• Journal of the Semiconductor & Display Technology
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• v.21 no.1
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• pp.27-32
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• 2022

There has always been a demand for orthodontic treatment. Orthodontic treatment allows tooth to be arranged by flexible arch wire fixed with tooth-attached brackets. Arch wire generate constant pressure to tooth brackets which moves the teeth to proper place. When the bracket transmits force, the braced wing of the bracket may deform. Deformed tie wing will lead to lost tension of elastic ligature. Then, lacking grip between tie wing and ligature might delay the tooth movement. Furthermore, tooth brackets used for orthodontic treatment make contact with in direct oral surface and this cause feeling of irritation that comes from height of tooth braces. This study suggests an optimal teethe bracket design to make up for inconvenience by shorten the height of bracket and complement the shape of bracket to reduce strain rate using finite element analysis. As a result, new optimal design of teethe bracket indicates lower strain rate of the bracket wing and takes good effects of shorten body height in terms of convenience.

• Journal of the korean academy of Pediatric Dentistry
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• v.38 no.1
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• pp.51-55
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• 2011

Supernumerary teeth are dental abnormalies in the permanent dentition and the primary dentition. The etiology is unclear, but it may occur due to dichotomy of the tooth bud or hyperactivity of dental lamina. They occur more in the permanent dentition than in the primary dentition, with the most common site being the premaxillary area. Supernumerary teeth can be classified by morphology and position. Supplemental tooth refers to normal shape tooth. The treatment of supernumerary teeth depends on its shape, position, effect on dentition, and child's physiological condition. In this case, supernumerary primary tooth in the maxillary molar area was revealed by radiographical and clinical examination, but it was difficult to determine which is the supernumerary tooth. The tooth on the mesial side was extracted to induce the formation of adequate space and to prevent excessive space loss, and the result was favorable.

• Journal of Periodontal and Implant Science
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• v.36 no.4
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• pp.817-827
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• 2006

Purpose : This study was designed 1) to compare the perception of dental professionals and lay people with respect to minor variations in maxillary anterior tooth size and alignment and their relation to the surrounding soft tissues, and 2) to evaluate the normal tooth-gingiva topographical relationships in periodontally healthy young subjects, Materials and methods : Maxillary anterior teeth were intentionally diagrammed in varying degree of deviation with respect to one of three common anterior esthetic discrepancies including variations in crown length, shape of gingival margin, and length of interproximal contact, 17 images were generated to be preferentially selected by 2 groups consisting of dental professionals and lay people (total of 740). Smiling photographs of 120 dental students who had healthy periodontium were taken and the photographic images were analyzed to be classified as 17 kinds of altered image groups. Results : The results demonstrated noticeable difference between the varying levels of discrepancy. Both group preferred gingival margin of lateral incisor to be 0.5mm lower than that of central incisor. Lay people preferred the gingival margin shape that has 2/9 horizontal component of the crown width, while dental professionals preferred the gingival margin shape that has 1/9 horizontal component of the crown width. Lay people preferred longer length of the interproximal contact (two thirds of the crown length), whereas dental professionals preferred shorter length of the interproximal contact (half of the crown length). Photographic analysis of normal esthetic gingival topography revealed 2/9 horizontal component and short length of the interproximal contact which was of the hybrid nature of the preferences shared by lay people and dental professionals. Conclusion: The results of this study show that dental professionals and lay people demonstrated significant difference in their preference of dental esthetic components, which may then influence the decision making process by dental professionals with respect to designing the anterior esthetic gingival line.

• Restorative Dentistry and Endodontics
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• v.39 no.3
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• pp.220-225
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• 2014

A fiber-reinforced composite (FRC) fixed prosthesis is an innovative alternative to a traditional metal restoration, as it is a conservative treatment method. This case report demonstrates a detailed procedure for restoring a missing anterior tooth with an FRC. A 44-year-old woman visited our department with an avulsed tooth that had fallen out on the previous day and was completely dry. This tooth was replanted, but it failed after one year. A semi-direct technique was used to fabricate a FRC fixed partial prosthesis for its replacement. The FRC framework and the pontic were fabricated using a duplicated cast model and nanofilled composite resin. Later on, interproximal contact, tooth shape, and shade were adjusted at chairside. This technique not only enables the clinician to replace a missing tooth immediately after extraction for minimizing esthetic problems, but it also decreases both tooth reduction and cost.

