Lecture 2 - The Microbiology of Periodontal Diseases PDF

Chapter 4 Lecture 2 Microbiology of Periodontal Diseases Copyright © 2014, 2007, 2001, 1996 by Saunders, an imprint of Elsevier Inc.  Virulence the strength (how strong - how m...

Chapter 4 Lecture 2 Microbiology of Periodontal Diseases Copyright © 2014, 2007, 2001, 1996 by Saunders, an imprint of Elsevier Inc.  Virulence the strength (how strong - how much destruction they can produce)  The presence of dental plaque biofilm is essential to the initiation and progression of gingivitis and periodontitis. have to have microorganisms (bacteria)  Studies evaluating the relationship between oral hygiene and periodontal diseases have shown that poor plaque control correlates to a greater prevalence and severity of periodontal diseases. who doesn’t brush very well/or at all = more likely to have disease clinical signs of inflammation Copyright © 2014, 2007, 2001, 1996 by Saunders, an imprint of Elsevier Inc. 2  General Characteristics of Plaque Formation  Dental plaque biofilms are defined as accumulations of microbes on the surface of the teeth or other solid oral structures, not easily removed by rinsing.  Dental plaque biofilms are different than material alba, which are loosely adherent bacteria and tissue debris that can be easily removed by the mechanical action of a strong water spray. disclosing agent (educate client where the plaque is) Copyright © 2014, 2007, 2001, 1996 by Saunders, an imprint of Elsevier Inc. 3  General Characteristics of Plaque Formation (Cont.)  Biofilm is a film of microorganisms bound in the sticky polysaccharide matrix they produce, the glycocalyx. Glycocalyx contains a network of channels and canals that allow for the exchange of nutrients among various microbes and for the removal of their waste products. supplying products nutrients and taking the waste The biofilm structure also provides protection for its microorganisms from invasion by intruders, including other bacteria, antimicrobial drugs, and antiseptic rinses. bacteria will not get killed easily (protection) difficult to kill the all the bacteria and microorganisms because.. 1. protective layer 2. to kill the bacteria, you need a very high dose of antibiotics (maybe combination of antibiotics) mainly gram-negative bacteria - dosage is too high (could possibly kill the person) Copyright © 2014, 2007, 2001, 1996 by Saunders, an imprint of Elsevier Inc. 4  Bacterial Characteristics  Dental plaque biofilm consists mostly of bacteria.  Biofilm is not a random accumulation of assorted types of bacteria but a specific and complex arrangement based on bacterial characteristics. Copyright © 2014, 2007, 2001, 1996 by Saunders, an imprint of Elsevier Inc. 5  Morphotypes  Bacteria can be classified on the basis of their shape or their morphologic characteristics; this classification is referred to as morphotype.  Bacteria may be: Cocci—Round in shape Bacilli—Rod or elongated in shape Spirochetes—Spiral in shape Copyright © 2014, 2007, 2001, 1996 by Saunders, an imprint of Elsevier Inc. 6  Cell Wall Characteristics  Laboratory procedures classify bacteria as either gram positive or gram negative, based on a staining technique that causes gram- positive organisms to stain violet (purple) and gram-negative organisms to stain safranin (red). Copyright © 2014, 2007, 2001, 1996 by Saunders, an imprint of Elsevier Inc. 7  Characteristics of Gram-Positive Bacteria  The capsule is the outer surface component of gram- positive bacteria.  The glycocalyx (sticky extracellular matrix or slime layer) is a loose gel-like polysaccharide substance around the bacteria that is important in bacterial adherence (attachment) to the tooth surface. Copyright © 2014, 2007, 2001, 1996 by Saunders, an imprint of Elsevier Inc. 8  Characteristics of Gram-Negative Bacteria  Most bacteria that are pathogens in periodontal diseases are gram negative.  The outer membrane of the cell wall of gram-negative bacteria is made up of proteins, called receptors, that are important in adherence and contain complex lipopolysaccharides (LPS). Copyright © 2014, 2007, 2001, 1996 by Saunders, an imprint of Elsevier Inc. 9  Characteristics of Gram-Negative Bacteria (Cont.)  LPS, also known as endotoxins, are released when the cell wall is disrupted.  LPS are highly potent destructive substances that directly damage host tissue or cause tissue damage through the activation of host inflammatory responses. inflammation can be excessive and give destruction to the whole tissue  Vesicles (often called microvesicles or blebs) are surface structures containing parts of the outer membrane and therefore contain LPS. Copyright © 2014, 2007, 2001, 1996 by Saunders, an imprint of Elsevier Inc. 10  Cell Surface Appendages  Cell surface appendages are important in the attachment of bacteria to tooth surfaces and to each other.  