• Journal of Korean Neurosurgical Society
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• 제51권6호
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• pp.323-327
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• 2012

Objective : The purpose of this study was to verify the appropriateness of ovariectomized rats as the osteoporosis animal model. Methods : Twelve female Sprague-Dawley rats underwent a sham operation (the sham group) or bilateral ovariectomy [the ovariectomy (OVX) group]. Eight weeks after operations, serum biochemical markers of bone turnover were analyzed; osteocalcin and alkaline phosphatase, which are sensitive biochemical markers of bone formation, and C-terminal telopeptide fragment of type I collagen C-terminus (CTX), which is a sensitive biochemical marker of bone resorption. Bone histomorphometric parameters and microarchitectural properties of 4th lumbar vertebrae were determined by micro-computed tomographic (CT) scan. Results : The OVX group showed on average 75.4% higher osteocalcin and 72.5% higher CTX levels than the sham group, indicating increased bone turnover. Micro-CT analysis showed significantly lower bone mineral density (BMD) (p=0.005) and cortical BMD (p=0.021) in the OVX group. Furthermore, the OVX group was found to have a significantly lower trabecular bone volume fraction (p=0.002). Conclusion : Our results showed that bone turnover was significantly increased and bone mass was significantly decreased 8 weeks after ovariectomy in rats. Thus, we propose that the ovariectomized rat model be considered a reproducible and reliable model of osteoporosis.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제26권3호
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• pp.270-278
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• 2000

This study was conducted to compare the vein graft with the nerve graft, and evaluated the availability of the vein graft on the reconstruction of the inferior alveolar nerve defect. The experimental animals were 12 rabbits weighing $1.5{\sim}2.0kg$, divided into 3 groups : sham operation group, vein conduit group and nerve graft group. All nerves were excised and histomorphometric analysis was performed at 2, 4, 6, 12, 16 weeks after operation. The obtained results were as follows. 1. Histologic examination revealed the regenerated nerve fibers within the lumen of the vein graft and nerve graft at 6 weeks after repair. 2. Axon diameter was significantly larger in nerve graft group(p<0.05) than in vein graft group at 6weeks, and larger in nerve graft group than in vein graft group at 16weeks. 3. Axon density was higher in the vein graft group at 16 weeks. 4. The myelin of the regenerated nerve fibers in distal segment of the vein graft group was thick, approaching the proximal segment at 16weeks. This means remyelination in distal segment in the vein graft group. These results suggested that autogenous vein graft may be used as an alternative to autogenous nerve graft.

• Journal of Periodontal and Implant Science
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• 제47권4호
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• pp.194-210
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• 2017

Purpose: The aim of the present study was to evaluate the healing of post-extraction sockets following alveolar ridge preservation clinically, radiologically, and histologically. Methods: Overall, 7 extraction sockets in 7 patients were grafted with demineralised bovine bone mineral and covered with a porcine-derived non-crosslinked collagen matrix (CM). Soft tissue healing was clinically evaluated on the basis of a specific healing index. Horizontal and vertical ridge dimensional changes were assessed clinically and radiographically at baseline and 6 months after implant placement. For histological and histomorphometric analysis, bone biopsies were harvested from the augmented sites during implant surgery 6 months after the socket preservation procedure. Results: Clinically, healing proceeded uneventfully in all the sockets. A trend towards reduced horizontal and vertical socket dimensions was observed from baseline to the final examination. The mean width and height of resorption were 1.21 mm (P=0.005) and 0.46 mm (P=0.004), respectively. Histologically, residual xenograft particles ($31.97%{\pm}3.52%$) were surrounded by either newly formed bone ($16.02%{\pm}7.06%$) or connective tissue ($50.67%{\pm}8.42%$) without fibrous encapsulation. The CM underwent a physiological substitution process in favour of well-vascularised collagen-rich connective tissue. Conclusions: Socket preservation using demineralised bovine bone mineral in combination with CM provided stable dimensional changes of the alveolar ridge associated with good reepithelialisation of the soft tissues during a 6-month healing period.

