• Journal of Korean Society of Forest Science
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• v.107 no.4
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• pp.402-411
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• 2018

This study was conducted to develop ingrowth estimation equations on Pinus densiflora found in Gangwon Province and in the center of Korean Peninsula, based on the National Forest Inventory (NFI)'s permanent sampling plot data. For this study, identical sampling plots in $5^{th}$ and $6^{th}$ NFI data were collected in order to identify ingrowth amounts for the last 5 years. Following two-stage approaches in developing the ingrowth estimation equations, the logistic regression model was used in the first stage to estimate the ingrowth probability. In the second stage, regression analysis on sampling plots with ingrowth occurrence was used to estimate the ingrowth amount. A candidate model was finally selected as an optimal model after a verification based on three evaluation statistics which include mean difference (MD), standard deviation of difference (SDD) and standard error of difference (SED). In results, a logistic regression model based on the number of sampling plot which did not result in ingrowth (model VI), was selected for an ingrowth probability estimation equation and exponential function including the species composition (SC) variable was optimal for an ingrowth estimation equation (model VII). The ingrowth estimation equations developed in this study also evaluated the estimation ability in various forest stand conditions, and no particular issue in fitness or applicability was observed.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.20 no.2
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• pp.127-132
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• 1998

$Medpor^{(R)}$(porous polyethylene) Surgical Implants are used for the augmentation or restoration of bony contour in craniofacial defects. The purpose of this study is to evaluate the ingrowth of soft tissue and bone after application in calvaria of rats. The experiment was carried out in 60 rats. The reflected periosteum was resutured after implantation of $Medpor^{(R)}$ as a experimental site, while in the calvarial bone the reflected periosteum resutured without implantation as a control site. The histologic examination was performed after 1-, 2-, 4-, 8-, 12-, 24-weeks implantation in calvaria of rats. I concluded that there was abundant ingrowth of soft tissue and bone without any adverse tissue response and that it shows good stability.

• Proceedings of the KACD Conference
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• 2003.11a
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• pp.620-620
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• 2003

The purpose of this study was to see the occurrence of the epithelial ingrowth in the periapical lesion and its relevance with the clinical symptoms. The subjects of this study included 129 specimens which were obtained from the apical surgery during the year of 2001-2002. The patterns of epithelial ingrowth were classified as either as either lining or networking. The clinical records were reviewed and the relevance between the clinical symptoms and the pattern of the epithelial ingrowth were evaluated under the light microscope.(중략)

• Macromolecular Research
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• v.15 no.3
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• pp.256-262
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• 2007

The purpose of this study was to determine the effect of surface modification on the fibrovascular ingrowth into porous polyethylene (PE) spheres ($Medpor^{(R)}$), which are used as an anophthalmic socket implant material. To make the inert, hydrophobic PE surface hydrophilic, nonporous PE film and porous PE spheres were subjected to plasma treatment and in situ acrylic acid (AA) grafting followed by the immobilization of arginine-glycine-aspartic acid (RGD) peptide. The surface-modified PE was evaluated by performing surface analyses and tested for fibroblast adhesion and proliferation in vitro. In addition, the porous PE implants were inserted for up to 3 weeks in the abdominal area of rabbits and, after their retrieval, the level of fibrovascular ingrowth within the implants was assessed in vivo. As compared to the unmodified PE control, a significant increase in the hydrophilicity of both the AA-grafted (PE-g-PAA) and RGD-immobilized PE (PE-g-RGD) was observed by the measurement of the water contact angle. The cell adhesion at 72 h was most notable in the PE-g-RGD, followed by the PE-g-PAA and PE control. There was no significant difference between the two modified surfaces. When the cross-sectional area of tissue ingrowth in vivo was evaluated, the area of fibrovascularization was the largest with PE-g-RGD. The results of immunostaining of CD31, which is indicative of the degree of vascularization, showed that the RGD-immobilized surface could elicit more widespread fibrovascularization within the porous PE implants. This work demonstrates that the present surface modifications, viz. hydrophilic AA grafting and RGD peptide immobilization, can be very effective in inducing fibrovascular ingrowth into porous PE implants.

