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INTRODUCTION

"PERIODONTAL DISEASE" PERIODONTAL DISEASE A number of distinct clinical entities that affect the periodontium

"Most common" Most common gingivitis periodontitis Both are chronic bacterial infections

"The organisms may produce the..." The organisms may produce the diseases indirectly direct invasion of the tissues

"The host response to the..." The host response to the microorganisms may be protective destructive both protective and destructive

"Gingivitis" Gingivitis Inflammation of the gingiva Crevicular exudate is usually present Bleeding is sometimes present

"Periodontitis" Periodontitis Inflammation extends deeper into the periodontium resulting in pocket formation bone loss tooth mobility

"There are many classifications of..." There are many classifications of periodontal diseases One classification is shown in the next table

Classification of Periodontal Diseases Gingivitis Nonspecific gingivitis Pregnancy gingivitis Acute Necrotizing Ulcerative Gingivitis (ANUG) Necrotizing Ulcerative Periodontitis (NUP) HIV-associated gingivitis

"Periodontitis" Periodontitis Juvenile Periodontitis Prepubertal periodontitis Localized juvenile periodontitis Generalized juvenile periodontitis Juvenile diabetic periodontitis

"Periodontitis" Periodontitis Adult periodontitis Conventional (Slight, Moderate, Advanced) Rapidly progressive Refractory Periodontal abscess

"The primary cause of the..." The primary cause of the most common forms of gingivitis and periodontitis is plaque bacteria Small amounts of plaque can be controlled or tolerated without causing periodontal disease

"When specific bacteria within the..." When specific bacteria within the plaque either increase to sufficient numbers produce virulence factors both the balance shifts towards disease production

"Disease can also occur by..." Disease can also occur by a reduction in the host defense capacity (AIDS)

"Major difficulty in identifying the..." Major difficulty in identifying the etiologies of the various periodontal diseases is that things are not clear-cut The organisms believed to play a role are often present in lower numbers in what appears to be a healthy state Something changes the apparent status quo and disease ensues

"Non-specific Plaque Hypothesis (..." Non-specific Plaque Hypothesis (old) Periodontal disease results from an increase in numbers of bacteria, not a change in the types of bacteria Specific Plaque Hypothesis (today) Most periodontal diseases have their own characteristic flora

Specific Plaque Hypothesis Resulted from the development of AnO2 microbiology techniques in the 1960s Since then, characteristic microfloras have been associated with most of the different periodontal diseases and stages of disease

Koch's Postulates 1. Observe the organism in every case of the disease 2. Grow the organism in pure culture in the laboratory 3. Get the disease when you reintroduce the organism into a susceptible animal 4. Observe the organism in and isolate it from the new animal

"For ethical reasons," For ethical reasons, we can’t apply Koch's postulates in human studies of periodontitis It would be unethical to allow someone to develop a disease that cannot be reversed So all our microbiological information comes either from animal studies or human studies of associations of certain bacteria with specific Periodontal Diseases

"The factors we can use..." The factors we can use are shown in the next table

Identification of the Bacterial Etiology in Periodontal Disease 1. Large numbers of the bacteria are associated with the disease state and absence or reduced numbers are associate with health 2. Elimination or suppression of the organism reverses or reduces the disease

"3." 3. Elevated host responses to the bacteria are associated with the disease 4. Animal pathogenicity similar to periodontal disease occurs upon implantation of the organism(s) into germ-free animals

"5." 5. The bacteria possess potentially pathogenic mediators that could contribute to the disease process

MECHANISMS IN THE PRODUCTION OF PERIODONTAL DISEASES

Potential Bacterial Mechanisms in Periodontal diseases Bacterial invasion of tissues Exotoxins Cell constituents (such as endotoxins) Histotoxic end products Enzymes Immunologic ‑host responses

Bacterial Invasion of Tissues Originally it was thought that bacteria didn’t actively invade the periodontium They were thought to act only through enzymes or toxins or through an antibody response to their antigens

"More recently," More recently, it’s been shown that bacteria can invade the periodontal tissues Some of the bacteria that have been identified are shown in the next table

