• Progress in Medical Physics
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• v.26 no.1
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• pp.52-58
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• 2015

The automated dental cavity detection program for a new concept intra-oral dental x-ray imaging device, an auxiliary diagnosis system, which is able to assist a dentist to identify dental caries in an early stage and to make an accurate diagnosis, was to be developed. The primary theory of the automatic dental cavity detection program is divided into two algorithms; one is an image segmentation skill to discriminate between a dental cavity and a normal tooth and the other is a computational method to analyze feature of an tooth image and take an advantage of it for detection of dental cavities. In the present study, it is, first, evaluated how accurately the DRLSE (Direct Regularized Level Set Evolution) method extracts demarcation surrounding the dental cavity. In order to evaluate the ability of the developed algorithm to automatically detect dental cavities, 7 tooth phantoms from incisor to molar were fabricated which contained a various form of cavities. Then, dental cavities in the tooth phantom images were analyzed with the developed algorithm. Except for two cavities whose contours were identified partially, the contours of 12 cavities were correctly discriminated by the automated dental caries detection program, which, consequently, proved the practical feasibility of the automatic dental lesion detection algorithm. However, an efficient and enhanced algorithm is required for its application to the actual dental diagnosis since shapes or conditions of the dental caries are different between individuals and complicated. In the future, the automatic dental cavity detection system will be improved adding pattern recognition or machine learning based algorithm which can deal with information of tooth status.

• Journal of the korean academy of Pediatric Dentistry
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• v.37 no.4
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• pp.532-536
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• 2010

Hidden caries is a subtype of the occlusal pit and fissure caries type and is defined as a dentinal caries lesion near the occlusal surface of the tooth seen on a radiograph. In visual examination, the occlusal enamel is seen intact or is minimally perforated. Covert caries, Occlult caries or Fluoride syndrome are used as synonym. The percentage of occlusal dentin lesions that are clinically undetected ranges from 1.4-50%. Little is known about the mechanisms involved in the development of hidden caries. But it is thought that extensive use of topical fluoride or the special bacteriological profile has been a major factor. This case report is about detection and treatment of hidden caries of two children who visited the department of pediatric dentistry, Yonsei University Dental Hospital. The color of caries dentin found in hidden caries lesion is lighter than cavity forming caries, which makes it more difficult to detect caries by visual examination. Therefore diagnosis of hidden caries is often accomplished after clinical sign is recognized by patients. The use of advanced caries detection aids such as Diagnodent.. with periodic radiographic examination is seemed to be helpful for early detection of hidden caries.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.29 no.1
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• pp.275-282
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• 1999

Purpose: The objective of this study was to compare clinical examination of dental caries and secondary caries with panoramic examination. and to examine bone lesions and dental anomaly of unerupted state. Materials and Methods: In this study. clinical records and panoramic radiographs were available for 89 first grade students in elementary school. Dental caries of occlusal surfaces. proximal surfaces. and buccolingual surfaces were examined. Secondary caries was examined too. In addition. the central lesion and dental anomaly of unerupted state were examined in panoramic radiographs. Results: The obtained results were as followed: 1. Carious detectability of clinical examination in occlusal and buccolingual surface was higher than that of panoramic examination. but it is statistically insignificant(p>0.05). In proximal surface. carious detect ability of panoramic examination was higher than that of clinical examination. and it is statistically significant(p<0.01). 2. In contrast to clinical examination only. when the two examination methods were combined. there was additional detection of dental caries(26.7％ in occlusal surface. 48.2％ in proximal surface. 33.3％ in buccolingual surface. and 38.3％ totally). 3. In detection of secondary caries. panoramic examination had lower ability than clinical examination in all three surfaces. but in case that both methods were combined. totally 36.0％ extra carious lesions were detected. 4. In panoramic examination. detectability of secondary caries in upper teeth is lower than lower teeth. 5. In panoramic examination. it was possible to detect the central lesions and dental anomalies of unerupted state which cannot be detected in clinical examination. Conclusion: It is useful to combine the panoramic examination with clinical examination in order to increase carious detectability and to evaluate the central lesions and dental anomalies of unerupted state

• The Transactions of The Korean Institute of Electrical Engineers
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• v.65 no.8
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• pp.1424-1429
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• 2016

Segmentation is one of the first steps in most diagnosis systems for characterization of dental caries in an early stage. The purpose of automatic dental cavity detection system is helping dentist to make more precise diagnosis. We proposed the semi-automatic method for the segmentation of dental caries on digital x-ray images. Based on a manually and roughly selected ROI (Region of Interest), it calculated the contour for the dental cavity. A snake algorithm which is one of active contour models repetitively refined the initial contour and self-examination and correction on the segmentation result. Seven phantom tooth from incisor to molar were made for the evaluation of the developed algorithm. They contained a different form of cavities and each phantom tooth has two dental cavities. From 14 dental cavities, twelve cavities were accurately detected including small cavities. And two cavities were segmented partly. It demonstrates the practical feasibility of the dental lesion detection using Computer-aided Detection (CADe).