• Journal of the Korean institute of surface engineering
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• v.29 no.2
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• pp.81-92
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• 1996

The cementless fixation of bone ingrowth by porous coatings on artificial hip joint prostheses are replacing polymethylmethacrylate(PMMA) bone cement fixations. However, the major interests in the field of porous metal coating are environmental corrosivity accelerated by metal ion release, deterioration in the mechanical property of the coating, and the mechanical failure of the coatings as well as the substrate. Therefore, the selection of right materials for coatings and the development of porous coating techniques must be accomplished. Because of the existing problems in Ti and Ti alloys which are used extensively, this study is focused on the plasma spraying technique for coating on super stainless steel substrate. In order to determine the optimum conditions which satisfy the requirement for the porous coatings, under the plasma spraying, we selected the experimental parameters which extensively influenced on the characteristics of the coating through the pre-examination. Spray distance has been selected among 120, 160, and 200mm and primary gas flow rate among 70, 100, and 130 SCFH. Current and secondary gas($H_2$) flow rate was fixed at 400A, and 15 SCFH respectively. To understand the characteristics of the coatings, surface morphology, cross-sectional micro-structure, surface roughness, residual stress, and corrosion resistance were elucidated and the best conditions for the bone ingrowth improvement on artificial hip joint prostheses were found.

• Advances in biomechanics and applications
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• v.1 no.2
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• pp.95-109
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• 2014

Peri-acetabular bone ingrowth plays a crucial role in long-term stability of press-fit acetabular cups. A poor bone ingrowth often results in increased cup migration, leading to aseptic loosening of the implant. The rate of peri-prosthetic bone formation is also affected by the polar gap that may be introduced during implantation. Applying a mechano-regulatory tissue differentiation algorithm on a two-dimensional plane strain microscale model, representing implant-bone interface, the objectives of the study are to gain an insight into the process of peri-prosthetic tissue differentiation and to investigate its relationship with implant-bone relative displacement and size of the polar gap. Implant-bone relative displacement was found to have a considerable influence on bone healing and peri-acetabular bone ingrowth. An increase in implant-bone relative displacement from $20{\mu}m$ to $100{\mu}m$ resulted in an increase in fibrous tissue formation from 22% to 60% and reduction in bone formation from 70% to 38% within the polar gap. The increase in fibrous tissue formation and subsequent decrease in bone formation leads to weakening of the implant-bone interface strength. In comparison, the effect of polar gap on bone healing and peri-acetabular bone ingrowth was less pronounced. Polar gap up to 5 mm was found to be progressively filled with bone under favourable implant-bone relative displacements of $20{\mu}m$ along tangential and $20{\mu}m$ along normal directions. However, the average Young's modulus of the newly formed tissue layer reduced from 2200 MPa to 1200 MPa with an increase in polar gap from 0.5 mm to 5 mm, suggesting the formation of a low strength tissue for increased polar gap. Based on this study, it may be concluded that a polar gap less than 0.5 mm seems favourable for an increase in strength of the implant-bone interface.

• Korean Journal of Bronchoesophagology
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• v.3 no.2
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• pp.253-260
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• 1997

Successful regeneration of a cartilage framework using perichondrium has been reported by several authors but there are some arguments surrounding mucosal regeneration. Some authors report that regeneration of mucosa is completed by ingrowth from neighboring tissue but others insist that it occurs via metaplasia from the squamous epithelium. This study was designed to investigate the differences, especially in mucosal regeneration between nonvascularized and vascularized flaps via immunohistochemical study. A morphologic study was carried out to elucidate the characteristics o( the regenerated mucosa which was sutured on the vascularized perichondrium and fabricated in a rabbit ear. A nonvascularized perichondrial-mucosal composite flap with the same dimension was transferred in the control group. BrdU was labelled on both normal mucosa and grafted mucosa in the experimental group without my statistically significant differences. In cytokeratin stain, it was regarded that mucosal coverage of the control group occurred by ingrowth from the neighboring mucosa. It can be conceived that metaplasia of the grafted mucosa occurs in a vascularized composite flap transferred group.