Presence of Bacteria in Tissues Adult Periodontitis: Porphyromonas gingivalis Prevotella intermedia Capnocytophaga sputigena Capnocytophaga gingivalis Juvenile Periodontitis: Actinobacillus actinomycetemcomitans Mycoplasma ANUG (NUP): Prevotella intermedia

"These organisms were identified using..." These organisms were identified using immunological techniques.  This means that only certain specific organisms were looked for and, therefore, others may be present Recent studies using tissue cultures showed that P. gingivalis and A.a. could invade oral epithelial cells

Exotoxins Many bacteria produce exotoxins (Corynebacterium diphtheria, Streptococcus pyogenes, Clostridium botulinum) Generally, the recognized periodontopathogens are not known to produce toxins

"An exception is the leukotoxin..." An exception is the leukotoxin of A. actinomycetemcomitans This leukotoxin may enable A. a  to destroy leukocytes in the gingival crevice, assisting the microorganism in its ability to colonize and invade the gingival tissues

Cell Constituents Cellular constituents of Gram-positive and Gram-negative bacteria may also play a role in periodontal disease These include endotoxins bacterial surface components capsular components

"Large numbers of Gram-negative..." Large numbers of Gram-negative bacteria in pockets = high concentrations of endotoxin

Activities of Endotoxin Produce leukopenia Activate the clotting system Activate the complement system by the alternate pathway Lead to a localized Schwartzman phenomenon with tissue necrosis following multiple exposures to endotoxin

"Produce cytotoxic effects on cells..." Produce cytotoxic effects on cells such as fibroblasts Induce bone resorption in organ culture Activate macrophages to synthesize cytokines

Activities of Peptidoglycan Peptidoglycan (in cell walls of Gram-positive bacteria) affects the host in many ways as shown in the next table

"Complement activation" Complement activation Immunosuppressive activity Stimulation of the reticuloendothelial system Immunopotentiating properties

"Bone resorption" Bone resorption Stimulate macrophages to produce prostaglandin and collagenase

Capsular material and slime These are also capable of tissue destruction

Histotoxic Bacterial End Products Both Gram-positive and Gram-negative subgingival bacteria produce a wide variety of toxic end products that are capable of tissue destruction These are shown in the next table

"Fatty acids" Fatty acids Organic acids such as butyric and propionic acids Amines Volatile sulfur compounds Indole Ammonia Glycans

Enzymes Many of the bacteria in the pocket are able to produce enzymes that may play a role in periodontal disease initiation and progression

Hyaluronidase Hyaluronidase influences gingival permeability Occurs in higher concentrations in periodontal pockets than in healthy sulci There are more hyaluronidase producing bacteria in the periodontal pockets than supragingivally

"Topical application of hyaluronidase to..." Topical application of hyaluronidase to gingival epithelium leads to widening of the intercellular spaces and increased permeability

Collagenase Collagen is degraded in periodontal disease Mainly due to tissue collagenase but Also due to bacterial collagenase Porphyromonas gingivalis and some strains of A. actinomycetemcomitans produce collagenase

Gingipain Porphyromonas gingivalis produces many proteinases Some are called as “gingipains” (derived from the words gingivalis and papain a proteolytic enzyme)

"Three of these gingipains (..." Three of these gingipains (HRGP, RGP2, KGP) rapidly degrade TNF-alpha, a proinflammatory cytokine This cytokine is important to the function of polymorphonuclear leukocytes

"These and other bacterial enzymes..." These and other bacterial enzymes of suspected periodontopathogens that may cause periodontal destruction include those shown in the next table

Bacterial Enzymes That May Cause Periodontal Destruction Elastase Hemolysin Collagenase Keratinase Gelatinase Arylsulfatase Aminopeptidases Neuraminidase Phospholipase A DNAse Alkaline phosphatase RNAse Acid phosphatase

Immunologic‑Host Responses Bacterial factors also aid in evasion of host defenses as shown in the next table

