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  • Ortopedik ve Dental Malzemeler Yard. Do. Dr. Feride Sermin Utku

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  • Biocompatibility

    Success of implant operation depends on the kind of tissue response to the surgical procedure and any interaction between tissues and implants.

    Biocompatibility entails

    mechanical,

    chemical,

    pharmacological and

    surface compatibility.

    Biocompatibility entails local and systemic response of tissues.

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  • Systemic Effects by Implants PMMA lowers blood pressure due to the reaction toward

    MMA monomers.

    Systemic effects of: biodegradable implants such as absorbable suture and surgical

    adhesives,

    biodegradable polymer scaffolds

    large number of wear and corrosion particles released by metallic and polymeric implants. Various organs have different affinities for different metallic elements.

    Corrosion-resistant metal alloys release some elements into the body. Interfere with physiologic activities.

    Divalent ions may inhibit enzymes.

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  • Systemic Effects by Implants

    Mammary augmentation with silicone gel in a

    silicone rubber envelope. Median 16 years of use.

    Rupture.

    Autoimmune diseases, i.e. Systemic sclerosis and chronic connective tissue inflammation were claimed to have developed after mammary augmentation with silicon.

    T cell memory to silica was observed in the off-spring of women after receiving silicone breast implants.

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  • Carcinogenicity

    Chemical structure and function structural or pharmacological similarity to known carcinogenic agents (aromatic amines, polynuclear aromatic hydrocarbons with multiple ring structures, alkylating agents, aflatoxins, halogenated hydrocarbons, chloroform, polychlorinated biphenyls, pesticides, metallic nickel, cadmium and cobalt)

    Carcinogenecity studies

    Short-term

    Long-term

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  • Response to Implants

    Type of cell Description

    metals (except noble metals) evoke a severe tissue reaction. Less reaction with Titanium due to oxide layer Co-cr and SS must be passivated

    Ceramic, carbon Biocompatible, minimal tissue reaction, sometimes a thin layer of encapsulation

    Glass-ceramic Some glass-ceramics showed direct bonding between implant and bone

    polymers Quite inert if there are no unbound additives antioxidants, fillers, anti-discoloring agents, plasticizers, etc., and free monomers

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  • tissue response

    implant : tissue

    Minimal response Thin collagenous

    membrane encapsulation

    Chemically induced response

    Physically Induced Response

    Acute, mild inflammatory response

    nflammatory response to particulate

    Chronic, severely inflammatory response

    Tissue growth into porous materials

    Necrotic response

    Layer of necrotic debris

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  • Biyomateryallerin Olas Etkileri

    A) biyotolere etki

    Uyguland blgede snrl fibrz bir doku ile evriliyorsa

    B) biyoinert etki

    Uygulanan kemik dokuyla arada snrl fibrz bir doku olmadan birleir. Dokuyla biyomateryal arasnda herhangi bir etkileim olmamaktadr.

    C) Biyoaktif etki

    Biyomateryal uyguland dokuda benzer hcrelerin oluumunu aktive etmektedir.

    D) Toksik etki

    Biyomalzemelerin alerjik, immn, nonimmn, mutajenik, karsinojenik ve enflamatuvar etkileri grlr.

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  • Biyouyumluluk

    Baz aratrmaclar gerekten tam anlamyla biyouyumlu ve biyoinert malzeme olmadn sylemektedirler.

    Bu yzden biyouyumluluk materyal seiminin en nemli parametresidir.

    Biyolojik ortam iin malzeme tasarm, birbiriyle etkileen ayr dinamik unsurun varlndan dolay son derece zordur. Bunlar:

    1. Biyomateryal yzeyinin kimyasal yaps

    2. Aradaki pellikl (arayz) tabakas

    3. Konak hcre yantdr.

    Biyomateryale tutunan pellikl tabakas evreyle fizyolojik etkileime araclk eder. Bu yzden yzey kimyasnn, pellikl komponentlerinin ve adsorbsiyon mekanizmasnn tanmlanmas, oluacak yant kontrol etmede birincil neme sahiptir.