• Journal of Periodontal and Implant Science
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• 제50권5호
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• pp.327-339
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• 2020

Purpose: The purpose of this study was to examine the local tissue reactions associated with 3 different poly(lactic-co-glycolic acid) (PLGA) prototype membranes and to compare them to the reactions associated with commercially available resorbable membranes in rats. Methods: Seven different membranes-3 synthetic PLGA prototypes (T1, T2, and T3) and 4 commercially available membranes (a PLGA membrane, a poly[lactic acid] membrane, a native collagen membrane, and a cross-linked collagen membrane)-were randomly inserted into 6 unconnected subcutaneous pouches in the backs of 42 rats. The animals were sacrificed at 4, 13, and 26 weeks. Descriptive histologic and histomorphometric assessments were performed to evaluate membrane degradation, visibility, tissue integration, tissue ingrowth, neovascularization, encapsulation, and inflammation. Means and standard deviations were calculated. Results: The histological analysis revealed complete integration and tissue ingrowth of PLGA prototype T1 at 26 weeks. In contrast, the T2 and T3 prototypes displayed slight to moderate integration and tissue ingrowth regardless of time point. The degradation patterns of the 3 synthetic prototypes were similar at 4 and 13 weeks, but differed at 26 weeks. T1 showed marked degradation at 26 weeks, whereas T2 and T3 displayed moderate degradation. Inflammatory cells were present in all 3 prototype membranes at all time points, and these membranes did not meaningfully differ from commercially available membranes with regard to the extent of inflammatory cell infiltration. Conclusions: The 3 PLGA prototypes, particularly T1, induced favorable tissue integration, exhibited a similar degradation rate to native collagen membranes, and elicited a similar inflammatory response to commercially available non-cross-linked resorbable membranes. The intensity of inflammation associated with degradable dental membranes appears to relate to their degradation kinetics, irrespective of their material composition.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제35권1호
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• pp.13-17
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• 2013

Purpose: This study evaluated the capability of bone formation of silk fibroin particles coated with hydroxyapatites (HA/SF), as bone graft material when put into the calvarial defect of rats. Methods: Twenty Sprague Dawley rats were used for this study and round shaped defects were formed in the center of parietal bones (diameter: 8.0 mm). The defect was filled with (1) HA/SF (experimental group), or (2) left as a vacant space (control group). The animals were sacrificed at 4 or 8 weeks, postoperatively. The specimens were decalcified and stained with Masson's trichrome for histomorphometric analysis. Results: The average of new bone formation was $33.18{\pm}3.10%$ in the experimental group and $20.49{\pm}5.79%$ in the control group at 4 weeks postoperatively. That was $42.52{\pm}7.74%$ in the experimental group and $25.50{\pm}7.31%$ in the control group at 8 weeks postoperatively. The difference between the groups was significantly higher at both 4 weeks and 8 weeks postoperatively (P<0.05). Conclusion: The rat calvarial defect was successfully repaired by HA/SF graft. The HA/SF graft showed more new bone formation compared with the unfilled control.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제36권1호
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• pp.39-42
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• 2010

Maxillary sinus lift and bone graft are used to reconstruct atrophic maxilla molar area for endosseous dental implants. Many different grafting materials and techniques can be used for maxillary sinus bone graft. Bio-$Oss^{(R)}$ has been proposed as bone substitute and successfully utilized as osteoconductive filler. Platelet rich plasma (PRP) is an autologous material with many growth factors, such as PDGF, TGF-$\beta$, IGF, VEGF, facilitating bone healing process. And Platelet poor plasma (PPP) is the by-product in procedure of producing PRP. Six rabbits were used as experimental animal. Both maxillary sinus were grafted with Bio-$Oss^{(R)}$ and PRP, and Bio-$Oss^{(R)}$ and PPP. Rabbits were sacrificed at 4, 8 and 12 weeks. The grafting sites were evaluated by histomorphometric analysis. As a result, using PRP showed excellent bone formation in the early stage, but no further significant effect after that. In late stage, the ability of bone formation of using PRP was even worse than using PPP. The further studies need to be considered in this case.

• The Journal of Advanced Prosthodontics
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• 제2권4호
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• pp.142-147
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• 2010

PURPOSE. One of the major keys to achieve successful osseointegration of the implant is its surface properties. The aim of this study was to investigate the bone response to dental implants with different surface characteristics using the rabbit tibia model. Tricalcium phosphate (TCP) coated, anodic oxidized and turned (control) surfaces were compared. MATERIALS AND METHODS. Seventy two implants were placed in the tibia of eighteen rabbits. Nine rabbits were sacrificed at 3 weeks of healing and the remaining nine were sacrificed at 6 weeks of healing. The bone-to-implant contact (BIC) and the bone volume density (BVD) were assessed by light microscope after 3 and 6 weeks of healing. RESULTS. Statistical analysis showed that no significant differences in the BIC and BVD were observed between the different implant surfaces and the control group at 3 weeks and 6 weeks of healing. Data also suggested that the BVD of all the surfaces showed significant difference at 3 and 6 weeks. CONCLUSION. The present study has showed that osseointegration occurred in all investigated types of surface-treated implants. In the current study all of the threads of the implants were observed to calculate BIC and BVD values (instead of choosing some of the threads from the bone cortex for example), which didn't make BIC or BVD percentage values better than in the control group, therefore the clinical relevance of these results remains to be shown.

