• Journal of the korean academy of Pediatric Dentistry
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• v.31 no.4
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• pp.569-578
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• 2004

The purpose of this study was to clarify the palatal arch length, width and height in the primary and permanent dentition. Samples were consisted of normal occlusions both in the primary dentition(50 males and 50 females) and in the permanent dentition(50 males and 50 females). With their upper plaster casts were used and through 3-dimensional laser scanning(3D Scanner, DS4060, LDI, U.S.A.), cloud data, polygonization, section curve and loft surface, fit and horizontal plane were based to measure the palatal arch length, width and height(Surfacer 10.0, Imageware, U.S.A.). T-tests were applied for the statistical analyze of the data. The results were as follows : 1. In the measurement values, the values of the male were higher than those of the female except primary anterior palatal height. There were not only statistically significant differences in anterior palatal width(p<0.05) and posterior palatal width(p<0.01) in primary dentition but palatal width(p<0.05), anterior palatal length(p<0.01), middle and posterior palatal length(p<0.05) in permanent dentition between male and female. 2. In the indices of palate, there were statistically significant differences in height-length index(p<0.05) and width-length index(p<0.01) between male and female in primary dentition. In permanent dentition, there was statistically difference between male and female. 3. In the measurement values, posterior palatal width was increased most greatly. Posterior palatal height, anterior palatal width and anterior palatal length were followed by descending order. On the other hand, anterior palatal height and posterior palatal length were decreased. 4. In the indices of palate, the height-length index, the width-length index and posterior height-width index were increased, but the others were decreased.

• The Journal of Korean Academy of Prosthodontics
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• v.46 no.4
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• pp.420-430
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• 2008

Statement of problem & Purpose: Articulators are very important for education and overall clinical situation in the field of prosthodontics, however preexisting articulators are designed and built based on maxillofacial structures and mean values of mandibular movement of Western people. Purpose of this research is to find out a adequate basis for applicating these articulators, presently used for clinical education, for Korean. Material and methods: 59 Korean adults (41 males, 18 females), aged between 24 to 41, where selected for this study. Two pairs of both maxillary and mandibular models were made for each examinee. These models where attached to both KaVo PROTARevo 7 and Hanau Modular semiadjustable articulators by using facebow transfer, than sagittal condylar inclination, occlusal plane inclination and position of mandibular on the articulator where measured. Result and conclusion: 1. Mean sagittal condylar inclination for KaVo PROTAR semiadjustable articulator was $33.75^{\circ}$(standard deviation $12.46^{\circ}$) meanwhile Hanau Modular semiadjustable articulator showed $40.72^{\circ}$(standard deviation $12.09^{\circ}$) for mean sagittal condylar inclination. 2. Mean occlusal plane inclination for KaVo PROTAR semiadjustable articulator was $-2.76{\circ}$(standard deviation $3.63^{\circ}$) meanwhile Hanau Modular semiadjustable articulator showed $11.87^{\circ}$ (standard deviation $3.63^{\circ}$) for mean occlusal plane inclination. 3. On the average center of the mandibular dentition were in the range of 5 to 7 mm of the central position of the articulator. Both anterior and posterior dentition were positioned at the center of the articulator vernacularly for KaVo PROTAR semiadjustable articulators, meantime for Hanau Modular semiadjustable articulator, anterior dentition was positioned 5 mm downwards and 3mm upwards for posterior dentition from vertically central position of the articulator.

• The korean journal of orthodontics
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• v.29 no.4 s.75
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• pp.445-456
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• 1999

As a result of increased education and communication, the field of orthodontics has recently been expanded to include a greater number of adult treatment procedures. With this increased demand for adult orthodontic treatment, a problem that frequently arises is the placement of appliances on teeth restored with porcelain. But conventional acid-etching is ineffective in the preparation of porcelain surface for mechanical retention of orthodontic attachments. Also, it is possible to damage on porcelain. The purpose of this study was to evaluate the effect of composite bonding materials and the porcelain surface treatment methods on shear bond strength, and to observe the porcelain fracture rates. To accomplish this purpose, this study was carried out with feldsphatic porcelain, Ceram II. Porcelain surface treatment methods were divided into intact glazed porcelain which had not treatment and surface roughening. Surface roughening by etching with Hydroluoric acid(HF), sandblasting with Microetcher II and compound treatment with etching and sandblasting. Bonding materials were Ortho-two and Transbond. All porcelain specimens were applicated with porcelain primer. 1. In comparision according to porcelain surface treatment, surface roughening groups by HF etching and sandblasting had higher shear bond than intact group. No significant difference was found in Transbond group. 2. Ortho-two group had the higher shear bond strength than that of Transbond group in B:.u etching and sandblasting. 3. E(Transbond. Intact)group had the lowest shear bond strength in all experimental group. The bond strength was higher than clinically successful bond strength. 4. Non-treated group had very higher porcelain rates than treated group. 5. This study indicates that porcelain surface-roughening may not be necessary to attachment of orthodontic brackets to porcelain surfaces.

