• Journal of Korean society of Dental Hygiene
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• v.10 no.1
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• pp.185-195
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• 2010

Objectives : The purpose of this study is to opportunity of oral examination and positively utilizing the oral-health educational method of being preferred on the basis of the contents promote workers' oral health. Methods : This study carried out questionnaire research by self-administrated method, which was selected by convenience sampling method, from February 9th to March 6th, 2009 targeting 237 workers where are located in Gunsan city of Jeollabuk-do Province. Results : 1. Workers' interest and recognition of importance in oral health were high, and were low in subjective oral-health knowledge level, on the other hand. 2. Workers were indicated to be high in the response rate of work-site oral examination and, on the other hand, to be high in the dissatisfied rate at work-site oral examination. 3. As for work-site oral examination, the workers were indicated to positively recognize participation in work-site oral-health education along with high necessity. 4. Workers were indicated to prefer the most a method of lecture such as dentist along with contents in prevention and curing method of periodontal disease. Conclusions : An efficient result is thought to be probably obtained given offering an opportunity of oral examination and positively utilizing the oral-health educational method of being preferred on the basis of the contents with the highest preference, in order to promote workers' oral health.

• The Journal of the Korean dental association
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• v.56 no.9
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• pp.479-490
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• 2018

3D printing technology supporting the specific patient medical services is actively being implemented in dentistry. The purpose of this study is to introduce the legal and institutional considerations to the medical practitioners in dentistry who must observe when they manufacture medical devices using 3D printers, and to provide a ways to activate and enhance their utilization in the domestic approval point of view for medical devices. Through the public data of government agencies and related organizations, the statutory system and compliance matters related to the manufacture of 3D printing medical devices have been examined and reviewed for the government's improvement efforts. Through the study, the government has been actively improving the system and making policy, but the active interest and participation of medical professionals and related workers are continually required to solve the problems which are scattered. 3D printing technology is expected to be more frequently utilized in the field of dentistry in near future. Therefore, it is essential to establish measures to improve the regulation through continuous cooperation with the related ministries with the long-term point of view enhancing smooth entry to the market for the medical devices by taking data from the continued research.

• Journal of the Korean Ceramic Society
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• v.48 no.2
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• pp.152-159
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• 2011

The green and hard machining characteristics of dental ceramics are of great interest to dental industry. The green bodies of TZP/$Al_2O_3$ composites were prepared by the cold isostatic pressing, and machined on the CNC lathe using PCD (polycrystalline diamond) insert under various machining conditions. With increasing nose radius of PCD insert, surface roughness initially increased due to increased cutting resistance, but decreased by the onset of sliding fracture. The lowest surface roughness was obtained at spindle speed of 1,300 rpm and lowest feed rate. Hard bodies were prepared by pressureless sintering the machined green bodies at several temperatures. The grinding test for sintered hard body was conducted using electroplated diamond bur with different grit sizes. During grinding, grain pull out in the composite was occurred due to thermal expansion mismatch between the alumina and zirconia. The strength of the composite decreased with alumina contents, due to increased surface roughness and high monoclinic phase transformed during grinding process. The final polished samples represented high strength by the elimination of a phase transformation layer.

• Imaging Science in Dentistry
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• v.38 no.2
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• pp.117-120
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• 2008

The odontogenic keratocyst (OKC) is a developmental odontogenic cyst typically occurring in the jaws. Since the first description of OKC was published in 1956, the lesion has been of particular interest because of its specific histopathologic features, high recurrence rate, and aggressive behavior. Recurrences most commonly arise within bone at the site of the original cyst. However, as lining cells may find their way into surrounding tissues either from implantation during surgery or from cortical perforation recurrences may arise at a distance from the original cyst. Here, we report a rare case of recurrent OKC which was first developed in mandible and recurred within the masticatory space.

