• Journal of Periodontal and Implant Science
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• v.50 no.5
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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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• v.38
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• pp.2.1-2.9
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• 2016

Background: We reviewed the biological and mechanical properties of porous hydroxyapatite (HA) compared to other synthetic materials. Computer-aided design/computer-aided manufacturing (CAD/CAM) was also evaluated to estimate its efficacy with clinical and radiological assessments. Method: A systematic search of the electronic literature database of the National Library of Medicine (PubMed-MEDLINE) was performed for articles published in English between January 1985 and September 2013. The inclusion criteria were (1) histological evaluation of the biocompatibility and osteoconductivity of porous HA in vivo and in vitro, (2) evaluation of the mechanical properties of HA in relation to its porosity, (3) comparison of the biological and mechanical properties between several biomaterials, and (4) clinical and radiological evaluation of the precision of CAD/CAM techniques. Results: HA had excellent osteoconductivity and biocompatibility in vitro and in vivo compared to other biomaterials. HA grafts are suitable for milling and finishing, depending on the design. In computed tomography, porous HA is a more resorbable and more osteoconductive material than dense HA; however, its strength decreases exponentially with an increase in porosity. Conclusions: Mechanical tests showed that HA scaffolds with pore diameters ranging from 400 to $1200{\mu}m$ had compressive moduli and strength within the range of the human craniofacial trabecular bone. In conclusion, using CAD/CAM techniques for preparing HA scaffolds may increase graft stability and reduce surgical operating time.

• Journal of Yeungnam Medical Science
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• v.8 no.1
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• pp.127-135
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• 1991

Successful middle ear surgery requires the availability of al safe, effective bonding material. Side effect caused by synthetic materials have led to the use of biologic adhesive. However, they carry the risk of transmission of infectious diseases if they are prepared from pooled human blood. The adhesive strength of ammonium sulfate fibrin adhesive produce an adhesive strength that is half that of the homologous commercial product. It is, however, good enough for use in several otolaryngological operations, tympanoplasty, facial nerve repair, reconstruction of ossicles, reconstruction of posterior wall of ear canal and obliteration of frontal sinus and mastoid antrum using bone dust.

• Polymer(Korea)
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• v.30 no.1
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• pp.14-21
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• 2006

Tissue engineering techniques require the use of a porous biodegradable/bioresorbable scaffold, which server as a three-dimensional template for initial cell attachment and subsequent tissue formation in both in vitro and in vivo. Small intestinal submucosa (SIS) has been investigated as a source of collagenous tissue with the potential to be used as biomaterials because of its inherent strength and biocompatibility. SIS-loaded poly(L-lactide-co-glicolide)(PLGA) scaffolds were prepared by solvent casting/particle leaching. Characterizations of SIS/PLGA scaffold were carried out by SEM, mercury porosimeter, and so on. Muscle-derived stem cells can be differentiated in culture into osteoblasts, chondrocytes, and even myoblasts by the controlling the culture environment. Cellular viability and proliferation were assayed by 3-(4,5-dimethylthiazole-2-yl)-2,5-diphenyltetrazolium-bromide(MTT) test. Osteogenic differential cells were analyzed by alkaline phosphatase(ALP) activity. SIS/PLGA scaffolds were implanted into the back of athymic nude mouse to observe the effect of SIS on the osteoinduction compared with controlled PLGA scaffolds. Thin sections were cut from paraffin embedded tissues and histological sections were conducted hematoxylin and eosin (H&E), Trichrome, and von Kossa. We observed that bone formatioin of SIS/PLGA hybrid scaffold as natural/synthetic scaffold was better thean that of only PLGA scaffold. It canb be explained that SIS contains various kinds of bioactive molecules for osteoinduction.

