• The korean journal of orthodontics
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• v.41 no.5
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• pp.354-360
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• 2011

Objective: To investigate the effects of different pilot-drilling methods on the biomechanical stability of self-tapping mini-implant systems at the time of placement in and removal from artificial bone blocks. Methods: Two types of artificial bone blocks (2-mm and 4-mm, 102-pounds per cubic foot [102-PCF] polyurethane foam layered over 100-mm, 40-PCF polyurethane foam) were custom-fabricated. Eight mini-implants were placed using the conventional motor-driven pilot-drilling method and another 8 mini-implants were placed using a novel manual pilot-drilling method (using a manual drill) within each of the 2-mm and 4-mm layered blocks. The maximum torque values at insertion and removal of the mini-implants were measured, and the total energy was calculated. The data were statistically analyzed using linear regression analysis. Results: The maximum insertion torque was similar regardless of block thickness or pilot-drilling method. Regardless of the pilot-drilling method, the maximum removal torque for the 4-mm block was statistically higher than that for the 2-mm block. For a given block, the total energy at both insertion and removal of the mini-implant for the manual pilot-drilling method were statistically higher than those for the motor-driven pilot-drilling method. Further, the total energies at removal for the 2-mm block was higher than that for the 4-mm block, but the energies at insertion were not influenced by the type of bone blocks. Conclusions: During the insertion and removal of mini-implants in artificial bone blocks, the effect of the manual pilot-drilling method on energy usage was similar to that of the conventional, motor-driven pilot-drilling method.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.34 no.3
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• pp.285-292
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• 2008

Purpose: The present study was performed to evaluate the effect of surface treatment of the cervical area of implant on bone regeneration in fresh extraction socket following implant installation. Materials and methods: The four minipigs, 18 months old and 30 kg weighted, were used. Four premolars of the left side of both the mandible and maxilla were extracted. ${\phi}$3.3 mm and 11.5 mm long US II plus implants (Osstem Implant co., Korea) with resorbable blasting media (RBM) treated surface and US II implants (Osstem Implant co., Korea) with machined surface at the top and RBM surface at lower portion were installed in the socket. Stability of the implant was measured with $Osstell^{TM}$ (Model 6 Resonance Frequency Analyser: Integration Diagnostics Ltd., Sweden). After 2 months of healing, the procedures and measurement of implant stability were repeated in the right side by same method of left side. At four months after first experiment, the animals were sacrificed after measurement of stability of all implants, and biopsies were obtained. Results: Well healed soft tissue and no mobility of the implants were observed in both groups. Histologically satisfactory osseointegration of implants was observed with RBM surface, and no foreign body reaction as well as inflammatory infiltration around implant were found. Furthermore, substantial bone formation and high degree of osseointegration were exhibited at the marginal defects around the cervical area of US II plus implants. However, healing of US II implants was characterized by the incomplete bone substitution and the presence of the connective tissue zone between the implant and newly formed bone. The distance between the implant platform (P) and the most coronal level of bone-to-implant contact (B) after 2 months of healing was $2.66{\pm}0.11$ mm at US II implants group and $1.80{\pm}0.13$mm at US II plus implant group. The P-B distance after 4 months of healing was $2.29{\pm}0.13$mm at US II implants group and $1.25{\pm}0.10$mm at US II plus implants group. The difference between both groups regarding the length of P-B distance was statistically significant(p<0.05). Concerning the resonance frequency analysis (RFA) value, the stability of US II plus implants group showed relatively higher RFA value than US II implants group. Conclusion: The current results suggest that implants with rough surface at the cervical area have an advantage in process of bone regeneration on defect around implant placed in a fresh extraction socket.

• The korean journal of orthodontics
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• v.36 no.4
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• pp.308-320
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• 2006

Rapid canine retraction, first introduced by Liou, is a distraction osteogenesis applied to the periodontal ligament tissue. Rapid tooth movement was facilitated by establishing minimal bony resistance on the distal surface of the canine by socket preparation and by osteogenesis on the mesial side in response to the periodontal distraction. Since undesired buccal tipping or extrusion of the canine during retraction tends to occur, it is crucial to maintain the firm path of movement and the axis of the canine during retraction. In order to improve the predictability of the canine movement, lingually extended distraction screws with heavy labial guiding wires were designed. Prefabricated plastic canine models for the estimation of socket depth and miniscrew implants for anchorage reinforcement were also devised. Applying these devices to a female patient with Class II anterior protrusion, the whole treatment was effectively finished in 13 months. Loss of vitality or periodontal problems did not occur throughout treatment, and stable occlusion was maintained during 10 months of retention. This case report demonstrates that a predictable rapid canine retraction can be achieved through the use of this modified technique.

