• The Journal of Korean Academy of Prosthodontics
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• v.56 no.4
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• pp.347-353
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• 2018

Gradual attrition is a normal process of aging, but severe attrition causes occlusal disharmony, functional disorder and esthetic problems. The collapse of posterior support may cause attrition of anterior teeth, and loss of occlusal vertical dimension (OVD). And it induces the pathologic change of the TMJ, unaesthetic facial appearance and decreased masticatory function. In this case, 70 year-old male presented with decreased vertical dimension and esthetic problems due to worn dentition. Based on assessment of intraoral findings, diagnostic cast and radiographic examination, full-mouth rehabilitation with increase of OVD was planned. After 10 month follow-up, occlusal stability is maintained and through this procedure, satisfactory outcomes were achieved in esthetic and functional aspects.

• The Journal of Korean Academy of Prosthodontics
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• v.57 no.4
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• pp.405-415
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• 2019

Excessive tooth wear can cause irreversible damage to the occlusal surface and can alter the anterior occlusal relationship by destroying the structure of the anterior teeth needed for esthetics and proper anterior guidance. The anterior deep bite is not a morbid occlusion by itself, but it may cause problems such as soft tissue trauma, opposing tooth eruption, tooth wear, and occlusal trauma if there are no stable occlusal contacts between the lower incisal edge against its upper lingual surface. The most important goal of treatment is to form stable occlusal contact in centric relation. In this case report, patients with decrease in vertical dimension and anterior deep bite due to maxillary posterior tooth loss and excessive tooth wear were treated full mouth rehabilitation with increased vertical dimension to regain the space for restoration and improve anterior occlusal relationship and esthetics. The functional and aesthetic problems of the patient could be solved by the equal intensity contact of all the teeth in centic relation (CR), anterior guidance in harmony with the functional movement, and restoration of the wear surface beyond the enamel range.

• Journal of Periodontal and Implant Science
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• v.37 no.4
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• pp.805-824
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• 2007

Purpose: Developments in micro/macrostructures of implants and surgical techniques brought out stable outcomes of implant dentistry. The aim of this study was to evaluate the distributions of implant patients, the types of implanted sites, and the success or survival rates of various implant systems and to analyze the implant placement done at each specificintraoral site and situation. Materials and Methods: The data of dental implantations collected between 1992 and 2006 at the Department of Periodontology in 00000 University Hospital were analyzed. Results: 1. Largest part of the patients were at the age of 40s and 50s in bothgender who lost their teeth mostly by periodontaldiseases and caries at the posterior intraoral sites as major ones. Bone densities of type II(mandible) and III(maxilla) were likely to be seen with quantity of type B. Lengths of the implants between 10 and 15 mm and wide platform took the largest part. 2. Survival rates of $Implantium^{(R)}(98.8%)$, $Xive^{(R)}(100%)$ and ITI $TE^{(R)}(100%)$ were high when $Frialit-2^{(R)}$ showed 82%(poor bone density area) or 87.2%(combined with additional therapy). $IMZ^{(R)}$ had lowest cumulative survival(67.5%) and success rate(49.4%) amongst all. 3. Replacement with 2 wide or 3 regular platforms showed no significant differences in survival rate and marginal bone loss atmandibular posterior area. In single restoration of mandibular second molar, 5-year success rate of machined surface $Br{\aa}nemark^{(R)}(70.37%)$ was lower than that of rough surface $ITI^{(R)}$ SLA(100%). 4. Replacement of single tooth in anterior area showed high survival rate of 94.5%. 5. The success rates of $Br{\aa}nemark$ Ti-Unite and ITI SLA at posterior maxilla with poor bone density both showed stable outcomes. 6. 10-year cumulative survival rate of implants with maxillary sinus augmentation by lateral window approach appeared to be 96.60%. Low survival rate(75%) was shown when there were more than two complications combined. Height of grafted bone remained stable above the implant apex. Conclusions : Rough surfaced implants showed stable outcomes in most of the situation including poor bone density and additional therapy combined.

