Etiology of Periodontal Diseases Part 1 PDF

Faculty of Dentistry Periodontology I Etiology of Periodontal Disease part (1) Dr : Fatma El-Sayed Assistant professor of Oral medicine, periodontology and oral diagnosis Ass. prof./ Fatma E...

Faculty of Dentistry Periodontology I Etiology of Periodontal Disease part (1) Dr : Fatma El-Sayed Assistant professor of Oral medicine, periodontology and oral diagnosis Ass. prof./ Fatma E. A. Hassanein 1 Table of Contents Intro d uctio n to Perio d o ntal Mechanisms of Plaque Formation 1 5 D iseases 2 Prim ary Etio lo g ical Facto rs 6 Dental Biofilm 3 D ental Plaq ue 7 Biofilm Properties 4 Types of Dental Plaque 8 Factors Affecting Plaque Formation  Periodontal diseases Periodontal diseases are multi-factorial inflammatory diseases. They result from a complex interaction between host and bacteria. Their progression depends on local and systemic factors. Ass. prof./ Fatma E. A. Hassanein 3 ([email protected])  Etiology and pathogenesis of periodontitis Cofactors Supra- und sub- Periodontal gingivale plaque trauma Inflammation Periodontal destruction Genetic Disturbance in factors Immune Immune reaction raction Environment al factors Ass. prof./ Fatma E. A. Hassanein 4 ([email protected])  Etiology: What causes periodontal disease? Today‘s perception: Influence of risk factors Environmental factors and acquired risk factors (also temporary) PMN antibodies Cytookines pathosis Prostanoids CT & bone antigens metabolism MMP Bacterial LPS Host reaction attack Virulence factors Genetic risk Ass. prof./ factors Fatma (life long) E. A. Hassanein 5 ([email protected])  Etiology: What causes periodontal disease? Today‘s perception: Influence of risk factors Environmental factors and acquired risk factors (also temporary) PMN antibodies Cytookines pathosis Prostanoids CT & bone antigens metabolism MMP Bacterial LPS Host reaction attack Virulence factors Genetic risk factors (life long) Ass. prof./ Fatma E. A. Hassanein 6 ([email protected]) Etiology of periodontal disease Primary etiological factor: Microbial dental plaque Secondary etiological factors: Modifying factors Absence of beneficial bacteria Ass. prof./ Fatma E. A. Hassanein 7 ([email protected]) Acquisition of oral flora At birth, the oral mucous membrane is sterile. After 6-10 hrs. there are aerobic flora. At the 6th month (with eruption of teeth) anaerobic bacteria appear in the oral cavity. With continued eruption of teeth, sites as contact areas have a more complex flora. Ass. prof./ Fatma E. A. Hassanein 8 ([email protected]) Bacteria in the Oral Cavity Most oral bacteria are harmless commensals under normal circumstances.. Disease can occur A) Increased bacterial mass or pathogenicity under specific B) Suppression of beneficial bacteria conditions: C) Reduced host response Ass. prof./ Fatma E. A. Hassanein 9 ([email protected]) Healthy Equilibrium Healthy Balance between bacterial plaque aggression and reparative tissue capacity. Imbalance can lead to periodontal diseases. Ass. prof./ Fatma E. A. Hassanein 10 ([email protected])  Differences between bacteria Gram-positive bacteria Gram-negative bacteria Thick peptidoglycan wall (50%) Thin peptidoglycan wall (5-10%) Teichoic acid (major surface Lipopolysaccharide (LPS)/ toxic component/ highly antigenic) Ass. prof./ Fatma E. A. Hassanein 11 ([email protected])  Materia alba Dental plaque dental pellicle Calculus White cheese like soft yellow -grayish is an organic Hard deposit that accumulation deposits that form glycoprotein film forms by A soft accumulation the biofilm firmly derived from the mineralization of of salivary proteins adhering to the tooth saliva and deposited dental plaque ,some bacteria ,many surface on the tooth surface. Generally covered by desquamated Primarily composed Pellicle contains no a layer of epithelial cells ,and of bacteria in a matrix bacteria in its early unmineralized dental occasional of salivary stages, but later on, plaque disintegrating food glycoprotein's and oral bacteria deposit debris extracellular on the pellicle with Lacks organized polysaccharides few epithelial cells structure and is Impossible to remove and PMNs. therefore not as by rinsing or the use complex as dental of sprays plaque. Easily displaced with a water spray. Ass. prof./ Fatma E. A. Hassanein 12 ([email protected])  Microbiology Biofilm, Plaque, Bacterial-cluster Ass. prof./ Fatma E. A. Hassanein 13 ([email protected]) Microbial dental plaque is the primary cause of Primary periodontal diseases. Etiological Factor Plaque composition (Initiating varies among patients and