Fimbriae, or pili, are small proteins that are attached to the external surface of both gram-negative and gram-positive bacteria.  They mediate (act as a go-between) the adherence process to hydroxyapatite. Copyright © 2014, 2007, 2001, 1996 by Saunders, an imprint of Elsevier Inc. 11 Cell Surface Appendages (Cont.)  Flagellae are long, fine, wavy filamentous structures that are used for bacterial movement. Bacteria may have single or multiple flagellae, arranged at either or both ends or distributed around the cell. Copyright © 2014, 2007, 2001, 1996 by Saunders, an imprint of Elsevier Inc. 12  Classification of Periodontal Bacteria  Bacteria are classified on the basis of their characteristics. Aerobic requries oxygen Anaerobic requires no oxygen (absence of oxygen) Facultative Anaerobic mainly requires oxygen but can survive in the absence of oxygen too Copyright © 2014, 2007, 2001, 1996 by Saunders, an imprint of Elsevier Inc. 13  Oxygen Environment  Bacteria are also classified on the basis of their ability to grow in the presence or absence of oxygen.  Bacteria that require oxygen to grow are called aerobes. supragingival  Anaerobes do not need oxygen to grow. (in deep pockets - subgingival)  Facultative anaerobic organisms can grow in both aerobic and anaerobic environments. Copyright © 2014, 2007, 2001, 1996 by Saunders, an imprint of Elsevier Inc. 14  Bacterial Metabolism  Bacteria need nutrients to grow, but their requirements and waste products vary.  Gram-positive organisms, such as Streptococcus mutans, dental carries are fermentative or saccharolytic. These organisms obtain their energy by breaking down complex organic compounds, such as sugars, to smaller end products, such as lactic acid. Copyright © 2014, 2007, 2001, 1996 by Saunders, an imprint of Elsevier Inc. 15  Bacterial Metabolism (Cont.)  Many gram-negative organisms, including those that are pathogens in periodontal disease, are known as nonfermentative or asaccharolytic. These organisms use proteins for energy and growth. less saliva - disease is produced Copyright © 2014, 2007, 2001, 1996 by Saunders, an imprint of Elsevier Inc. 16  Oral Microbial Ecosystems  The oral cavity is made up of several unique environments, or ecosystems, in which microorganisms thrive.  The five major ecosystems are the: where bacteria can live Tongue Buccal mucosa Saliva Supragingival tooth surfaces Subgingival tooth surfaces Copyright © 2014, 2007, 2001, 1996 by Saunders, an imprint of Elsevier Inc. 17  Dorsum of the Tongue  The majority of the microorganisms on the tongue are gram-positive members of the Streptococcus family including Streptococcus salivarius and S. sanguinis. gram-negative is bad  In addition, gram-negative bacteria are associated with halitosis (bad breath) and periodontal diseases in the normal oral microbiota of the tongue, including Porphyromonas gingivalis. enlarged papillae black hairy tongue white hairy tongue tongue cleaning more bacteria = use mouthwash don’t confuse with hairy leukoplakia Copyright © 2014, 2007, 2001, 1996 by Saunders, an imprint of Elsevier Inc. 18  Oral Mucosal Surfaces  Oral mucosal surfaces include the: Buccal mucosa Floor of the mouth Hard and soft palates  Mucosal surfaces are either covered with keratinized epithelium or nonkeratinized epithelium.  Streptococci are the predominant type of bacteria on these surfaces. Copyright © 2014, 2007, 2001, 1996 by Saunders, an imprint of Elsevier Inc. 19  Saliva  Saliva represents an environment for microorganisms that is protective in nature.  Saliva contains shed gingival tissue cells and plaque biofilm from other locations in the oral cavity on their way to being swallowed.  Saliva is involved in the removal of biofilms from within the oral cavity because of fluid movement in the mouth.  Antimicrobial proteins in saliva help regulate microbe attachment to oral cavity surfaces. Copyright © 2014, 2007, 2001, 1996 by Saunders, an imprint of Elsevier Inc. 20  Tooth Surfaces  Tooth-adherent plaque biofilms are classified as either supragingival or subgingival plaque biofilm. Supragingival plaque biofilm is deposited on the clinical crowns of the teeth. Subgingival plaque biofilm is located in the gingival sulcus or periodontal pocket. calculus Copyright © 2014, 2007, 2001, 1996 by Saunders, an imprint of Elsevier Inc. 21  Tooth Surfaces (Cont.)  Small amounts of supragingival plaque biofilm are difficult to detect without placing a disclosing solution on the teeth or scraping the tooth surfaces with an instrument.  As plaque accumulation grows, it becomes visible as a white- yellow mass. plaque needs to be removed with an instrument (even if there is no calculus) Copyright © 2014, 2007, 2001, 1996 by Saunders, an imprint of Elsevier Inc. 22  Tooth Surfaces (Cont.)  Supragingival plaque biofilm forms in sites that are protected from the normal cleansing action of the tongue, cheek, and lips.  