• Journal of Periodontal and Implant Science
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• v.50 no.2
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• pp.106-120
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• 2020

Purpose: A new form of porous polyethylene, characterized by higher porosity and pore interconnectivity, was developed for use as a tissue-integrated implant. This study evaluated the effectiveness of porous polyethylene blocks used as an onlay bone graft in rabbit mandible in terms of tissue reaction, bone ingrowth, fibrovascularization, and graft-bone interfacial integrity. Methods: Twelve New Zealand white rabbits were randomized into 3 treatment groups according to the study period (4, 12, or 24 weeks). Cylindrical specimens measuring 5 mm in diameter and 4.5 mm in thickness were placed directly on the body of the mandible without bone bed decortication, fixed in place with a titanium screw, and covered with a collagen membrane. Histologic and histomorphometric analyses were done using hematoxylin and eosin-stained bone slices. Interfacial shear strength was tested to quantify graft-bone interfacial integrity. Results: The porous polyethylene graft was observed to integrate with the mandibular bone and exhibited tissue-bridge connections. At all postoperative time points, it was noted that the host tissues had grown deep into the pores of the porous polyethylene in the direction from the interface to the center of the graft. Both fibrovascular tissue and bone were found within the pores, but most bone ingrowth was observed at the graft-mandibular bone interface. Bone ingrowth depth and interfacial shear strength were in the range of 2.76-3.89 mm and 1.11-1.43 MPa, respectively. No significant differences among post-implantation time points were found for tissue ingrowth percentage and interfacial shear strength (P>0.05). Conclusions: Within the limits of the study, the present study revealed that the new porous polyethylene did not provoke any adverse systemic reactions. The material promoted fibrovascularization and displayed osteoconductive and osteogenic properties within and outside the contact interface. Stable interfacial integration between the graft and bone also took place.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.42
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• pp.5.1-5.9
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• 2020

Immunomodulation is a technique for the modulation of immune responses against graft material to improve surgical success rates. The main target cell for the immunomodulation is a macrophage because it is the reaction site of the graft and controls the healing process. Macrophages can be classified into M1 and M2 types. Most immunomodulation techniques focus on the rapid differentiation of M2-type macrophage. An M2 inducer, 4-hexylresorcinol, has been recently identified and is used for bone grafts and dental implant coatings.

• Proceedings of the Polymer Society of Korea Conference
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• 2006.10a
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• pp.358-358
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• 2006

The graft copolymerization of methyl methacrylate (MMA), butyl acrylate (BA) and acrylamide (AAm) onto oil palm empty fruit bunch (OPEFB) fiber were successfully carried out in aqueous solution using $H_{2}O_{2}/Fe^{2+}$ as initiator. For all monomers the percentage of grafting increases with the amount of monomer and can be controlled by setting the appropriate reaction conditions. The optimum reaction period were found to be 120 minutes for all monomers whereas the optimum temperature and the amount of initiator needed for grafting depend on the type of the monomer used. The mechanisms of grafting vinyl monomer onto OPEFB were proposed. The grafted products were characterized by gravimetric analysis, FTIR and SEM.

• Proceedings of the Korea Concrete Institute Conference
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• 2006.05b
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• pp.77-80
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• 2006

Graft copolymerized polycarboxylate(PC)-type superplasticizers(PCs) which have carboxylic acid with $\pi$ bond among the molecular structure and polyethyleneglycol methyl ether methacrylate(PMEM) were synthesized by free radical reaction and investigated the chemical structure, polymerization condition, and physical and chemical properties. Also, the effects of PCs in the dispersion, adsorption and hydration of cement were evaluated. As the molecular weight of graft chain decreases, the adsorption amount on cement particles increased. It was advantageous for the flow to reduce molar ratio, the lower the side bone molecular weight, and increase the molar ratio, the larger the side bone molecular weight. The hydration reaction speed was highly delayed at day 1, due to increase in molar ratio and reduction in side bone molecular weight, but it was recovered in the days after.

• Fashion & Textile Research Journal
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• v.6 no.3
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• pp.384-392
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• 2004

The purpose of this study is in development of effective filter-type polymer adsorbent for removal of pollutants from wastewater by UV irradiation graft polymerization. Photografting of acrylic acid (AA) on polypropylene (PP) nonwoven fabric using benzophenone (BP) as a photosensitizer was investigated. Inhibition of homopolymerization was achieved by adding various concentrations of $FeSO_4{\cdot}7H_2O$, $CuSO_4{\cdot}5H_2O$ and Mohr's salt. As AA concentration was increased, the degree of grafting was increased as to a specific value and then decreased, and the effect of BP concentration showed the same tendency. It was also found that the degree of grafting increased with reaction time and reaction temperature. Addition of the polyfunctional monomers and $H_2SO_4$ to the grafting system accelerated the photografting. The melting temperature, molecular weight and breaking stress and breaking strain were decreased with the increase in the degree of grafting.

