• Journal of Dental Rehabilitation and Applied Science
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• v.40 no.3
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• pp.125-134
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• 2024

Purpose: The aim of this study was to determine which scan range would provide the most accurate bite registration when performing a bite scan after scanning an upper and lower arch using an intraoral scanner. Materials and Methods: The occlusal contact points were recorded using articulating paper for 30 adults, and the results of various ranges of buccal bite scan were compared based on this. Buccal bite scan of 5 ranges (1st premolar to 2nd premolar, 1st premolar to 1st molar, 1st premolar to 2nd molar, 2nd premolar to 1st molar, and canines to another side canine of the maxillary teeth) was performed, and then the buccal bite scan file was used in a CAD program to confirm the occlusal area in the scan file through data editing and alignment, leaving the buccal area of the teeth. Afterwards, the degree of agreement between the occlusal contact points obtained from the articulating paper and the occlusal area obtained from the scan file was compared, and statistical analysis was performed using the homoscedastic T-test (α = 0.05). Results: The alignment success and alignment failure rates among each group were 77.23% and 40.85% in canine to another side canine, 68.23% and 28.89% in bilateral first premolar to second premolar, 63.76% and 29.97% in bilateral first premolar to first molar, 61.31% and 32.04% in bilateral first premolar to second molar, 67.55% and 27.46% in second premolar to first molar. The results of the anterior scan of both canines showed higher alignment success and failure rates compared to the scan results of all maxillary posterior teeth. In the alignment success rate, statistical significance was not found depending on the scan range of the posterior teeth, but in comparing the results of the posterior teeth and both canines, statistical significance was observed except for the scan results of the second premolar to the first molar. There was no statistical significance in the alignment failure rate depending on the scan range of the posterior teeth, and statistical significance was observed in the results of the posterior teeth and both canines. Conclusion: When taking a buccal bite scan, in the case of scanning the anterior teeth, more occlusal area appear than when scanning the posterior teeth, and in the case of scanning the posterior teeth, there is no significant difference in the bite registration depending on the scan range.

• The Journal of Korean Academy of Prosthodontics
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• v.46 no.4
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• pp.381-395
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• 2008

Purpoose: For decades dental implants have been used widely in the field of prosthetic dentistry. However there is confusion when establishing treatment plans in cases where some teeth are remained but an insufficient number of implants can be used due to limited anatomical status and ecomomical problems. Many clinicians have tried to connect natural teeth and implants, and it still has controversy. But, there have been few studies on mechanical analysis of connecting natural teeth and implants with konus telescopic removable partial dentures. The purpose of this study was to analyze the stress distribution of prosthesis, abutment and alveolar bone when teeth and implants were connected with the konus telescopic denture, by means of 3-dimensional finite element analysis. Material and methods: The assumption of this study was that there were 2 mandibular canine (11 mm in length, 4 mm in diameter) and 2 implants(10 mm in length, 4 mm in diameter) which are located in the second premolar region. The mandible, teeth, implants, abutments, and connectors are modeled, and analyzed with the commercial software, ANSYS Version 8.1(Swanson, Inc., USA). The control group used implants instead of natural teeth. 21038 elements, 23544 nodes were used in experimental group and 107595 elements, 21963 nodes were used in control group, Stress distribution was evaluated under 150 N vertical load on 3 experimental conditions - between teeth and implants (Load case 1), posterior to implants (Load case 2), between natural teeth (Load case 3). Results: 1. In all load cases, higher von mises stress value was observed in the experimental group. 2. Maximum von miss stress observed in all load cases and all locations were as follows ; a. 929.44 Mpa in the experimental group, 640.044 Mpa in the control group in outer crown and connector - The experimental group showed 1.45 times high value compared with the control group. b. 145,051 Mpa in the experimental group, 142.338 Mpa in the control group in abutment - The experimental group showed 1.02times high value compared with the control group. c. 32.489 Mpa in the experimental group, 25.765 Mpa in the control group in alveolar bone - The experimental group showed 1.26times higher value compared with the control group. 3. All maximum von mises stress was observed in load case 2, and maxim von mises stress in alveolar bone was 32.489 Mpa at which implant failure cannot occur. 4. If maximum von mises stress is compared between two groups, the value of the experimental group is 1.02 times higher than the control group in abutment, 1.26 times higher than the control group in alveolar bone. Conclusion: If natural teeth and implants are connected with the konus telescopic denture, maximum stress will be similar in abutment, 1.26 times higher in alveolar bone than the control group. With this result, there may be possible to make to avoid konus telescopic dentures where natural teeth and implants exist together.