Subgingival plaque biofilm can only be observed when it is removed from the pocket with an instrument. Copyright © 2014, 2007, 2001, 1996 by Saunders, an imprint of Elsevier Inc. 23 Copyright line. Slide 24  Tooth Surfaces (Cont.)  Plaque biofilm deposits also form on orthodontic appliances, permanent and temporary restorations including implants fixtures and restorations, fixed and removable partial dentures, and full dentures. inlay (like a filling) Copyright © 2014, 2007, 2001, 1996 by Saunders, an imprint of Elsevier Inc. 25  Supragingival Plaque Formation  The development of dental plaque is a complex and dynamic process that forms in stages. Copyright © 2014, 2007, 2001, 1996 by Saunders, an imprint of Elsevier Inc. 26  Pellicle Formation Step 1 of Plaque Formation  Proteins from the saliva, termed salivary glycoproteins, attach to the tooth surface forming an amorphous and tenacious pellicle. hard to remove with a toothbrush  Toothbrushing does not remove it; only polishing the teeth with an abrasive agent will remove the pellicle.  Pellicle re-forms on the clean tooth surfaces within minutes. Copyright © 2014, 2007, 2001, 1996 by Saunders, an imprint of Elsevier Inc. 27  Pellicle Formation (Cont.) like a foundation of a colony of where it is forming Step 1 of Plaque Formation (cont.)  Pellicle influences the subsequent colonization of bacteria on the tooth surface.  Certain proteins in saliva that form part of the pellicle can enhance the ability of specific microorganisms, such as the Actinomyces species, to bind to tooth surfaces.  Not all of the bacteria available in saliva can attach to the pellicle, only those with binding sites for pellicle constituents. specific attachment Copyright © 2014, 2007, 2001, 1996 by Saunders, an imprint of Elsevier Inc. 28  Initial Bacterial Colonization of Pellicle Step 2 of Plaque Formation  Bacterial cells stick to the pellicle through specific receptor mechanisms.  Oral bacteria vary in their ability to adhere to different surfaces. For example: Streptococcus mutans and S. sanguinis colonize in supragingival plaque. S. salivarius is present in high proportions on the tongue and in saliva. Copyright © 2014, 2007, 2001, 1996 by Saunders, an imprint of Elsevier Inc. 29  Initial Bacterial Colonization of Pellicle (Cont.) made up of gram-positive cocci Step 2 of Plaque Formation (cont.)  The initial plaque biofilm that forms on the pellicle is made up of predominately gram- positive coccal facultative anaerobic bacteria, largely streptococci. Copyright © 2014, 2007, 2001, 1996 by Saunders, an imprint of Elsevier Inc. 30  Initial Bacterial Colonization of Pellicle (Cont.) Step 2 of Plaque Formation (cont.)  The first organisms adhere and form a first layer monolayer of cells, and, within a few hours, these organisms form small colonies.  These microcolonies of cocci form a series of columns that extend out from the pellicle. Copyright © 2014, 2007, 2001, 1996 by Saunders, an imprint of Elsevier Inc. 31  Growth and Maturation of Plaque Step 3 of Plaque Formation  As plaque biofilm matures, it increases in mass and thickness.  Maturation of plaque also requires that different types bacteria cells attach to each other. Copyright © 2014, 2007, 2001, 1996 by Saunders, an imprint of Elsevier Inc. 32  Growth and Maturation of Plaque (Cont.) Step 3 of Plaque Formation (cont.)  The material in the plaque among the bacteria is called the intermicrobial matrix. inbetween the bacteria (forms a protective layer) The intermicrobial matrix is composed of salivary material, gingival exudate, and microbial substances such as polysaccharides. Copyright © 2014, 2007, 2001, 1996 by Saunders, an imprint of Elsevier Inc. 33  Extracellular Polysaccharides  Bacteria, such as Streptococcus mutans, S. sanguinis, S. mitis, and S. salivarius, have the capability to produce metabolic products from sucrose. These products serve as either an energy source or as material to help retain the bacteria in the plaque. Copyright © 2014, 2007, 2001, 1996 by Saunders, an imprint of Elsevier Inc. 34  Extracellular Polysaccharides (Cont.)  Glucosyltransferase is the enzyme that breaks down sucrose into its components— simple sugars, glucan, and fructan.  Fructose is the energy source, whereas glucan helps retain (attach) bacterial organisms. Copyright © 2014, 2007, 2001, 1996 by Saunders, an imprint of Elsevier Inc. 35  Extracellular Polysaccharides (Cont.)  A small amount of lipid and LPS (endotoxin) from gram-negative cell walls is present in plaque.  Inorganic components, primarily calcium and phosphate, is low in early plaque, but it significantly increases as plaque is transformed into calculus. calculus - hard substance contains calcium and phosphate in early plaque (softer) Copyright © 2014, 2007, 2001, 1996 by Saunders, an imprint of Elsevier Inc. 36  Bacterial Coaggregation  Bacterial coaggregation occurs when certain bacteria adhere to previously attached cells in plaque biofilm, forming complex aggregations.  