• Journal of Dental Rehabilitation and Applied Science
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• v.31 no.4
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• pp.364-370
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• 2015

Fixed restoration using implants for patients with posterior partial edentulism is generalized technique. As patient demands increase, the functional and esthetic implant restoration to achieve similar results to lost natural teeth is becoming an important issue. It is inevitable to use customized CAD/CAM abutments rather than ready-made abutments for the creation of implant prosthesis which closely resembles natural teeth. Using CAD/CAM abutment made it possible to obtain natural emergency profiles for posterior implant prostheses, ensuring more comfortable, efficient management of oral hygiene. However, keratinized gingiva with sufficient width and height for a natural emergence profile is required to use a large diameter CAD/CAM abutment which ensures stability and esthetics of hard/soft tissue around the implants. In this case, for esthetical and functional implant zirconia prosthesis, soft tissue graft was performed and customized CAD/CAM abutments were used following ridge augmentation, sinus graft and implantation. Satisfactory results were obtained functionally and esthetically through periodic clinical evaluation, and I hereby report this case.

• Journal of Periodontal and Implant Science
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• v.31 no.4
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• pp.749-763
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• 2001

Osseointegrated titanium implants have become an integral therapy for the replacement of teeth lost. For dental implant materials, titanium, hydroxyapatite and alumina oxide have been used, which of them, titanium implants are in wide use today. Titanium is known for its high corrosion resistance and biocompatability, because of the high stability of oxide layer mainly consists of $TiO_2$. With the development of peri-implantitis, the implant surface is changed in surface topography and element composition. None of the treatments for cleaning and detoxification of implant surface is efficient to remove surface contamination from contaminated titanium implants to such extent that the original surface elemental composition. In this sights, the purpose of this study was to evaluate rough surface titanium implants by means of scanning electron microscopy(SEM) and X-ray photoelectron spectroscopy(XPS) with respect to surface appearance and surface elemental composition. Moreover, it was also the aim to get the base for treatments of peri-implantitis. For the SEM and XPS study, rough surface titanium models were fabricated for control group. Six experimental groups were evaluated: 1) long-time room exposure, 2 ) air-powder abrasive cleaning for 1min, 3) burnishing in citric acid(pH1) for 1min, 4) burnishing in citric acid for 3min, 5) burnishing in tetracycline for 1min, 6) burnishing in tetracycline for 3min. All experimental treatments were followed by 1min of rinsing with distilled water. The results were as follows: 1. SEM observations of all experimental groups showed that any changes in surface topography were not detected when compared with control group. (750 X magnification) 2. XPS analysis showed that in all experimental groups, titanium and oxygen were increased and carbon was decreased, when compared with control group. 3. XPS analysis showed that the level of titanium, oxygen and carbon in the experimental group 3(citric acid treatment for 1min, followed by 1min of distilled water irrigation) reached to the level of control group. 4. XPS analysis showed that significant differences were not detected between the experimental group 1 and the other experimental groups except of experimental group 3. The Ti. level of experimental group 2, airpowder abrasive treatment for lmin followed by 1min of saline irrigation, was lower than the Ti. level of tetracycline treated groups, experimental group 5 and 6. From the result of this study, it may be concluded that the 1min of citric acid treatment followed by same time of rinsing with distilled water gave the best results from elemental points of view, and can be used safely to treat peri-implantitis.

• Journal of Periodontal and Implant Science
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• v.36 no.3
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• pp.661-671
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• 2006

The purpose of this study was to evaluate cumulative survival rate (CSR, %) of mandibular posterior single tooth implants replaced with ITI SLA (sand-blasted, large-grit, acid-etched) implant system and compare the CSR between first and second molar. The findings from the results were as follows; 1. Total of 158 implants were inserted into 147 patients. 68 patients were males, 79 patients were females and their mean age was 47.8 years. 98 implants were placed in first molar area and 60 implants were placed in second molar area. In terms of diameter, implants with wide diameter over 4.8mm dominated (91.1%). Implants with length over lOmm were used (96.2%). 2, In the two cases, there was a slight transient numbness which recovered within 1-2 months. Nine SynOcta screw type abutments demonstrated screw loosening, There were ten cases of crown fallen-out from decementation. 3. Only one failed out of 158 implants. The CSR was 99.4%. The CSRs for first molar and second molar were 99% and 100%, respectively. From the results, it was concluded that single tooth replacement implant in the mandibular posterior area, might be considered as the effective treatment modality comparable to the conventional crown and bridge.

