• Maxillofacial Plastic and Reconstructive Surgery
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• v.17 no.3
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• pp.239-252
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• 1995

The present study was aimed to evaluate the effect of demineralized freeze-dried bone (DFDB) and resorbable hydroxyapatite (RHA) on bone formation in the extracted socket. The lower left and right 2nd and 3rd premolar were extracted in adult dogs. The one group was grafted with DFDB into the extracted socket, and the other group grafted with RHA. The extracted socket was sutured without any graft materials as control. The animals were killed on the 1st, 2nd, 4th, and 8th week after the graft for macroscopic and microscopic examination. Results obtained were as follows : 1. Macroscopically, nor infection of the graft site and dislodgement of the grafted material were noted in any animals used. 2. Young trabeculae of osteoid were formed in the socket wall in control group at 2 weeks after the graft. Osteoid tissue was formed in DFDB group at 1 week after graft, and a fine osteoid tissue was grown through the RHA particles in RHA group at 2 weeks graft. 3. The grafted groups showed more rapid bone formation than the control. Between the grafted groups, DFDB group showed more rapid formation than RHA group, DFDB group showed osteoinductive bone formation and RHA group showed osteoconductive bone formation. These results suggest that DFDB and RHA are useful to preserve the alveolar bone and to improve new bone formation by immediate grafting into the extraction sockets.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.48 no.6
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• pp.371-381
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• 2022

Objectives: This study determined the effect of platelet-rich fibrin (PRF) on extraction socket bone regeneration and assessed the patterns and determinants of bone regeneration after the surgical extraction of impacted mandibular third molars. Materials and Methods: This prospective study randomly allocated 90 patients into two treatment groups: A PRF group (intervention group) and a non-PRF group (control group). After surgical extractions, the PRF group had PRF placed in the extraction socket and the socket was sutured, while the socket was only sutured in the non-PRF group. At postoperative weeks 1, 4, 8, and 12, periapical radiographs were obtained and HLImage software was used to determine the region of newly formed bone (RNFB) and the pattern of bone formation. The determinants of bone regeneration were assessed. Statistical significance was set at P<0.05. Results: The percentage RNFB (RNFB%) was not significantly higher in the PRF group when compared with the non-PRF group at postoperative weeks 1, 4, 8, and 12 (P=0.188, 0.155, 0.132, and 0.219, respectively). Within the non-PRF group, the middle third consistently exhibited the highest bone formation while the least amount of bone formation was consistently observed in the cervical third. In the PRF group, the middle third had the highest bone formation, while bone formation at the apical third was smaller compared to the cervical third at the 8th week with this difference widening at the 12th week. The sex of the patient, type of impaction, and duration of surgery was significantly associated with percentage bone formation (P=0.041, 0.043, and 0.018, respectively). Conclusion: Placement of PRF in extraction sockets increased socket bone regeneration. However, this finding was not statistically significant. The patient's sex, type of impaction, and duration of surgery significantly influenced the percentage of bone formation.

• Journal of Periodontal and Implant Science
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• v.38 no.3
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• pp.503-510
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• 2008

Purpose: To evaluate bone formation on the implant surface between machined fixture and RBM surface fixture through analyzing of distribution and concentration of Ca and P by EPMA. Material and Methods: Fixtures had divided in 2 group: Machined(Group I), RBM (Group II). Total 4 fixtures were implanted on rabbit which sacrificed on 2 week and 4 week for the histological specimens. By these specimens EPMA value were measured, compared and analysed by each group to figure out the evidence of clinical use of RBM implant. Result: After 2 weeks and 4 weeks, it was analyzed that bone formation area, distribution and concentration of Ca and P by EPMA. In distribution and concentration of P Group II was higher than Group I, but there were no statistical significances. In new bone formation area, Group II was more higher than Group I with statistically significances. Both of group, after 4 weeks area is little bit higher than after 2 weeks area but there is no statistically significances. Conclusion: RBM implant was better than machined implant on the early bone formation.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.36 no.3
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• pp.161-171
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• 2010