Filament-shaped bacteria become coated with cocci, presenting a “corn cob” appearance. Copyright © 2014, 2007, 2001, 1996 by Saunders, an imprint of Elsevier Inc. 37  Bacterial Coaggregation (Cont.)  Corn cob formation is restricted to species with mutually attractive surface molecules that can bind to each other.  The corn cob complex is made up of a central filament surrounded by cocci, usually a type of S. sanguinis.  The filaments can be either gram-positive Actinomyces species and Corynebacterium matruchotii or gram-negative Fusobacterium nucleatum. dental diseases - lot of belong to strepto p.gingivalis - periodontal disease Copyright © 2014, 2007, 2001, 1996 by Saunders, an imprint of Elsevier Inc. 38  Bacterial Coaggregation (Cont.)  Other bacteria can aggregate together to form structures that resemble “test tubes” or “bristle brushes.” The central axis is made up of a filamentous bacterium, and the bristles are gram- negative rods. Copyright © 2014, 2007, 2001, 1996 by Saunders, an imprint of Elsevier Inc. 39  Bacterial Coaggregation (Cont.)  Generally, early colonizers coaggregate with streptococci or the Actinomyces species, whereas late colonizers primarily coaggregate with the Fusobacteria species. Copyright © 2014, 2007, 2001, 1996 by Saunders, an imprint of Elsevier Inc. 40  Bacterial Coaggregation (Cont.)  In another type of bacterial aggregation, one organism acts as a bridge between two other bacteria that do not interact. acts as a mediator For example, some strains of S. sanguinis aggregate with both Actinomyces naeslundii genospecies and Prevotella loescheii, which do not coaggregate with each other.  These interactions may be an important mechanism for the attachment of new organisms and for the ability of organisms to resist the forces that would remove them. Copyright © 2014, 2007, 2001, 1996 by Saunders, an imprint of Elsevier Inc. 41  Microbial Succession  As plaque ages, its composition changes, which is referred to as microbial succession.  Initial colonizers alter the environment at the tooth surface, enabling new and different bacterial species to inhabit the developing plaque biofilm.  After the first day of plaque growth, the proportion of gram-positive streptococci decreases. Actinomyces and Veillonella strains become more prominent. Copyright © 2014, 2007, 2001, 1996 by Saunders, an imprint of Elsevier Inc. 42  Microbial Succession (Cont.)  During the next 3 weeks, cocci continue to decrease as a result of the increase in filamentous bacteria. These filamentous forms invade the plaque and replace many of the streptococci in the deeper levels of the biofilm. Copyright © 2014, 2007, 2001, 1996 by Saunders, an imprint of Elsevier Inc. 43  Microbial Succession (Cont.)  As the plaque increases in thickness, further changes occur. Plaque becomes anaerobic. This lower oxygen level allows the growth of anaerobes such as spirochetes and gram- negative rods. At this point, no additional bacterial species can join the plaque, although the absolute numbers of bacteria may continue to increase. association wil not allow any members to join (different species of bacteria) change in the microbial from day 1 to finally organized Copyright © 2014, 2007, 2001, 1996 by Saunders, an imprint of Elsevier Inc. 44  Microbial Succession (Cont.)  The most important difference between mature and immature plaque biofilm is that the maturation process gives supragingival plaque the potential to invade the subgingival space and to cause localized gingival disease. initial gingival disease - gingivitis 12-24 hrs - will form - break down the colonies and formation of more advanecd plaque stuff not enough to mature, once it’s matured supra plaque will partly migrate to the subgingival space periodontium includes gingival periodontal disease = gingivitis and periodontitis - disease can subside but the changes are irreversible but no bone will grow back - if it causes recession - no gingiva will grow back Copyright © 2014, 2007, 2001, 1996 by Saunders, an imprint of Elsevier Inc. 45  Subgingival Plaque Formation  The bacterial composition of subgingival plaque is partly influenced by bacteria in the adjacent supragingival plaque. However, the microbiota in subgingival plaque is generally more anaerobic, more gram-negative, more motile, and more asaccharolytic (using proteins rather than sugars for nutrients) than supragingival plaque. more destructive, asaccharolytic - which can use proteins than sugars for energy as compared to supragingival plaque Copyright © 2014, 2007, 2001, 1996 by Saunders, an imprint of Elsevier Inc. 46 attached plaque is more harmful to the tooth in the subgingival area (within the sulcus) more harmful for periodontal (along the disease epithelium) (invade through the epithelium to the connective tissue) how it produces destruction to the epithelial tissue, and bone (bone loss) Copyright line. Slide 47  Subgingival Environment  The maturation of supragingival plaque is accompanied by inflammation in the gingiva.  