• Journal of Computational Design and Engineering
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• v.3 no.4
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• pp.385-397
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• 2016

Scaffolds are essential in bone tissue engineering, as they provide support to cells and growth factors necessary to regenerate tissue. In addition, they meet the mechanical function of the bone while it regenerates. Currently, the multiple methods for designing and manufacturing scaffolds are based on regular structures from a unit cell that repeats in a given domain. However, these methods do not resemble the actual structure of the trabecular bone which may work against osseous tissue regeneration. To explore the design of porous structures with similar mechanical properties to native bone, a geometric generation scheme from a reaction-diffusion model and its manufacturing via a material jetting system is proposed. This article presents the methodology used, the geometric characteristics and the modulus of elasticity of the scaffolds designed and manufactured. The method proposed shows its potential to generate structures that allow to control the basic scaffold properties for bone tissue engineering such as the width of the channels and porosity. The mechanical properties of our scaffolds are similar to trabecular tissue present in vertebrae and tibia bones. Tests on the manufactured scaffolds show that it is necessary to consider the orientation of the object relative to the printing system because the channel geometry, mechanical properties and roughness are heavily influenced by the position of the surface analyzed with respect to the printing axis. A possible line for future work may be the establishment of a set of guidelines to consider the effects of manufacturing processes in designing stages.

• The Journal of the Korean dental association
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• v.11 no.12
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• pp.783-786
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• 1973

The healing response may very with the tissue, the site and the degree of wound. the author observed histochemically the epithelial regeneration in the har palate wound of healthy male albino rats, varying in age from 120 to 150 days, and weighing about 100 gm. The deep wounds were made antero-posterior linealy by surgical knife to the depth of bone level. They were sacrified by ether anesthesia on 1, 2, 4, 7, 10 and 14 days after wounding. the staining methods used were Mcmanus' PAS reaction, Mowry's modification of the Hale reaction employing Muller's colloidal iron reagent, alloxan-Schiff reaction and hematoxylin-eosin stain. The results were as follows : 1. In the wound healing of hard palate, the epithelium had marked PAS positive reaction in the granular and the prickle cell layers on the from 2nd to 7th day. 2. Alloxan-Schiff reactions of regenerated epithelium were slightly increased on 7th day.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.21 no.2
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• pp.131-138
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• 1999

The purpose of this study is to evaluate the effects of resorbable plate in the healing process of mandibular fracture. Reduction and rigid fixation was carried out on the artificial mandibular fracture site of the rabbits, using a resorbable screw, 1.5mm in diameter and 4.0mm in length, and an absorbable plate 1.5mm in thickness(Lactosorb$^{(R)}$). En block tissue specimens with plate were taken from the rabbits at 4, 6, 8, and 10 weeks intervals and specimen were observed with light microscope under the hematoxylin-eosin staining, to observe the inflammatory reaction and tissue healing process. The following conclusions were drawn: 1. The subject displayed good healing with no signs of detachment of the fixation plate. 2. At 4 weeks, the plate was covered by the connective tissue. Then at 6 weeks, bone regeneration was discovered around the plate. 3. During the period of healing, no inflammatory reaction or foreign body reaction, as a result of using resorbable plate, were observed. 4. At 8 weeks, the initial phase of the absorption of the plate was observed. Then at 10 weeks, macrophage were observed around the plate, indicating the absorption phase was in process. From the above results, it can be determined that when the resorbable plate is applied to rabbit, full recuperation occurs naturally in the absence of inflammatory reaction and foreign body reaction. The selected study is clinically valuable in proving this procedure.

• Journal of Dental Rehabilitation and Applied Science
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• v.32 no.4
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• pp.263-273
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• 2016

In the implant prosthetic procedure, the soft tissue reaction was varied with the material and surface treatment of the abutment. It may be the cause of the peri-implantitis, and hence it can affect the long-term prognosis of the implant prosthesis. Titania and zirconia abutment presented superior biocompatibility and stable soft tissue reaction, while gold alloy abutment showed unfavorable reaction sometimes. A soft tissue reaction can be differed by the surface characteristics even in the same material type. Because rougher surface induces a bacterial attachment, the part contacting a soft tissue should have smooth surface. Additional surface treatment can enhance the cellular response without increasing bacterial attachment. Repeated removal and insertion of the abutment and the shape of the abutment may affect the soft tissue reaction, also. Ultrasonic cleaning and argon plasma cleaning are effective way to clean the retained micro-dust on the customized abutment.