Introduction: This study was to assess the effectiveness of new bone formation and regeneration by using a rhBMP-2 and $\beta-TCP$ as a carrier in rabbits’mandible. Materials and Methods: The mandibles of 36 rabbits were exposed and cortical bone was penetrated for this study. The experimental subjects were divided into 3 groups each 12 rabbits ; control group, experimental group 1, and experimental group 2. Control group had the defect itself without any treatment, in the experimental group 1, $\beta-TCP$P only was grafted, and in the experimental group 2, rhBMP-2 soaked in $\beta-TCP$ was grafted. The rabbits were sacrificed after 1, 2, 3, 4, 6, and 8weeks, and new bone formation area was examined and measured for bone quantitative and qualitative analysis with light, fluorescent and polarized microscopy. Results: In the experimental group 1, new bone formation from the adjacent host bone was made by osteoconduction, and in the experimental group 2, direct new bone formation by osteoinduction of rhBMP-2 as well as new bone formation by osteoconduction of $\beta-TCP$ were observed. Conclusion: rhBMP-2 of experimental group 2 is very effective in the bone formation in early 2weeks and bone remodelling from 3weeks.

• Journal of Korean Institute of Industrial Engineers
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• v.28 no.4
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• pp.360-367
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• 2002

The machine-part group formation is to group the sets of parts having similar processing requirements into part families, and the sets of machines needed to process a particular part family into machine cells. The purpose of this study is to develop a two-phase machine-part group formation algorithm based on Self-Organizing Maps (SOM). In phase I, it forms machine cells from the machine-part incidence matrix by means of SOM whose output layer is one-dimension and the number of output nodes is the twice as many as the number of input nodes in order to spread out the input vectors. In phase II, it generates part families which are assigned to machine cells by means of machine ratio related with processing part and it gives machine-part group formation. The proposed algorithm performs remarkably well in comparison with many well-known algorithms for the machine-part group formation problems.

• Journal of Institute of Control, Robotics and Systems
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• v.20 no.12
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• pp.1225-1230
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• 2014

This paper investigates the group average-consensus and group formation-consensus problems for first-order multi-agent systems. The control protocol for group consensus is designed by considering the positive adjacency elements. Since each intra-group Laplacian matrix cannot be satisfied with the in-degree balance because of the positive adjacency elements between groups, we decompose the Laplacian matrix into an intra-group Laplacian matrix and an inter-group Laplacian matrix. Moreover, average matrices are used in the control protocol to analyze the stability of multi-agent systems with a fixed and undirected communication topology. Using the graph theory and the Lyapunov functional, stability analysis is performed for group average-consensus and group formation-consensus, respectively. Finally, some simulation results are presented to validate the effectiveness of the proposed control protocol for group consensus.

• Journal of Periodontal and Implant Science
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• v.29 no.1
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• pp.153-171
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• 1999

The purpose of this study was to evaluate the effect of modified calcium sulfate paste on periodontal regeneration. l-wall intrabony defect(mesio-distal width: 4mm, depth: 4mm) was surgically created on the distal side of P2 and mesial side of p4 in four dogs. The control group(GFS) was treated with conventional flap operation alone, and the experimental group(CS) was treated with conventional flap operation with modified calcium sulfate paste application. Both control and experimental groups were sacrificed after 8weeks of healing period, The results of histological and histometric observations were as follows. 1. The length of the junctional epithelium was 0.41${\pm}$0.01mm in the control groups, 0.47${\pm}$0.01mm in the experimental group. 2. The connective tissue attachment was 0.28${\pm}$0.02mm(6.15${\pm}$0.28%) in the control group, 0.18${\pm}$0.01mm(3.41${\pm}$0.14%) in the experimental group. The control group showed more connective tissue attachment. 3. The new cementum formation was 3.80${\pm}$0.06mm(84.80${\pm}$0.33%) in the control group, 4.49${\pm}$0.06mm(87.57${\pm}$0.15%) in the experimental group. Both groups showed a lot of new cementum formation. 4. The new bone formation was 1.43${\pm}$0.03mm(32.37%) in the control group, 2.04${\pm}$O.09mm(40.94%) in the experimental group. 5. The inflamatory cells were observed partially around resorbed calcium sulfate in the connective tissue of the experimental group. 6. Partially resorbed calcium sulfate were found within the connective tissue, around alveolar bone, and in the newly formed alveolar bone, On the basis of these results, newly formed calcium sulfate paste enhanced new bone formation and new cementum formation. The resorption rate of calcium sulfate seems to be controlled by the add-in compounds. Thus research about biocompatibility and adequate resorptionrate is required to develop a improved material.