Because inflamed gingiva is less closely adapted to the tooth surface, the formation of supragingival plaque moves apically into the gingival crevice. Copyright © 2014, 2007, 2001, 1996 by Saunders, an imprint of Elsevier Inc. 48 Subgingival Environment (Cont.)  In addition, edema causes gingival enlargement. The swollen gingival margin covers the supragingival biofilm, which is beneath the gingiva, and permits the growth of anaerobic organisms.  This newly created subgingival space, which is protected from normal oral cleansing mechanisms, facilitates further maturation of plaque biofilm. Copyright © 2014, 2007, 2001, 1996 by Saunders, an imprint of Elsevier Inc. 49 Subgingival Environment (Cont.)  The subgingival environment is bathed in fluid from the plasma in blood vessels, rather than in saliva.  Inflammation in response to plaque organisms causes an increase in capillary permeability, which allows the plasma to escape. Copyright © 2014, 2007, 2001, 1996 by Saunders, an imprint of Elsevier Inc. 50 Subgingival Environment (Cont.)  When the fluid leaks into the gingival crevice it is referred to as the gingival crevicular fluid (GCF).  Inflammation increases the GCF flow, along with gingival bleeding, which results in the presence of proteins that provide excellent sources of nutrients for the bacteria in the biofilm. brushing, probing, flossing can cause bleeding Copyright © 2014, 2007, 2001, 1996 by Saunders, an imprint of Elsevier Inc. 51  Microbiologic Composition  Composition and structure of subgingival plaque is significantly different from supragingival plaque.  Limited access to the oral cavity allows anaerobic bacteria to grow and restricts the addition of salivary bacteria. when the pocket deepens, more anaerobic bacteria  In addition, the subgingival area is not subject to the mechanical forces that dislodge bacteria from teeth.  This allows motile organisms that are completely unattached to the plaque matrix to proliferate and survive. Copyright © 2014, 2007, 2001, 1996 by Saunders, an imprint of Elsevier Inc. 52  Tooth Surface  The structure of the tooth-adjacent biofilm is similar to supragingival plaque.  The microbiota is dominated by gram-positive filamentous bacteria. Gram-positive and gram-negative cocci and rods are also present.  In the apical portion, fewer filamentous organisms are found, and gram-negative rods dominate the bacterial structure. Copyright © 2014, 2007, 2001, 1996 by Saunders, an imprint of Elsevier Inc. 53  Tissue-Associated Subgingival Plaque  Biofilm closest to the soft tissues of the pocket contain a large number of flagellated motile bacteria and spirochetes.  These motile bacteria are loosely adherent to the surface.  This loosely adherent mass is made up of late colonizing bacteria that activate the host response, resulting in the most destructive processes observed in periodontal disease. gingival margin can break down - gingival recession attached - more destructive (always tissue attached) - bone loss etc.. Copyright © 2014, 2007, 2001, 1996 by Saunders, an imprint of Elsevier Inc. 54  Periodontal Microbiota  Early theories concerning plaque suggested that the severity of inflammation was directly related to the quantity of plaque in the mouth. These theories were based on the beliefs that plaque was a homogeneous bacterial mass and that all plaques have equal potential to cause disease. Early theories centered on the nonspecific plaque hypothesis. the more bacteria - the more destruction - did not specify which organism in the plaque Copyright © 2014, 2007, 2001, 1996 by Saunders, an imprint of Elsevier Inc. 55  Periodontal Microbiota (Cont.)  Improvements in microbial research led to the development of the specific plaque hypothesis. The emphasis of these theories is on the overgrowth of specific microbial species that are responsible for most cases of periodontitis. Copyright © 2014, 2007, 2001, 1996 by Saunders, an imprint of Elsevier Inc. 56  gram-negative - as disease progresses, bacilli or rods gram positive - healthy bacteria, more cocci Subgingival Health can be in healthy or in disease area  The gingival crevice harbors microorganisms in both healthy and diseased subgingival areas.  