• The Journal of Advanced Prosthodontics
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• v.7 no.3
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• pp.183-190
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• 2015

PURPOSE. This study evaluated the fracture load of customized zirconia abutments with titanium insert according to preparation depths, with or without 5-year artificial aging. MATERIALS AND METHODS. Thirty-six identical lithium disilicate crowns (IPS e.max press) were fabricated to replace a maxillary right central incisor and cemented to the customized zirconia abutment with titanium insert on a $4.5{\times}10$ mm titanium fixture. Abutments were fabricated with 3 preparation depths (0.5 mm, 0.7 mm, and 0.9 mm). Half of the samples were then processed using thermocycling (temperature: $5-55^{\circ}C$, dwelling time: 120s) and chewing simulation (1,200,000 cycles, 49 N load). All specimens were classified into 6 groups depending on the preparation depth and artificial aging (non-artificial aging groups: N5, N7, N9; artificial aging groups: A5, A7, A9). Static load was applied at 135 degrees to the implant axis in a universal testing machine. Statistical analyses of the results were performed using 1-way ANOVA, 2-way ANOVA, independent t-test and multiple linear regression. RESULTS. The fracture loads were $539.28{\pm}63.11$ N (N5), $406.56{\pm}28.94$ N (N7), $366.66{\pm}30.19$ N (N9), $392.61{\pm}50.57$ N (A5), $317.94{\pm}30.05$ N (A7), and $292.74{\pm}37.15$ N (A9). The fracture load of group N5 was significantly higher than those of group N7 and N9 (P<.017). Consequently, the fracture load of group A5 was also significantly higher than those of group A7 and A9 (P<.05). After artificial aging, the fracture load was significantly decreased in all groups with various preparation depths (P<.05). CONCLUSION. The fracture load of a single anterior implant restored with lithium disilicate crown on zirconia abutment with titanium insert differed depending on the preparation depths. After 5-year artificial aging, the fracture loads of all preparation groups decreased significantly.

• The Journal of Korean Academy of Prosthodontics
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• v.56 no.4
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• pp.375-383
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• 2018

Clinicians are faced with many difficulties when planning prosthodontic restorations with implants in a complete edentulous patient. When planning fixed implant prosthetics, it is often necessary to have additional surgery due to highly reduced alveolar bone, as well as high treatment costs and long-term treatment durations can be required. In addition, lack of interocclusal space can be a problem when planning implant supported overdentures. In this study, we planned to place a small number of implants on the anterior maxilla and used them as the abutments for distal-extension removable partial dentures on the posterior side in a maxillary fully edentulous patient. This would reduce the possibility of additional invasive operations such as alveolar bone graft, shorten the treatment time, and be relatively easy for elderly patients to burden. In this case, the patient was provided with a distal-extension removable partial denture and anterior implant fixed prostheses, which was similar to the previous one, and showed good adaptation, and chewing efficiency and esthetics was recovered.

• The korean journal of orthodontics
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• v.30 no.2 s.79
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• pp.223-233
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• 2000

An epidemiological investigation was carried out at Yongin, Kyungkido, South Korea to determine the prevalence of symptoms of temporomandibular disorders and parafunctional habits in adolescent aged 16, 17 and 18 years. 2,098 students(male 507, female 1,591) were randomly selected and investigated with the questionnaire. The results were obtained as follows, 1. The prevalence of symptoms of temporomandibular disorders was $80.9\%$ total, $77.3\%$ for male and $82.0\%$ for female with significance between male and female(P<0.05). 2. The prevalence of symptoms of temporomandibular disorders was gradually increased according to increasing age with significant difference among ages(P<0.001) 3. The most frequent symptom in the temporomandibular disorders is pain on chewing($65.9\%$), and then clicking($50.7\%$), Pain on mouth opening($41.8\%$), and pain on TMJ($36.8\%$) 4. There was little corelationship between clenching habits and symptoms of temporomandibular disorders(r=0.166), and also between bruxing habits and those(r=0.057).