• Journal of Periodontal and Implant Science
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• 제45권4호
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• pp.136-144
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• 2015

Purpose: The objective of this study was to comparatively assess the bone regenerative capacity of absorbable collagen sponge (ACS), biphasic calcium phosphate block (BCP) and collagenated biphasic calcium phosphate (CBCP) loaded with a low dose of recombinant human bone morphogenetic protein-2 (rhBMP-2). Methods: The CBCP was characterized by X-ray diffraction and scanning electron microscopy. In rabbit calvaria, four circular 8-mm-diameter defects were created and assigned to one of four groups: (1) blood-filled group (control), (2) rhBMP-2-soaked absorbable collagen sponge (0.05 mg/mL, 0.1 mL; CS group), (3) rhBMP-2-loaded BCP (BCP group), or (4) rhBMP-2-loaded CBCP (CBCP group). The animals were sacrificed either 2 weeks or 8 weeks postoperatively. Histological and histomorphometric analyses were performed. Results: The CBCP showed web-like collagen fibrils on and between particles. Greater dimensional stability was observed in the BCP and CBCP groups than in the control and the CS groups at 2 and 8 weeks. The new bone formation was significantly greater in the BCP and CBCP groups than in the control and CS groups at 2 weeks, but did not significantly differ among the four groups at 8 week. The CBCP group exhibited more new bone formation in the intergranular space and in the center of the defect compared to the BCP group at 2 weeks, but a similar histologic appearance was observed in both groups at 8 weeks. Conclusions: The dose of rhBMP-2 in the present study enhanced bone regeneration in the early healing period when loaded on BCP and CBCP in rabbit calvarial defects.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제34권1호
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• pp.19-27
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• 2008

Thirty-six sinus grafts were performed in 34 patients with an alveolar crest bone height in the posterior maxilla of 3 to 5 mm before grafting. The sinuses were grafted using Bio-Oss alone or mixed with fibrin glue. Group 1 was the control group and included 25 patients who received a xenograft mixed in saline. Group 2 comprised 9 patients who received a xenograft and fibrin glue. The study was further subdivided at the time of 9 months. This histologic study evaluated by hematoxylin-eosin (H&E) and histomorphometric analysis whether fibrin glue in combination with Bio-Oss enhances bone regeneration in sinus floor elevation in humans. The new bone formation was better in Group 2 than in Group 1, but the difference was not significant. The absorption of the graft material was faster in Group 2 than in Group 1, in the short term, but better in Group 1 over the long term, although the difference was not significant. Lamellar bone was formed earlier in Group 1 compared to Group 2, but the difference was not significant. Overall, the surgery site stabilized earlier with new bone formation in Group 2 than in Group 1, but the difference was not significant. Combining a fibrin sealant and Bio-Oss could lead to improved scaffolds for bone tissue engineering based on the synergistic effects of the biomaterials. Therefore, Bio-Oss or Bio-Oss plus Tisseel may be used depending on the situation.

• 대한치과교정학회지
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• 제50권1호
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• pp.42-51
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• 2020

Objective: The objective of this study was to evaluate the effects of cetirizine, a histamine 1 receptor antagonist, on bone remodeling after calvarial suture expansion. Methods: Sixty male Sprague-Dawley rats were divided into 4 groups; the phosphate-buffered saline (PBS)-injected no expansion group, cetirizine-injected no expansion group, PBS-injected expansion group, and cetirizine-injected expansion group, and were observed at 7, 14, and 28 days. Five rats per group were examined at each observation day. Daily injections of cetirizine or PBS were administered to the relevant groups starting 2 weeks prior to expander insertion. A rapid expander was inserted in the calvarial bone to deliver 100 cN of force to the parietal suture. The specimens were prepared for hematoxylin and eosin and tartrate-resistant acid phosphatase (TRAP) staining. Suture opening and bone regeneration were evaluated using microcomputed tomography and bone histomorphometric analysis. Serum blood levels of osteocalcin and carboxy-terminal collagen crosslinks (CTX) were also evaluated. Results: TRAP-positive cell counts and CTX levels decreased while osteocalcin levels increased in the cetirizine-injected expansion group at observation day 28. In the expansion groups, the mineralized area gradually increased throughout the observation period. At day 28, the cetirizine-injected expansion group showed greater bone volume density, greater mineralized area, and narrower average suture width than did the PBS-injected expansion group. Conclusions: Cetirizine injection facilitated bone formation after suture expansion, mostly by suppressing osteoclastic activity. Histamine 1 receptor antagonists may aid in bone formation after calvarial suture expansion in the rat model.