In healthy subgingival areas, the gingival crevice harbors microorganisms found in the early stages of homeostasis - internal balance - anytime one biofilm formation. increases, the other deceases These organisms are gram-positive and facultative anaerobic species. when it starts colonizing - it will become gram-negative Cocci, the predominant morphotype, make up almost two thirds of the microorganisms. Gram-positive facultative anaerobic rods tend to be filamentous forms, such as Actinomyces. from positive to negative, to cocci to bacilli, will change from motile to nonmotile as the disease advances Copyright © 2014, 2007, 2001, 1996 by Saunders, an imprint of Elsevier Inc. 57  Subgingival Health (Cont.)  Several species of streptococci produce extracellular polysaccharides from sucrose that enhance bacterial accumulation on the tooth.  Various bacterial groups in healthy and diseased subgingival juvenile - young adults/children areas are demonstrated in the following figure. Copyright © 2014, 2007, 2001, 1996 by Saunders, an imprint of Elsevier Inc. 58 Copyright line. Slide 59  more organisms - more gingivitis affect gingiva, no attachment/ chances of severe gingivitis bone loss (superficial) - no periodontal pocket - it has pseudo pocket specific pathogens that can cause disease Gingivitis (reversible) periodontitis is deeper - bone loss etc.. (irreversible)  Gingival inflammation can be initiated by any number of bacterial species if they are present in high numbers as a result of poor oral hygiene.  This type of gingival inflammation is in contrast to a specific infection, in which a limited number of bacteria are known to create progressive periodontitis lesions. periodontitis might not look as severe as gingivitis but it has gone down to PDL, bone loss etc.. inflammation - gingiva enlargement causing gingiva pocket periodontal pocket - deeper involvement causing apical migration of epithlieal attachment -deeper pockets (true/periodontal pocket) - causing bone loss and Copyright © 2014, 2007, 2001, 1996 by Saunders, an imprint of Elsevier Inc. 60 attachment loss  Chronic Periodontitis  The continued presence and growth of pathogenic bacterial biofilm causes the inflammatory process to extend into the periodontal ligament, cementum, and alveolar bone, and leads to the loss of attachment of the gingiva to both the tooth and the supporting bone. gingiva recession Copyright © 2014, 2007, 2001, 1996 by Saunders, an imprint of Elsevier Inc. 61  Chronic Periodontitis (Cont.)  In the early stages of periodontitis, bacterial components are similar to that of gingivitis.  Periodontitis becomes more complex as the biofilm matures. Clients with chronic periodontitis have higher proportions of anaerobes, gram-negative organisms, and spirochetes; the predominant organisms are gram-negative anaerobic rods. Copyright © 2014, 2007, 2001, 1996 by Saunders, an imprint of Elsevier Inc. 62  Chronic Periodontitis (Cont.)  Porphyromonas gingivalis seems to be the most important periodontal pathogen on the basis of its numeric presence and its possession of specific virulence factors, such as the production of LPS. if gingivitis is left untreated, it can lead to periodontitis BUT it is not considered early stages of periodontitis Copyright © 2014, 2007, 2001, 1996 by Saunders, an imprint of Elsevier Inc. 63  Chronic Periodontitis (Cont.)  Certain groups of bacteria tend to be found in sites with chronic periodontal disease. highest virulence  These organisms have been called “red complex” and “orange complex” bacteria.  These bacteria have been characterized as late colonizers and tend to reside in the biofilm closest to the soft-tissue lining of the pocket. Copyright © 2014, 2007, 2001, 1996 by Saunders, an imprint of Elsevier Inc. 64  Chronic Periodontitis (Cont.) closer to the wall - can be very harmful  The red complex bacteria is made up of Porphyromonas gingivalis, Tannerella forsythia, and Treponema denticola. latest stages - more complex - more pathogenic (dangerous)  The orange complex bacteria are considered less virulent and include Prevotella intermedia, Fusobacterium nucleatum, Campylobacter species, Eubacterium nodatum, and Peptostreptococcus micros, among others. less virulent Copyright © 2014, 2007, 2001, 1996 by Saunders, an imprint of Elsevier Inc. 65  Chronic Periodontitis (Cont.)  The other complexes, referred to as yellow, green, blue, and purple, are earlier colonizers; therefore they reside deeper in the biofilm (closer to the tooth surface) and are less associated with clinical disease. Copyright © 2014, 2007, 2001, 1996 by Saunders, an imprint of Elsevier Inc. 66  Localized Aggressive Periodontitis chronic periodontitis is more common  Localized aggressive periodontitis (LAP) is characterized by a rapid destruction of periodontal attachment over a short period.  LAP usually involves destruction around the permanent incisors and the first molars in otherwise healthy children or teenagers who exhibit relatively little dental plaque and gingival inflammation. individual’s higher tendency to develop calculus and plaque and the composition of saliva - some people don’t brush often and not a lot of build up vs some people who brush often, have a lot of build up Copyright © 2014, 2007, 2001, 1996 by Saunders, an imprint of Elsevier Inc. 67  Localized Aggressive Periodontitis (Cont.)  