• Korean Journal of Ichthyology
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• v.1 no.1_2
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• pp.83-92
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• 1989

The pharyngeal teeth and the masticatory process of the basioccipital bone were compared in ten species of Korean bitterlings. Three species, Acheilognathus lanceolata, A. limbatus, A. signifier and Rhodeus ocellatus, which are characterized by the absence of serrations on the side of the pharyngeal teeth, are found to, have reduced occlusal grooves on the outside of occlusal margin, Among Korean bitterlings, differences are found in the developmental degrees of the anterior part of the masticatory process, the grooves on the occlusal surface and the chewing area on the pharyngeal first tooth. The occlusal grooves in herbivorous species are considered to be more developed than those in omnivorous species. Considering these findings, the combination of developmental degrees in the three pharyngeal elements suggests generally the phylogenetic relationships among the Korean bitterlings.

• Journal of Oral Medicine and Pain
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• v.21 no.1
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• pp.67-78
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• 1996

This study was performed to compare the TMJ sounds by means of vibration-related items by Sonopak such as integral, high integral, above 300/(0-300) ratio, peak amplitude, peak frequency and median frequency before and after occlusa1 splint therapy as well as counselling, physical modalities. For this study 22 patients with craniomandibular disorders (CMDs) were selected and examined by routine diagnostic procedure for CMDs including Transcranial and Panoramic radiographs and were classified into 3 CMDs subgroups : disc displacement with reduction, disc displacement without reduction, and degenerative joint disease. Visual analogue scale (VAS) about joint sound was recorded during treatment period and VAS treatment index (VAS Ti) was calculated from the VAS data and treatment duration. The author evaluated and compared treatment results by several parmeters such as symptom duration, timing of joint sound, parafunctional habits, trauma, and diagnostic classification. The obtained results were as follows : 1. Before the treatment, the highest value of peak amplitude was observed in disc displacement with reduction group and value of median frequency was highest in degenerative joint disease group. In addition the highest values of peak frequency and ratio ware observed in degenerative joint disease group, though they were not significant. Furthermore the lowest value of high integral was observed in disc displacement without reduction group and though it was not significant, value of integral was lowest in that group. 2. Among 3CMDs subgroups disc displacement with reduction group showed the significantly decreased value of high integral and degenerative joint disease group had the significantly decreased value of integral after conservative treatment including occlusal splint therapy. Conclusively conservative treatment including occlusal splint therapy vay be effective in the treatment of CMDs including TMJ sound. 3. Fair prognosis for conservative treatment was observed in acute group under 6 months than chronic group, 6 months over in symptom duration but there was no statistical difference. The result for conservative treatment was observed slightly poor in subjects with bruxism, clenching, unilateral chewing habit and trauma history but there were no statistical differences.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.1
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• pp.371-379
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• 2015

This study examined the symptoms of temporomandibular disorder and the relationship with the psychological character using Symptom Check List-90-Revision (SCL-90-R). The self-administered questionnaire survey was implemented from March 1, 2014 to June 30, 2014 targeting 294 University Students in Daejeon and Gangwon area aged 20-31 years old (Men 140 persons, Women 54 persons). The data showed that the teeth grinding and the unilateral chewing out of corrupt practices in the mouth in relation to the use of the lower jaw showed a significant correlation (p<0.01) with the depth of symptoms of temporomandibular disorder, as the result of the simple psychodiagnosis inspection (SCL-90-R), and a significant correlation (p<0.05) with the depth of symptoms of temporomandibular disorder in the item excluding phobic anxiety (PHOB). The somatization (SOM) criteria out of individual psychological characteristic appeared to have the significant plus (+) effect on the depth of symptoms of temporomandibular disorder as a result of implementing multiple regression analysis by controlling the individual characteristic variables to check the influence of the psychological character of the study object on the symptom of temporomandibular disorder.

