• Imaging Science in Dentistry
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• v.38 no.2
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• pp.89-93
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• 2008

Purpose: To evaluate the difference of the movement of the mandibular condyles between trans cranial and panoramic TMJ radiographs to view the movement of the mandibular condyles. Materials and Methods: Thirty-four paired transcranial and panoramic TMJ radiographs of patients were used to evaluate the movement of the mandibular condyle. The distances, from the most superior point of the mandibular condyle to the most inferior point of the articular eminence on both radiographs, were measured. The measurements were taken at closed state and maximum opening state of each radiograph on both side. Differences between matched pairs were analysed by paired t-test, with significance established at P<0.05. Results and Conclusion: The mean distance, from the most superior point of the mandibular condyle to the most inferior point of the articular eminence on both radiographs, was statistically different at each side (P<0.05). At closing state, the mean distance measured on panoramic TMJ radiographs was longer than on transcranial radio-graphs (0.85 mm at right side, 1.20 mm at left side). But at maximum opening state, the mean distance on transcranial radiographs was longer (1.00 mm at right side, 0.62 mm at left side) than panoramic TMJ radiographs.

• Journal of dental hygiene science
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• v.19 no.4
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• pp.245-253
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• 2019

Background: This study aimed to analyze correlations between depression, cognitive function, oral health state, ability to perform activities of daily living, oral dryness symptoms, and oral health-related quality of life, and determine factors influencing the latter. Methods: This was a cross-sectional study based on questionnaires completed by 260 participants with suspected dementia, residing in South Korea. Psychiatrists, psychiatric nurses, and dental hygienists visited clinics in the participating regions for examination and questionnaire administration. General characteristics, the geriatric depression scale, ability to perform activities of daily living, cognitive function, oral health state, and oral health-related quality of life were analyzed. Independent t-tests, one-way analysis of variance (ANOVA), correlation analysis and multiple regression analysis were conducted, identifying factors affecting oral health-related quality of life. Data analysis was performed using SPSS ver. 20.0 (IBM Corp., USA), and the significance was set at p<0.05. Results: Approximately 65.0% of participants were female, 63.5% were in their 70s, and 90.0% had health insurance. About 21.5%, 42.0%, and 36.5% were normal, slightly impaired, and had dementia, respectively. High cognitive impairment was associated with poor oral health. Sex, education levels, marital status, and living arrangements influenced oral health-related quality of life. According to the regression analysis, geriatric depression and oral dryness affected the Geriatric Oral Health Assessment Index scores. Conclusion: In conclusion, oral dryness and depression levels among elders influenced oral health-related quality of life. The results showed that to enhance elders' oral health-related quality of life, it is essential to not only improve their oral health state, but also relieve oral health problems, especially oral dryness, and take into consideration their psychological aspects.

• International Journal of Stem Cells
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• v.16 no.2
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• pp.202-214
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• 2023

Background and Objectives: To investigate the role of exosomes from periodontal ligament cells (PDLCs) in bone marrow mesenchymal stem cell (BMSC) migration. Methods and Results: Human PDLCs were applied cyclic tension stretching. Exosomes were extracted from cultured PDLCs by ultracentrifugation, then characterized for their size, morphology and protein markers by NTA, TEM and western blotting. The process that PKH26-labeled exosomes taken up by BMSCs was assessed by confocal microscope. BMSC migration was examined by Transwell assay. Exosomes derived from PDLCs were identified. Cyclic tension stretch application on PDLCs can enhance the migration ability of BMSCs through exosomes. The exosomal miRNA expression profiles of unstretched and stretched PDLCs were tested by miRNA microarray. Four miRNAs (miR-4633-5p, miR-30c-5p, miR-371a-3p and let-7b-3p) were upregulated and six (miR-4689, miR-8485, miR-4655-3p, miR-4672, miR-3180-5p and miR-4476) were downregulated in the exosomes after stretching. Sixteen hub proteins were found in the miRNA-mRNA network. Gene Ontology and KEGG pathway analyses demonstrated that the target genes of differentially expressed exosomal miRNAs closely related to the PI3K pathway and vesicle transmission. Conclusions: The exosomes derived from cyclic tension-stretched PDLCs can promote the migration of BMSCs. Alternation of microRNA profiles provides a basis for further research on the regulatory function of the exosomal miRNAs of PDLCs during orthodontic tooth movement.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.43 no.1
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• pp.42-45
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• 2017