• Journal of the korean academy of Pediatric Dentistry
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• v.35 no.3
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• pp.532-538
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• 2008

Lesch-Nyhan syndrome is a rare X-linked recessively inherited disorder, caused by complete absence or decrease in activity of hypoxanthine guanine phosphoribosyl transferase(HPRT), an enzyme involved in purine metabolism. This enzyme deficiency gives rise to nephropathy symptoms, such as hyperuricosuria and hyperuricemia by excessive uric acid production and neuropathy symptoms, such as mental retardation, choreoathetosis and self mutilation behavior. Patients with Lesch-Nyhan syndrome have tendency to bite their lip, tongue and finger. In severe cases, partial or even total amputation of tongue or finger occur. Self-inflicted bites are often complicated by secondary infection to the injured site as well as pain. Furthermore tissue loss by biting results in esthetic problems. The dental management of self mutilation includes treatment with appliances such as soft mouth guard or lip bumper, extraction of all the teeth, and orthognathic surgery. We report a case of a 13 year-old boy with Lesch-Nyhan syndrome, who severely injured himself on his tongue. At first, conservative treatment using soft mouth guard was considered, but it could not prevent trauma on his tongue. Therefore, extraction of the lower anterior and posterior teeth was carried out.

• The Journal of Korean Academy of Prosthodontics
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• v.57 no.1
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• pp.18-23
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• 2019

Patients with cleft lip and palate have several problems such as oro-nasal communication, dental cross-bite caused by the insufficient growth of maxilla, poor pronunciation and esthetic problem. Removable denture with maxillary double crown near cleft palate and with clasp in the posterior teeth was used to solve the problems of the patient with cleft lip and plate. Double crowns make up for the insufficient mucosal support caused by the mucosa and alveolar bone loss in cleft lip and palate. Double crowns also allow easy repair of denture in case of abutment teeth extraction. In this case, 55-year-old female patient had bilateral cleft lip and palate and few remaining teeth on anterior maxilla. Prosthetic treatment was done for patient with bilateral cleft lip and palate to close oro-nasal communication using maxillary double crown and clasp retained removable denture. As a result, oro-nasal communication was effectively closed and the cross-bite was easily corrected by double crown and clasp retained denture. In addition, pronunciation and appearance were also improved.

• Journal of dental hygiene science
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• v.16 no.1
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• pp.53-61
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• 2016

Eating supports to gain energy and nutrition and improves quality of life. Ageing affects the food intake ability due to loss of natural teeth and the progressive muscle degeneration. Our objective was to investigate how the food intake ability (FIA) and the remaining teeth could influence on oral health related quality of life in the elderly. This study was performed with 503 elderly subjects living in Daejeon, Korea. The questionnaire with the FIA with 30 Korean food and Oral Health Impact Profile 14 (OHIP-14) and oral examination were surveyed. The five groups according to cluster analysis of FIA had the different numbers of remaining teeth and functional posterior teeth with opposing teeth or prosthesis significantly: group 1, $21.78{\pm}8.27$ and $2.80{\pm}2.63$; group 2, $16.75{\pm}7.87$ and $2.16{\pm}2.44$; group 3, $14.68{\pm}9.77$ and $1.73{\pm}2.30$; group 4, $9.93{\pm}8.13$ and $0.78{\pm}1.68$; group 5, $10.18{\pm}8.37$ and $0.51{\pm}1.22$. The more foods the subjects could masticate, the better oral health related quality of life they had. The medium FIA, soft FIA and the number of remaining teeth could explain 46% of OHIP-14, but hard FIA could not in the multiple regression model. We suggested to develop the oral health program for the elderly to be able to eat the food with medium physical property at least be helpful to improve oral health related quality of life.

• Restorative Dentistry and Endodontics
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• v.19 no.1
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• pp.231-254
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• 1994

Fracture of cusp, on posterior teeth, especially those carious or restored, is major cause of tooth loss. Inappropriate treatments, such as unnecessarily wide cavity preparations, increase the potential of further trauma and possible fracture of the remaining tooth structures. Fracture potential may be directly related to the stresses exerted upon the tooth during masticatory function. The purpose of this study is to evaluate the fracture resistance of tooth, restored with composite resin inlay. In this study, MOD inlay cavity prepared on maxillary first premolar and restored with composite resin inlay. Three dimensional finite element models with eight nodes isoparametric solid element, developed by serial grinding-photographing technique. These models have various occlusal isthmus and depth of cavity, 1/2, 1/3 and 1/4 of isthmus width and 0.7, 0.85 and 1.0 of depth of cavity. The magnitude of load was 474 N and 172 N as presented to maximal biting force and normal chewing force. These loads applied onto ridges of buccal and lingual cusp. These models analyzed with three dimensional finite element method. The results of this study were as follows : 1. There is no difference of displacement between width of occlusal isthmus and depth of cavity. 2. The stress concentrated at bucco-mesial comer, bucco-disal comer, pulpal line angle and the interface area between internal slopes of cusp and resin inlay. 3. The vector of stress direct to buccal and lingual side from center of cavity, to tooth surface going on to enamel. The magnitude of vector increase from occlusal surface to cervix. 4. The crack of tooth start interface area, between internal slop of buccal cusp and resin inlay. It progresses through buccopulpal line angle to cervix at buccomesial and buccodistal comer. 5. The influence with depth of cavity to fracture of tooth was more than width of isthmus. 6. It would be favorable to make the isthmus width narrower than a third of the intercuspal distance and depth of cavity is below 1 : 0.7.