• Journal of Periodontal and Implant Science
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• v.25 no.2
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• pp.341-356
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• 1995

The purpose of this study was to evaluate the effect of demineralized freeze dried bone and demineralized bone gel with guided tissue regeneration treatment around titanium implants with dehisced bony defects and also evaluate space maintaining capacity of demineralized bone gel type and DFDB powder type under e-PTFE membrane. In 3 Beagle dogs, mandibular premolar was extracted and four peri-implant osteotomies were formed for dehiscence. After insertion of implants, the four peri-implant defects were treated as follows. 1) In control group. no graft material and barrier membrane were applied. 2) In experimental group.1, the site was covered only with the e-PTFE membrane. 3) In experimental group 2,received DFDB powder and covered by the e-PTFE membrane. 4) In experimental group 3, demineralized bone gel and e-PTFE membrane were used. By random selection, animals were sacrificed at 4, 8, 12 weeks. The block sectioned specimens were prepared for decalcified histologic evaluation(hematoxylin and eosin staining) and undecalcified histologic evahiation(Von Kossa's and toluidine blue staining) with light microscopy. The results of this study were as follows. 1) In control group, there was a little new bone formation and connective tissue was completely filled in the defect area. 2) Experimental group 1 showed lesser quantity of bone formation as compared to the bone grafted group. Thin vertical growth of new bone formation around implant fixture was shown. 3) Experimental group 2 showed thick bucco-lingual growth of new bone formation and grafted bone particles were almost resorbed in 12 week group. 4) In experimental group 3, most grafted bone particles were not resorbed in 12 week group and thick bucco-lingual bone formation was shown in dehisced defect base area. 5) There was no remarkable differences in space making capacity and new bone formation procedure between demineralized freeze-dried bone powder type and demineralized bone gel type.

• Journal of Intelligence and Information Systems
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• v.12 no.2
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• pp.17-32
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• 2006

Recently, community computing has been proposed for group formation and group decision-making. However, legacy community computing systems do not support group need identification for ad hoc group formation, which would be one of key features of ubiquitous decision support systems and services. Hence, this paper aims to provide a multi-agent based methodology to enable nomadic community computing which supports ad hoc need identification and group formation. Focusing on supporting group decision-making of relatively small sized multiple individual in a community, the methodology copes with the following three characteristics: (1) ad hoc group formation, (2) context-aware group need identification and (3) using mobile devices working in- and out-doors. NAMA-US, an RFID-based prototype system has been developed to show the feasibility of the idea proposed in this paper.

• Economic and Environmental Geology
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• v.10 no.1
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• pp.19-35
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• 1977

The study area is located in between Hacheonri and Weolgulri, Jecheon-gun where the formations of Okcheon group and Chosun group come in contact and the stratigraphy and geological age of the Okcheon group have been debated among previous workers. The dolomitic limestone which distributed at Cheongam and Dumusil is clarified as the Hyangsanri dolomite formation and the quartzite distributed at Cheongam and Howeunri as Taehyangsan quartzite formation. The newly named Soorumsan schist interbedded in the Great Limestone Series was previously classified Seochangri formation. It is also classified that the formation formerly named as Seochangri was divided into newly named Manji schist which seems to be correlated to Kemyeongsan and Munjuri formation. The formation formerly named as Buknori is clarified as Hwanggangri formation. The Samtaesan formation has been clarified as the lower and upper limestone beds which belong to the Great Limestone Series. The area divided into two groups, that is, Okcheon system of Pre-cambrian age occupies western part and the Great Limestone Series of Chosun system of Cambro-Ordovician age eastern part of this area. Okcheon system consists in ascending order of Manji schist, Hyangsanri dolomite, Taehyangsan quartzite, Munjuri schist, and Hwanggangri formation of meta-tillite. The Great Limestone Series of Chosun group consists in ascending order of lower limestone, Soorumsan schist, Hoosanri quartzite and upper limestone formations. Busan augen gneiss seems to be igneous origin. Unmetamorphosed shale interbed can be traced in the Soorumsan schist. Previous study (Kims, 1974) reveals that meta-volcanic rocks are distributed from south to north along contact zone of the Okcheon and Chosun groups, and it has been confirmed that the meta-volcanics crop out continuously from the adjacent southern quardrangle into the southern part of the area studied, intruding along the fault zone between the Okcheon and Chosun groups which seems to be upthrust as in the area south. This evidence coincides with Kims' work (1974) which states that the Precambrian Okcheon group is largely overturned and thrusted over the Chosun group.