• Textile Coloration and Finishing
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• v.15 no.3
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• pp.154-160
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• 2003

Polypropylene nonwoven fabrics were grafted with acrylic acid by a preirradiation method by using electron beam accelerator. The effect of irradiation dose, storage time, concentration of acrylic acid, reaction temperature, reaction time and Mohr's salt concentration on the degree of grafting were investigated in detail. The grafted Polypropylene nonwoven fabrics were characterized using IR spectroscopy and SEM. The results showed that the degree of grafting increased with increasing absorbed dose and the Mohr's salt in the acrylic acid solution promoted grafting efficiency.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.32 no.1
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• pp.16-22
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• 2010

Objective: Bisphosphonate related osteonecrosis of the jaw (BRONJ) is reported in patients taken bisphosphonate for a long time, however, the mechanism of osteonecrosis in BRONJ was not clarified yet. This study was designed to investigate the effect of short administraion zoledronate on the healing pattern of periosteum and sinus membrane after iliac bone graft into maxillary sinus. Methods: In this study, 18 Newzeland rabbits were used. The animals were divided into 2 group. In the experimental group, rabbits were treated with weekly peritoneal injection (0.06 mg/kg/week) of zoledronate for three times. In the control group, rabbits were treated with saline solution injection instead of zoledronate. Periosteum and sinus membrane were harvested from one rabbit of the experimental group and one of the control group in the fourth week. The autogeneous bone was harvested from ilium and grafted into maxillary sinus. The rabbits were sacrificed at 1, 2, 4 and 8 weeks after bone graft. The healing pattern of periosteum and sinus membrane were evaluated histologically. Results: Inflammatory reaction in the periosteum was less conspicuous and healing process appeared earlier in experimental group compared with control group at 1, 2, 4 weeks. There were no differences of microscopic findings of sinus membrane between both groups at any weeks. Conclusion: Short-term use of zoledronate decreased the inflammatory reaction and enhanced healing process in the periosteum. These findings suggest the possibility that zoledronte suppress the function of macrophages.

• Applied Chemistry for Engineering
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• v.9 no.6
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• pp.935-941
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• 1998

New type of chitosan deriertives was synthesised by graft copolymerization of mono(2-methacryloyl oxyethyl) acid phosphate into chitosan. The reaction conditions showing the highest percentage of grafting were an initiator concentration of $3.5{\times}10^{-3}M$, monomer concentration of 0.19 M, and reaction temperature of $40^{\circ}C$, while rate of grafting showed same value after elapsing 4hours of reaction time. The antifungal activity of chitosan depending on content of free amine and kind of monomer was examined against Candida albicans, Trichophyton rubrum and Trichophyton uiolaceum by shake flask method. The pH value of buffer solution to show the highest antifungal activity was 5.75, and the selectivity of mold strain was observed.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.32 no.2
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• pp.138-141
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• 2006

Introduction : In recent years, vascularized, i.e., living bone grafts, have been widely applied in the field of oral and maxillofacial surgery, as a method of treatment of congenital or acquired non-unions, and a large defects in mandible. The vascularized fibular graft has been especially used for this purpose because of its shape and mechanical strength. The postoperative hypertrophy of grafted fibula is of particular interest to us. Material and methods : This study was undertaken to determine the volume change(indirect methods) and radiographic appearance of a free vascularized fibular graft as it responds to the mechanical and physiologic features of its new environment. In order to elucidate the long term effect on fibular mass after mandibular reconstruction, change in various method of volume change was utilized as indirect measure of change in long-term. Results : The younger the patient, the more prominent and rapid the hypertrophy of the graft. the hypertrophy of the graft never exceeded the diameter of the recipient bone, except for callus enlargement after stress fracture of the grafted bone. Conclusion : Etiologic explanations for this phenomenon have not been clarified in the previeous literature. some of the factors implicated include a periosteal reaction or new bone formation, as seen at the onset of bone union after a fracture in a child, a reaction to the mechanical loading on the graft and a reaction to the circulatory changes resulting from the grafting procedure.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.38 no.1
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• pp.2-8
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• 2012

Introduction: Auto-tooth bone graft material consists of 55% inorganic hydroxyapatite (HA) and 45% organic substances. Inorganic HA possesses properties of bone in terms of the combining and dissociating of calcium and phosphate. The organic substances include bone morphogenetic protein and proteins which have osteoinduction capacity, as well as the type I collagen identical to that found in alveolar bone. Auto-tooth bone graft material is useful as it supports excellent bone regeneration capacity and minimizes the possibility of foreign body reaction,genetic diseases and disease transmission. Materials and Methods: Implant placement combined with osteoinductive regeneration,preservation of extraction socket, maxillary sinus augmentation, and ridge augmentation using block type,powder type, and block+powder type autobone graft materialwere performed for 250 patients with alveolar bone defect and who visited the Department of Oral and Maxillofacial Surgery, College of Dentistry, Dankook University from September 2009 to August 2011. Results: Clinical assessment: Among the 250 patients of auto-tooth bone graft, clinical assessment was performed for 133 cases of implant placement. The average initial stabilization of placed implants was 74 implant stability quotient (ISQ). Radiological assessment: The average loss of crestal bone in the mandible as measured 6 months on the average after the application of prosthesis load was 0.29 mm, ranging from 0 mm to 3.0 mm. Histological assessment: In the histological assessment, formation of new bone, densified lamellated bone, trabecular bones, osteoblast, and planting fixtures were investigated. Conclusion: Based on these results, we concluded that auto-tooth bone graft material should be researched further as a good bone graft material with osteoconduction and osteoinduction capacities to replace autogenous bone, which has many limitations.