• Journal of Dental Rehabilitation and Applied Science
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• v.32 no.4
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• pp.307-313
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• 2016

Overdenture is one of the methods of patients with severely worn dentition. Remaining natural teeth help preserve alveolar bone and proprioception and provide rigid support. Also, overdenture distributes the concentrated stress applied to the abutment tooth and denture supporting tissues. There is an advantage that it can provide long-term stability to denture. In this case, the patient with only a few teeth due to severe wear and caries was satisfied with good function and favorable esthetics by using overdenture.

• Journal of Dental Rehabilitation and Applied Science
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• v.34 no.1
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• pp.56-62
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• 2018

When it comes to treat patient with loss of vestibule, conventional denture impression have limitation which can cause problems of excessive border extension. Suction denture with closed mouth technique which was introduced to solve this problem, forms negative pressure being sealed denture flanges by mobile mucosa when the patient swallows and chews. Also, it can decrease patient's visiting time by taking impression and gothic arch tracing at once. In this case, considering patient's chief complain which is a loose fit of present lower denture, suction dentures with closed mouth technique was planned.

• Journal of Technologic Dentistry
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• v.11 no.1
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• pp.115-120
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• 1989

Many attempts for the compfrt, esthetics and improvement of Masticatory function of the patients with removable prosthesis have been made for several decades. The search for the ideal denture occlusion has been going on in an effort to find the tooth form which provides maximum denture stability and masticatory efficiency without damaging the health of the underlying bone. For the purpose, the basic concept of lingualized occlusion were suggested by payne(1941) and pound(1973) discussed a similar occlusal concept and used term " lingualized occlusion." The purpose of this literature study is to clarify and amplify a method to achieve bilateral balanced occlusion with the occlusal arrangement termed " lingualized occlusion." Lingualized occlusion can be achieved by use of anatomic teeth for the mandibular denture. Lingualized occlusion can be used in most denture combination. It is particulary helpful when the patient places high priority on esthetics but a nonanatomic occlusal scheme is indicated by oral conditions such a severe alveolar resorption, a class II jaw relationship or displaceable supporting tissue. Advantages of lingualized occlusion are summarized as follows : 1) Most of the advantages attributed to both the anatomic and nonanatomic forms are retained. 2) Cusp form is more natural in appearance compare to nonanatomic tooth form. 3) Good pnetration of the food bolus is possible. 4) Bilateral mechanical balanced occlusion is readily obtained for a region around arotric relation. 5) Bertical forces are centralized on the mandibular teeth. Lingualized occlusion provides a useful combination of several occlusal concept. Many. advantages of anatomic and nonanatomic occlusions are accomplished but the lingualized occlusal concept is not is not a panacea, and all other procedures still must be carefully excuted.

• The KIPS Transactions:PartB
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• v.11B no.2
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• pp.133-140
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• 2004

Recently, the dental information systems were rapidly developed in order to store and process the data of patients. But, these systems should serve a doctor a good quality information against disease for diagnostic and surgery purpose so as to success in this field. This function of the system it important to persuade patients to undergo proper surgical operation they needed. Hence, 3D teeth model capable of simulating the dental surgery and treatment is necessary Teeth manipulation of dentistry is performed on individual tooth in dental clinic. io, 3D teeth reconstruction system should have the techniques of segmentation and 3D reconstruction adequate for individual tooth. In this paper, we propose the techniques of adaptive optimal segmentation to segment the individual area of tooth, and reconstruction method of tooth based on contour-based method. Each tooth can be segmented from neighboring teeth and alveolar bone in CT images using adaptive optimal threshold computed differently on tooth. Reconstruction of individual tooth using results of segmentation can be manipulated according to user's input and make the simulation of dental surgery and treatment possible.

• Journal of Korean society of Dental Hygiene
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• v.13 no.5
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• pp.819-826
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• 2013

Objectives : The purpose of this study was to analyze the types of dental emergencies. This study was carried out for dental trauma patients visiting the emergency room in H hospital from 2005 to 2006. Methods : Subjects were 252 patients. Demographic characteristics consisted of age, gender, dentition, and dental related injury. Results : Male patients had 1.65 times higher tooth injury than female. Teenagers had higher prevalence of tooth injury. Main cause of dental injury was falling down. Young children accounted for 41.7% of the injuries. Late evening was the highest outbreak time of injury. The most commonly affected teeth were central incisor and lateral incisor. The damage of oral soft tissue was more common than the that of alveolar bone. Main area of primary tooth loss was gingiva(10.7%), tongue or soft palate(7.5%), and frenulum(6.0%). Subluxation(28.6%) and luxation(28.6%) were main cause for the primary teeth. Tooth fracture(50.0%) were the most common injury. Conclusions : Thus, to understand the incidence, causes and patterns of dental trauma is to help preserving natural teeth. The results of this study could provide the clinical guidelines on the treatment of dental emergency patients.