• Journal of Korean society of Dental Hygiene
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• v.19 no.4
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• pp.577-589
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• 2019

Objectives: The purpose of this study was to investigate the effects of general and oral health on quality of life in the elderly living alone and with family. Methods: We analyzed data from the $6^{th}$ Korea National Health and Nutrition Examination Survey. Distribution of the elderly living alone and with family based on the general characteristics and general and oral health was analyzed using complex-sample chi-square tests. Multiple logistic regression was used to analyze the factors affecting quality of life by calculating the 95% confidence intervals. Results: In the elderly living alone, the quality of life significantly correlated with restriction of activity, perceived general and oral health status, perceived stress, and speech difficulties. Further, in the elderly living with family, lower quality of life significantly correlated with restriction of activity, perceived health status, walking days per week, life time smoking history, Community Periodontal Index, and chewing and speech difficulties. Conclusions: The elderly are concerned with self-maintenance of general and oral health. Therefore, systematic policies related to health services need to be developed and operated at the national level. It is especially necessary to take social interest in the elderly living alone and a more continuous and professional approach in their health care.

• Biomedical Science Letters
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• v.26 no.4
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• pp.327-335
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• 2020

As the interest in oral health is increasing with quality of life. The most representative oral diseases include dental caries, periodontal disease, and malocclusion, as well as dry mouth and oral mucosa. Cinnamaldehyde have an antioxidant effect that has been studied not only to treat rheumatism and hypertension, but also to protect liver, and gastrointestinal tract, but there are few studies related to the control of oral diseases. The purpose of this study was the effect of enhanced orofacial pain when oral administration of cinnamaldehyde in the oral diseases. Cinnamaldehyde (5, 12.5, 25, and 50 mg/kg) orally administered at a dose of 1 mL, and the change in biological response was confirmed after a week. In addition, 5% formalin (30, 50 μL) was injected into TMJ and subcutaneous areas of the whiskers of rats to observe the change in the threshold of the improved orofacial pain model. As a result of the experiment, in the xerostomia model, drinking water was decreased in the cinnamaldehyde-administered group, feed intake and weight increased, and saliva was also increased compared to the naïve group. In particular, the most significant increase trend was observed at the concentrations of 25 and 50 mg/kg. In addition, it was confirmed that the pain behavioral response of the orofacial area improved by oral diseases decreased depending on the concentration of cinnamaldehyde. Based on these results, cinnamaldehyde effectively reduced symptoms related to xerostomia and showed improved pain relief in the orofacial areas.

• Imaging Science in Dentistry
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• v.51 no.4
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• pp.351-361
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• 2021

Purpose: The clivus is a region in the anterior section of the occipital bone that is commonly imaged on large-volume cone-beam computed tomography (CBCT). There have been several reports of incidental clivus variations and certain pathological entities that have been attributed to the variations. This study aimed to evaluate the effects of these variations within the scope of dentistry. Materials and Methods: Medical databases (PubMed, Scopus, and Web of Science) were searched using a controlled vocabulary (clival anomalies, cone-beam CT, canalis basilaris medianus, fossa navicularis magna, clival variation). The search was limited to English language, humans, and studies published in the last 25 years. The articles were exported into RefWorks^® and duplicates were removed. The remaining articles were screened and reviewed for supporting information on variations of the clivus on CBCT imaging. Results: Canalis basilaris medianus and fossa navicularis magna were the most common anomalies noted. Many of these variations were asymptomatic, with most patients unaware of the anomaly. In certain cases, associated pathologies ranged from developmental (Tornwaldt cyst), to acquired (recurrent meningitis). While no distinct pathognomonic aspects were noted, there were unique patterns of radiographic diagnosis and treatment modalities. Most patients had a normal course of follow-up. Conclusion: Interpretation of CBCT volumes is a skill every dentist must possess. When reviewing large-volume CBCT scans, the clinician should be able to distinguish pathology from normal anatomic variations within the skull base. The majority of clivus variations are asymptomatic and will remain undetected unless incidentally noted on radiographic examinations.