The aim of this report was to discuss a complication resulting from a transconjunctival approach to treating an orbital fracture. A 30-year-old male patient presented with a fracture to the zygomatic orbital complex. He was treated with transconjunctival conventional surgical treatment. Two days after surgical treatment, the patient presented with secondary chemosis which was initially slight and then subsequently worsened. The clinical situation was managed with topical and systemic corticosteroids and resolved within one postoperative month. Two-year follow-up showed ptosis of the upper eyelid and limited infraversion in the affected eye. This unusual complication associated with an orbital trauma was resolved with minor functional alterations, although the consequences observed after 2 years were not completely satisfactory.

• Journal of Oral Medicine and Pain
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• v.14 no.1
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• pp.19-24
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• 1989

The purpose of this study was to investigate the reliability of electromyographic examination in a day and detect the objective measurement timing of electromyography. 18 normal students who were in dental collage of C national university were selected for this study. They had no symptoms on temporomandibular joint area, no restorations and missing tooth on dentition. Their molar relationship was normal or class I of Angle's classification. Electromyography had been taken every one hour from 9:00 A.M. to 5:00 P.M. in the state of clenching and rest by using Bioelectric processor EM2 interfaced with mandibular kinesiograph K-6 diagnostic system. We compared and analyzed the variances of electromyography values of each subjects. The obtained results were as follows : There were no significant differences on variability of electromyography values in each state clenching and rest. In the aspect of this circumstances, the use of electromyography could be a good objective procedure to diagnose the temporomandibular disorders and to detect the effect to the treatment of temporomandibular disorders at any time in a day from 9:00 A.M. to 5:00 P.M.

• Journal of Korean society of Dental Hygiene
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• v.9 no.3
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• pp.248-261
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• 2009

Objective : This study was performed in order to figure out Oral Health Actual Condition in Elementary School Teachers in Deagu area. This study was conducted from March through May 2008. Method : A total of three hundred and ten Elementary School Teachers were surveyed. The collected data were analyzed by Oral Health Actual Condition and cognition, Diet habit or living and one's own intellect health state, Oral disease sign symptoms of percent and 2-test and One-way ANOVA test by using SPSS12.0 Program. Results : 1. The most of result Frequencies of tooth brushing per one day were 3 over 91.0% and Oral Examination, Oral Health Education need. 2. The result of oral disease sign and symptom were hypersensitivity due to cold food(39.0%), halitosis(21.6%), gingival bleeding tendency(21.3), clicking sound on TMJ(18.7%), hypersensitivity due to tooth burshing(17.1%), easy crown fracture and to be fine(10.0%), pain on TMJ or limitation of mouth opening(7.1%). 3. The most of result age a group oral hygiene assistance article age 20 for interdental tooth brushing(46.4%), age 50 over not used interdental tooth brushing 38.5%. 4. The result of sign and symptom and snack following was statistically significant(P<0.05), health of own cognition and Oral health of own cognition was statistically significant(P<0.001). Conclusion : The study of understanded the Subjective Elementary School Teachers Oral Health Actual Condition and Promotion of Oral Health follow up Oral examination and Oral Health Education have to system groping.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.25 no.2
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• pp.319-330
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• 1995

This study was designed to evaluate the interrelationship between the condylar head position in transcranial view and the articular disc position in the arthrography. The condylar positions were assessed by subjective method and linear measurement method on the transcranial view. The subjects for this study consisted of 24 symptomatic joints with normal disc position, 37 joints with anterior disc displacement with reduction and 44 joints with anterior disc displacement without reduction that were classified by arthrotomography under the fluoroscopic guidance. The interrelationship between the condylar head position in transcranial view and the articular disc position in the arthrography was evaluated by Chi square test. The obtained results were as follows : 1. There was no significant interrelationship between the position of condylar head in closed mouth state on transcraniaJ view and articular disc position in the arthrography (p>0.05). 2. There was no significant interrelationship between the changes of interarticular distance in 1 inch opening state and articular disc position in the arthrography (p>0.05). 3. There was no significant interrelationship between the position of condylar head related to the apex of articular eminence in 1 inch opening state and articular disc position in the arthrography(p>0.05). 4. There was significant interrelationship between the changes of interarticular distance that is assessed by linear measurement method in maximum opening state and articular disc position in the arthrography(p<0.05), but there was no significant interrelationship when the condylar head position was assessed by subjective method(p>0.05). 5. There was significant interrelationship between the degree of condylar translation in maximum opening state and articular disc position in the arthrography(p<0.05). 6. The correlation coefficient between two methods to assess the position of condylar head were 0.7989: the condylar head position in articular fossa in closed state, 0.6847: interarticular space in 1 inch opening state, 0.8965: the degree of condylar translation in 1 inch opening state, 0.5944: the changes of interarticular space in maximum opening state, 0.9215: the degree of condylar translation in maximum opening state.