• Journal of Korean Neurosurgical Society
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• v.64 no.4
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• pp.562-574
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• 2021

Objective : This study is to evaluate the efficacy and safety of demineralized bone matrix (DBM) gel versus DBM gel with recombinant human bone morphogenetic protein-2 (rhBMP-2) used in transforaminal lumbar interbody fusion (TLIF). Methods : This study was designed as a prospective, multi-center, double-blind method, randomized study. All randomized subjects underwent TLIF with DBM gel with rhBMP-2 group (40 patients) as an experimental group or DBM gel group (36 patients) as a control group. Post-operative observations were performed at 12, 24, and 48 weeks. The spinal fusion rate on computed tomography scans and X-rays films, Visual analog scale pain scores, Oswestry disability index and SF-36 quality of life (QOL) scores were used for the efficacy evaluation. The incidence rate of adverse device effects (ADEs) and serious adverse device effects (SADEs) were used for safety evaluation. Results : The spinal fusion rate at 12 weeks for the DBM gel with rhBMP-2 group was higher with 73.68% compared to 58.82% for the DBM gel group. The 24 and 48 weeks were 72.22% and 82.86% for the DBM gel with rhBMP-2 group and 78.79% and 78.13%, respectively, for the DBM gel group. However, there were no significant differences between two groups in the spinal fusion rate at 12, 24, and 48 weeks post-treatment (p=0.1817, p=0.5272, p=0.6247). There was no significant difference between the two groups in the incidence rate of ADEs (p=0.3836). For ADEs in the experimental group, 'Pyrexia' (5.00%) was the most common ADE, followed by 'Hypesthesia', 'Paresthesia', 'Transient peripheral paralysis', 'Spondylitis' and 'Insomnia' (2.50%, respectively). ADEs reported in control group included 'Pyrexia', 'Chest discomfort', 'Pain', 'Osteoarthritis', 'Nephropathy toxic', 'Neurogenic bladder', 'Liver function analyses' and 'Urticaria' (2.86%, respectively). There was no significant difference between the two groups in the incidence rate of SADEs (p=0.6594). For SADE in the experimental group, ''Pyrexia' and 'Spondylitis' were 2.50%. SADE reported in the control group included 'Chest discomfort', 'Osteoarthritis' and 'Neurogenic bladder'. All SADEs described above were resolved after medical treatment. Conclusion : This study demonstrated that the spinal fusion rates of DBM gel group and DBM gel with rhBMP-2 group were not significantly different. But, this study provides knowledge regarding the earlier postoperative effect of rhBMP-2 containing DBM gel and also supports the idea that the longer term follow-up results are essential to confirm the safety and effectiveness.

• The Journal of Korean Academy of Prosthodontics
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• v.22 no.1
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• pp.33-50
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• 1984

The purpose of this study was to investigate whether the ashed tooth powder is utilized as an alternative material of the implant to recovery the bony defect. For this purpose its biocompatibility was evaluated comparing to the synthetic calcium phosphate compounds, such as Syntograft and Calcitite, as well as the vacuum firing porcelain (Ceramco Inc.) which is anticipated to use as a matrix to aid sintering. Bony defects to exposure the bone marrow, $3{\times}5$ mm in size, were created in the right and left tibias of fifteen rabbits, and then the ashed tooth powder at $950^{\circ}C$, the porcelain powder, Syhtograft and Calcitite were inserted in the defects of twelve rabbits of the experimental group and the blood clot only was filled in the defects of three rabbits of the control group. The experimental and control rabbits were sacrificed at 1st, 2nd 3rd week after implantation and the histologic examination was performed. The ashed tooth powder in order to make the needed form of the implant was molded using the cylindrical mold 1 cm high, 1 cm in diameter under the pressure of $1000kg/cm^2$ and the ashed tooth powder was sintered at $1100^{\circ}C$ for 1 hour and the mixture of the porcelain powder and the ashed tooth powder at the weight ratio of 7:3, 6:4, 5:5, 4:6 were molded in the same manner and were sintered at $925^{\circ}C$. From this sintered material, square shaped implants were prepared in the dimension of $2{\times}4{\times}6mm$. The prepared implants were surgically placed in the subperiosteum of lateral surfaces of the right and left mandibular bodies. The dogs were sacrificed at 4 weeks, and then the specimens were examined using the light and scanning electron microscopes. The results of this study were obtained as follows: 1. Any inflammatory response was not noted after implanting of the ashed tooth powder, Syntograft, Calcitite and the porcelain powder during the whole experimental period after implantation. 2. Induction of the new bone formation was significantly shown in the ashed tooth powder, Syntograft and Calcitite. 3. The more the porcelain powder was contained in the implants, the more the porosity was and the bigger the pore size was under the scanning electron microscope. And there was ingrowing of the fibrous connective and the osteoid tissue. 4. The osteoid tissues were found to be directly fused to the implant of the ashed tooth powder, and the mixture implant of the porcelain powder and the ashed tooth powder at the weight ratio of 4:6 under the light and scanning electron microscopes.