• Proceedings of the KACD Conference
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• 2001.11a
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• pp.592.1-592
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• 2001

Conventional intraoral radiography continues to be the most widely used for the diagnosis of dental caries. But conventional intraoral film has several shortcomings, including processing error, increased radiation dose, etc. Recently, various digital radiographs substitude for conventional radiography to overcome these disadvantages. The digital radiographies are numerous advantages, including elimination of processing errors, lower radiation dose, image quality enhancements such as contrast and density modulation.(omitted)

• Imaging Science in Dentistry
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• v.34 no.1
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• pp.19-23
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• 2004

Purpose: To compare the diagnostic accuracy of Kodak Insight film with other intra-oral films in the detection of dental caries. Materials and Methods : Periapical radiographs of 99 extracted human teeth with sound proximal surfaces and interproximal artificial cavities were made on Kodak Ultra speed, Ektaspeed, Agfa Ektaspeed and Kodak Insight films and automatically processed. Six dentists examined the presence of dental caries using a five-point confidence rating scale and compared the diagnostic accuracy by ROC (Receiver Operating Characteristic) analysis and ANOVA test. Results: The sensitivity of Kodak Ultra speed, Ektaspeed, Agfa Ektaspeed and Insight film were 0.84, 0.77, 0.75 and 0.79 respectively. The specificity of Kodak Ultra speed, Ektaspeed, Agfa Ektaspeed and Insight film were 0.97. 0.95. 0.96 and 0.94 respectively. The mean ROC areas (Az) of Kodak Ultra speed, Ektaspeed, Agfa Ektaspeed and Insight film were 0.917, 0.910, 0.894, 0.909 respectively. There was no significant differences between Az of Insight film and other films (p = 0.178). Conclusion: Theses results suggested that Kodak Insight film have the comparative diagnostic accuracy of dental caries with Ultraspeed and Ektaspeed films.

• Imaging Science in Dentistry
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• v.47 no.2
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• pp.109-115
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• 2017

Purpose: The aim of this study was to assess the ex vivo diagnostic ability of 9 different cone-beam computed tomography (CBCT) settings in the detection of recurrent caries under amalgam restorations in primary teeth. Materials and Methods: Fifty-two primary teeth were used. Twenty-six teeth had dentine caries and 26 teeth did not have dentine caries. Black class II cavities were prepared and restored with amalgam. In the 26 carious teeth, recurrent caries were left under restorations. The other 26 intact teeth that did not have caries served as controls. Teeth were imaged using a $100{\times}90-mm$ field of view and a 0.2-mm voxel size with 9 different CBCT settings. Four observers assessed the images using a 5-point scale. Kappa values were calculated to assess observer agreement. CBCT settings were compared with the gold standard using a receiver operating characteristic analysis. The area under the curve (AUC) values for each setting were compared using the chi-square test, with a significance level of ${\alpha}=.05$. Results: Intraobserver kappa values ranged from 0.366 to 0.664 for observer 1, from 0.311 to 0.447 for observer 2, from 0.597 to 1.000 for observer 3, and from 0.869 to 1 for observer 4. Furthermore, interobserver kappa values among the observers ranged from 0.133 to 0.814 for the first reading and from 0.197 to 0.805 for the second reading. The highest AUC values were found for setting 5 (0.5916) and setting 3 (0.5886), and were not found to be statistically significant(P>.05). Conclusion: Variations in tube voltage and tube current did not affect the detection of recurrent caries under amalgam restorations in primary teeth.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.18 no.6
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• pp.604-613
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• 2009

Recently, researches to develop phased array ultrasonic examination techniques are proceeded to diagnose dental caries and the status of surgical operation of dental implant. Sound field analysis of phased array ultrasonic transducers were carried out in order to characterizing the ultrasonic phased array beams. The sound field of ultrasonic radiation was calculated for the sample called "gypsum-improved stone" with the similar characteristics of dental materials. Industrial phased array ultrasonic devices were utilized for the insptriion of the artificial flaws machined in the gypsum-improved stone. Dental implants were made at the pig jaw bone and defect images were confirmed for the dental implants.

• Proceedings of the KACD Conference
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• 2007.11a
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• pp.627-627
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• 2007

• Journal of the korean academy of Pediatric Dentistry
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• v.42 no.3
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• pp.218-225
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• 2015

This study used sodium fluorescein to improve imaging diagnostic ability by increasing the fluorescence difference between sound enamel and caries lesions. It also made it easier to discriminate between stain and caries lesions using quantitative light-induced fluorescence (QLF). Half of the specimen surface was covered with nail varnish as a control. Specimens were divided randomly in six decalcification groups and decalcified for different lengths of time. Then, ${\Delta}F$ was measured using QLF-D. After applying 0.075% sodium fluorescein, we measured ${\Delta}F$ again and compared it with the initial value. After cutting the central portion of the specimen, we measured the lesion depth using scanning electron microscopy. The lesion surfaces observed with QLF were darker than normal enamel, whereas they were lighter than normal enamel after applying fluorescein. Longer decalcification time was associated with greater fluorescent dye penetration. The ${\Delta}F$ measured after applying fluorescein was higher than the initial value (p < 0.05). Due to QLF measurement using fluorescein being more sensitive for diagnosing early decalcification, this approach will enable early diagnosis of dental caries before the cavity formation stage, allowing the treatment of early caries lesions. With QLF and sodium fluorescein, we can easily discriminate between stain and caries lesions.