• Journal of Life Science
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• v.16 no.2 s.75
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• pp.302-309
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• 2006

To evaluate the biocompatibility of untreated and anodized titanium specimens, the specimens were implanted in the subcutaneous tissue of the abdominal region of female mice for two weeks. The reaction of connective tissue to specimens was histologically studied. The implants were encapsulated by fibrous connective. tissue consisting of fibroblast, fibrocyte and other cellss including neutroophil, macrophage and giant multinucleated cell. some newly formed blood vessels were located in the fibrous capsule surrounding the implant. Giant multinucleated cells were observed at the fibrous capsule adjacent to the implant. Kind of cell types and the thickness of fibrous capsules were examined quantitatively. Most of cell types located in the fibrous capsule were fibroblast and fibrocyte. The average thickness of fibrous capsules for the anodized specimens was much thinner than that of the untreated titanium specimen. Biocompatibility of titanium specimens were also studied by using cell culture method. The number of MG-63 cells was significantly increased on the anodized titanium specimens in vitro experiment. Our observations suggest that anodized titanium specimens are more effective for the improvement of biocompatibility in vivo and in vitro.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.36 no.2
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• pp.71-77
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• 2010

Introduction: The purpose of this study is to evaluate the effect of platelet rich plasma in bone formation and osseointegration of implant installed in the bone marrow space. Materials and Methods: Five beagle dogs were used as experimental animals. Two implants were installed on each tibia in the dogs. Implants of the control group were installed with no additional graft. Those of the experimental group 1 were installed with autogenous bone graft from the ilium autogenous bone. Platelet rich plasma (PRP) alone was used in experimental group 2 and the mixture of PRP and autogenous bone was used in experimental group 3. The animals were sacrificed at 8 weeks after implantation. The parts of tibia containing implant were harvested and radiographs were taken for radiographic examination. The specimens were prepared for histological examination and histomorphometric analysis of implant-bone contact ratios. Results: 1. All implants showed sufficient osseointegration in the cortical bone radiographically and histologically, but osseointergration in the marrow space was not satisfactory. 2. Histomorphometrically, the implant-bone contact ratios in the bone marrow was sequentially high in the experimental group 3 (autogenous bone + PRP group), group 1 (autogenous bone group), group 2 (PRP group), and control group (non-additive). 3. It was verified that there was statistical significance between two experimental groups (group 1 and 3) and the other groups (group 2 and control group). (P<0.005) 4. However, there was no statistical significance between group 3 and group 1, also group 2 and control group respectively. Conclusion: These results suggest that platelet rich plasma is effective to osseointegration in the implant installation but there is no statistical significance.

• The Journal of Korean Academy of Prosthodontics
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• v.41 no.5
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• pp.674-688
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• 2003

Statement of Problem : With increasing demand of the implant-supported prosthesis, it is advantageous to use the different platform width of the fixture according to bone quantity and quality of the patients. Purpose : The purpose of this study was to assess the loading distributing characteristics of two implant designs according to each platform width of fixture, under vertical and inclined loading using finite element analysis. Material and method : The two kinds of finite element models were designed according to each platform width of future (4.1mm restorative component x 11.5mm length, 5.0mm wide-diameter restorative component x 11.5mm length). The crown for mandibular first molar was made using UCLA abutment. Each three-dimensional finite element model was created with the physical properties of the implant and surrounding bone. This study simulated loads of 200N at the central fossa in a vertical direction, 200N at the outside point of the central fossa with resin filling into screw hole in a vertical direction and 200N at the buccal cusp in a 300 transverse direction individually Von Mises stresses were recorded and compared in the supporting bone, fixture, and abutment screw. Results : The stresses were concentrated mainly at the cortex in both vertical and oblique load ing but the stresses in the cancellous bone were low in both vertical and oblique loading. Bending moments resulting from non-axial loading of dental implants caused stress concentrations on cortical bone. The magnitude of the stress was greater with the oblique loading. Increasing the platform width of the implant fixture decreased the stress in the supporting bone, future and abutment screw. Increased the platform width of fixture decreased the stress in the crown and platform. Conclusion : Conclusively, this investigation provides evidence that the platform width of the implant fixture directly affects periimplant stress. By increasing the platform width of the implant fixture, it showed tendency to decreased the supporting bone, future and screw. But, further clinical studies are necessary to determine the ideal protocol for the successful placement of wide platform implants.

