high level of surgical risks due to their close proximity to the mandibular canal and maxillary sinus. A total of 68 patients who received treatment at Livingwell Dental Hospital between 2004 and 2010 and underwent apical surgery in the maxillary or mandibular molar area were enrolled in this study. A total of 160 roots collected from 75 molar teeth were subjected to surgical endodontic treatment and subsequently evaluated clinically as well as radiographically. Based on the results of the study, the clinical success rate was found to be 78.8% in cases involving radiological healing. Likewise, 90.7% of the roots recorded a robust clinical survival rate, but with incomplete healing as shown by radiography. The results indicate that the apical procedure involving molar teeth is a prognosis-friendly method that promises positive outcomes and higher success rate based on long-term follow-up observations.

• Imaging Science in Dentistry
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• 제52권1호
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• pp.93-101
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• 2022

Purpose: This study compared the effectiveness of complementary metal-oxide semiconductors (CMOS) and photostimulable phosphor (PSP) plates as intraoral imaging systems in terms of time efficacy, patient comfort, and subjective image quality assessment in real clinical settings. Materials and Methods: Fifty-eight patients (25 women and 33 men) were included. Patients were referred for a full-mouth radiological examination including 1 bitewing radiograph (left and right) and 8 periapical radiographs for each side (left maxilla/mandible and right maxilla/mandible). For each patient, 1 side of the dental arch was radiographed using a CMOS detector, whereas the other side was radiographed using a PSP detector, ensuring an equal number of left and right arches imaged by each detector. Clinical application time, comfort/pain, and subjective image quality were assessed for each detector. Continuous variables were summarized as mean±standard deviation. Differences between detectors were evaluated using repeated-measures analysis of variance. P<0.05 was accepted as significant. Results: The mean total time required for all imaging procedures with the CMOS detector was significantly lower than the mean total time required for imaging procedures with PSP (P<0.05). The overall mean patient comfort scores for the CMOS and PSP detectors were 4.57 and 4.48, respectively, without a statistically significant difference (P>0.05). The performance of both observers in subjectively assessing structures was significantly higher when using CMOS images than when using PSP images for all regions (P<0.05). Conclusion: The CMOS detector was found to be superior to the PSP detector in terms of clinical time efficacy and subjective image quality.

• Imaging Science in Dentistry
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• 제52권4호
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• pp.351-357
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• 2022

Purpose: Convolutional neural networks (CNNs) have rapidly emerged as one of the most promising artificial intelligence methods in the field of medical and dental research. CNNs can provide an effective diagnostic methodology allowing for the detection of early-staged diseases. Therefore, this study aimed to evaluate the performance of a deep CNN algorithm for apical lesion segmentation from panoramic radiographs. Materials and Methods: A total of 1000 panoramic images showing apical lesions were separated into training (n=800, 80%), validation (n=100, 10%), and test (n=100, 10%) datasets. The performance of identifying apical lesions was evaluated by calculating the precision, recall, and F1-score. Results: In the test group of 180 apical lesions, 147 lesions were segmented from panoramic radiographs with an intersection over union (IoU) threshold of 0.3. The F1-score values, as a measure of performance, were 0.828, 0.815, and 0.742, respectively, with IoU thresholds of 0.3, 0.4, and 0.5. Conclusion: This study showed the potential utility of a deep learning-guided approach for the segmentation of apical lesions. The deep CNN algorithm using U-Net demonstrated considerably high performance in detecting apical lesions.

• 치과방사선
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• 제28권1호
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• pp.111-126
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• 1998

In this study, radiographic evaluation was made using panoramic radiography and cross-sectional tomography of SCANORA/sup (R)/ in male and female adults in their 20's on the relationship between the maxillary sinus floor and the apex of the maxillary molar, to test the accuracy and effectiveness of the cross-sectional tomography, and to use this information in the assessment of preop. and postop. root canal treatment, apical surgery, extraction and implantology. Forty-one adults with an average age of 24.4 years were studied using panoramic radiography and cross-sectional tomography. In panoramic view and cross-sectional view, the position of the apices of maxillary molars were classified as separated, contacted, or protruded type; the general shape of the maxillary sinus floor was evaluated horizontally and vertically from cross-sectional tomography. The accuracy of each radiography was tested using maxilla from 5 fresh cadavers from the Anatomy Lab at Yonsei University Dental College, and panoramic view and cross-sectional tomography were taken in the same condition as with the patients. The results were as follows: 1. Panoramic view and cross-sectional view were taken in the maxilla specimen, and the actual distance between the maxillary sinus floor and the tooth apices were measured in the specimen; the median values of the distance from the tooth apices to the maxillary sinus floor in the panoramic view, cross-sectional view and in the actual maxilla specimen were 2.83 mm, 4.51mm, and 4.l5mm, respectively. In the cross-sectional view, the measured distance was close to the actual distance but in the panoramic view, the measured distance was far from the actual distance. 2. When the results of the panoramic view and cross-sectional view were compared, 40.5％ of the results agreed with each other in the two radiographic methods and buccal roots of the 2nd molar were the closest to the maxillary sinus floor in the cross-sectional tomography. 3. In cross-sectional view, when the vertical relationship of the maxillary sinus floor and maxillary roots was assessed, in 1st molars, type II (the sinus floor that extends down to the buccolingual furcation area) was predominant, while in 2nd molars, type I (the sinus floor located above the level connecting the buccal and lingual apices) was predominant. In the horizontal relationship, in 1st molars, type II (the lowest floor of the maxillary sinus located in between the buccal and lingual roots) was predominant; in 2nd molars, type I (the lowest floor of the maxillary sinus located on the buccal side of the buccal roots) and type II appeared in similar frequency. In conclusion, the SCANORA/sup (R)/ cross-sectional tomography was more effective than the frequently used panoramic view, in that the relationship of the maxillary molars and maxillary sinus floor can be evaluated more accurately and the buccolingual cross-sectional view can also be observed. And maxillary sinus floor that was close to maxillary 2nd molar had tendency to be located on buccal side than that close to 1st molar. Therefore, cross-sectional tomography is an effective and accurate method to evaluate the position of the teeth in relation to the sinus floor preoperative and can be easily used to diagnose localized periapical lesions. Also, the image quality obtained was quite satisfactory.