factor) sites. Ass. prof./ Fatma E. A. Hassanein 14 ([email protected]) A structured, resilient, yellow-grayish microbial community. Found on teeth and other oral surfaces. Dental Embedded in a matrix of bacterial and Plaque salivary origin. Firmly adherent to tooth surfaces that they resist wash off by salivary flow. Ass. prof./ Fatma E. A. Hassanein 15 ([email protected])  Dental Plaque Plaque develops naturally on teeth, and forms part of the defense systems of the host by helping to prevent colonization of enamel by exogenous (and often pathogenic) microorganisms (colonization resistance). Ass. prof./ Fatma E. A. Hassanein 16 ([email protected])  Types of Dental Plaque Supragingi Subgingiva val plaque: l plaque: Above the Below the gingival gingival margin. margin. Ass. prof./ Fatma E. A. Hassanein 17 ([email protected])  Types of dental plaque Supragingival Subgingival plaque plaque attached plaque unattached plaque Coronal plaque Marginal plaque Tooth associated Epithelium associated Connective tissue associated Ass. prof./ Fatma E. A. Hassanein 18 ([email protected]) Classification Based on its relationship to the gingival margin ,plaque is differentiated into two categories Types Supragingival plaque Subgingival plaque ▪Clinically ▪ it can be detected clinically only after it reached a ▪Identified only by running the end detected by: certain thickness after 1 to 2 days with no oral of a probe around gingival margin hygiene..small amount of plaque detected by using Disclosing agent. ▪Color ▪Grey to yellowish-grey ▪Within the gingival sulci or ▪Location ▪At or above the gingival margin periodontal pocket ▪Composition ▪50% matrix ▪Little or no matrix (matrix) ▪Flora ▪Mostly gram positive ▪mostly gram negative ▪Motile bacteria ▪Few ▪Common ▪Anaerobic/ ▪Aerobic unless thick ▪Highly anaerobic aerobic ▪Metabolism ▪Predominantly carbohydrates ▪Predominantly proteins ▪Types ✓Coronal plaque: only on tooth surface ✓Unattached ✓Marginal plaque: which is associated with the tooth ✓ Attached(tooth associated , surface at the gingival margin epithelum asso ,connective tissue Ass. prof./ Fatma E. A. Hassanein associated 19 ([email protected])  Supragingival Plaque Supragingival plaque Dominated by: Gram +ve facultative cocci mainly Streptococci and rods mainly Actinomyces species Ass. prof./ Fatma E. A. Hassanein 20 ([email protected])  Subgingival Plaque o Subgingival plaque subdivided into: Tooth-associated: Gram-positive cocci and rods. Streptococci and Actinomyces species - Tissue-associated: Loosely organized, predominantly gram-negative bacteria. (Prophyromonas gingivalis, Prevotella intermedia, Aggregatibacter actinomycitim cometans, Capnocytophaga) Apical bacteria lying free within the pocket Ass. prof./ Fatma E. A. Hassanein 21 ([email protected]) Plaque Composition Cells: Intercellular Bacterial matrix: cells, Organic and epithelial inorganic cells, materials. leukocytes, macrophages. Ass. prof./ Fatma E. A. Hassanein 22 ([email protected])  Organic constituents: Polysaccharides, proteins, glycoproteins, lipids, DNA. Intercellular Matrix Inorganic constituents: Calcium, phosphorus, and trace minerals. Ass. prof./ Fatma E. A. Hassanein 23 ([email protected])  Phases of plaque formation Pellicle Bacterial Biofilm formation proliferation Bacteria colonization Plaque maturation , Clean Adsorption of Secondary primary colonization colonization coagregation hard salivary surface by individual organisms components Ass. prof./ Fatma E. A. Hassanein 24 ([email protected]) Phase I Phase II Phase III Phase IV Phases of plaque formation Adsorption Pellicle formation (Phase 1) Retention Bacterial accumulation (Phase 2) Adhesion Tooth surface: Ecological niches for Primary colonizers (early colonizers) Mitosis Bacterial proliferation (Phase 3) Cohesion Primary colonizers as suitable surface for late colonizer Metabolism Biofilm organization (Phase 4) Matrix formation Differentiation Matrix formation Extension Establishing of plaque Subgingival propagation Ass. prof./ Fatma E. A. Hassanein 25 ([email protected]) Phases of plaque formation Pellicle formation Bacterial adherence Formation of intermicrobial matrix Bacterial colonization and plaque maturation Dispersion Ass. prof./ Fatma E. A. Hassanein 26 ([email protected]) Phases of plaque formation 1- Pellicle formation Early pellicle (4 h) A thin film, 1µm (2 hrs) up to 4 µm (24-48 hrs) on hard nonrenewable surfaces (early pellicle). Caused by adsorption of glycoproteins from the Mature pellicle (days) saliva (mucin) and antibodies. Establishment and incorporation of additional components of GCF and