• Restorative Dentistry and Endodontics
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• v.22 no.1
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• pp.305-324
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• 1997

Numerous materials such as amalgam, IRM, SuperEBA, dessicated ZOE, and Ketac-Silver have been used as a root-end filling material or to repair furcation perforations. But so far no material has been found to satisfy all of the requirements of an ideal restorative material. Recently, mineral trioxide aggregate (MTA) has been suggested for use as a root end filling material and for the repair of furcation perforations. The purpose of this study was to compare the effect of MTA on the proliferation of MC3T3/E1 osteoblastic cell, formation of bone nodule, alkaline phosphatase activity, and finally the tissue reaction of bone with those of amalgam, IRM, SuperEBA, dessicated ZOE, and Ketac-Silver. The following conclusions were drawn within the limits of the experimental results : 1. MTA showed a excellent proliferation of osteoblastic cell and Ketac-Silver showed moderate proliferation of osteoblastic cell. The rest of test materials showed no proliferation of osteoblastic cell. 2. Many of definite bone nodules were found in the MTA group. In contrast, Ketac-Silver group showed no definite bone formation but only showed mild sign of bone formation. 3. Alkaline phosphatase activity of Ketac-Silver and MTA showed similar results. But both of them showed higher activity than that of other materials (p<0.005). 4. The tissue reaction to implanted MTA in the calbarium of mouse was milder than that observed with other materials. The tissue reaction of dessicated ZOE showed the worst results among the test materials.

• Journal of Periodontal and Implant Science
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• v.28 no.4
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• pp.559-568
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• 1998

direct bone apposition during bone remodelling. To address these problem, we developed a new ceramic, calcium metaphosphate(CMP), and report herein the biologic response to CMP in subcutaneous tissue, muscle and bone. Porous CMP blocks were prepared by condensation of anhydrous $Ca(H_2PO_4)_2$ to form non-crystalline $Ca(PO_3)_2$. Macroporous scaffolds were made using a polyurethane sponge method. CMP block possesses a macroporous structure with approximate pore size range of 0.3-1mm. CMP blocks were implanted in 8mm sized calvarial defect, subcutaneous tissue and muscle of 6 Newzealand White rabbits and histologic observation were performed at 4 and 6 weeks later. CMP blocks in subcutaneous tissue and muscle were well adapted without any adverse tissue reaction and resorbed slowly and spontaneously. Histologic observation of calvarial defect at 4 and 6 weeks revealed that CMP matrix were mingled with and directly apposed to new bone without any intervention of fibrous connective tissue. CMP blocks didn't show any adverse tissue reaction and resorbed spontaneously also in calvarial defect. This result revealed that CMP had a high affinity for bone and was very biocompatible. From this preliminary result, it was suggested that CMP was a promising ceramic as a bone substitute and tissue engineering scaffold for bone formation.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.28 no.1
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• pp.35-41
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• 2006