• Journal of Periodontal and Implant Science
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• v.38 no.2
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• pp.135-142
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• 2008

Purpose: Numerous studies have shown that crestal bone resorption around the implant was related to the location of the implant abutment junction(IAJ). Recently it was hypothesized that platform switching termed the inward horizontal repositioning of the IAJ might limit bone resorption around the implants. The purpose of this clinical study was to evaluate the effect of platform switching on crestal bone resorption. Materials and Methods: The crestal bone loss of 65 external hex implants in 26 patients were radiographically measured at crown placement and follow-up examinations. 23 standard implants(non-platform switching group, NP) were connected with the matching abutments and 42 wide implants(platform switching group, PS) were connected with the 1 mm smaller diameter abutments. Results: There was significant difference of crestal bone loss between NP group and PS group. For implants in the NP group, mean crestal bone loss was $1.18{\pm}0.68\;mm$ at crown placement and $1.42{\pm}0.41\;mm$ at follow-up. The meal bone loss in PS group was $0.47{\pm}0.52\;mm$ at crown placement and $0.60{\pm}0.65\;mm$ at follow-up. When the crestal bone changes according to placement depths of implants were compared, subcrestal position of IAJ had a significantly less bone loss in PS group, but it was not in NP group. Conclusion: Within the limits of the present study, it was concluded that platform switching technique might decrease crestal bone loss around the implants. Additionally, when the IAJ of implant was placed 1 mm deeper in the alveolar bone, the effect of platform switching on bone loss was enhanced.

• Journal of Periodontal and Implant Science
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• v.43 no.3
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• pp.111-120
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• 2013

Periodontitis is a common oral disease that is characterized by infection and inflammation of the tooth supporting tissues. While its incidence is highly associated with outgrowth of the pathogenic microbiome, some patients show signs of predisposition and quickly fall into recurrence after treatment. Recent research using genetic associations of candidates as well as genome-wide analysis highlights that variations in genes related to the inflammatory response are associated with an increased risk of periodontitis. Intriguingly, some of the genes are regulated by epigenetic modifications, supposedly established and reprogrammed in response to environmental stimuli. In addition, the treatment with epigenetic drugs improves treatment of periodontitis in a mouse model. In this review, we highlight some of the recent progress identifying genetic factors associated with periodontitis and point to promising approaches in epigenetic research that may contribute to the understanding of molecular mechanisms involving different responses in individuals and the early detection of predispositions that may guide in future oral treatment and disease prevention.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.19 no.3
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• pp.217-231
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• 1997

Autogenous bone grafting has a broad range of applications and implications, and also limitations, though it is the oldest and most important reconstructive techniques in the oral and maxillofacial surgical field.Further understanding of bone healing mechanisms, bone physiology and bone biology, transplantation immunology, and development of tissue banking procedures had enabled oral and maxillofacial surgeons to reconstruct even the most difficult bony defects successfully with the preserved allogeneic bone implant. Now autogenous bone and allogeneic bone implants present a wide variety of surgical options to surgeons, whether used separately or in combination. The surgeons are able to make judicious and fruitful choices, only with a through knowledge of the above-mentioned biologic principles and skillful techniques. The author evaluated 116 cases where allogeneic bones were transplanted for oral and maxillofacial reconstruction.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.13 no.4
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• pp.1825-1844
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• 2019

Political campaigns circulate manipulative opinions in online communities to implant false beliefs and eventually win elections. Not only is this type of manipulation unfair, it also has long-lasting negative impacts on people's lives. Existing tools detect political manipulation based on a supervised classifier, which is accurate when trained with large labeled data. However, preparing this data becomes an excessive burden and must be repeated often to reflect changing manipulation tactics. We propose a practical detection system that requires moderate groundwork to achieve a sufficient level of accuracy. The proposed system groups opinions with similar properties into clusters, and then labels a few opinions from each cluster to build a classifier. It also models each opinion with features deduced from raw data with no additional processing. To validate the system, we collected over a million opinions during three nation-wide campaigns in South Korea. The system reduced groundwork from 200K to nearly 200 labeling tasks, and correctly identified over 90% of manipulative opinions. The system also effectively identified transitions in manipulative tactics over time. We suggest that online communities perform periodic audits using the proposed system to highlight manipulative opinions and emerging tactics.