• The Journal of Advanced Prosthodontics
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• v.6 no.5
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• pp.361-371
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• 2014

PURPOSE. In case of large horizontal discrepancy of alveolar ridge due to severe resorption, cantilevered crown is usually an unavoidable treatment modality. The purpose of this study was to evaluate the clinical criteria for the placement of the aforementioned implant crown. MATERIALS AND METHODS. The mandible model with 2 mm thick cortical bone and cancellous bone was fabricated from CT cross-section image. An external connection type implant was installed and cantilevered crowns with increasing offset of 3, 4, 5, 6, and 7 mm were connected. Vertical load and $30^{\circ}$ oblique load of 300 N was applied and stress around bone and implant component was analyzed. A total of 14 cases were modeled and finite element analysis was performed using COSMOS Works (Solid works Inc, USA). RESULTS. As for the location of the vertical load, the maximum stress generated on the lingual side of the implant became larger according to the increase of offset distance. When the oblique load was applied at $30^{\circ}$, the maximum stress was generated on the buccal side and its magnitude gradually decreased as the distance of the offset load increased to 5 mm. After that point, the magnitude of implant component's stress increased gradually. CONCLUSION. The results of this study suggest that for the patient with atrophied alveolar ridge following the loss of molar teeth, von-Mises stress on implant components was the lowest under the $30^{\circ}$ oblique load at the 5 mm offset point. Further studies for the various crown height and numbers of occusal points are needed to generalize the conclusion of present study.

• The korean journal of orthodontics
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• v.43 no.2
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• pp.83-95
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• 2013

Objective: To evaluate the changes in cortical bone thickness, alveolar bone height, and the incidence of dehiscence and fenestration in the surrounding alveolar bone of posterior teeth after rapid maxillary expansion (RME) treatment using cone-beam computed tomography (CBCT). Methods: The CBCT records of 20 subjects (9 boys, mean age: $13.97{\pm}1.17$ years; 11 girls, mean age: $13.53{\pm}2.12$ year) that underwent RME were selected from the archives. CBCT scans had been taken before (T1) and after (T2) the RME. Moreover, 10 of the subjects had 6-month retention (T3) records. We used the CBCT data to evaluate the buccal and palatal aspects of the canines, first and second premolars, and the first molars at 3 vertical levels. The cortical bone thickness and alveolar bone height at T1 and T2 were evaluated with the paired-samples t-test or the Wilcoxon signed-rank test. Repeated measure ANOVA or the Friedman test was used to evaluate the statistical significance at T1, T2, and T3. Statistical significance was set at p < 0.05. Results: The buccal cortical bone thickness decreased gradually from baseline to the end of the retention period. After expansion, the buccal alveolar bone height was reduced significantly; however, this change was not statistically significant after the 6-month retention period. During the course of the treatment, the incidence of dehiscence and fenestration increased and decreased, respectively. Conclusions: RME may have detrimental effects on the supporting alveolar bone, since the thickness and height of the buccal alveolar bone decreased during the retention period.

• Journal of Periodontal and Implant Science
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• v.38 no.4
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• pp.589-594
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• 2008

Purpose: Osseointegration of implants in patients with pneumatized maxillary sinuses is difficult to achieve due to the deficiency of available bone in the posterior maxilla after loss of teeth. Maxillary sinus elevation is a method to overcome this problem. In this study, we evaluated the implant survival rate and the relationship between implant survival in patients with sinus elevation by the lateral approach. Materials and Methods: A total of 48 patients were consecutively treated with sinus elevation by the lateral approach between February 2003 & August 2006 at the dental hospital of Chonbuk National university. A total of 113 implants were placed. The mean healing period was 7.1 months and implants were placed after a mean period of 5.6 months. The mean observation period was 21.8 months. Results: Out of the 113 implants placed, fifteen failed, resulting in a survival rate of 86.7%, 18 cases of sinus membrane perforation were observed out of 65 sinuses treated. 33 implants were placed in a perforated site and 10 failed, representing a 60.7% implant survival. 80 implants were placed in a nonperforated site and 5 failed, representing a 92.6% implant survival. Conclusions: Implant placement with sinus elevation is an acceptable treatment for short term results. Sinus membrane perforation and postoperative complications, however, may have an effect on implant failure.