• Journal of Korean Dental Science
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• 제6권2호
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• pp.50-57
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• 2013

Purpose: Autogenous tooth bone graft is proven to be efficient. We evaluated the bone healing effect and clinical capabilities of autogenous tooth bone materials as a scaffold when growth factor is used together with this material. Materials and Methods: Subjects were those who needed implant placement and bone graft because of missing tooth or alveolar bone defect and who kept their autogenous tooth or needed extraction of other tooth. Group I included autogenous tooth bone graft with growth factor, whereas Group II had only autogenous tooth bone graft. We investigated the bone healing state through computed tomography taken just before surgery and 3 to 4 months after surgery to evaluate the effectiveness of bone graft. Group I had 9 patients, whereas Group II had 5 patients. We compared the pre- and post-operative increase of the Hounsfield unit and bone height by analyzing the computed tomography images. Result: Sinus bone grafts numbered 8 cases, and vertical ridge augmentation was performed together with 3 cases of these. Vertical ridge augmentation was performed in 2 cases, and horizontal ridge augmentation in 1 case alone. Socket graft was done in 3 cases. The post-operative mean value of the Hounsfield unit was 960 in Group I and 836.7 in Group II, but the increase was almost similar, i.e., 636.9 in Group I and 634.7 in Group II on the average. Increase of bone height was 7.6 mm in Group I and 11.1 mm in Group II on the average. This difference was attributable to the fact that most of the cases were sinus bone graft in Group II. Conclusion: In this study, we suggest the possibility of autogenous tooth bone graft materials as a scaffold besides their bone healing ability.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제38권
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• pp.41.1-41.6
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• 2016

Background: The goal of this study was to retrospectively evaluate the prognosis of minimal invasive horizontal ridge augmentation (MIHRA) technique using small incision and subperiosteal tunneling technique. Methods: This study targeted 25 partially edentulous patients (10 males and 15 females, mean age $48.8{\pm19.7years$) who needed bone graft for installation of the implants due to alveolar bone deficiency. The patients took the radiographic exam, panoramic and periapical view at first visit, and had implant fixture installation surgery. All patients received immediate or delayed implant surgery with bone graft using U-shaped incision and tunneling technique. After an average of 2.8 months, the prosthesis was connected and functioned. The clinical prognosis was recorded by observation of the peri-implant tissue at every visit. A year after restoration, the crestal bone loss around the implant was measured by taking the follow-up radiographs. One patient took 3D-CT before bone graft, after bone graft, and 2 years after restoration to compare and analyze change of alveolar bone width. Results: This study included 25 patients and 39 implants. Thirty eight implants (97.4 %) survived. As for postoperative complications, five patients showed minor infection symptoms, like swelling and tenderness after bone graft. The other one had buccal fenestration, and secondary bone graft was done by the same technique. No complications related with bone graft were found except in these patients. The mean crestal bone loss around the implants was 0.03 mm 1 year after restoration, and this was an adequate clinical prognosis. A patient took 3D-CT after bone graft, and the width of alveolar bone increased 4.32 mm added to 4.6 mm of former alveolar bone width. Two years after bone graft, the width of alveolar bone was 8.13 mm, and this suggested that the resorption rate of bone graft material was 18.29 % during 2 years. Conclusions: The bone graft material retained within a pouch formed using U-shaped incision and tunneling technique resulted with a few complications, and the prognosis of the implants placed above the alveolar bone was adequate.

• Journal of Periodontal and Implant Science
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• 제46권2호
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• pp.72-83
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• 2016

Purpose: The goal of this study was to evaluate the long-term success of horizontal alveolar crest augmentation of the retromolar region of the mandible with particulated bone, as well as factors affecting subsequent peri-implant bone loss. Methods: A total of 109 patients (68 female, 41 male) suffering from alveolar ridge deficiencies of the maxilla and mandible were included in this study. All patients were treated with particulated retromolar bone grafts from the mandible prior to the insertion of endosseous dental implants. Mesial and distal peri-implant crestal bone changes were assessed at six time points. Several parameters, including implant survival and the influence of age, gender, localisation of the implant, diameter, covering procedures, and time points of implant placement, were analysed to identify associations with bone level changes using the Mann-Whitney U-test, the Kruskal-Wallis test, and Spearman's rank-order correlation coefficient. Results: A total of 164 dental implants were placed in the maxilla (n=97) and in the mandible (n=67). The mean observation period was $105.26{\pm}21.58$ months after implantation. The overall survival rate was 97.6% after 10 years. Overall, peri-implant bone loss was highest during the first year, but decreased over time. The mean amount of bone loss after 10 years was 2.47 mm mesially and 2.50 mm distally. Bone loss was significantly influenced by implant type and primary stability. Conclusions: The use of particulated autologous retromolar bone grafts is a reliable technique for the horizontal reconstruction of local alveolar ridge deficiencies. Our results demonstrate that implants placed in augmented bone demonstrated similar bone level changes compared to implants inserted in non-augmented regions.