• Restorative Dentistry and Endodontics
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• v.20 no.2
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• pp.655-669
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• 1995

Restorative procedures can lead to weakening tooth due to reduction and alteration of tooth structure. It is essential to prevent fractures to conserve tooth. Among the several parameters in cavity designs, cavity isthmus is very important. In this study, amalgam 0 cavity was prepared on maxillary first premolar. Two dimensional finite element models were made by serial photographic method and isthmus(1/4, 1/3, 1/2, 2/3 of intercuspal distance) were varied. Three or four-nodal mesh were used for the two dimensional finite element models. The periodontal ligament and alveolar bone surrounding the tooth were excluded in these models. 1S model was sound tooth with no amalgam cavity. B model was assumed perfect bonding between the restoration and cavity wall. Both compressive and tensile forces were distributed directly to the adjacent regions. A load of 500N was applied vertically at the first node from the lingual slope of the buccal cusp tip. This study analysed von Mises stress, 1 and 2 directional normal stress and Y and Z axis translation with FEM software Super SAPII Version 5.2 (Algor Interactive System Co.) and hardware 486 DX2 PC. The results were as :follows : 1. 1S model was slightly different with 1B model in stress distibution. 1S, 2B, 3B, 4B models showed similiar stress distribution. 2. 1S model and four B models showed similiar pattern in Y axis and Z axis translation. 3. 1S model and four B models showed the bending phenomenon in the translation. 4. As increasing of the width of the cavity, experimental group was similiar with the control group in stress distribution. 5. As increasing of the width of the cavity, experimental group was similiar with the control group in Y and Z axis tranlation.

• Journal of the Korean Society of Industry Convergence
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• v.20 no.2
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• pp.169-176
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• 2017

Dental implants are required to have biomechanical functions and biostability in order to perform authoring, pronunciation, and aesthetic functions in the oral cavity. In terms of biostability, pure titanium for medical have good biostability and no rejection in the alveolar bone. with appropriate strength in terms of strength as well as biocompatibility. In recent years, various surgical methods and devices have been developed to improve the convenience and safety of the procedure. However, as the number of procedures increases, the screw loosening of the abutment screw connecting the artificial root and the abutment There are many reports of artificial root and abutment fracture. Fig. 1 is an example of a case where the upper part of the abutment screw is arbitrarily modified to remove the abutment by the abutment fracture due to the loosening of the abutment screw. The fundamental cause of abduction of the abutment screw is caused by the slight movement due to the lowering of the retention force of the abutment screw. It is necessary to minimize loosening of the abutment screw to avoid problems such as fracture during the period of using the implant. The purpose of this study is to investigate the structure of the abutment screw to prevent the loosening of the abutment screw by forming 0.5mm slot.

• Restorative Dentistry and Endodontics
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• v.36 no.1
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• pp.12-18
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• 2011

Objectives: This retrospective study evaluated the therapeutic effects of the intentional replantation (IR) procedure performed on the maxillary and mandibular molars of 35 patients. Materials and Methods: For the subjects, IR was performed due to difficulties in anatomically accessing the lesions and/or close proximity to the thick cortical bone, inferior alveolar nerve, or maxillary sinus, which rendered the ordinary periradicular surgery impossible. The patients'progress was followed for a year and up to 2 years and 4 months. The success of the procedure was evaluated in terms of clinical and radiographic success (%). Results: The results revealed the following: (a) 1 case (3%) of failed tooth extraction during IR; (b) 2 cases (6%) of extraction due to periodontal diseases and inflammatory root resorption; (c) 3 cases (9%) of normally functioning teeth in the oral cavity with minor mobility and apical root resorption, and; (d) 29 cases (82%) of normally functioning teeth without obvious problems. Conclusions: IR was confirmed to be a reliably repeatable, predictable treatment option for those who cannot receive conventional periradicular surgery because of anatomic limitations or patient factors.

• The Journal of Korean Academy of Prosthodontics
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• v.57 no.1
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• pp.75-80
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• 2019

Fall is the most common cause of trauma in the elderly and a major reason of dental injury. Maxillary anterior region is the most vulnerable area to the traumatic fall. Loss of teeth and adjacent tissue in this area results in maxillofacial defects and inappropriate maxillomandibular relationship. Reconstruction of the loss requires comprehensive and careful planning to fulfill not only functional but also esthetic demand. Prosthetic approach can avoid surgically extensive intervention, reducing both treatment cost and time. This clinical report describes a 78-year-old woman with the loss of teeth and alveolar bone in maxillary anterior region due to a traumatic fall, rehabilitated with a metal-ceramic fixed dental prosthesis using gingival porcelain.

• The Journal of Advanced Prosthodontics
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• v.11 no.3
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• pp.169-178
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• 2019

PURPOSE. While dental implants have displayed high success rates, poor mechanical fixation is a common complication, and their biomechanical response to occlusal loading remains poorly understood. This study aimed to develop and validate a computational model of a natural first premolar and a dental implant with matching crown morphology, and quantify their mechanical response to loading at the occlusal surface. MATERIALS AND METHODS. A finite-element model of the stomatognathic system comprising the mandible, first premolar and periodontal ligament (PDL) was developed based on a natural human tooth, and a model of a dental implant of identical occlusal geometry was also created. Occlusal loading was simulated using point forces applied at seven landmarks on each crown. Model predictions were validated using strain gauge measurements acquired during loading of matched physical models of the tooth and implant assemblies. RESULTS. For the natural tooth, the maximum vonMises stress (6.4 MPa) and maximal principal strains at the mandible ($1.8m{\varepsilon}$, $-1.7m{\varepsilon}$) were lower than those observed at the prosthetic tooth (12.5 MPa, $3.2m{\varepsilon}$, and $-4.4m{\varepsilon}$, respectively). As occlusal load was applied more bucally relative to the tooth central axis, stress and strain magnitudes increased. CONCLUSION. Occlusal loading of the natural tooth results in lower stress-strain magnitudes in the underlying alveolar bone than those associated with a dental implant of matched occlusal anatomy. The PDL may function to mitigate axial and bending stress intensities resulting from off-centered occlusal loads. The findings may be useful in dental implant design, restoration material selection, and surgical planning.