1. Introduction of Biomaterials in Medical Fields Dong Kyun Rah, M.D. Department of Plastic Surgery Medical Engineering Yonsei University College of Medicine

2. Classification of Transplantation autograft autograft isograft isograft homograft(allograft) homograft(allograft) heterograft(zenograft) heterograft(zenograft)

3. Graft versus Host Reaction Immunologic immature of host Immunologic immature of host Immunologic suppression of host Immunologic suppression of host Host AB type and Graft AA type Host AB type and Graft AA type

4. Properties of Biomaterials chemically inert chemically inert no toxicity no toxicity no immunogenecity no immunogenecity no potentiation of infection no potentiation of infection efficacy efficacy

5. Artificial Skin 1. Biobrane 2. Transcyte(formerly dermgraft-TC ) 3. Apligraf(Graftskin) 4. Integra 5. Alloderm

6. Biobrane Dow Hickam/Bertek Phamaceuticals, sugar land, Tx Bilaminate membrane consisting of nylon mesh fabric bonded to a thin layer of silicone, The nylon mesh is coated with peptide derived from porcine type I collagen, in order to aid adherence the silicone is semi-permeable. “As the wound heals, Biobrane separates, and can readily be peeled away from the surface.

7. Transcyte(formerly dermgraft-TC ) Aadvanced Tissue Inc, La jolla CA, USA The collagen-coated nylon mesh in Biobrane is seeded with neonatal fibroblast in order to improve its healing properties. As nylon is not biodegradable, this material cannot act as a dermal substitute. Formerly, this fibroblast-seeded Biobrane was known as Dermagraft-TC, where TC stood for temporary cover. The neonatal fibroblast within the Transcyte inner Biobrane are allowed to grow 17 days during which they produce fibronectin, type I collagen, proteoglycan & growth factors.

8. Apligraf(Graftskin) - living skin equivalent, human skin equivalent ( Organogenesis Inc, Canton MA, USA) Apligraf is combining - a gel of type I bovine collagen, - living neonatal allogeneic fibroblast - cornified neonatal allogeneic keratinocyte epidermal layer “ Two different cell type ’composite’ most sophisticated commercially available tissue-engineered product”

9. Integra (Integra life science Corporation, Plainsboro, NJ, USA “The most widely accepted synthetic skin substitute for burn.” Integra is a bilaminar structure, consisting of cross-linked bovine collagen & glycosaminoglycans, coated on one side silicone membrane that provide epidermal function. The pore size is 70 - 200 um: migration of the patient’s endothelial cells & fibroblast. Smaller pores delay, or even prevent, biointegration, whereas larger pores provide an insufficient attachment area for invading host cells..

10. Alloderm ( LifeCell, Woodland, TX, USA) Alloderm is human cadaveric skin dermis epidermis & cellular component of the dermis prior to cryopreservation to avoid immune response” Alloderm functions as a dermal graft but, as it has little barrier function, it is questionable whether it can be classed as a skin substitute for wound closure. Following application to a wound bed, - repopulated by host cells, - revascularised - incorporated into the tissue. “Its role is as a template for dermal regeneration”

11. Bone Substitute for Craniofacial Reconstruction

12. Bone Substitute Bone Hydroxyapatite Polyethylene(Medpor) Methyl methacrylate Proplast Polytetrafluoroethylene(Goretex) Degradable bone substitute

13. Bone Graft inlay graft, demonstration little absorption onlay graft more resorption than inlay graft Salyer : Bone graft in craniofacial surgery. Clin Plast Surg 1987;14:27-35.

14. Donor calvarium, iliac bone, rib bone It seemes that there is less resorption of cranial bone than is the case with rib or iliac bone. But the difference between the resorption rates of cranial and rib or iliac bone comes from the different proportions of the cortical and canellous components

15. Demineralized Bone Pathologic Change - 8-12 weeks: new bone growth was noticed in histologic evaluations. - 12 weeks: Fragmentation of demineralized bone with new bone formation. (hydrolytic enzyme was the main causative factor of this degradation) -4 years: lacking osteocytes(lacunae), osteoblasts on (surface) but active resorption, osteoclasts, and inflammation, fibrous changes were not observed.

16. Advantages pliable, easy to shape to fit craniofacial defect, limitless supply, free from donor morbidity Demineralized bone paste developed demineralized bone paste composed of living osteoblasts of homograft, which theoretically provide osteogenic cells inducing osteogenisis, It can be used in combination with biomaterials such as hydroxyapatite.

17. Hydroxyapatite Hydroxyapatite (HA) forms the principal mineral component of bone constitutes 60% of the calcified human skeleton. Certain marine corals have a structure that is similar to that of human bone.

18. Hydroxyapatite HA have excellent biocompatibility when direct contact with viable bone show osteoconduction & osteointegration. no osteoinductive without growth factors.

19. Ceramic Hydroxyapatite Synthesized in crystal form at low pH heated (sintered) at 700 to 1300 0 C to form a solid mass of HA.( two forms) dense porous

20. Nonceramic Hydroxyapatite Produced by direct crystallization at physiologic pH and temperature without heating to form a structurally stable implant. The dry cement is composed of tetracalcium phosphate dicalcium phosphate Sets in approximately 15 minutes converts to HA within 4 hours

21. Collagraft Bone graft matrix: (Collagen & Zimmer) available for long bone fractures or traumatic bone defects anywhere in the human skeleton Composition purified type I bovine dermal fibrillar collagen (PFC), mixture with 65% ceramic HA 35% of beta tricalcium phosphate (TCP) granules Autogenous bone marrow can be added to the mixture.

22. Polyethylene(Medpor) - simple linear carbon chain structure - it elicits a minimal tissue reaction - standard substance to biomaterials. Property: - The porous structure provides ingrowth of soft tissue(1 week), bone(3 weeks) - easy to carve, difficult to remove Usage: - reconstruct skull base, medium sized cranial defects augmentation face,

23. Methyl Methacrylate used as bone cement, aceptable space filler with no resorption, stronger than skull bone by compression & torsion testing Property: -two different components, mixing powder polymer and a liquid monomer. The chemical reaction is exothermic and the associated toxicity is related to the free monomer. The free monomer has direct vascular effects in experimental animals

24. Proplast composite material consisting of tetrafluorethylene with carbon fibers (Proplast I) or aluminum oxide (Proplast II). not superior to hydroxyapatite, better than silastic, methyl methacrylate, and other solid materials. As Porplast II is white, certain esthetic advantages in facial contour reconstruction. augmentation, the complication rate is relatively low, if used for facial augmentation

25. - If some growing bone, disrupted because not strong enough to withstand the force of the invading fibrous and osseous tissues. - In facial augmentation, infection(4.1%), displacement(3.5%), implant removal (7.6%). It is a porous implant material that is no longer manufactured in the United States.

26. Polytetrafluoroethylene (Gore-tex) microstructure composed of solid nodes & fibrils and host cell migration and collagen deposition between the fibrils. The current Gore-Tex product sold for facial implant is subcutaneous augmentation material (SAM). The advantages of Gore-Tex pliable, minimal foreign body response, absence of nodular scarring.

27. Disadvantages is not rigid enough to be carved. To solve this problems, the SAM implant was reinforced with layers of fluorinated ethylene propylene (FEP) ‘ guided tissue regeneration ’ used for dentolveolar bone augmentation. Overall complication rate is about 1%, with 95% patient satisfaction.

28. A Scientist can not be a Doctor but A Doctor can be a Scientist ! Dr. Murray