• Journal of dental hygiene science
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• v.5 no.4
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• pp.233-238
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• 2005

The study was intended to investigate elementary schoolers' oral health status according to whether the school have and manage an school oral health clinic or not in order to provide useful information for continuously developing the school oral health clinic 1,163 children in Hwasan elementary school in Hwasung city and 485 children in S elementary school in the same locality were selected as the experimental group and the control group, respectively, and orally examined from May 1st to 30th, 2004. The findings from the oral examination were as follows. 1. DMF rate was higher in the higher grades in both the groups. The rate was lower in the experimental group with 45.1% of the children than in the control group with 65.3% of the children. 2. DMFT rate also were higher as the grades were higher in both the groups. The ratio was lower in the experimental group with 30.4% of the children than in the control group with 44.6% of the children. 3. DMFT index was 1.0 in number in the experimental group and 1.6 in the control group. Index increase from the 1st grade to the sixth grade was also more positive in the experimental group. 4. DT rate was a little higher in the experimental group in the first graders, but comparatively decreased to the grades while increased in the control group. In the sixth graders, the rate was 42.4% in the experimental group and 87.7% in the control group, the former was less than the latter by about 50% point. 5. FT rate was a little higher in the control group for the first graders but increased in the experimental group to the grades. The rate in the sixth graders was higher by more than double in the experimental group. Based on the above findings, the region of the study had better oral health statistics than in other regions. The operation of school oral health clinics that provide dental health care to children at the right time seems to contribute to enhancing their dental health status by preventing against dental diseases and changing their relevant knowledge, attitude and behaviors. In the future, more school oral health clinics should gradually be prepared to push ahead with a sustained, extensive dental health project geared toward school-aged children. To make it happen, dental hygienists who are professional medical personnels should be taken advantage of, and in order to beef up the efficiency of preventive measures and oral health education, the best dental health care services should be offered by harnessing dental hygienists and dentists who work at public dental clinics run by local governments.

• The Journal of Korean Academy of Prosthodontics
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• v.32 no.1
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• pp.120-147
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• 1994

This study was performed for the purpose of evaluating the stress distribution around threaded type implants, cylindrical type implants and teeth connected with rigid or non-rigid connector. The stress distribution around the surrounding bone was analyzed by three-dimensional photoelastic method. Twelve mandibular photoelastic epoxy resin models and a circular polariscope were used to record the isochromatic fringes. After the stress distribution around the implant and tooth was observed, the results were as follows ; 1. In threaded type implants, stress concentrated patterns were observed at the neck either vertical or 25 degree lateral force. 2. The stress concentrated patterns were observed at the tooth apical portion and neck portions of the implant and tooth when a threaded implant was connected with the tooth by either a rigid or non-rigid connector. More force was generated at the tooth neck portion by a rigid connector and more force at the implant neck portion by a non-rigid connector. 3. The stress concentrated patterns were observed at the apical portion of the implant and tooth when a cylindrical type ,implant was connected with the tooth either by a rigid or non-rigid connector. More force was generated at the tooth apical portion by a rigid connector and more force at the neck portion of the tooth and implant by a non-rigid connector. 4. The stress around the tooth was more equally distributed in a threaded type implant than in a cylindrical implant when the tooth was connected with either a rigid or non-rigid connector. 5. The stress around a threaded type implant was progressively more equally distributed in the following order : 1) when used a single implant, 2) a non-rigid connection with the implant and tooth, 3) a rigid connection with the implant and tooth, 4) a rigid connection with two implant fixtures.

• Journal of dental hygiene science
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• v.14 no.1
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• pp.67-73
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• 2014

This study analyzed 548 pieces of these, which were reported in the Journal of Dental Hygiene Science of having been published from 2001 to Vol. 12, No. 6 in 2012. In conclusion, as for analysis of research design, first, it was the largest in cross sectional research. Second, the research subjects of survey theses were higher in order of dental hygienist and dental hygiene student. Third, number of thesis authors was the largest in order of two persons and three persons. Fourth, statistical method was in order of descriptive statistics, t-test, and ANOVA. Research theme was in order of dental health behavioral science and clinical dental hygiene. Fifth, as for research-expense benefit, only 17.7% was supported research funds. As a result of this study, there should be a research on thesis of diverse designs in the future. There is a need of being performed actively a research on alienated classer or special subjects as well as a research on activity related to dental hygiene.