• Journal of Microbiology and Biotechnology
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• v.26 no.10
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• pp.1817-1823
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• 2016

Areca nut (AN) chewing is a habit in many countries in Central, Southern, and Southeast Asia. It is strongly associated with the occurrence of oral, pharyngeal, and esophageal cancer as well as systemic inflammation. However, the association between AN intake and the development of gastric lesions has not yet been identified. The aim of this study was to investigate the effect of AN on gastric diseases using a mouse model for Helicobacter pylori infection. We studied four groups of mice: those fed a normal diet (ND), those fed a diet containing 2.5% AN (AD), those fed ND and infected with H. pylori PMSS1 strain (ND/HP), and those fed AD and infected with H. pylori PMSS1 strain (AD/HP). Food intake and body weight were monitored weekly during the experiments. At 10 weeks, the mice were sacrificed, and the stomach weight, H. pylori colonization, and gastric inflammation were evaluated. The stomach weight had increased significantly in the ND/HP and AD/HP groups along with increases in H. pylori colonization; however, there was no significant difference between these two groups with respect to stomach weight and colonization. On histological grading, mononuclear cell infiltration was severer in the AD/HP group than in the ND/HP group. These data suggest that chronic gastric inflammation was aggravated by AN treatment in the mice with H. pylori-induced gastric lesions. Furthermore, as previously suggested, this animal model is useful to determine the effect of potential carcinogens on gastric lesions induced by H. pylori infection.

• Analytical Science and Technology
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• v.13 no.3
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• pp.378-384
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• 2000

This Study has been carried out to develop a method of analysis of 8 permitted synthetic food colors [including Brilliant Blue FCF(B1), Indigocarmine (B2), Fast green FCF(G3), Amaranth (R2), Erythrosine (R3), Allura red (R40), Tartrazine (Y4), Sunset Yellow FCF (Y5)] in Korean foods by HPLC. After adjusting to 0.5% HCl, each of the food colors extracted was eluted by Sep-pak $C_{18}$ cartridge. Eluates were then determined by high performance liquid chromatograph with a UV-VIS detector. Recoveries of the 8 synthetic food colors were found to be 81.2-98.0% for soft drinks, 80.6-96.1% for candy, 79.8-96.3% for chewing gum, 76.5-91.7% for cereals, 79.9-93.8% for ice cream and 78.6-94.7% for jelly, respectively. The detection limits were $0.05-0.1{\mu}g/g$.

• Asian Journal of Turfgrass Science
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• v.21 no.1
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• pp.51-67
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• 2007

Survey was initiated on insect pest species damaging the landscaping trees in golf courses to get the basic information for the development of insect management program. Four country clubs were selected as survey sites; Tongue Country Club and Youngwon Country Club in Gyeongnam, Daegu Country Club in Gyeongbuk, and Dongrae Benest Golf Club in Busan. We found that 60 species of 44 genera in 34 families of six orders from 88 species of 54 genera in 33 families of 22 orders surveyed. Most landscaping trees were damaged by one or two species of insect pests, but tree species such as Robinia pseudoacacia, Prunus leveilleana var. pendula, Castanea crenata, Quercus dentata, and Q. variabilis were damaged by more than five species of insects. Most insect species damaged one or two tree species. However, Adoretus tenuimaculatus(Coleoptera: Scarabaeidae) damaged 67 tree species of 41 genera. The Coleoptera and Honmoptera species were 36.4% and 36.3% of the total insect species, respectively. Insect pest occurring in high frequency was 9% of total insect species, while infrequent one was 73%. The insect species with chewing and sucking mouth part types were 49% and 51%, respectively.

• The Journal of the Korea Contents Association
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• v.14 no.6
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• pp.271-280
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• 2014

The purpose of this study was to offer basic data for developing effective program for promotion elderly people's oral condition, and oral health behavior upon the appearance of denture. This study was performed by utilizing health questionnaire survey and oral examination survey for first year(2010) law data of the 5th korea national health and nutrition examination survey. The research subjects were 1419 people who were aged over 65 and completed the oral examination and oral questionnaire survey. In the general characteristics, the need of denture was indicated highly in the male elderly. Factors of having relationship with a need of denture in oral health condition were indicated to be chewing difficulty(p<0.001) and dental caries(p<0.0001). The case of not using oral hygiene device was high in a need of denture(p<0.001). Also, a case of not dental treatment was indicated to be high in a need of denture(p<0.001). Through these related findings, the elderly's oral condition and oral health behavior were indicated to have high relationship with a need of denture. There is a need of securing basic data for promoting the elderly's oral health in the future and of seeking a plane for application in order to improve the elderly's health in the aging society. Therefore there is a need of securing and seeking elderly's health program which is considered the aging society's characteristics to improve the elderly's health promotion.