• The korean journal of orthodontics
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• v.33 no.3 s.98
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• pp.211-222
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• 2003

The purpose of this study was to determine whether there is an association between disk displacement of the Temporomandibular Joint (TMJ) and dentofacial asymmetry In orthodontic patients. The subjects consisted of 60 female orthodontic patients between the ages of 18 and 38 years (mean age 23.3 years) who had visited the Department of Orthodontics at Seoul National University Dental Hospital from January 2000 to April 2002. On the basis of magnetic resonance imaging (MRI) of their bilateral TMJs, the subjects were divided Into four groups'. bilateral normal group (twenty-one persons); disk displacement of right TMJ group (six persons); disk displacement of left TMJ group (nine persons); and disk displacement of both TMJs group (twenty-four persons) Postero-anterior (PA) cephalograms and diagnostic models which had been taken before orthodontic treatment were measured. In the linear measurements, a line connecting the right and left Latero-Orbitale (Lo) represented the horizontal reference line (H). The vertical reference line (V) was constructed as a line bisecting and running perpendicular to H. One-way analysis of variance (ANOVA) was used to test whether the mean values of measurements between groups were significantly different. In addition, Bonferronil's multiple comparison test was performed at a level of 0.05. The results were as follows; 1 In the diagnostic model analysis, the overjet, nght molar relationship, and left molar relationship were significantly different among the four groups. 2. In the PA cephalometric analysis, differences in the right and left vertical position of the lower first molar and Ag were significantly dissimilar among the four groups. 3. If the disk displacement of TMJ was present on one side, the ipsilateral ramus was shorter, resulting in asymmetry in the vertical position of Ag. This study indicated that dentofacial asymmetry might be related to the disk displacement of TMJ.

• Journal of dental hygiene science
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• v.11 no.4
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• pp.339-344
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• 2011

Matrix metalloproteinase(MMP)-9 is considered important in tissue destruction in periodontitis. The aim of this study was to investigate the influence of smoking on MMP-9 in the gingival crevicular fluid(GCF). GCF samples in upper incisors area from 332 male subjects were collected after the informed consent. The dental examination included the assessment of oral hygiene, gingival inflammation and probing pocket depth. A quantitative assessment of MMP-9 levels in GCF was performed utilizing and immunological procedure. The mean MMP-9 concentrations found in GCF of smokers(30.86 ng/ml) and quit-smokers(29.82 ng/ml) differed from non-smokers(11.33 ng/ml), adjusted by age, gingival index and Community periodontal index(p<0.001). Smoking seems to influence MMP-9 in GCF regardless of gingival inflammation and age. It means smoking can destruct the periodontal tissue for itself.

• Journal of dental hygiene science
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• v.12 no.1
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• pp.71-77
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• 2012

Sex Hormones exert significant influence in body physiology throughout life. Some reports suggested increased sex hormone levels correlate with an increased prevalence of gingivitis. The objectives of this pilot study are to(1) address the link between menstrual cycle and MMP-9, MMP-8, IL-$1{\beta}$ of gingival crevicular fluid during 4 weeks and (2) discuss the major biomarker of periodontal status. 7 female and 3 male volunteer who didn't have smoking habit, medical and dental disease after informed consent, were seen twice a week for 4 weeks. GCF samples were collected and GCF levels of MMP-9, MMP-8, IL-$1{\beta}$ were measured by enzyme-linked immunosorbent assay. The GCF levels of MMP-9, MMP-8, IL-$1{\beta}$ had fluctuation according to menstrual cycle, but the changes of those were not significant by Friedman matched samples test. There is no difference between female and male subjects by Mann-Whitney U test. The correlation of MMP-8, MMP-9 and IL-$1{\beta}$ showed strong by Spearman correlation(0.644-0.945). This study confirms menstrual cycle doesn't influence the periodontium of healthy female subjects.

• Journal of dental hygiene science
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• v.8 no.2
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• pp.97-101
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• 2008

This study was aimed to provide basic data which are fairly useful to improve satisfaction level of patients by analyzing factors related to each functional satisfactions of dental implant treatment. The subjects of this study were 120 patients who received implant treatment and analyzed with t-test, one-way ANOVA and pearson's correlation. The results of this study were as follows. 1. Differences of each functional satisfaction according to general characteristics was not reveal statistically significant. 2. A group to got periodic scaling and tooth brushed four or more times a day showed the highest satisfaction of social and esthetic function(p < .05). 3. A group to implantation in premolar area showed the highest satisfaction of masticatory function and a group to implantation in incisor to be high in satisfaction of social and esthetic function, but the differences were not statistically significant 4. A group to got implant treatment at a dental hospital showed the highest satisfaction of both social and esthetic function, and at a general hospital were found lowest(p < .05). 5. Masticatory function, social function, esthetic function, and overall satisfaction were found to be in a positive correlations, and especially, the correlation coefficient between the overall satisfaction and social function was found to be highest(p < .01).

• Journal of the korean academy of Pediatric Dentistry
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• v.27 no.1
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• pp.113-121
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• 2000

This study was aimed to provide an epidemiologic study so that we could accommadate their orthodontic needs adequately and to obtain the reliable quantitative information regarding the characteristics of orthodontic patients who visited the Department of pediatric dentistry, Chonnam National University Hospital from 1986 to 1999, October. The results were as follows. 1 The total number of orthodontic patients were 1,381(male 658, female 723) and the number of annual patients showed irregular trend and the number of male were slightly higher than that of female. 2. According to the investigation made by age group, the group of under 5 years, 6 to 7, 8 to 9, 10 to 11, 12 to 13 and above 14 years showed 8.4%, 29.6%, 34.3%, 21.2%, 5.7% and 0.8%, respectively. 3. The patients corresponding to primary dentition were 15.7% of total patients and mesial step, distal step and flush terminal plane were 83%, 4.6% and 12.4% respectively. By the way 82% of mesial step had anterior crossbite at the same time. 4. The patients corresponding to Angle classification were 84.3% of total patients and Class I malocclusion, Class II div. 1, Class II div. 2 and Class III was 34.7%, 34.6%, 2.1% and 28.6%, respectively.