The familial pattern of disease suggests a genetically determined susceptibility.  Clients frequently have defective polymorphonuclear neutrophils (PMNs) that have impaired ability to migrate to and phagocytose bacteria, thereby increasing the individual’s susceptibility to infection. chemotaxis - movement of the cell - once they reach the area where the organism are present - they engulf it and destroy it (phagocyotosis) - these actions are impared for patients who have this disease - therefore, individuals are more prone to infection Copyright © 2014, 2007, 2001, 1996 by Saunders, an imprint of Elsevier Inc. 68  Localized Aggressive Periodontitis (Cont.)  Gram-negative rods dominate including: Actinomyces naeslundii Fusobacterium nucleatum Campylobacter rectus  In some populations, Aggregatibacter actinomycetemcomitans has been implicated as one of the major pathogens. Aa - imp. bacteria for aggressive periodontitis (AP) - main pathogen Copyright © 2014, 2007, 2001, 1996 by Saunders, an imprint of Elsevier Inc. 69  Generalized Aggressive Periodontitis  Generalized aggressive periodontitis is similar to localized aggressive periodontitis. A rapid destruction of periodontal attachment occurs over a short period. The subgingival microbiota consists of predominately gram-negative rods.  The difference between aggressive and localized aggressive periodontitis is that the destruction involves most, if not all, of the dentition in aggressive periodontitis. invovles most of the teeth LAP - involves mainly incisors and first molars Copyright © 2014, 2007, 2001, 1996 by Saunders, an imprint of Elsevier Inc. 70  Necrotizing Ulcerative Gingivitis different from gingivitis and Periodontitis  Necrotizing ulcerative gingivitis (NUG) or necrotizing ulcerative periodontitis (NUP) is another form of aggressive periodontitis. destruction of tisssues  Necrotic, ulcerative lesions of the interdental papillae, sometimes severe pain, rapid loss of supporting structures, and bleeding significant halitosis are clinical characteristics of bad odor/breath NUG.  NUG has a characteristic histopathologic profile. The outer surface bacteria of the supragingival biofilm are similar to the subgingival biofilm of periodontal lesions. Copyright © 2014, 2007, 2001, 1996 by Saunders, an imprint of Elsevier Inc. 71  Necrotizing Ulcerative Gingivitis and Periodontitis (Cont.) a lot of immune cell  A PMN-rich or a polymorphonuclear leukocyte (PML)–rich zone with a necrotic zone containing spirochetes and gram-negative rods characterizes NUG. NUG can go into NUP (not the same thing) The adjacent connective tissue is infiltrated with spirochetes.  NUG is referred to as NUP when the infection invades the deeper tissues and bone loss occurs. Copyright © 2014, 2007, 2001, 1996 by Saunders, an imprint of Elsevier Inc. 72 Copyright line. Slide 73  Necrotizing Ulcerative Gingivitis and Periodontitis (Cont.) **Fusiform bacilli and Borelia vincenti**  NUG and NUP lesions have large numbers of spirochetes and Prevotella intermedia, with gram- negative rods accounting for more than 50% of the bacterial population.  High levels of Fusobacterium and Selenomonad species have also been identified. Copyright © 2014, 2007, 2001, 1996 by Saunders, an imprint of Elsevier Inc. 74  Virulence of Periodontal Pathogens ability to cause disease  The virulence or pathogenicity of a microorganism is its ability to cause disease.  In general, virulence is related to three things: Proximity to the tissue organisms should be powerful Ability to evade host defenses enough to evade Ability to destroy tissue Copyright © 2014, 2007, 2001, 1996 by Saunders, an imprint of Elsevier Inc. 75  Proximity to the Tissue Proximity to the Tissue  A microorganism must be in close proximity to the periodontal tissue, and it must be able to withstand the forces of saliva and GCF flow that are capable of washing it away.  Colonization is mediated by cell surface characteristics. Fimbriae and extracellular polysaccharides, such as glucan  Bacterial interactions are important for colonization and for the availability of nutrients. Copyright © 2014, 2007, 2001, 1996 by Saunders, an imprint of Elsevier Inc. 76  Evasion of Host Defenses Ability to Evade Host Defenses  Periodontal pathogens have strategies to overcome cellular defense systems. For example: Porphyromonas gingivalis, Tannerella forsythia, and Treponema denticola have enzymes (proteases) that degrade the host immune system proteins. Aggregatibacter actinomycetemcomitans produces a leukotoxin that kills or impairs PMNs. WBC Porphyromonas gingivalis releases a factor that interferes with PMN movement to a site of infection. can kill the