• Nuclear Engineering and Technology
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• v.55 no.8
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• pp.2854-2863
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• 2023

Objective: To present a hybrid approach that incorporates a constrained beam-hardening estimator (CBHE) and deep learning (DL)-based post-refinement for metal artifact reduction in dental cone-beam computed tomography (CBCT). Methods: Constrained beam-hardening estimator (CBHE) is derived from a polychromatic X-ray attenuation model with respect to X-ray transmission length, which calculates associated parameters numerically. Deep-learning-based post-refinement with an artifact disentanglement network (ADN) is performed to mitigate the remaining dark shading regions around a metal. Artifact disentanglement network (ADN) supports an unsupervised learning approach, in which no paired CBCT images are required. The network consists of an encoder that separates artifacts and content and a decoder for the content. Additionally, ADN with data normalization replaces metal regions with values from bone or soft tissue regions. Finally, the metal regions obtained from the CBHE are blended into reconstructed images. The proposed approach is systematically assessed using a dental phantom with two types of metal objects for qualitative and quantitative comparisons. Results: The proposed hybrid scheme provides improved image quality in areas surrounding the metal while preserving native structures. Conclusion: This study may significantly improve the detection of areas of interest in many dentomaxillofacial applications.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.49 no.6
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• pp.311-323
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• 2023

Immunosuppressants are vital in organ transplantation including facial transplantation (FT) but are associated with persistent side effects. This review article was prepared to compare the two most used immunosuppressants, cyclosporine and tacrolimus, in terms of mechanism of action, efficacy, and safety and to assess recent trials to mitigate their side effects. PubMed and Google Scholar queries were conducted using combinations of the following search terms: "transplantation immunosuppressant," "cyclosporine," "tacrolimus," "calcineurin inhibitor (CNI)," "efficacy," "safety," "induction therapy," "maintenance therapy," and "conversion therapy." Both immunosuppressants inhibit calcineurin and effectively down-regulate cytokines. Tacrolimus may be more advantageous since it lowers the likelihood of acute rejection, has the ability to reverse allograft rejection following cyclosporine treatment, and has the potential to reinnervate nerves. Meanwhile, graft survival rates seem to be comparable for the CNIs. To avoid nephrotoxicity, various immunosuppressants other than CNIs have been studied. Despite averting nephrotoxicity, these medications show increases in acute rejection or other types of adverse effects compared to CNIs. FT has been a topic of interest for oral and maxillofacial surgeons, and the postoperative usage of immunosuppressants is crucial for the long-term prognosis of FT. As contemporary transplantation regimens incorporate novel medications along with CNIs, further research is required.

• Imaging Science in Dentistry
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• v.50 no.1
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• pp.23-30
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• 2020

Purpose: This study was conducted to assess the effectiveness of a metal artifact reduction (MAR) algorithm activated at different times during cone-beam computed tomography (CBCT) acquisition on the magnitude of artifacts generated by a zirconium implant. Materials and Methods: Volumes were obtained with and without a zirconium implant in a human mandible, using the OP300 Maxio unit. Three modes were tested: without MAR, with MAR activated after acquisition, and with MAR activated before acquisition. Artifacts were assessed in terms of the standard deviation (SD) of gray values and the contrast-to-noise ratio (CNR) in 6 regions of interest with different distances (10 to 35 mm, from the nearest to the farthest) and angulations(70° to 135°) from the implant region. Results: In the acquisitions without MAR, the regions closer to the implant(10 and 15mm) had a higher SD and lower CNR than the farther regions. When MAR was activated (before or after), SD values did not differ among the regions (P>0.05). The region closest to the implant presented a significantly lower CNR in the acquisitions without MAR than when MAR was activated after the acquisition; however, activating MAR before the acquisition did not yield significant differences from either of the other conditions. Conclusion: Both modes of MAR activation were effective in decreasing the magnitude of CBCT artifacts, especially when the effects of the artifacts were more noticeable.