• Journal of international Conference on Electrical Machines and Systems
• /
• v.2 no.1
• /
• pp.9-15
• /
• 2013

This paper presents a uniform analytical model by energy method and Fourier series expansion to analyze detent force in uneven magnetic field for permanent magnet linear synchronous motor (PMLSM). The model reveals that detent force in long-primary type is mainly influenced by non-ideal distribution of permanent magnet magnetic motive force, while nounified air-gap permeance makes a great impact on detent force of short-primary type. Hence, magnetic field similarity of motor design techniques referring rotary counterpart are adopted. For long-primary type novel method of splitting edge magnets is proposed to reduce end effects force, and optimal widths of edge tooth in short-primary type also verify the effectiveness of magnetic field similarity. The experimental results validate finite element analysis results.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
• /
• v.22 no.1
• /
• pp.87-94
• /
• 1992

The purpose of this study was to evaluate the effect of scatter radiation to dental x-ray film with long time-exposure in the different structures of the tooth, by using pinhole camera. For this study, pinhole camera, skull with tooth, and pocket dosimeter were used. The radiation with 70 and 90kVp and exposure time (minimum: 2.5 min., maximum 10 hrs.) was projected to the film in the pinhole camera. And density of the obtained x-ray film was measured with densitometer. In the intra-oral film taking, the amount of exposure of the scatter radiation affecting the thyroid gland area was measured with the dosimeter at the thyroid gland. The density of radiographs was compared in radiation projected with or without the metal cone of dental machine. The effect of the back scatter radiation to the film was also evaluated when the lead foil was removed. The obtained results were as follows: 1. A pinhole camera was a valuable device for locating the source of x-ray. 2. The scatter radiation affected the dental x-ray film when the radiation source was exposed. more than 5 hours'. In that case, the density of the scatter radiation could be observed visually. 3. The scatter radiation caused by short exposure of dental radiation didn't affect the diagnostic quality of the dental x-ray film. 4. The differences of densities between the tooth and the soft tissue according to exposure time showed 0.16 in 5 hours' exposure & 0.17 in 10 hours' exposure at 70 kVp & 0.12 in 5 hours' exposure & 0.13 in 10 hours' exposure at the 90kVp. 5. The differences of densities between the tooth and the soft tissue according to kVp showed no difference between 5 hours' exposure of tooth at 70 kVp and soft tissue at 90 kVp, but showed 0.05 high density in tooth when 10 hours' exposure at 90 kVp. 6. No difference of density was on radiographs taken with or without dental machine cone. 7. Back scatter radiation was recorded image of radiographs for only 3 min. 8. The amounts of the scatter radiation exposed to the thyroid gland in intraoral film taking were 1.12 mr in upper anterior, 0.55 mr in upper posterior, 2.75 mr in lower anterior, and 1.92 mr in lower posterior teeth.

• Applied Microscopy
• /
• v.38 no.4
• /
• pp.375-382
• /
• 2008

In order to investigate shape of synaptic vesicles of the tooth pulp afferent boutons and their presynaptic endings (p-endings), and the neuroactive substance of the p-endings in the trigeminal nucleus principalis, rat incisor tooth pulp afferents were labeled by the horseradish peroxidase (HRP) and quantitative ultrastructural analysis and postembedding immunogold labeling were performed. Labeled tooth pulp afferent boutons contained clear, spherical synaptic vesicles (diameter: $45{\sim}55\;nm$) and occasionally dense core vesicles(diameter: $80{\sim}120\;nm$). They formed symmetrical synapses with unlabeled axon terminals (p-endings) containing pleomorphic synaptic vesicles. The ratio of short to long diameter (form factor) of synaptic vesicles of pulp afferent boutons was 0.6 to 0.99, whereas that of p-endings was 0.25 to 0.99. In addition, most of the p-endings showed GABA-like immunoreactivity. These results indicate that the shape of synaptic vesicles is quite different between the tooth pulp afferent boutons and p-endings, and the p-endings may contain GABA as a neuroactive substance in the trigeminal nucleus principalis.

• Imaging Science in Dentistry
• /
• v.48 no.3
• /
• pp.191-199
• /
• 2018

Purpose: This study classified alveolar arch forms and evaluated differences in alveolar bone thickness among arch forms in the anterior esthetic region using cone-beam computed tomography (CBCT) images. Materials and Methods: Axial views of 113 CBCT images were assessed at the level of 3 mm below the cementoenamel junction (CEJ) of the right and left canines. The root center points of teeth in the anterior esthetic region were used as reference points. Arch forms were classified according to their transverse dimensions and the intercanine width-to-depth ratio. The buccolingual alveolar bone thickness of each tooth was measured at 3 mm below the CEJ and at the mid-root level. Differences in the mean thicknesses among arch forms were analyzed. Results: Anterior maxillary arches could be classified as long narrow, short medium, long medium, and long wide arches. Significant differences in buccolingual alveolar bone thickness among the arch groups were found at both levels. The long wide arches presented the greatest bone thickness, followed by the long medium arches, while the long narrow and short medium arches were the thinnest. Conclusion: Arch forms were classified as long narrow, short medium, long medium, and long wide. The buccolingual alveolar bone thickness exhibited significant differences among the arch forms.

