• Korean journal of food and cookery science
• /
• v.18 no.6
• /
• pp.704-715
• /
• 2002

This study intended to compare dietary and snack habits of primary students in the schools providing and non-providing lunch to clarify the correlation between those conditions and the occurrence of dental caries. Furthermore, this study also focused on evaluating educational effects by providing children with nutritional education program. 1. As a result of dietary habit analysis, it was found that children from the school providing lunch were better in terms of breakfast regularity, eating speed. optimum amount of intake, and meal time regularity than those from the school non-providing lunch. In particular, it was noted that children from the school providing lunch took a little more meat, fish, seaweed and milk or dairy products than those from school non-providing lunch. Thus, it could be assumed hat children provided with lunch have more reasonable dietary habit than those without lunch program. In general, it was found that there was a slight positive change in children's dietary habit after nutritional instruction than before, suggesting that the nutritional education had effects on improving their dietary habit. 2. It was found that primary students often took snacks causing dental caries such as caramel, chocolate, sweets and biscuits, and children from the school providing lunch were more willing to reduce those snacks upon recognizing the causes of dental caries than those from the school non-providing lunch. For the children who chewed gum with physical cleansing effects, it was shown that the highest frequency wat twice or three times a week. Moreover, the ratio of children who took snacks following dinner which might affect their dental caries and the ratio of children who selected snacks because of TV commercial were both reduced after nutritional education. Also the consumption of detergent foods like vegetable, fruit, protein. seaweed. milk or dietary products after nutritional education was increased. 3. It was found that children from the school providing lunch took more often all food groups except for food group IV affecting dental caries than those from the school non-providing lunch. The average number of consuming foods which cause dental caries was 5.04 times per person a day, and most of those were rather taken by liquid than solid food. The average eating times of rinsing foods which kill the bacteria on the surface of teeth and prevent from dental caries, was 9.33 for a person a day, which was a little higher than recommended time. Exposed time for dental caries for a person a day was 100.9 min, of which liquid dental caries was 56.2 min and solid dental caries was 44.6 min, suggesting that liquid food had a high potential to cause dental caries.

• The korean journal of orthodontics
• /
• v.29 no.4 s.75
• /
• pp.445-456
• /
• 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 Rehabilitation and Applied Science
• /
• v.26 no.3
• /
• pp.221-239
• /
• 2010

Bone loss may occur depending on the loading conditions. careful treatment planning and prosthetic procedures are very important factors for the proper distribution of stress. Evaluate the stress distributions according to numbers and location of implants in three-unit fixed partial dentures. A mandible missing the right second premolar, first molar and second molar was modeled. Using the CT data. we modeled a mandible with a width of 15mm, a height of 20mm and a length of 30mm, 2mm-thickness cortical bone covering cancellous bone mallow. An internal type implant and A solid type abutment was used. A model with 3 implants placed in a straight line, offset 1.5 mm buccally, offset 1.5 mm lingually and another model with 3 implants offset in the opposite way were prepared. And models with 2 implants were both end support models, a mesial cantilever model and a distal cantilever model. Three types of loading was applied; a case where 155 N was applied solely on the second premolar, a case where 206 N was applied solely on the second molar and a case where 155 N was applied on the first premolar and 206 N was applied on the first and second molar. For all the cases, inclined loads of 30 degrees were applied on the buccal cusps and vertical loads were applied on the central fossas of the teeth. Finite element analysis was carried out for each case to find out the stress distribution on bones and implants. This study has shown that prostheses with more implants caused lower stress on bones and implants, no matter what kind of load was applied. Furthermore, it was found out that inclined loads applied on implants had worse effects than vertical loads. Therefore, it is believed that these results should be considered when placing implants in the future.

• Journal of Astronomy and Space Sciences
• /
• v.25 no.2
• /
• pp.157-166
• /
• 2008

We have investigated a statistical relationship between sawtooth oscillations and geomagnetic storms during 2000-2004. First of all we selected a total of 154 geomagnetic storms based on the Dst index, and distinguished between different drivers such as Coronal Mass Ejection (CME) and Co-rotating Interaction Region (CIR). Also, we identified a total of 48 sawtooth oscillation events based on geosynchronous energetic particle data for the same 2000-2004 period. We found that out of the 154 storms identified, 47 storms indicated the presence of sawtooth oscillations. Also, all but one sawtooth event identified occurred during a geomagnetic storm interval. It was also found that sawtooth oscillation events occur more frequently for storms driven by CME $({\sim}62%)$ than for storms driven by CIR $({\sim}30%)$. In addition, sawtooth oscillations occurred mainly $({\sim}82%)$ in the main phase of storms for CME-driven storms while they occurred mostly $({\sim}78%)$ during the storm recovery phase for CIR-driven storms. Next we have examined the average characteristics of the Bz component of IMF, and solar wind speed, which were the main components for driving geomagnetic storm. We found that for most of the sawtooth events, the IMF Bz corresponds to -15 to 0 nT and the solar wind speed was in the range of $400{\sim}700km/s$. We found that there was a weak tendency that the number of teeth for a given sawtooth event interval was proportional to the southward IMF Bz magnitude.