• Journal of Technologic Dentistry
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• v.28 no.1
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• pp.121-142
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• 2006

Collecting materials for study on teaching efficiency and satisfaction of clinical training, it changes. Dental technology's educational procedure to many ways of a prospect. In a circumstance that needed higher level of education, this study is aimed on realizing an importance of clinical training through the various materials that previously carried out and offering basic knowledge to take better clinical training for the students. Study results below 1. This Investigation conducted on 123 of sophomores(70.3%) and 52 of juniors(29.7%) who have been taken clinical training, and men's proportion(51.45%)is a bit higher than girls(48.6%). The 64% of respondents taken largest proportion were 20 to 24 years old. As 67.9% of respondents attended daytime school and 30.3% of them attended nighttime one, their school time shows a little difference. In a question about relation ship, one answered "Harmonious" took largest proportion by 72.6% during training, and about the degree of satisfaction of campus life who answered "normal" were the most with 59.4%. 2. About the reason choosing dental technology as a major, 41.1% taken the most answered "due to the specialized job", "Getting job easily" was second with 26.9%, and third was "recommended from around" with 18.3%. 50.3% of the respondents answered "normal" about the Satisfaction of their major, student marked in grade "B" most with 51.4% 3. In a investigation result about clinical training statues and preference, most(72.6%) choose place less than 10 for clinical training, and 60.6% of them resided own home. About their commuting time from home to training place, 44% was under 30min, 40% took time 30-60min. It shows students prefer shotter distance in terms of choosing training place. 4. Each part manager took large proportion as a clinical trainer with 33.7%, Training curriculum reform and developing method were most answer as a improvement measure after completing training with 30%. 5. The average of total score about clinical training was 3.15 of 5. In the detailed question, 'satisfaction of clinical training' got 3.38 as a highest score, the lowest score was 2.86 that is about satisfaction of clinical training period. The average score about efficiency of study was 2.86 and in detailed question, 'a Role model' got 3.26 as a highest score and participation of student got 3.05 as a lowest score. 6. The result of T-test to see the difference of the satisfaction according to the general character and clinic training condition between teaching efficiency is that the degree of satisfaction of clinical training showed statistical significance only in the degree of satisfaction of campus life(p<0.05), and teaching efficiency has a statistical significance with their age, grade, and satisfaction of campus life (p<0.05). 7. The relation between of teaching efficiency of clinical training and satisfaction of clinical training of dental technologic student has a statistical meaning in significance leveler 0.01. Now, therefore we suggest following based on these result. 1. To elevate satisfaction of clinical training, it agentry needs development of consistent clinical training curriculum. 2. To grasp the satisfaction and requirement, in needs to measure anxiousness and satisfactory degree after completing training 3. To train efficiently and evaluate efficiency over the teaching activities, it needs to develop measuring tools for teaching efficiency in terms of teacher's important rules in a clinical training. 4. Strengthen the relations with the study developing and managing curriculum gathering theoretical knowledge and practice. And make an effort to apply to their students. 5. Let the trainee take a class setting a belief, sense of value, function and obtain behavior by making the students comfort over clinical training as increasing teaching efficiency.

• Journal of Technologic Dentistry
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• v.28 no.1
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• pp.177-198
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• 2006

This study purposed to offer basic data for safety education of the dental laboratory technology after the investigation of how much the students in the dept. of dental laboratory technology are aware of the danger of each instrument, equipment or laboratory procedure that they use during laboratory and how much they demand safety education for this. The objects for this study were 423 students who were in the dept. of dental laboratory technology. In this regard, four colleges which have the dept. of dental laboratory technology were randomly selected to do a questionnaire survey. SPSS 12.0 was used to analyze the collected data. The results were as follows: As for satisfaction with their major, the respondents answered Satisfied (59.1%), Average (35.5%) and Dissatisfied (5.4%). In terms of the production process of a partial denture, they considered casting, polishing the casting body, polishing denture and burn out were most dangerous in order. As for the production process of a full denture, what they regarded as the most dangerous in order was polishing denture, deflasking and wax wash. Regarding the laboratory procedures of porcelain material, casting, trimming casting body, polishing porcelain material and burn out were the most dangerous procedures that they perceived. With regard to materials for use, alcohol, polishing, metal and wire were the most dangerous ones they thought. As for the handling characteristics of each material, small towns showed a higher demand for safety of the handling characteristics of alcohol. In terms of school year and sex, juniors and girls had higher scores in the demand for safety of the handling characteristics of acid. Regarding the handling characteristics of each equipment and instrument, all of small towns, juniors and girls showed the highest demand for safety of the handling characteristics of alcohol lamps. With regard to scores in the demand for safety of other characteristics, all of small towns, juniors and girls had the highest demand for safety of emergency treatment. Concerning the demand for safety education by the completion of safety education, in terms of each material, highest was the demand for safety of acid from the group which completed safety education. In regard to equipments and instruments, when it came to the demand for safety of the handling characteristics of casting machine, the educated group's demand for safety of acid was higher. Regarding other characteristics, the group which was not educated gained higher scores in the demand for safety of emergency treatment. 11. In all areas(materials, machines and others), small towns, girls and juniors showed higher scores in the demand for safety. Based on the above results, it was found that when students conduct the laboratory of dental technology, they would think that many materials, instruments or equipments for use are very dangerous. However, safety education was not fully given to them. Regarding the scores in the damned for safety education, the highest was 4.16 and the lowest was 3.43, which suggests that the scores were generally very high. In this regard, it is necessary to continue delivering a systematic safety education of materials, equipments or instruments used during the laboratory of dental technology. Therefore, through the analysis of each material, instruments or facility used in every laboratory and each process, safety accident types and accident risk factors should be investigated to develop educational materials for this. Moreover, it is required to open safety education as a single course of study or insert safety contents of all materials and machines into the class of dental laboratory instrument or dental materials for the purpose of a systematic and thorough safety education to prevent a safety accident during laboratory.