bacterial products (mature pellicle). Ass. prof./ Fatma E. A. Hassanein 27 ([email protected]) Phases of plaque formation 1-Pellicle formation Early pellicle (4 h) Functions of the pellicle: Positive: 1. Protection against desiccation 2. protection against demineralization Mature pellicle (days) 3. support the remineralization Negative: Prerequisite for bacteria deposition Ass. prof./ Fatma E. A. Hassanein 28 ([email protected]) Phases of plaque formation Pellicle formation Bacterial adherence Formation of intermicrobial matrix Bacterial colonization and plaque maturation Dispersion Ass. prof./ Fatma E. A. Hassanein 29 ([email protected]) Phases of plaque formation 2- Bacterial adherence - Plaque formation with bacteria deposition - Within 2 days 10-20 cell layers Ass. prof./ Fatma E. A. Hassanein 30 ([email protected])  Phases of plaque formation 2- Bacterial adherence a) Transport to the Surface Initial transport of bacteria to the tooth surface. Random contact through sedimentation or active movement. Saliva flow or mechanical contact may be more important than bacterial motility. Ass. prof./ Fatma E. A. Hassanein 31 ([email protected])  Phases of plaque formation 2- Bacterial adherence b) Initial Adhesion Reversible adhesion of bacteria to the pellicle. Non-specific interactions. Weak attractive forces via electrostatic and hydrophobic interactions. Adhesion of bacteria through van-der-Waals- forces, with interposed H+ions and Gkykocalix (Pili, Fimbrien) Ass. prof./ Fatma E. A. Hassanein 32 ([email protected])  Phases of plaque formation 2- Bacterial adherence c) Strong Attachment Firm anchorage between bacteria and the pellicle. Specific interactions between adhesins and receptors form (Irreversible Adhesion). Determines whether bacteria will remain on the surface. Adhesins in the Glycocalyx (Lectin: Protein + sugar residue) bind specifically on the pellicle surface Saliva can block adhesins through salivary aggultinin or secretory immunoglobulin A Ass. prof./ Fatma E. A. Hassanein 33 ([email protected]) Phases of plaque formation Pellicle formation Bacterial adherence Formation of intermicrobial matrix Bacterial colonization and plaque maturation Dispersion Ass. prof./ Fatma E. A. Hassanein 34 ([email protected]) Phases of plaque formation 3- Formation of intermicrobial matrix Organic substances formed of polysaccharides: 1. Glucans: Sticky adhesive material, role in colonization. 2. Levans: Energy source when hydrolyzed. 3. Mutans: Non-degradable, act as a skeleton, role in irreversible adhesion. Ass. prof./ Fatma E. A. Hassanein 35 ([email protected]) Phases of plaque formation Pellicle formation Bacterial adherence Formation of intermicrobial matrix Bacterial colonization and plaque maturation Dispersion Ass. prof./ Fatma E. A. Hassanein 36 ([email protected])  Phases of plaque formation 4- Bacterial colonization and plaque maturation Plaque Division of Secondary Tertiary maturation and attached cells. colonizers. colonizers. concept of biofilm. Ass. prof./ Fatma E. A. Hassanein 37 ([email protected])  4-Bacterial Colonization and Plaque Maturation a) Division of the attached cells B) Secondary colonizers C) Tertiary colonizers After one week of plaque Mature plaque mass creating an oxygen accumulation, other Gram-negative deprived environment dominated by species may also be present in Division of the attached cells to gram negative anaerobic plaque. produce confluent growth. microorganisms which contribute to These species represent what is an increased pathogenicity of the considered to be the "tertiary plaque biofilm. colonizers" ❑ Outgrowth Once attached, pioneer species multiply. ❑ The forming micro-colony ❑ The secondary colonizers include spreads first in the plane of the Gram-negative species such as: 1. Porphyromonas gingivalis (PG) surface (Horizontal) and then, 2. Campylobacter rectus, as space becomes limited, 1. Fusobacterium nucleatum 3. Eikenella corrodens, ❑ upwards creating palisades of (F.n), 4. Aggregatibacter cells. 2. Prevotella intermedia, (P.i) actinomycetem comitans, (A.a) 1. Streptococci and rods 3. Capnocytophaga species. 