• The Journal of the Korean dental association
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• v.56 no.6
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• pp.314-322
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• 2018

Among developmental anomalies of tooth shape, fusion and gemination are comparatively common. Developed with different etiologies, both fusion and gemination show similar clinical features. Therefore, many clinicians have difficulty diagnosing those morpho-anatomic anomalies. The purpose of this study is to report malformed right maxillary first molar in a 20-year-old female. With the aid of computed tomography (CT), the tooth was diagnosed as fusion with supernumerary tooth and dental caries lesion was detected. After performing direct pulp capping, the tooth was permanently restored with microhybrid composite resin using direct method to alter union groove into smooth surface for improving oral hygiene management. Until 6 months of follow-up visits, patient's chief complaint was resolved and tooth is still vital. In conclusion, identifying exact anatomy, conservative treatment and improving oral hygiene are essential in managing unusual morphologic anomalies of tooth.

• The korean journal of orthodontics
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• v.47 no.6
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• pp.384-393
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• 2017

Fusion of teeth is a developmental anomaly. It occurs at the stage of tooth formation, which determines the shape and size of the tooth crown, when one or more teeth fuse at the dentin level during the morphodifferentiation of the dental germs. Such teeth show macrodontia and may cause crowding, as well as esthetic and endodontic problems. In this article, we report a rare case of a maxillary central incisor fused to a supernumerary tooth showing labial and palatal talon cusps, which was orthodontically moved across the midpalatal suture. A 13-year-old Caucasian boy sought treatment for the unesthetic appearance of his maxillary central incisor and anterior crowding. He was rehabilitated successfully via a multidisciplinary approach involving orthodontic, nonsurgical endodontic, periodontal, and prosthodontic treatments. After a 26-month treatment period, the patient's macroesthetics and microesthetics were improved. The overall improvement of this macrodontic tooth and its surrounding tissues through multidisciplinary treatment was documented using cone-beam computed tomography.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.41 no.3
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• pp.163-174
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• 2004

The 3D tooth model in which each tooth can be manipulated individualy is essential component for the orthodontic simulation and implant simulation in dental field. For the reconstruction of such a tooth model, we need an image segmentation algorithm capable of separating individual tooth from neighboring teeth and alveolar bone. In this paper we propose a CT image normalization method and adaptive optimal thresholding algorithm for the segmenation of tooth region in CT image slices. The proposed segmentation algorithm is based on the fact that the shape and intensity of tooth change gradually among CT image slices. It generates temporary boundary of a tooth by using the threshold value estimated in the previous imge slice, and compute histograms for the inner region and the outer region seperated by the temporary boundary. The optimal threshold value generating the finnal tooth region is computed based on these two histogram.

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

• Journal of the Korean Society for Precision Engineering
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• v.23 no.6 s.183
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• pp.44-51
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• 2006

This paper deals with the aspects of die design for the multistage fine tooth hub gear in the cold forging process. In order to manufacture the cold forged product for the precision hub gear used as the ARD 370 system of bicycle, it examines the influences of different designs on the metal flow through experiments and FE-simulation. To find the combination of design parameters which minimize the damage value, the low gear length, upper gear length and inner diameter as design parameters are considered. An orthogonal fraction factorial experiment is employed to study the influence of each parameter on the objective function or characteristics. The optimal punch shape of fine tooth hub gear is designed using the results of FE-simulation and the artificial neural network. To verify the optimal punch shape, the experiments of the cold forging of the hub gear are executed.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.10a
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• pp.769-772
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• 2005

This paper deals with the aspects of die design for the multistage fine tooth hub gear in the cold forging process. In order to manufacture the cold forged product fur the precision hub gear used as the ARD 370 system of bicycle, it examines the influences of different designs on the metal flow through experiments and FE-simulation. To find the combination of design parameters which minimize the damage value, the low gear length, upper gear length and inner diameter as design parameters are considered. An orthogonal fraction factorial experiment is employed to study the influence of each parameter on the objective function or characteristics. The optimal punch shape of fine tooth hub gear is designed using the results of FE-simulation and the artificial neural network. To verify the optimal punch shape, the experiments of the cold forging of the hub gear are executed.