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  • The Defense System/Immune Response Immunity:

    Resistance of the body to microbes

    Elimination of worn-out or damaged body cells

    Destruction of abnormal or mutant cell

    The body reacts to foreign materials in ways to get rid of them.

    Either moved, extruded or walled-off.

    If particulate or fluid, it can be ingested by giant cells and removed.

    Immune response is a stimulus-response sequence of events.

    Immune response:

    Non-specific defense (during the initial exposure to a foreign organism)

    Specific defense

    Humoral (antibodies)

    Cell-mediated (sensitized lymphocytes).

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  • Effector cells of immune system White-blood cells (leukocytes colorless blood corpuscles capable of ameboid

    movement)

    Polymorphonuclear granulocytes

    Neutrophils (50-70%) bone marrow- phagocytosis of bacteria, cell debris and antibody-primed foreign matter

    Eosinophils (1-4 %) bone marrow. Unknown function

    Basophils (0.1 %) bone marrow release of histamine and other chemicals (similar to tissue mast cells)

    Lymphocytes (20-40%) bone marrow and lymphoid tissue. B cells: production of antibodies after transformation into plasma cells. T cells : responsible for cell-mediated immunity

    Monocytes (2-8%) bone marrow. Transformed into tissue macrophages with phagocytic activity.

    Macrophages - major function is phagocytosis of bacteria, cell debris and antibody-primed foreign matter. Found scattered throughout the tissues of the body. In liver, spleen, lymph nodes and bone marrow they form part of the lining of vascular and lymphatic channels.

    Plasma cells - derived from B-lymphocytes in lymphoid tissue and are responsible for humoral immunity

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    1. Neutrophils are short lived. They disintegrate and disappear after 24-48 hours.

    2. Monocytes differentiate into macrophages and these cells are very long-lived. (up to months)

    3. Monocytic emigration may continue for day to weeks, and

    chemostatic factors are activated over longer periods of time.

  • Inflammation- clotting and provisional matrix formation

    Injury to vascularized tissue in the implantation procedure: immediate development of provisional matrix at the implant site. occur early, in minutes to hours following implantation of a device.

    Provisional matrix consists: fibrin, produced by activation of the coagulation and

    thrombosis systems,

    Inflammatory products released by the complement system, activated platelets, inflammatory cells and endothelial cells.

    to provide structural and biochemical components to the process of wound healing. Provisional matrix may be viewed as a naturally derived, biodegradable, sustained release

    system in which mitogens, chemo-attractants, cytokines and growth factors are released to control subsequent wound-healing processes.

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  • Acute inflammation Neutrophils (polymorphonuclear leukocytes, PMNs) and other motile white

    cells emigrate or move from the blood vessels to the perivascular tissues and the injury site.

    Specific receptors for chemostactic agents on the cell membranes of leukocytes are important in the emigration or movement of leukocytes.

    Following the localization of leukocytes at the injury (implant) site, phagocytosis and the release of enzymes occurs following activation of neutrophils and macrophages.

    The major role of the neutrophil in acute inflammation is to phagocytose microorganisms and foreign materials.

    Acute inflammation normally resolves quickly, usually less than 1 week, depending on the extent of injury at the implant site.

    The presence of acute inflammation (PMNs Polymorphonuclear Granulocytes) at the tissue/implant interface at time periods beyond 1 week suggests the presence of an infection. (fig 2)

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  • Acute inflammation

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  • Chronic inflammation

    Persistent inflammatory stimuli lead to chronic inflammation.

    Characterized by:

    Presence of macrophage, monocytes and lymphocytes (production of antibodies)

    Proliferation of blood vessels and connective tissue.

    Factors:

    Chemical and physical properties of the materials in themselves

    Motion in the implant site by the materials

    Infection

    Short durat