• The Journal of Korean Academy of Prosthodontics
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• v.48 no.2
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• pp.158-165
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• 2010

Purpose: The objective of the present study was to histologically evaluate durability and bone regeneration capacity of new synthetic membranes in comparison to clinically available collagen membrane. Material and methods: To the skulls of 12 rabbits, we created 4 bone defects of 6 mm in diameter on each of them. Each of defects were covered with at least one of 5 membranes; No membrane, Collagen ($Ossix^{TM}$), PLGA, HA-coated-PLGA and HA-PLGA/PLGA. After 4, 8, 12 weeks, we cut the skulls and dyed with H-E. And then, the histologic observation was done. Results: In current study, the control group which did not use the membrane showed bone regeneration at 12 weeks and covered the bone defect partially. New bones were formed through the underneath of endocranium, and the upper defect was filled with connective tissues and fats. Collagen membrane ($Ossix^{TM}$) showed new bones after 4 weeks, and they were formed through the membrane which maintained until 12 weeks. PLGA, HA-coated-PLGA, HA-PLGA/PLGA showed bone regeneration after 4 weeks and after 8 weeks, they mostly filled defects. At 12 weeks, we could find new bones and previous bones almost look alike and also, they united well. Membranes were unnoticeable after 4 weeks and were absorbed. Conclusion: Bone formation and maturation of PLGA, HA-coated-PLGA and HA-PLGA/PLGA were faster than the control group. They showed no difference on the application of HA and after 4 weeks, they were absorbed.

• Journal of Periodontal and Implant Science
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• v.49 no.4
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• pp.215-227
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• 2019

Purpose: To histologically characterize periodontal healing at 8 weeks in surgically created dehiscence defects in beagle dogs that received a collagen matrix with periodontal ligament (PDL) progenitor cells. Methods: The bilateral maxillary premolars and first molars in 6 animals were used. Standardized experimental dehiscence defects were made on the buccal side of 3 premolars, and primary culturing of PDL progenitor cells was performed on the molars. Collagen matrix was used as a scaffold and a delivery system for PDL progenitor cells. The experimental sites were grafted with collagen matrix (COL), PDL progenitor cells with collagen matrix (COL/CELL), or left without any material (CTL). Histologic and histomorphometric analyses were performed after 8 weeks. Results: The defect height from the cementoenamel junction to the most apical point of cementum removal did not significantly differ across the CTL, COL, and COL/CELL groups, at $4.57{\pm}0.28$, $4.56{\pm}0.41$, and $4.64{\pm}0.27mm$ (mean ${\pm}$ standard deviation), respectively; the corresponding values for epithelial adhesion were $1.41{\pm}0.51$, $0.85{\pm}0.29$, and $0.30{\pm}0.41mm$ (P<0.05), the heights of new bone regeneration were $1.32{\pm}0.44$, $1.65{\pm}0.52$, and $1.93{\pm}0.61mm$ (P<0.05), and the cementum regeneration values were $1.15{\pm}0.42$, $1.81{\pm}0.46$, and $2.57{\pm}0.56mm$ (P<0.05). There was significantly more new bone formation in the COL/CELL group than in the CTL group, and new cementum length was also significantly higher in the COL/CELL group. However, there were no significant differences in the width of new cementum among the groups. Conclusions: PDL progenitor cells carried by a synthetic collagen matrix may enhance periodontal regeneration, including cementum and new bone formation.