• Journal of Dental Rehabilitation and Applied Science
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• v.30 no.4
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• pp.278-288
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• 2014

Purpose: The aim of the study was to evaluate preprosthetic initial survival rate and factors associated with survival of osseointegrated implants placed in edentulous area of maxilla and mandible and to suspect the possible causes leading to failure. Materials and Methods: A total of 2158 endosseous implants that had been inserted between 2004 through 2013 were placed in 770 patients. The clinical comparisons were performed to evaluate implant loss in relation to age and gender of patients, position, system, length and diameter of implant, and bone graft technique. Results: According to position, the survival rates were 98.23% in maxillary anterior site, 96.98% in maxillary posterior site, 97.85% in mandibular anterior site and 98.76% in mandibular posterior site (P < 0.05). According to diameter of implant, the survival rates were 100% under 3.0 mm, 97.09% between 3.0 to 3.5 mm, 98.19% between 3.5 to 4.0 mm and 98.29% between 4.0 to 4.5 mm but relatively lower survival rate was 75% in 5.0 mm-over (P < 0.05). The survival rates of implants were 89.51%, 98.28%, 98.34% and 99.27% in the group with isolated sinus graft, with isolated GBR, with sinus graft and GBR simultaneously and without bone graft, especially (P < 0.05). Conclusion: This study establishes a relationship between survival rate of implant and position, diameter of implant system and bone graft technique. In conclusion, there were low survival rates in maxillary posterior site, in dental implants with wide diameter of 5 mm-over, and in the group with isolated sinus graft.

• Journal of Dental Rehabilitation and Applied Science
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• v.32 no.3
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• pp.232-239
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• 2016

Purpose: In this paper, we introduce a wide clinical application of root resection therapy and additional benefits on the next prosthetic or dental implant treatment procedures in the age of dental implants. Materials and Methods: Additional clinical benefits of root resection were monitored by clinical and radiographic evaluation. Results: No complication was reported in all the cases, and the favorable results of root resection were maintained for long period. Conclusion: In compromised multirooted teeth, variety clinical treatment modality should be considered for enhancing the reconstruction of alveolar ridge around root resected in preparation for next implantation.

• Journal of Periodontal and Implant Science
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• v.36 no.2
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• pp.461-471
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• 2006

In order to achieve a satisfactory esthetic result of periodontal surgery or implant in maxillary anterior area, periodontists must be aware of normal alveolar bone anatomy. The purpose of this study was to evaluate the relationship of alveolar bone morphology to tooth shape and form. 78(mean age : 25 yrs) periodontally healthy volunteers participated in this study. Two maxillary central incisor and one lateral incisor were selected to study. With minimal local anesthesia, gutta-percha cone inserted to labial gingival sulcus of selected teeth just after bone sounding with periodontal probe. Metal ball (4mm diameter) attached to palatal fossa of central incisor. Then, periapical radiograph was taken according to long cone paralleling technique. After film scan, labial alveolar bone profile reproduced along interproximal bone and apical ends of gutta-percha cones on computer screen. By utilizing computer program, the distance from height of interproximal bone to the labial bone crest in central incisor-central incisor and central incisor-lateral incisor area was measured and converted to real distance by using vertical length of metal ball on film. After measuring crown length & width of central incisor, the 10 individuals ranked lowest GW/L ratio (crown width/length ratio) and the 10 ranked highest were selected as having a long-narrow(group N), or a short-wide(group W) form of the central incisors. Means of the distance from height of interproximal bone to the labial bone crest of group N, W were calculated and compared by means of independent t-test. The results were as follows: 1. Mean distance from the height of the interproximal bone to the labial bone crest was $3.5{\pm}0.7mm$ between two central incisor, and $2.8{\pm}0.6mm$ between central and lateral incisor. 2. Mean GW/L ratio of group N was 0.57, and group W was 0.8. Mean distance from the height of the interproximal bone to the labial bone crest of group N was higher than group W in both measured area(measurements of group N, W were $3.9{\pm0.2mm$ and $3.5{\pm}0.2mm$ between two central incisor, $3.0{\pm}0.2mm$ and $2.8{\pm}0.2mm$ between central and lateral incisor), but there were no statistically significant differences when the groups were compared. Within the limits of the present study, there was a tendency that subjects with long-narrow teeth have more scalloped alveolar bone profile than subjects with short-wide teeth in upper anterior area, but no statistically significant differences were found.