• The Journal of Korean Academy of Prosthodontics
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• v.44 no.2
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• pp.250-263
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• 2006

Statement of problem: Ti-alloy has been used widely since it was produced in the United States in 1947 because it has high biocompatibility and anticorrosive characteristics. Purpose: The pure titanium, however, was used limitedly due to insufficient mechanical charateristics and difficult manufacturing process. Our previous study was focused on the development of a new titanium alloy. In the previous study we found that the Ti-Ta-Nb alloy had better mechanical characteristics and similar anticorrosive characteristics to Ti-6Al-4V Material and methods: In this study, the cytotoxicity of the Ti-Ta-Nb alloy was evaluated by MTT assay using MSCs(Mesenchaimal stem cells) and L929 cells(fibroblast cell line). The biocompatibility of the Ti-Ta-Nb alloy was performed by inserting the alloy into the femur of the rabbits and observing the radiological and histological changes surrounding the alloy implant. Results: 1. In the cytotoxicity test using MSCs, the 60% survival rate was observed in pure titanium, 84% in Ti-6Al-4V alloy and 95% in Ti-10Ta-10Nb alloy. 2. In the animal study, the serial follow-up of the radiographs showed no separation or migration revealing gradual bone ingrowth surrounding the implants. Similar radiographic results were obtained among three implant groups pure titanium, Ti-6Al-4V alloy and Ti-10Ta-10Nb alloy. 3. In the histologic examination of the bone block containing the implants. the bone ingrowth was prominent around the implants with the lapse of time. There was no signs of any tissue rejection, degeneration, or inflammation. Active bone ingrowth was observed around the implants. In the comparison of the three groups, the rate of bone ingrowth was better in the Ti-10Ta-10Nb alloy group than those in pure titanium group or Ti-6Al-4V alloy group. In conclusion, Ti-10Ta-10Nb alloy revealed better biocompatibility in survival rate of the cells and bone ingrowth around the implants. Therefore we believe a newly developed Ti-10Ta-10Nb alloy can replace currently used Ti-6Al-4V alloy to increase biocompatibility and to decrease side effects. Conclusion: In conclusion, Ti-10Ta-10Nb alloy revealed better biocompatibility in survival rate of the cells and bone ingrowth around the implants. Therefore we believe a newly developed Ti-10Ta-10Nb alloy can replace currently used Ti-6Al-4V alloy to increase biocompatibility and to decrease side effects.

• Proceedings of the KOSOMBE Conference
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• v.1997 no.05
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• pp.443-446
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• 1997

• Journal of Ecology and Environment
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• v.46 no.1
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• pp.85-98
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• 2022

Background: Korean white pine (Pinus koraiensis) is a major commercial species, and the importance of the oak trees (Quercus spp.) is increasing due to various factors such as environmental and ecological values. However, more information is required to clearly understand the growth characteristics of these species especially regarding thinning intensity. This study was performed to provide the basic information to develop the silvicultural guideline and field manual by analyzing tree and stand characteristics in line with thinning intensity in the Korean white pine plantation and oak-dominated natural deciduous forest. Results: Diameter at breast height (DBH) and volume changes by the thinning intensity in the Korean white pine plantation were significantly different from those in the oak-dominated deciduous natural forest. In particular, DBH distribution in the pine stand appeared that there were more large diameter trees as the thinning intensity was higher. DBH periodic annual increment (PAI) of the pine stand was higher as the thinning intensity was stronger and the growth period was shorter. This trend was similarly shown in the natural deciduous forest, but the amount of PAI was smaller than in pine stand. The volume PAI after thinning was not decreased over time. In each stand type, the PAI tended to be lower as stand density was higher. The volume PAI in the pine stand was significantly higher than that in the oak-dominated natural deciduous forest. Dead trees occurred the most in the unthinned plots of each stand type, and those were higher in the natural deciduous forest. Ingrowth trees were observed only in the natural deciduous forest, and its distribution was the lowest in unthinned plots; Korean white pine as ingrowth occurred the most frequently among many tree species. Conclusions: Different effects of thinning treatment on DBH and volume PAI, mortality, and ingrowth were observed for each stand. With respect to forest growth, Korean white pine plantation was superior to the oak-dominated natural deciduous forest. The results of this study offer fundamental information for the development of silvicultural guidelines for Korean white pine plantations and oak-dominated natural deciduous forests in Korea.