• Journal of the korean academy of Pediatric Dentistry
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• v.38 no.2
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• pp.161-169
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• 2011

Longitudinal serial cephalometric films in the every second year from fifty girls were used for the analysis of growth pattern of maxillary alveolar bone (MAE). Six parameters regarding MAB height were measured and were compared with stature and chronological age. Descriptive analysis. correlation coefficient test and linear regression analysis were done for the statistical analyses. 1. The height of MAE increased until 14 years although growth velocity was gradually decreased. which was different with stature growth pattern. 2. The correlation coefficients between chronological age and MAB height were high and had no statistical differences with those of stature and MAB height. In addition. the correlation coefficients between chronological age groups within each parameter of MAB were very high. 3. The growth amount of MAB could be predicted using linear regression analysis on the basis of chronological age data. The growth pattern between MAE and statue was quite different because of the growth pattern difference between skeletal and neuronal system. Therefore. growth pattern of Korean MAB must be considered in dental treatment of youth. Also. close relationship between chronological age and MAB height would be useful when clinicians want to predict growth amount of MAE for the dental implant treatment.

• The Journal of Korean Academy of Prosthodontics
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• v.47 no.3
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• pp.295-300
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• 2009

Statement of problem: As the number of elders is growing with the advancement of medicine, partially or fully edentulous patients have increased. Medically compromised conditions are common in the older population so that it should be taken into account in prosthetic treatment planning as well as their economic conditions. In the older patients, removable prosthesis has been preferred to implant prosthesis. However, cast metal based removable partial dentures also has several limitations. Purpose: In this report, we present several cases of Valplast$^{(R)}$ flexible denture which were fabricated in patients who had medically compromised conditions or whose remaining teeth showed a relatively poor prognosis. Results & Conclusion: This article describes an alternative treatment for a partially edentulous patient with mouth opening limitation, after cancer surgery, compromised general condition and questionable remaining teeth. In these patients, Valplast$^{(R)}$ flexible denture was used because of its unique characteristics and the results were all satisfactory. Patients had 1-2 check-up and there were no postoperative pain or fracture of denture up to now.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.1
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• pp.72-78
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• 2016

This study examined the oral health-related quality of life of the elderly using the oral health index and dental prosthesis status, and explored methods to improve the oral health status. The data collected from 'The fifth Korean national health and nutrition examination survey 2010' were analyzed. The subjects were 2273 elderly people, aged 65 years or older, who had completed an oral examination, health questionnaires and nutrition examination. Statistical analysis was done using the SPSS 22.0 for Windows. Frequency analysis, multiple regression analysis and structural equation model were used for statistical analysis. The general characteristics, oral health index and dental prosthesis showed differences in the subjective oral health status associated with as age, ST, FS-T, T-Health, maxillary crown needs, maxillary denture needs, mandibular denture needs, chewing status associated with the income level, FS-T, maxillary crown needs, maxillary denture needs, mandibular denture needs, speaking status associated with the ST, T-Health, maxillary implant status, and maxillary denture needs. In conclusion, both the oral health index and dental prosthesis needs affect the oral health related quality of life of the elderly. Governments should implement a variety of oral health programs and dental prosthesis policies to improve the quality of life related oral health of the elderly.

• Journal of dental hygiene science
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• v.14 no.4
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• pp.477-487
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• 2014

Of the many pathogenic Candida species, Candida albicans is the main fungal pathogen of humans. The oral environmental factors considered in the Candida albicans colony forming unit test contain both host and microbial factors associated with candidiasis. In particular, Candida biofilms can develop on surfaces of prosthesis. The purpose of this study was to investigate the distribution of oral Candida species between the type of prosthesis and the situation of oral environment in patient with prosthetic appliance. The patients were 30 elderly subjects with different types of prosthesis, 7 who wore denture, 12 who wore implant and 15 who wore removable orthodontic appliance. We used Candida albicans colony forming unit test using saliva to exam the distribution of Candida albicans related with 5 oral environmental factors, gender, smoking or nonsmoking, alcohol/nonalcohol consumption, the type of prosthetic appliance and its treatment duration as well as tooth brushing frequency per day. In conclusion, for the patient's gender, site in the oral cavity and the type of prosthetic appliance and its treatment duration was associated with an increase in the distribution of Candida albicans in saliva. The distribution of Candida albicans within the oral cavity performs to be modulated to varying extents by oral environmental factors and, further investigations are required to elucidate these complex interactions.