It is well known that concentration of C-reactive protein(CRP) in the serum increase as nonspecific reaction of the various tissue injury. The CRP, synthesized in the hepatocyte, is one of 'acute phase proteins' in the serum. The main signal patterns of this protein are regulated by synthesis of interleukin-I secreted from macrophage in the area of tissue injury. Many studies were performed for quantitative analysis for CRP according to various surgical operation, but the study for fracture patients associated with trauma, especially in mandible, are rare. The mandible fracture have intrinsic danger for infection in oral bacteria associated with open wound in oral cavity, and, are difficult for detection of tissue reaction between surgical swelling and infection by facial swelling. In this study, quantitative analysis for CRP associated tissue injury in mandibular fracture and surgical intervention was done, the results were as follows: 1. After initial mandibular trauma, the value of serum CRP diminished sequentially, most high value was presented in post-traumatic 2 days. 2. The CRP was diminished significantly 2 days after surgical intervention, and maintained normal value in 5 days after surgery. 3. The change of CRP are higher value in surgical intervention than initial trauma, it suggested that tissue injury from surgery was severe than trauma. 4. The high value of CRP was obtained in mandibular fracture combined soft tissue injury than no associated soft tissue injury. 5. In measurement of CRP according to surgical approach, highest serum value in patients of combined intra-oral and extra-oral approach was showed, and intra-oral approach, extra-oral approach, in sequential orders. 6. The CRP value are more higher in patient of 2 fracture site than only one fracture site. From the results obtained in this study, CRP has showed different values in mandibular fracture associated with severity of tissue injury and surgical intervention, and quantitative analysis of CRP value in serum can be applied to the clinical management of mandibular fracture.

• Archives of Plastic Surgery
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• v.32 no.3
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• pp.293-298
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• 2005

Osseointegrated prosthetic auricular reconstruction can be classified as either direct or indirect. In the $Br{\aa}nemark $ system of direct osseointegration, implants are placed into the mastoid process of the temporal bone. In the Epitec system of indirect osseointegration, implants are inserted into a three-dimensional carrier plate that is fixed to the mastoid by means of screws. We experienced forty-four cases using the indirect system and seventeen cases using the direct system. We compared with two systems by complications, such as skin reaction, implant loosening, implant loss. There were no specific differences in the skin reaction around the implants and abutments in relation to age or system used. The degree of skin reaction was different according to the conditions around the implant: in cases of virgin microtia, a skin flap was used to cover the implant, in contrast to grafted skin coverage for failed autogenous reconstruction. In both systems, the skin reaction was more severe and frequent in skin flap than in grafted skin. Loosening of the implant was more frequent in the direct system; however, accidental detachment of the implant from the abutment was more frequent in the indirect system. To reduce complications of skin reaction in osseointegrated prosthetic auricular reconstruction, it is important for soft tissue around implant to immobilize. Therefore, grafted skin is better than skin flap as soft tissue around implant. And immobilization of soft tissue around implant by wound dressing is major facter.

• 한국생물공학회:학술대회논문집
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• 2003.10a
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• pp.644-647
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• 2003

Materials currently used as an injectable bulking agent in the dermatologic and urologic fields revealed several drawbacks such as particles migration, inflammatory reaction, allergic reaction, rapid volume shrinkage, and necessity of a donor site. In this study, we have developed injectable biomaterial comprising poly (DL- lactide-co-glycolide)(PLGA) and hyaluronic acid gel to overcome these problems. PLGA is a biocompatible synthetic material and hyaluronic acid is a common substance found in living organisms. We examined the feasibility of injection through needle and tested biocompatibility in animal model. After transplantation, injected sites and distant organs were examined histologically to verify a new tissue formation, inflammation, and particles migrations. Injected volume was maintained approximately 80 percent for 2 months. Results demonstrated that the developed material was injectable through various gauges of needles and induced a new bulking tissue formation without serious inflammatory reaction.

• Restorative Dentistry and Endodontics
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• v.6 no.1
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• pp.17-25
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• 1980

The purpose of this study was to evaluate the pulpal response against calcium hydroxide and zinc oxide containing various concentration of formocresol (0.1, 0.5, 1, 5, 10, 20 and 30%). The experiment was performed on dog's teeth (75 teeth from 5 dogs: Table 1.) and the teeth were routinly treated in laboratory procedures. Followings are the results obtained through microscopical examination. 1. In zinc oxide group, intlammatory reaction was severe in low concentrated formocresol and the (higher the concentration of formocresol the milder the inflammatory reaction was more evident. 2. In zinc oxide group, inflammatory change was milder at 3 weeks than 1 week, and proliferation of young connective tissue was seen at 3 weeks. 3. In calcium hydroxide group, inflammatory change in relation to the concentration of formocresol was not noticeable. 4. In calcium hydroxide group, repair process with decreased inflammatory reaction and fibrosis, and dentin bridge like layer was found at 3 weeks.