• The Journal of Korean Academy of Prosthodontics
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• v.41 no.5
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• pp.640-655
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• 2003

Statement of problem : The beauty has a little different meaning according to a time, culture, and nation. Purpose : This study was undertaken to determine the Korean perception of the altered upper anterior dental esthetics including the lack of symmetry, the midline deviation, the gingival exposure, the inclination of incisal plane, the type of incisal plane, and the type of gingival line. Material and Method : 670 subjects were participated in this survey. A questionnaire accompanied by 12 sets of computer-manipulated images using 3D MAX 4.2 software was used to record the ranking of the geometric preference related to the anterior esthetic discrepancies in three or four degrees of alteration. The statistical significance of the differences between the groups was determined by a one-way ANOVA and a t-test. Results : The results obtained were as follows: 1) The Korean perception of the anterior dental esthetics according to the subjects' occupation, sex, and age was most affected by occupation. 2) The masked image emphasizing the dentition and lips appeared stranger than the non-masked image at the same alteration. 3) The lack of symmetry, which was expressed as a unilateral discoloration of the tooth, showed incongruity in any teeth of the anterior dentition. The incongruity was more severe as the degree occurred closer to the midline. 4) The deviation of midline was showed more severe strangeness as the degree of deviation increased. However, more than half of the subjects did not perceive a deviation of 5mm. 5) During smiling, the exposure of the upper gingiva showed more severe incongruity as the degree of gingival exposure increased. 77% of the subjects perceived strangeness at the gingival exposure of 4.5mm. 6) The inclination of the incisal plane appeared stranger as the degree of inclination increased. 62% of subjects perceived strangeness at the $7.5^{\circ}$ inclination of the incisal plane. 7) The type of incisal plane showed increasing strangeness in the order of convex/downward, straight/horizontal, and concave/upward. 80% of subjects perceived strangeness at concave/upward. 8) The type of gingival line was showed increasing incongruity in the order of the same, a little above, and a little under the zenith of the lateral incisor to the line joining the zenith of the central incisor and the canine. However, less than half the subjects did not perceive strangeness at any alteration of the gingival line. Conclusion : The Korean perception of the upper anterior dental esthetics was different to the westerner's perception in the some respects.

• Journal of the korean academy of Pediatric Dentistry
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• v.37 no.4
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• pp.512-518
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• 2010

The impaction of the maxillary permanent incisor is a common clinical problem and is mostly found at the "labial to the alveolar process." Surgical exposure and orthodontic treatment with fixed orthodontic appliances can be considered if normal eruption of the labillay impacted tooth is not expected. Surgical exposure of the impacted tooth, that is usually under the attached gingiva or is surrounded by alveolar bone through gingivectomy and removal of alveolar bone, may give a rise to complications such as diminution in the width of the attached gingiva, inflammation of the gingiva, and the loss of marginal alveolar bone. Therefore, closed eruption technique, which includes surgical exposure and orthodontic treatment with fixed orthodontic appliances followed by repositioning of surgical flap, is preferred. However, apically repositioned flap of the impacted tooth, which is beneath the movable submucosal area or is above the alveolar crestal area, can prevent unwanted exposures and facilitate successful tooth eruption. In this report, we described esthetic results of three patients with unerupted maxillary permanent incisor who were performed with an apically positioned flap without the loss of attached gingiva.

• The Journal of the Korean bone and joint tumor society
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• v.1 no.1
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• pp.68-76
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• 1995

To evaluate the clinical result of surgical treatment of malignant tumors in shoulder girdle, nine patients who were treated in Department of Orthopedics, Catholic University Medical College between January 1991 and December 1993, were evaluated. There were 5 men, 4 women. The mean age at operation was 47 years(range from 22 to 64 years). Of 9 patiens, 2 were soft tissue tumors(1 MFH, 1 dermatofibrosarcoma protuberance); one was treated with forequarter amputation, and the other with wide excision, Seven were bone tumor(2 chondrosarcoma, 1 osteosarcoma, 1 MFH, 1 plasmacytoma, 1 thyroid carcinoma metastasis, 1 malignant schwannoma); one patient was treated with segmental excision of proximal humerus, 4 with Malawer type I-A resection and arthroplasty or arthrodesis, 1 with Malawer type V-B resection and arthrodesis. Five patients received adjuvant chemotherapy, with or without local radiation therapy, and one patient received radiation therapy alone. All patients have survived now, but I had local recurrence. Functional results of arthrodesis and arthroplasty were similar.