• Journal of the korean academy of Pediatric Dentistry
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• v.33 no.3
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• pp.388-400
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• 2006

The time 18 months after birth is very important for the prevention of early childhood caries because this time is proper to assure the completion of weaning and to perform the diet counseling, and caries process is initiated or actively aggravated under the total influence of feeding pattern from this period. For the purpose of examining the infection status of Streptococcus mutans and Lactobacillus of 18 month old infants and their mothers, and analyzing the correlation between infection status versus various caries-risk factors, this study was performed on the 60 infants of 18 months old and their mothers through the microbiological screening of saliva samples and direct questionnaire to mothers about the caries risk factors. And the results were as follows, 1. The higher the mother's infection level of S. muntans, the higher the infant's infection level and transmission rate. 2. Compared with non-caries group, higher infection level of S. mutans in both infants and mothers and transmission rate were revealed in caries group. 3. The higher the infant's infection level of S. mutans, the higher the caries prevalence and deft values, the less the monthly income of the parents, the longer the period of breast feeding, and the higher the consumption rate of sugared snacks. 4. Most of Lactobacillus infected infants were revealed to be infected also with S. mutans and to have caries. 5. The higher deft value, less parents' monthly income, more frequent daily nursing and more irregular snacking patterns were found among Lactobacillus infected group compared with not-infected group.

• Journal of dental hygiene science
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• v.7 no.3
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• pp.179-185
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• 2007

The purpose of this study targeted on high school student in the department of liberal arts, industry in Daegu metropolitan city, is to get basic data necessary for the development of dental educational program, to discern prevention and treatment of temporomandibular joint disorder by observing the situation temporomandibular joint disorder and contribution element, of relationship of school life stress The results are as follows.: 1. The percentage of occurring temporomandibular joint disorder in the high school resulted in a joint noise at 61.8% and joint dislocation 6.9%, sharp pain 47.5% at time of chewing. 29.8% at the time of the non-chewing, lockjaw 11.3%, a headache appeared at 40.4%.2. In the contribution factor of occurring temporomandibular joint disorder, the cause of joint noise was the clench one's teeth, lip and cheek clench, For the pain at the time of chewing clench one's teeth, one side chewing, over-chewing, lip clench, sideways sleeping showed the difference. (P < 0.01) For the pain at the time of non-chewing, clench one's teeth, bruxism, one side chewing, lip and cheek clench were similar, and for the lockjaw, clench one's teeth, bruxism, sideways sleeping showed the difference. The plum evil thing period at time of the fault writing that statistically showed the difference. For the headache, the contribution factors were the all bad habits mentioned above excluding one side sleeping.(P < 0.01, P < 0.05). 3. The rate of experiencing temporomandibular joint disorder by oral and maxillofacia was 13.4% in industrial department, and 19.6% in liberal arts. And for the factor of wound was that exercise 26.8%, others 24.4%, fall-down 19.5%. And for the industrial, exercise 44.4%, fall-down 22.2%, others 14.9%. The treatment experience appeared at 5.0% in industrial department, 2.9% in liberal arts. And for the medical institutions, liberal arts were dental clinic 50%, orthopedics 50%, and the industrial department orthopedics 40%, oriental medicine clinic 30%, dental clinic 30%. 4. In case of temporomandibular joint disorder, there were no difference by grades or educational background. And at the time of chewing or non-chewing showed similar difference.(P < 0.01). 5. Compared to stress in the high school, it generally showed higher in liberal arts than in industrial department due to school record. Its scope was $3.75{\pm}1.14$ in liberal arts, $3.01{\pm}1.23$ in industrial department. 6. The school record, school life, stress problems by teachers, chewing/non-chewing pain of temporomandibular joint disorder, joint noise had a similar correlation.(P < 0.01, < 0.05).