• Journal of Periodontal and Implant Science
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• v.26 no.3
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• pp.605-624
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• 1996

Various bonegraft materials and the technique of guided tissue regeneration have been used to regenerate lost periodontal tissue. Calcium sulfate has been known as a bone graft material because of good biocompatibility, rapid resorption and effective osteoinduction. It has been known that calcium sulfate works as a binder to stabilize the defect when it is used with synthetic graft materials. The effects on the regeneration of pericxiontal tissue were studied in dogs after grafting 3-wall intrabony defects with calcium carbonate and calcium sulfate and covering with calcium sulfate barrier. The 3-wall intrabony defectstdmm width, 4mm depth, 4mm length) were created in anterior area and treated with flap operation alone(contol group), with porous resorbable calcium carbonate graft alonetexperirnental group 1), with calcium sulfate graft alonetexperimental group 2) and with composite graft of 80% calcium carbonate and 20% calcium sulfate with calcium sulfate barriertexperimental group 3). Healing responses were histologically observed after 8 weeks and the results were as follows: 1. The alveolar bone formation was $0.59{\pm}0.19mm$ in the control group, $1.80{\pm}0.25mm$ in experimental group 1, $1.61{\pm}0.21mm$ in experimental group 2 and $1.94{\pm}0.11mm$ in experimental group 3 with statistically significant differences between control group and all experimental groups(P<0.05). There were statistically significant differences between experimental group 1 and group 2 (P<0.05). 2. The new cementum formation was $0.48{\pm}0.19mm$ in the control group. $1.72{\pm}0.26mm$ in experimental group 1, $1.43{\pm}0.17mm$ in experimental group 2, $1.89{\pm}0.15mm$ in experimental group 3 with statiscally significant differences between control group and all experimental groups (p<0.05). There were statistically significant differences between experimental group 1 and group 2, and between experimental group 2 and group 3(P<0.05). 3. The length of junctional epithelium was $1.61{\pm}0.20mm$ in the contol group, $0.95{\pm}0.06mm$ in experimental group 1, $1.34{\pm}0.16mm$ in experimental group 2, $1.08{\pm}0.11mm$ in experimental group 3 with statiscally significant differences between control group and experimental group 1. and btween control group and experimental group 3(p<0.05). There were statistically significant differences between experimental group 1 ,and group 2, and between experimental group 2 and group 3(P<0.05). 4. The connective tissue adhesion was $1.67{\pm}O.20mm$ in the control group, $1.33{\pm}0.24mm$ in experimental group 1. $1.23{\pm}0.16mm$ in experimental group 2, $1.08{\pm}0.14mm$ in experimental group 3 with statistically significant differences between control group and all experimental groups(p<0.05). There were nostatistically significant differences between all experimental groups. As a result, epithelial migration was not prevented when calcium sulfate was used alone, but new bone and cementum formation were enhanced. Epithelial migration was prevented and new bone and cementum formation were also enhanced when calcium carbonate was used alone and when both calcium carbonate and calcium sulfate were used.

• Food Engineering Progress
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• v.21 no.3
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• pp.233-241
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• 2017

Scaffolds of cell substrates are biophysical platforms for cell attachment, proliferation, and differentiation. They ultimately play a leading-edge role in the regeneration of tissues. Recent studies have shown the potential of bioactive scaffolds (i.e., osteo-inductive) through 3D printing. In this study, rice bran-derived biocomposite was fabricated for fused deposition modeling (FDM)-based 3D printing as a potential bone-graft analogue. Rice bran by-product was blended with poly caprolactone (PCL), a synthetic commercial biodegradable polymer. An extruder with extrusion process molding was adopted to manufacture the newly blended "green material." Processing conditions affected the performance of these blends. Bio-filament composite was characterized using field emission scanning electron microscopy (FE-SEM) and energy dispersive X-ray spectroscopy (EDX). Mechanical characterization of bio-filament composite was carried out to determine stress-strain and compressive strength. Biological behaviors of bio-filament composites were also investigated by assessing cell cytotoxicity and water contact angle. EDX results of bio-filament composites indicated the presence of organic compounds. These bio-filament composites were found to have higher tensile strength than conventional PCL filament. They exhibited positive response in cytotoxicity. Biological analysis revealed better compatibility of r-PCL with rice bran. Such rice bran blended bio-filament composite was found to have higher elongation and strength compared to control PCL.