Bacterial Factors Important in Evading Host Defenses Inhibition of PMNs Leukotoxin Chemotaxis inhibitors Decreased phagocytosis and intracellular killing Resistance to C’‑mediated killing

"Endotoxicity" Endotoxicity IgA, IgG proteases Fibrinolysin Superoxide dismutase Catalase

"Many bacteria have one or..." Many bacteria have one or more of these factors  Examples include the ability of Porphyromonas gingivalis and Prevotella intermedia to inactivate both complement components and immunoglobulins

SPECIFIC BACTERIOLOGY OF PERIODONTAL DISEASES

Gingivitis Nonspecific Gingivitis Affects virtually the entire population to some degree The one periodontal disease that CAN be ethically studied, since it’s easily reversible

"Studies on gingivitis showed that..." Studies on gingivitis showed that there are four phases in its development

Phases Associated with Experimental Gingivitis Phase Time Period Characteristic Flora 1 0-2 days Predominantly Gm + cocci 2 2-4 days Increased filaments & fusiform bacilli 3 4-9 days Increased vibrios & spirochetes 4 10+ days Gingivitis

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"These types of studies were..." These types of studies were illuminating But they don't say anything about specific species of bacteria

"Other studies," Other studies, which identified specific bacteria, have found some differences between adults and children

Experimental Gingivitis in Children and Adults  (Organisms showing an increase) Children only Adults only Children & Adults Leptotrichia sp. Fusobact. sp. F. nucleatum Capnocytoph. sp. Eubacterium sp. Actino. WVa 963 Selenomonas sp. Lactobacillus sp. Selenomonas D04 T. socranskii E. saburrheum

"Perhaps one day we will..." Perhaps one day we will be able to discern differences in the clinical manifestations of nonspecific gingivitis based on specific bacteria

"Pregnancy Gingivitis" Pregnancy Gingivitis Occurs during pregnancy puberty menstruation following oral contraceptive use Not to everyone in these categories But there is a hormonal aspect to it

"Prevotella intermedia = major organism..." Prevotella intermedia = major organism involved P. intermedia requires vitamin K to grow in artificial media and in vivo may get its vitamin K from other bacteria

"Hormonal connection:" Hormonal connection: progesterone or estradiol can substitute for vitamin K Thus, when these hormones increase, the organism receives its growth factor

"Acute Necrotizing Ulcerative Gingivitis (..."  Acute Necrotizing Ulcerative Gingivitis (ANUG) Rapid onset (1 day) Characterized by painful, necrotic, ulcerative gingival lesions Psychological or physiological stress or both often present

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Organisms frequently found Prevotella intermedia Fusobacterium nucleatum Unnamed intermediate-sized spirochete Over the years, other bacteria, and even a virus, have been found to be elevated These include Fusobacterium spp., Selenomonas, and Cytomegalovirus

"HIV-associated gingivitis" HIV-associated gingivitis HIV associated gingivitis shows a characteristic linear erythema at the gingival margin

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Organisms frequently found in HIV associated gingivitis Candida albicans Porphyromonas gingivalis Prevotella intermedia Fusobacterium nucleatum Actinobacillus actinomycetemcomitans Campylobacter rectus

Periodontitis The American Academy of Periodontology has said that 5 - 9% of 5 -11 year olds experience loss of periodontal attachment and supporting bone in one or more locations And 12 to 15 year olds have a rate of periodontal disease ranging from a low of 5% to a high of 46%, depending on the populations surveyed and the methods of diagnosis

"Therefore," Therefore, periodontitis is not just a disease of older people

Animal Studies Socransky monoinfected rats  with Gm+ organisms (including A. viscosus, A. naeslundii, and S. mutans) and anaerobic, Gm- organisms, including C. ochraceus Results are shown in the next table.