• Journal of agricultural medicine and community health
• /
• v.35 no.1
• /
• pp.56-66
• /
• 2010

Objectives: The study aimed to explore dental status and denture satisfaction in some rural elderly people. Methods: A total of 546 participants aged over 65 years was surveyed cross-sectionally. The subjects were surveyed with regard to their denture satisfaction by a structured questionnaire. The Wilcoxon or Kruskal-Wallis test was used for analysis. Results: As for respondents' satisfaction for dentures by the Likert scale of 5 score, aesthetic satisfaction (3.73) was highest, followed by general satisfaction (3.56) and masticatory functions satisfaction (3.45). In addition, the educational level, occupation, monthly income, the number of remaining teeth, use of denture variables have statistically significant difference in the denture satisfaction of those elderly people interviewed. Conclusions: The results showed that denture satisfaction in some rural elderly people was different in each categories. Consequently, providing tailor-made oral health education programs for the effective denture management of the elderly people should be needed in order to improve the quality of life of the aged.

• Journal of dental hygiene science
• /
• v.13 no.1
• /
• pp.13-19
• /
• 2013

This study evaluated the change of color and the microhardness according to time-out using the office bleaching with in vitro test after bleaching one time 1 day per week, total three times, for the control group and three times per 1day for the experimental group. $L^*$ was increased in both groups. Group 1 showed a significant increase statistically between before and after tooth whitening (p<0.05). Group 2 showed a significant increase statistically between before and after tooth whitening (p<0.05). ${\Delta}E^*$ was huge in both groups. In group 1, it was great in terms of statistical significance between 1 day and 7 days after tooth whitening (p<0.05). In group 2, it was the greatest between before and 1 day after tooth whitening and was significant statistically as well (p<0.05). Vickers hardness number (VHN) decreased in both groups. In group 1, VHN decreased over time and the difference was significant statistically (p<0.05). In group 2, VHN decreased over time and the difference was significant statistically (p<0.05). Percentage microhardness loss was great in both groups. In group 1, it was the greatest between 1 day and 7 days after the treatment, and it was significant statistically (p<0.05). In group 2, it was the greatest between before and 1 day after the treatment, and it was significant statistically (p<0.05). Put together, the more frequent tooth whitening a day is, the longer the period of tooth whitening when applying the same frequency, the greater color change was, however the microhardness decreased, in regard to the results over time using 15% hydrogen peroxide tooth whitening product for professionals.

• Journal of Oral Medicine and Pain
• /
• v.32 no.1
• /
• pp.9-33
• /
• 2007

In the field of dentistry, there existed relatively few emergency patients or patients who need intensive care and thus had low medical dispute rates. However, these days, there is a general tendency of increased medical disputes. Although many medical disputes are caused by medical accidents of the dentists, because dental assistants are also lawfully involved in practicing dentistry, there is a possibility of medical disputes or medical accidents caused by dental assistants. Therefore, the role of the dental assistants cannot be ignored. This study consists of a survey given to dental hygienists currently working in general hospitals, dental hospitals and private dental clinics. Following is the results of the analysis of 275 respondents' backgrounds, medical disputes rates including patients' complaints, their understanding of medical regulations and their general understanding of overall dental practice and medical disputes. 1. 251 of 274(91.6%) respondents doubted the risk of medical accident and dispute. 2. 81(29.5%) dental hygienist experienced complaint from patients. They have been working in the private dental clinic, the rate of this experience was high. 3. 349 case of 1805(19.3%) the complaints by patients, highest percentage among its category, were those regarding dental fees and poor service. 4. 129 case of 1805(7.1%) patients' complaints, highest percentage among it's subcategory, were those regarding the absence of explanations of precautions or request of agreements before dental treatment. 5. 252 of 267 (94.4%) dental hygienists chart after a scaling treatment. However, only 55(20.7%) dental hygienists chart the fact of explaining the precautions. 6. 6(2.2%) dental hygienists do not inspect patients' medical history, if patients don't mention it. 7. 104 of 274(38.0%) dental hygienists responded to be capable of administering first aid treatment. 8. 115(41.8%) dental hygienists have a first aid kit and equipment. 9. In case of medical dispute, 268(97.8%) dental hygienists respond that, charting plays a big role in resolving the dispute. 10. In case of medical dispute, 272(93.3%) dental hygienists respond that, explanation and agreement before treatment have an important role in settlement of dispute 11. Only 160(58.4%) dental hygienists responded correct answer that the duration of keeping medical records is 10 years. 12. 124(45.3%) respondents thought that it is legal for a dental hygienist to take a panoramic dental X-ray, 71(25.9%) respondents thought that it is legal practice cervical resin treatment by dental hygienist, and 37(13.5%) respondents thought that it is legal extract primary teeth by dental hygienist. 13. 24(18.76%) respondents thought that it doesn't matter to tell patient's state to others 14. 272(99.27%) responded that receiving education for the prevention of medical disputes was needed and of them, 61.0% thought it was urgent. 15. 186(64.2%) has never had classes regarding the prevention of medical disputes while in school and 212(77.4%) has not had the same type of classes after graduating from school. 16. 256(93.4%) responded that there will be even more of an increased number of medical disputes. Among them, 83.3% of respondents though that due to the increased opportunity of acquiring information through the internet and mass media. The study shows that 29.5 percentage of dental hygienists have experienced the medical disputes and complaints and they are lack of recognition of medical regulations and dental hygienist's official duty. So, there is a big potential of the percentage to increase. Therefore, the correct understanding of explaining precautions and requesting agreement before dental treatments and performing them are mandatory. Moreover, classes regarding the prevention and counterplans of medical disputes need to be widely offered.