2. Actinomyces species Ass. prof./ Fatma E. A. Hassanein 38 ([email protected]) 4-Bacterial Colonization and Plaque Maturation Ass. prof./ Fatma E. A. Hassanein 39 ([email protected]) Phases of plaque formation 4- Bacterial colonization and plaque maturation d) Maturation of dental plaque The transition from early supra-gingival dental plaque to mature plaque growing below the gingival margin involves a shift in the microbial population from primarily gram-positive organisms to high numbers of gram-negative bacteria. Ass. prof./ Fatma E. A. Hassanein 40 ([email protected]) Phases of plaque formation Pellicle formation Bacterial adherence Formation of intermicrobial matrix Bacterial colonization and plaque maturation Dispersion Ass. prof./ Fatma E. A. Hassanein 41 ([email protected]) Phases of plaque formation 5- Dispersion Detachment of planktonic bacteria from the biofilm. Rolling, detaching in clumps, or swarming and seeding. Rapid multiplication and dispersal. Ass. prof./ Fatma E. A. Hassanein 42 ([email protected])  Biofilms are barriers that composed of microbial cells encased within a Dental plaque matrix of extracellular as a biofilm polymeric substances, such as polysaccharides, proteins, and nucleic acids. Ass. prof./ Fatma E. A. Hassanein 43 ([email protected])  Biofilm Structure ❑ Contains areas of high and low bacterial masses. ❑ Connected with aqueous channels. ❑ Channels provide nutrients and facilitate waste removal. Ass. prof./ Fatma E. A. Hassanein 44 ([email protected]) Microcolonies Bacteria grouped in microcolonies. Increased Surrounded by resistance to an antimicrobial intermicrobial agents. matrix. Biofilm protects bacteria from harmful substances. Ass. prof./ Fatma E. A. Hassanein 45 ([email protected])  Oral biofilm (dental plaque) Microcolonies surrounded by glycocalyx. Glycocalyx: composed of exopolysaccarides produced by bacteria. Biofilm contains water channels that permit passage of nutrients and waste products. Provides cell to cell communication and transfer of genetic information so they can change in response to their environment. Ass. prof./ Fatma E. A. Hassanein 46 ([email protected]) Oral biofilm (dental plaque) Functions 1. Defense against host protective mechanisms as well as antimicrobial agents. 2. Protects microorganisms from exogenous factors. 3. Permits cooperative interactions between bacterial cells of same or different species. 4. Organisms can be released from biofilm to colonize other sites. Ass. prof./ Fatma E. A. Hassanein 47 ([email protected])  A. Interactions among bacteria Properties B. Communication between bacteria of Biofilm C. Biofilms and antimicrobial resistance Ass. prof./ Fatma E. A. Hassanein 48 ([email protected])  A-Interactions Among Bacteria Metabolic byproducts of one species can be utilized by another. Early colonizers create anaerobic conditions for other species. Ass. prof./ Fatma E. A. Hassanein 49 ([email protected]) B- Communication Between Bacteria Bacteria communicate through quorum sensing. Signaling molecules trigger gene expression changes at a critical threshold concentration. Ass. prof./ Fatma E. A. Hassanein 50 ([email protected]) C- Biofilms and Antimicrobial Resistance Bacteria in biofilms are more resistant to antimicrobial agents. Resistance mechanisms vary among species, antibiotics, and habitats. Ass. prof./ Fatma E. A. Hassanein 51 ([email protected]) Factors Affecting Plaque Formation 1-Topography of supragingival plaque 2-Surface microroughness 3-Individual variables 4-Variation within the dentition 5-Impact of gingival inflammation 6-Impact of patient's age Ass. prof./ Fatma E. A. Hassanein 52 ([email protected])  1-Topography of Supragingival Plaque Early plaque formation on teeth follows a typical topographic pattern, with initial growth along the gingival margin and from the interdental spaces (i.e., the areas protected from shear forces). Later, a further extension in the coronal direction can be observed. Irregularities on the tooth surface can alter the pattern. Ass. prof./ Fatma E. A. Hassanein 53 ([email protected]) 2- Surface Microroughness Rough surfaces accumulate and retain more plaque and calculus. Examples: Crown margins, implant abutments, denture bases. Ass. prof./ Fatma E. A. Hassanein 54 ([email protected])  3-Individual Variables Rate of plaque formation differs among individuals. Heavy (fast) vs. light (slow) plaque formers. Ass. prof./ Fatma E. A. Hassanein 55 ([email protected]) 4- Variation Within the Dentition Plaque growth rate varies within a dental arch. Faster formation in the lower jaw, molar areas, buccal surfaces, and interdental regions. Ass. prof./ Fatma E. A. Hassanein 56 ([email protected]) 5- Impact of Gingival Inflammation Plaque formation is more rapid on tooth surfaces facing inflamed gingiva. Ass. prof./ Fatma E. A. Hassanein 57 ([email protected]) 6- Impact of Patient's Age Age does not influence de novo plaque formation. Older patients may have increased susceptibility to gingivitis. Ass. prof./ Fatma E. A. Hassanein 58 ([email protected]) Ass. prof./ Fatma E. A. Hassanein 59