Effect of Gram-positive and Gram-negative Organisms on the Periodontium Bone Osteo- Osteo-      Plaque Loss blasts clasts Gram + Much Slow Decrease Normal Gram - Minimal Rapid Normal Increase

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Human association studies Juvenile Periodontitis Prepubertal Periodontitis Localized Juvenile Periodontitis (LJP) Generalized Juvenile Periodontitis Periodontitis in Juvenile Diabetics

"Prepubertal Periodontitis" Prepubertal Periodontitis A rare form of periodontal disease Occurs during or immediately after the eruption of the primary teeth Microbiological findings are shown in the next table

Organisms Frequently Found in Prepubertal Periodontitis Fusobacterium sp. Selenomonas Campylobacter Prevotella Capnocytophaga A.a.  and P. gingivalis are rarely found

"Localized Juvenile Periodontitis (LJP" Localized Juvenile Periodontitis (LJP) Occurs in patients approximately 12 to 20 years of age Usually little gingival inflammation Minimal supragingival plaque The hallmark of the disease is Marked, localized, rapid alveolar bone loss involving the permanent first molars and often the incisors

"The one organism identified so..." The one organism identified so far is       A. actinomycetemcomitans However, there are patients with LJP without A. a., so another organism or organisms are probably involved in some cases

"One study of LJP in..." One study of LJP in China failed to find   A. a. in any samples from 23 diseased sites in 15 patients but found a high frequency and proportion of Eubacterium sp.

"In at least the US" In at least the US, Capnocytophaga species are elevated in LJP and may also play a role in the disease but,  Capnocytophaga gingivalis was among the predominant species in healthy sulci of Chinese patients

"In the US and Finland" In the US and Finland,  regarding A. a. Serotype b strains predominate in periodontitis patients Serotype c strains predominate in healthy individuals In contrast, in nonoral A. a. Serotype c seems to predominate in infections

"A majority of the A" A majority of the A. a. strains involved in disease harbored bacteriophages to the A. a. Diagnosed early, this disease responds well to local treatment and antibiotics that eradicate the disease-causing bacteria

"Generalized Juvenile Periodontitis" Generalized Juvenile Periodontitis Clinical findings are similar to LJP Rapid bone loss - except the bone loss is generalized rather than localized Heavy plaque Observable inflammation Usually occurs more frequently in young adults than in children, often beginning with the onset of puberty

Predominant Cultivable Flora in Generalized Juvenile Periodontitis Porphyromonas gingivalis - predominant Eikenella corrodens Prevotella intermedia Capnocytophaga Neisseria A. a. is present only in low numbers

"Periodontitis in Juvenile Diabetics" Periodontitis in Juvenile Diabetics Juvenile diabetics often have more severe periodontal disease than the general population Periodontitis begins near puberty and by age 19, over 1/3 are affected

Predominant Cultivable Flora in Periodontitis in Juvenile Diabetics Campylobacter Capnocytophaga

"Adult Periodontitis" Adult Periodontitis Conventional Adult Periodontitis Rapidly Progressive Periodontitis Refractory Periodontitis

"Conventional Adult Periodontitis" Conventional Adult Periodontitis The organisms associated with what one might call normal adult periodontal disease are shown in the next table

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Microbiology of Conventional Adult Periodontitis Porphyromonas gingivalis Prevotella intermedia Bacteroides forsythus Campylobacter rectus Fusobacterium nucleatum Treponema denticola Eikenella corrodens Actinobacillus actinomycetemcomitans

Rapidly Progressive Periodontitis (early-onset periodontitis) Rare Clinically similar to adult onset periodontitis but occurs in a younger age group, usually post pubertal to 35 years of age

Microbiology of Rapidly Progressive Periodontitis Porphyromonas gingivalis Prevotella intermedia Small spirochetes ~75% of patients have functional defects In neutrophils or monocytes This disease hasn't been studied much so the data is limited

Refractory Periodontitis Low plaque scores Low responsiveness to current conventional periodontal therapy

Microbiology of Refractory Periodontitis Porphyromonas gingivalis Prevotella intermedia Prevotella forsythus Campylobacter rectus

Viral isolates from periodontitis Viruses have also been found in gingivitis and in the pockets of periodontitis patients Human cytomegalovirus (HCMV) was detected in deep periodontal pockets of two adult and two localized juvenile periodontitis patients but not in any shallow periodontal sites