immune cells Copyright © 2014, 2007, 2001, 1996 by Saunders, an imprint of Elsevier Inc. 77  Tissue Destruction Ability to Destroy Tissue  The majority of the destruction of periodontal tissues is a result of the inflammation produced by the human host cells. mainly due to host inflammation  This destruction occurs in response to molecules released from bacteria, primarily the red and orange more of red and orange - the most destruction - complexes of bacteria.to release more molecules - more destruction of tissue  In addition, some bacterial products directly injure the host cells and tissues. Copyright © 2014, 2007, 2001, 1996 by Saunders, an imprint of Elsevier Inc. 78  Direct Effects Enzymes  The subgingival microbiota produce many enzymes that are capable of damaging host tissues. Porphyromonas gingivalis produces collagenase, the enzyme that degrades collagen in the tissues. collagen fibers Copyright © 2014, 2007, 2001, 1996 by Saunders, an imprint of Elsevier Inc. 79  Direct Effects (Cont.) Toxins and destruction  LPS, a gram-negative bacterial cell wall component, induces inflammatory reactions and stimulates osteoclast-mediated bone resorption.  Another type of bone-resorbing toxin is released from Aggregatibacter actinomycetemcomitans.. Copyright © 2014, 2007, 2001, 1996 by Saunders, an imprint of Elsevier Inc. 80  Direct Effects (Cont.) Toxins (cont.)  P. gingivalis, Prevotella intermedia, A. actinomycetem- comitans, and Capnocytophaga produce toxins that affect fibroblasts and, consequently, the synthesis and turnover of collagen.  In addition, several pathogens release volatile sulfides that inhibit both the synthesis of collagen and noncollagenous substances. Copyright © 2014, 2007, 2001, 1996 by Saunders, an imprint of Elsevier Inc. 81  Indirect Effects  Some microbial products have the potential to activate immune inflammatory reactions, which, in turn, cause tissue destruction. periodontitis - could be an effect of inflammation in the body These organisms have the potential to induce inflammation and bone resorption. Copyright © 2014, 2007, 2001, 1996 by Saunders, an imprint of Elsevier Inc. 82  Plaque Control  Plaque removal should be performed daily to keep the biofilm in the initial stages of formation.  Thorough mechanical cleaning of the teeth before the biofilm matures prevents the initiation of the disease process.  The role of the hygienist in educating clients about the role of plaque biofilm in causing disease and how to prevent or control disease effectively by daily oral hygiene procedures is crucial to the treatment of gingivitis and periodontitis and the long-term maintenance of oral health. Copyright © 2014, 2007, 2001, 1996 by Saunders, an imprint of Elsevier Inc. 83  Periodontal Therapy  Subgingival plaque biofilm deep in periodontal pockets is inaccessible to homecare procedures, making professional cleaning at regular intervals necessary to remove it, to disrupt its formation, and to keep biofilm in a more immature state.  Frequent recall intervals for professional plaque control procedures are effective; physical disruption of the plaque biofilm converts the pathogenic microbiota back to one more compatible with health. Copyright © 2014, 2007, 2001, 1996 by Saunders, an imprint of Elsevier Inc. 84  Microbiological Testing  Most evidence suggests that only a finite number of bacteria are responsible for dental caries and periodontal diseases.  This knowledge led to the development of microbial tests which can identify suspected pathogens  Microbial diagnosis may also be valuable in the treatments of aggressive periodontitis or in subjects who respond poorly to periodontal therapy.  The use of microbial tests to monitor the efficacy of chemotherapy or mechanical treatment is of particular interest. not responding to regular treatment - can do microbiological testing to find out specific organisms and specific antibiotics to give Copyright line. Slide 85  A variety of microbiological diagnostic tests are available for clinicians to use for evaluation of clients with periodontal disease.  Each one has its own set of advantages and disadvantages, and probably the most useful information for the clinician can be obtained using a combination of the various analytic methods.  The tests appear to have their greatest utility when used on clients with chronic or aggressive periodontitis who do not respond favorable to conventional mechanical therapy. Copyright line. Slide 86  The major limitation of all microbiological tests is that the information obtained is relevant to the site sampled, and may not be representative of the microflora of the entire dentition.  However, since it is often only specific sites that do not respond to initial therapy, knowing the constituents of the microflora that populate these sites is clinically relevant. Copyright line. Slide 87