• Imaging Science in Dentistry
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• v.51 no.4
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• pp.455-460
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• 2021

This report presents a rare case of maxillary osteoblastoma in a 17-year-old female. The patient presented with dull pain and facial asymmetry inferior to the left zygoma. An intraoral examination found a painless swelling on the buccal gingival tissue in the left posterior maxilla. Panoramic radiographs and multidetector computed tomographic images revealed an ill-defined, non-corticated, mixed attenuating entity of osseous density located within the left posterior maxilla apical to the left maxillary molars. The entity exhibited a heterogeneous internal structure with a fine granular appearance, and the periphery showed a partial hypo-attenuating rim along the antero-medial aspect. Expansion of the left posterior maxilla accompanied with displacement of the left maxillary sinus floor was noted. External root resorption of the first and second molars was noted, as well as postero-superior displacement of the third molar. The histopathologic diagnosis of the biopsy was osteoblastoma. Complete excision of the tumor was performed.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.22 no.1
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• pp.7-22
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• 1992

The stress distributions on a human mandible for 18 load cases under two different boundary conditions (mouth open and closed), using the three dimensional finite element modeling were studied. Also, the expected fracture loads for each load cases were calculated by using the Von-Mises yield criterion. The model of a mandible with all teeth was composed of 2402 hexahedron elements and 3698 nodes. CAD techniques were used to analyze the 3-dimensional results. The conclusions of this study were as follows: 1. In the mouth open state, the maximum stress occured at the condyle neck; when the lateral load was exerted, the maximum stress occured at the load side condyle. 2. In the mouth closed state, when the loads were exerted on the mandibular body and chin, the maximum stress occured at the loaded area, and when the loads were exerted on the angle and ramus, the maximum stress occured at the condyle neck. 3. The expected fracture loads in each load case were calculated using the Von-Mises yield criterion, and it was confirmed that the mandible in the mouth open state was more easily fractured than that in the mouth closed state, and the expected fracture loads are lesser in the cases that load direction is parallel at mandibular plane than 45°. 4. The magnitudes of the expected fracture loads increased in the order of angle, ramus, body and chin in case of the mouth closed state, while chin, body, angle and ramus in case of the mouth open state. 5. The Von-Mises stress concentration regions analyzed by F.E.M. corresponded well with the results of clinical studies.

• Journal of Oral Medicine and Pain
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• v.20 no.2
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• pp.385-397
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• 1995

The purpose of this study is to document the stress symptoms (Anxiety and depression) among dental students and the difference of stress level between classes and by gender. All students in dental college, Seoul National University, in the 1995 academic year, were tested with the Spielberger's State-Trait Anxiety Inventory and Beck Depression Inventory just before the first semestral examination when the stress levels of students are expected to be the highest. 303 students answered the test. The obtained results were as follows : 1. State Anxiety inventory scores of the second-year and first-year students were significantly higher than those of the fourth -year and third-year(p(0.01), and all classes showed mean state anxiety scores more than mild. 2. Trait Anxiety inventory scores of the second-year and first-year students were significantly higher than those of the third-year and forth-year(p(0.01), and all classes showed mean Trait Anxiety scores more than mild. 3. Beck Depression inventory scores of the second -year students were significantly higher than those of the third-year and fourth-year(p(0.01), and twenty two students(7.3%) among the fourth classes showed depression symptoms. 4. In the comparison of the mean scores of the State-Trait Anxiety Inventory and Beck Depression Inventory between male and female students, State Anxiety Inventory scores of the second-year female students were significantly higher than those of the second year male students(p(0.05), and there was no significant difference elsewhere.