"HCMV - is the virus..." HCMV - is the virus most often found Also found Epstein-Barr Virus Herpes Simplex Virus Human Papillomavirus Human Immunodeficiency Virus

"Periodontal abscess" Periodontal abscess Occurs with pre-existing periodontitis Acute infection Occurs in the walls of periodontal pockets as a result of the invasion of bacteria into the periodontal tissues More common in periodontitis patients with a systemic disease such as diabetes

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"Porphyromonas gingivalis" Porphyromonas gingivalis Fusobacterium Capnocytophaga Vibrio

Summary A summary of all the previous tables is shown in Table 26

"In general," In general, Gram-negative, anaerobic microorganisms are the principle bacteria associated with most periodontitis diseases The most commonly identified so far are shown in the next table

Gram-negative Bacteria Causing Periodontal Diseases Porphyromonas gingivalis Prevotella intermedia Bacteroides forsythus Campylobacter rectus Actinobacillus actinomycetemcomitans Capnocytophaga spp.

"These are thought to be..." These are thought to be the most important because they have been found in large numbers during active disease and they have been shown to possess a number of virulence factors Other bacteria found in lower numbers may be important but have not been studied to the same extent as these

DIAGNOSTIC TESTS FOR PERIODONTAL DISEASE

"Many laboratory tests have been..." Many laboratory tests have been and are being devised for studying the periodontal diseases (See table in handout)

"Some laboratories are providing identification..." Some laboratories are providing identification of organisms via a kit that the periodontist uses for collecting and sending in the proper samples

Additional Tests BANA Treponemes produce a protease that hydrolyzes benzoyl-DL-arginine-2-naphthylamide (BANA) This substrate has been used to measure whether there is active disease in a periodontal pocket

"It has been found that" It has been found that, of the various organisms that are BANA positive, T. denticola was the one making the greatest contribution in pockets Porphyromonas gingivalis and Bacteroides forsythus are also BANA positive and are believed to play a role in periodontal disease

"So the BANA test may..." So the BANA test may be a good one for assessing periodontal disease activity

"Perioscan tests for BANA in..." Perioscan tests for BANA in plaque samples Periocheck assays the presence of neutral proteases in crevicular fluid One study comparing the effectiveness of these tests concluded that they did not reliably reflect the clinical assessment of periodontal disease or the outcome following treatment

"Elastase" Elastase Measuring elastase levels in the saliva has shown a good correlation to active periodontitis Levels were low in edentulous subjects and in people with a healthy periodontium There was a good correlation between the elastase activity and the number of deep periodontal pockets

"Elastase activity was not a..." Elastase activity was not a good indicator of gingivitis Elastase levels dropped dramatically following clinically successful therapy

Possible problems with in office testing Not knowing whether the periodontal disease is active in the site at the time of testing It is believed that many periodontal diseases are episodic, that is, going from a period of active disease to a period of inactivity or no disease So one can’t be sure, that the disease is active in the site you are sampling

"Collecting a useful sample" Collecting a useful sample Flora can vary greatly depending on the site on the tooth that is sampled (see table 29 in handout) So test results are only as good as the sampling procedure

"In regard to the flora..." In regard to the flora present, the following is a quote from a 1987 article by WEC Moore, a microbiologist at the Department of Anaerobic Microbiology of the Virginia Polytechnic Institute who has done a TREMENDOUS amount of work culturing and identifying periodontal disease organisms

"“The periodontal flora is..." “The periodontal flora is complex.  We have found over 325 distinct bacterial species in the human gingival crevice.  Many of these species have never been formally described, most of them are ignored by some laboratories, identified differently by others, or lumped together in various groups by still others.

"“Some of the predominant..." “Some of the predominant species have special growth requirements and are not detected on some media that are widely used.  Identification criteria differ among laboratories.  Even with rigorous testing, identification of some species is questionable.  With minimal testing it is even less reliable.”

CONCLUSION We know a lot But there is still much to learn

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