• The Journal of Korea Assosiation for Disability and Oral Health
• /
• v.11 no.1
• /
• pp.5-8
• /
• 2015

Neuroblastoma is a common malignant tumor of the sympathetic nervous system in childhood, arises from embryonic neural crest cells. The period of tooth development is matched with peak times of diagnosis and treatment of neuroblastoma. The intensive multimodality treatment including radiotherapy and chemotherapy is used in patients with neuroblastoma has been shown to have late adverse effects and disturbances in dental development like tooth agenesis, microdontia, enamel hypoplasia and short roots. A 8-year old girl had been on medication and radiotherapy for neuroblastoma since she was 15 months old at Department Pediatrics, Chonnam National University Hospital. Oligodontia, microdontia, and short root formation was notable in clinical and radiological examination. Mobility of lower permanent incisor was detected and measured at about degree 2. Resin wire splint using mini-screw implantation on buccal alveolar bone was conducted for maintenance of mandibular incisors and alveolar bone. Excessive mobility has been eliminated and maintained well so far. Further treatment is planned for re-evaluation of mobility, preventing dental caries and regular oral hygiene management. Although we need further evaluation, this treatment could be one of alternative therapy for those who have similar dental anomalies.

• Journal of Dental Rehabilitation and Applied Science
• /
• v.30 no.2
• /
• pp.170-175
• /
• 2014

The growth disorder influences craniofacial development and early loss of permanent teeth. This case reports the importance of computerized tomography (CT) and surgical guide to identify horizontal bone loss, adjacent teeth and to guide drills when placing implants in a short stature patient. The patient has idiopathic short stature and the 3rd grade of intellectual disability. To recover posterior mandibular teeth, implant treatment was planned. CT images showed that the adjacent teeth were located markedly to the buccal side. A CT-based surgical guide was fabricated and implants was placed using flapless surgery. Bone dehiscence and fenestration may happen when the surgical guide was fabricated just based on adjacent clinical crowns. Thus, it is essential to analysis bone and teeth and to make surgical guide through CT, especially in atrophied bone on grow disorder patients. Furthermore, systematic researches are recommended to elucidate the relationship between growth disorder and tooth malposition.

• The korean journal of orthodontics
• /
• v.24 no.1 s.44
• /
• pp.221-231
• /
• 1994

The short-term effects of plaque control instruction were studied in 42 adolescent orthodontic patients under active fixed treatment. At first visit, all the patients were received plaque control instruction using materials such as oral hygiene education slides, dentiform, disclosing agents, tooth brush and interdental brush. After that, Pateints were asked to perform the tooth brushing according to instructions. Such a procedure was repeated every week lot 3 weeks. Plaque index and bleeding index were scored once a week for 4 weeks and were compared according to ages, sex and duration with fixed appliance. The results were as follows: 1. Plaque control instruction was effective in reducing plaque accumulation and gingival inflammation of the orthodontic patients. 2. The effect of plaque control instruction was continued during 3 weeks among all groups of subjects, and it was prominent at the first week. 3. There was no statistically significant difference in the effects of the plaque control of instruction according to sex, ages, or duration with fixed appliances.

• Journal of the Korean Society of Manufacturing Process Engineers
• /
• v.10 no.3
• /
• pp.13-18
• /
• 2011

This study deals with the effect of the honing in SCM420H planetary gears. The hardness, tooth profile, lead and roughness of the gear surface can be improved by honing. Therein, the honing techniques are welcomed especially as one of the physical surface improvement methods. As a result, gear honing reduces vibration and noise, and will increase the life of gear. And gear honing also changes the surface of gear tooth in a short time and price, so it is a very important method in manufacturing industry. But nowadays, it is hard to find the detail information of gear honing. The test gear is a planetary gear which is used in the automotive industry. It is manufactured by the hobbing, shaving, carburizing and honing. This study investigates the effect of honing in surface shape of SCM420H planetary gears, including fatigue strength test and characteristics of honing of SCM420H planetary gears.

• Journal of the Korean Society of Manufacturing Process Engineers
• /
• v.11 no.5
• /
• pp.54-59
• /
• 2012

This study dealt with effect of the grinding in SCM420H planetary gears. The hardness, tooth profile, lead and roughness of the gear surface can be improved by grinding process. Therein, the grinding techniques are widely used especially as one of the physical surface improvement methods. As the results, the gear grinding process reduced vibration and noise, and increased the life of the gear. And the gear grinding improved the surface of gear tooth in a short time and low cost, thus, it is a very important process in manufacturing industry. But nowadays, it is hard to find the detail information of gear grinding process. The test piece is a planetary gear which is used in the industrial machine. The manufacture process of the test piece contains hobbing, shaving, carburizing and grinding. This study investigated the effect of the grinding process to the physiognomy and the fatigue strength of test piece which was made by SCM420H.

• Journal of Technologic Dentistry
• /
• v.24 no.1
• /
• pp.107-126
• /
• 2002

The first function of occlusion is mastication. Therefore the functional restoration of occlusal surface is very important. The restoration of occlusal surface is three method as wax bite technique, F.G.P. technique, cone technique. Many dental technician is using compound method. I am using compound method of wax bite technique and cone technique. I have knew common point on each teeth during I have waxing up wax pattern. So I studied on the design waxup technique for mandible molar occlusion. The results of the study were as follows; 1. The dam wax up method can restore axial contour of teeth very easy and make short working time of wax pattern. 2. The height of dam must be same with cusp of adjacent teeth. 3. Automatically the contour of tooth is appeared if the contour of dam is relationship with cuspid line of adjacent teeth. 4. The height of contour of buccal, lingual surface is formed natural curve to add fluid wax by gravitation. 5. The development groove of mandible first premolar is appeared V form. 6. The development groove of mandible second premolar is appeared Y form. 7, The development groove of mandible first molar is appeared M form. 8. The development groove of mandible second molar is W form. 9. The embrasure is formed to carve around contact point area as round convex. It affects to axial form of tooth. 10. The buccal, lingual groove of molar is formed parallel with direction of teeth arrangement.