• Journal of Positioning, Navigation, and Timing
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• 제10권2호
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• pp.75-82
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• 2021

Fields of high-precision positioning applications are growing fast across the mass market worldwide. Accordingly, the industry is focusing on developing methods of applying State-Space Representation (SSR) corrections on low-cost GNSS receivers. Among SSR correction types, this paper analyzes Safe Position Augmentation for Real Time Navigation (SPARTN) messages being offered by the SAfe and Precise CORrection DAta (SAPCORDA) company and validates positioning algorithms based on them. The first part of this paper introduces the SPARTN format in detail. Then, procedures on how to apply Basic-Precision Atmosphere Correction (BPAC) and High-Precision Atmosphere Correction (HPAC) messages are described. BPAC and HPAC messages are used for correcting satellite clock errors, satellite orbit errors, satellite signal biases and also ionospheric and tropospheric delays. Accuracies of positioning algorithms utilizing SPARTN messages were validated with two types of positioning strategies: Code-PPP using GPS pseudorange measurements and PPP-RTK including carrier phase measurements. In these performance checkups, only single-frequency measurements have been used and integer ambiguities were estimated as float numbers instead of fixed integers. The result shows that, with BPAC and HPAC corrections, the horizontal accuracy is 46% and 63% higher, respectively, compared to that obtained without application of SPARTN corrections. Also, the average horizontal and vertical RMSE values with HPAC are 17 cm and 27 cm, respectively.

• Journal of Periodontal and Implant Science
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• 제44권2호
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• pp.50-56
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• 2014

Purpose: The aims of this study were to measure the distance of the intraosseous vascular anastomosis in the anterolateral wall of the maxillary sinus from different reference points, and to correlate the location of the intraosseous vascular anastomosis with the tooth position and the residual bone height of the maxilla. Methods: Computed tomography (CT) images were taken from 283 patients undergoing dental implants placement in the posterior maxilla. Three horizontal lines were drawn at the ridge crest, maxillary sinus floor, and the position of the anastomosis. A vertical second line at the center of each tooth was drawn perpendicular to the horizontal lines. The distance from the ridge crest to the maxillary sinus floor and the distance from the maxillary sinus floor to the bony canal were measured from the intersections of the horizontal and vertical lines. The residual alveolar bone height was used to categorize three groups: group 1,<4 mm; group 2, between 4 and 8 mm; and group 3, >8 mm. Results: The residual bone height values of different tooth positions were significantly different (P=0.0002). The distance from the maxillary sinus floor to the intraosseous vascular anastomosis was significantly different between groups 1 and 3 (P=0.0039). At the molar sites, a moderate negative correlation was found between the residual bone height and the distance from the maxillary sinus floor to the intraosseous anastomosis. The distances of the alveolar ridge crest and the maxillary sinus from the intraosseous vascular anastomosis were not significantly different between sexes. Conclusions: Within the limitations of this study, sites with a higher residual bone height in the molar regions were at a relatively high risk of artery damage during window osteotomy preparation; therefore, we recommend taking more precautions when using a lateral approach for sinus elevation.

• Journal of Mechanical Science and Technology
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• 제19권9호
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• pp.1720-1730
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• 2005

Automatic guided vehicle in the factory has an important role to advance the flexible manufacturing system. In this paper, we propose a novel object-transportation control algorithm of cooperative AGV systems to apply decentralized control to multiple AGV systems. Each AGV system is under nonholonomic constraints and conveys a common object-transportation in a horizontal plain. Moreover it is shown that cooperative robot systems ensure stability and the velocities of augmented systems convergence to a scaled multiple of each desired velocity field for cooperative AGV systems. Finally, the application of proposed virtual passivity-based decentralized control algorithm via system augmentation is applied to trace a circle. Finally, the simulation and experimental results for the object-transportation by two AGV systems illustrates the validity of the proposed virtual-passivity decentralized control algorithm.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제40권5호
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• pp.233-239
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• 2014

Implants are typically placed after performing ridge expansion by inserting screws of gradually increasing thickness and good clinical outcomes are often obtained. We placed 11 implants in 6 patients, and one implant failed during osseointegration but it was replaced immediately after removal and successful prosthetic treatments were completed. During these surgeries, buccal cortical plate complete fractures do not occur. Inserting screws for ridge expansion is a successful and predictable technique for implant placement in narrow alveolar bone.