• 대한치과보철학회지
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• 제54권2호
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• pp.103-109
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• 2016

목적: 상악 전치부 임플란트 식립시 골 이식 유무에 따른 임플란트의 변연골 소실량을 측정, 비교하여 임플란트 식립과 동시에 시행하는 골 이식의 임상적 의의를 평가하고자 한다. 대상 및 방법: 2011년 6월부터 2014년 5월 사이에 원광대학교 치과병원 임플란트 센터에서 상악 전치부에 임플란트를 식립하고 보철치료를 진행한 환자를 대상으로 진료기록부를 확인하여 임플란트 식립 시기, 고정체의 직경 및 길이, 지대주 연결방법, 골이식 유무를 조사하였다. 임플란트 식립 직후와 가장 최근 내원 시의 치근단 방사선 사진을 비교하였으며 Emago advanced v5.6 (Oral diagnostic systems, Amsterdam, Netherlands) 프로그램을 사용하여 임플란트 변연골 소실량을 측정하였다. 골 이식 유무가 임플란트 주위 변연골 소실에 미치는 영향을 알아보기 위하여 Window용 SPSS 프로그램을 이용한 독립표본 t 검정을 시행하였다. 결과: 환자 52명에서 83개 임플란트(골 이식 없이 식립된 임플란트 44개, 골 이식과 동시에 식립된 임플란트 39개)를 대상으로 6 - 45개월(평균 18.4개월)동안 관찰한 결과 골 이식 없이 식립된 임플란트는 $1.42{\pm}0.42mm$, 골 이식과 동시에 식립된 임플란트는 $1.28{\pm}0.45mm$의 변연골 소실을 보였다. 결론: 본 연구의 한계 내에서, 골 이식과 동시에 식립된 임플란트의 변연골 소실량이 유의하게 적었다.

• 한국치위생학회지
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• 제5권1호
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• pp.1-13
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• 2005

The study aimed to estimate the importance of job tasks, job training requirement and work satisfaction felt by dental hygienists to help dental hygienists work efficiently and effectively. A total of 142 dental hygienists working in dental hospitals located in J participated in the study. A SPSS 10.10 for Windows was used for statistical analysis. The statistical significance was defined as ${\alpha}$=.05. The results of the study are summarized as follows: 1. The mean score for the importance of job tasks was 4.09. The respondents considered dental clinic management and assistance to dentists the most important among their job descriptions showing the mean score of 4.44. The need for job training was 4.15 in average. The respondents wanted to have training on how to make a dental health insurance claim to receive payment other than any training with the mean score of 4.42. The work satisfaction of the respondents was 3.65 in average. The respondents were most satisfied with their work in dental assistance. 2. By the category of job tasks, the levels of importance of job tasks, job training requirement and work satisfaction were higher in plague removal with an ultrasonic scaler related to clinical oral prophylaxis, pit and fissure sealants related to preventive dental treatment and instruction in the correct usage of toothbrush related to public dental health education 3. In dealing with dental radiation machines, the radiation protection was considered the most important. While the training for periapical radiography was most needed, the respondents were satisfied with working in the same area. The levels of job importance, training requirement and work satisfaction were high in preventive dental care in the community performed in relation to the public dental health care. 4. In the dental health insurance claim category, the levels of importance of job task, training requirement and work satisfaction were higher in insurance claiming. The levels of job importance and training requirement were high in dental clinic management and assistance to dentists performed for preventive dental treatment. The work satisfaction was higher in maintaining medical chart records. The levels of job importance, training requirement and work satisfaction were higher in dental assistance in relation to dental protection. 5. There was significant relationship between the level of importance and work experience. Those with a longer period of work experience had higher levels of job importance in dental health insurance claim, dental clinic management and assistance to dentists and the overall task(pE0.05). 6. A significant relationship was observed between the need for job training in dental cleaning and preventive dental treatment and work experience. Those with more than 8 years of work experience demonstrated that job training is most needed(pE0.05). 7. The work satisfaction level was higher in the group with more than 8 years of work experience, compared with those in other work experience periods(pE0.05). 8. A positive correlation was seen between the level of importance and the need for job training among three variables.