• 대한치과보철학회지
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• 제55권2호
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• pp.212-217
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• 2017

임플란트의 협설 측으로 잔존 골조직이 불충분할 경우 골증대술을 시행하지 않기 위해서는 작은 직경의 임플란트를 사용할 수 있다. 작은 직경 임플란트의 경우는 파절 저항성이 낮고, 골과 임플란트의 접촉 면적이 좁아 구치부에는 부적절한 것으로 여겨져 왔다. 최근의 연구에서는 새로운 임플란트 합금의 개발 및 표면 처리방법의 발전으로 구치부에서도 표준 직경 임플란트와 유사한 성공률이 보고되고 있다. 이 증례에서는 구치부 상실 부위 잔존골의 협설 폭이 부족한 상황에서 작은 직경 임플란트를 이용하여 심미적, 기능적으로 만족스러운 치료 결과를 보였다. 현재까지 추적 검사 기간은 4년 이상 되었고 특이할만한 합병증 없이 유지되었다. 향후 장기적인 안정성에 대한 추가적인 연구가 필요할 것으로 사료된다.

• 대한치과의사협회지
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• 제55권1호
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• pp.30-41
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• 2017

Inadequate keratinized mucosa around dental implants can lead to more plaque accumulation, tissue inflammation, marginal recession and attachment loss. We evaluated the effects of free gingival and extracellular matrix membrane grafts performed to increase the insufficient width of keratinized tissue around dental implants in the posterior mandible. A 47-year-old female patient presented with discomfort due to swelling of the lower right second premolar area. Due to severe destruction of alveolar bone, the tooth was extracted. After 3 months, a guided bone regeneration (GBR) procedure was performed and then a dental implant was placed 6 months later. During the second-stage implant surgery, free gingival grafting was performed to increase the width of the keratinized tissue. After 12 months, a clinical evaluation was performed. A 64-year-old female patient had a missing tooth area of bilateral lower molar region with narrow zone of keratinized gingiva and horizontal alveolar bone loss. Simultaneous implant placement and GBR were performed. Five months after the first-stage implant surgery, a gingival augmentation procedure was performed with an extracellular matrix membrane graft to improve the width of the keratinized tissue in the second-stage implant surgery. After 12 months, a clinical evaluation was performed. In these two clinical cases, 12 months of follow-up, revealed that the increased width of the keratinized tissue and the deepened oral vestibule was well maintained. A patient showed a good oral hygiene status. In conclusion, increased width of keratinized tissue around dental implants could improve oral hygiene and could have positive effects on the long-term stability and survival rate of dental implants. When planning a keratinized tissue augmentation procedure, clinicians should consider patient-reported outcomes.

• Archives of Plastic Surgery
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• 제38권4호
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• pp.383-390
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• 2011

Purpose: To correct the upper lip depression after the correction of unilateral cleft lip, autologous grafts such as bone, dermal, fascial grafts and fat injections or alloplastic implants are used. Transplanted bones, dermis and fascia have a tendency to be absorbed and have donor morbidity. Fat injections are absorbed inconsistently and alloplastic implants have problems such as foreign body reactions, protrusions and infections. Authors corrected the upper lip depression using conchal cartilage graft in unilateral cleft lip deformity and the results was analysed with photos. Methods: 26-unilateral cleft lip and 2-microform cleft lip cases, totally 28 cases were performed. Their mean age was 21.89 years. The male and female cases were 12 and 16, respectively. Under anesthesia (general: 18 cases and local: 10 cases), cavum conchae (n=8), cymba conchae (n=16) and whole conchae (n=4) were harvested. Transversely cut the margin of the obtained cartilage, we cut out the most bent portion and put a partial-thickness incision on concave surface in cases of excessive convexity. Then, we performed the onlay graft of the conchal cartilage via scar revision site in unilateral cleft lip and via the reconstruction site of the cupid bow in microform cleft lip. The augmentation of the upper lip was evaluated with photos. Adapting the baseline connecting between the both cheilions as a horizontal standard line, we measured the highest point among the tangents between the upper lip and nose (point a), the lowest point (point c), the middle point between a and c (point b) and the vertical line from the alare (point d) to the horizontal standard line. To assess the postoperative symmetry, we compared cleft side upper lip contour index (%) A,B,C,D=(a,b,c,d)-ch ${\times}$ 100/(ch-ch) and non-cleft side upper lip contour index (%) A',B',C',D'= (a',b',c',d')-ch ${\times}$ 100 / (ch-ch).h) Results: After the surgery, no complication was found except in one case which double layers graft performed in the cleft lip deformity, the lateral portion was protruded. The upper lip contour index, the difference of A and A' were-0.83%, and thus the mild depression was persisted. Difference of B and B', C and C', D and D' were 0.83%, 1.07%, 0.90%. There were statistically significant difference, and thus the depression of upper lip were improved generally. Conclusion: Authors performed the onlay graft of the conchal cartilage in unilateral cleft lip deformity and found that the depression of the upper lip was well corrected except the uppermost part when photogrammetrically analyzed.