Dental Plaque Biofilm (Dr. Chiho Ahn).pdf

Dental Plaque - Biofilm Dr. Chiho Ahn, DMD, DMSc, CAGS, FACD Clinical Assistant Professor Diplomate, American Board of Periodontology Boston University Henry M. Goldman School of Dental Medicine Dental Plaque • Diverse microbial community found on tooth surface embedded in a matrix of polymers of...

Dental Plaque - Biofilm Dr. Chiho Ahn, DMD, DMSc, CAGS, FACD Clinical Assistant Professor Diplomate, American Board of Periodontology Boston University Henry M. Goldman School of Dental Medicine Dental Plaque • Diverse microbial community found on tooth surface embedded in a matrix of polymers of bacterial and salivary origin (Marsh 1992) • Yellow greyish color • Closely adhered to tooth surface that are not dislodged by rinsing • Primary cause of dental caries, gingivitis, periodontitis and periimplant infections Definitions Stages Microorganisms Interactions Hypothesis Koch’s Postulates Clinical Assessments Biofilm • Assemblage of microbial cells enclosed in primarily extracellular polymeric substance (EPS) matrix (Donlan 2002) • Plaque as Biofilm: Microbial community adhered to each other and to tooth surfaces (Non-shedding material) • Provide circulation within plaque to facilitate movement of nutrients and waste products Definitions Stages Microorganisms Interactions Hypothesis Koch’s Postulates Clinical Assessments Composition of Dental Plaque (Biofilm) Dental Plaque (Biofilm) Extracellular Matrix (75-80%) Inorganic Content Phosphate Calcium Definitions Stages Microorganisms (15-20%) Organic Content Protein Microorganisms Carbohydrates Interactions Gram +ve Gram -ve Lipids Hypothesis Koch’s Postulates Clinical Assessments Materia Alba • Deposit composed of dead epithelial cells, leukocytes, and microorganisms loosely attached to tooth surfaces • Loosely adhered to tooth surface and easily displaced by water spray Definitions Stages Microorganisms Interactions Hypothesis Koch’s Postulates Clinical Assessments Stains • External Stain • Located on outer surface of teeth easily removed by external cleaning • Due to poor OHI, foods, drinks, and tobacco • Intrinsic Stain • located within the teeth • Due to tetracycline medication and excessive fluoride ingestion Definitions Stages Microorganisms Interactions Hypothesis Koch’s Postulates Clinical Assessments Calculus • Mineralized bacterial plaque that forms on tooth surfaces • Divided into Supragingival and Subgingival Calculus in relation to gingival margin • Supragingival Calculus: Located at or above gingival margin (Easily visible) • Subgingival calculus: Located below gingival margin (Evaluated with tactile examination) Definitions Stages Microorganisms Interactions Hypothesis Koch’s Postulates Clinical Assessments Calculus (Composition) • Calculus consists of inorganic (~80%) and organic (~20%) components • Inorganic Content • Calcium phosphate (75.9%), Ca(PO)4 • Calcium carbonate (3.1%), CaCO3 • Traces of magnesium phosphate, Mg3(PO4)2 • Organic Content • • • • Definitions Carbohydrate (9.1%) Salivary proteins (8.2%) Lipids (0.2%) Traces of epithelial cells, leukocytes, and microorganisms Stages Microorganisms Interactions Hypothesis Koch’s Postulates Clinical Assessments Calculus (Composition) • Crystal forms of inorganic components are typical in calculus • Brucite • Early form of calculus • Mandibular anterior • 9% • Octacalcium phosphate • Supragingival calculus in bulk • Later calculus • 12% • Hydroxyapatite • Supragingival calculus in bulk • Mature calculus • 58% • Magnesium whitlockite • Posterior areas and sublingual • Mature calculus • 21% Definitions Stages Microorganisms Interactions Hypothesis Koch’s Postulates Clinical Assessments Growth of Bacteria Stages of Plaque Formation 1. Formation of a Conditioning Film 2. Bacterial Adhesion 3. Multiplication 4. Maturation 5. Detachment Tooth Surface Definitions Stages Microorganisms Interactions Hypothesis Koch’s Postulates Clinical Assessments Stage 1 - Formation of a Conditioning Film 1. Macromolecules adsorb to the tooth surface • Supragingival region: From saliva • Subgingival region: From GCF • Seconds after cleaning/initial exposure of oral environment Tooth surface 2. Form a conditioning film – Acquired Pellicle • Detected within 1 minute and in equilibrium by 2 hours Definitions Stages Microorganisms Interactions Hypothesis Koch’s Postulates Clinical Assessments Stage 2 - Bacterial Adhesion 1. Reversible Adhesion • Weak interaction b/w charges on microbial cell surface and acquired pellicle • Microorganisms are transported passively to the surface by flow of saliva or GCF 2. Irreversible Adhesion • Strong interaction between specific molecules on microbial cell surface (adhesins) and complementary molecules (receptors) in acquired pellicle 3. Co-Adhesion Tooth surface Tooth surface • Secondary and late colonizers adhere via cellsurface adhesions to receptors on already attached bacteria Definitions Stages Microorganisms Interactions Hypothesis Koch’s Postulates Clinical Assessments Stage 3 – Multiplication Growth of Attached Bacterial Cells (Co-Aggregation) + Synthesis of new outer membrane components Increased Bacterial Mass to form Biofilm Matrix Definitions Stages Microorganisms Interactions Hypothesis Tooth surface Koch’s Postulates Clinical Assessments Stage 4 – Maturation • Close proximity of cells with one another facilitates development of synergistic and antagonistic interactions • Metabolism of microorganisms produces gradients within the plaque in nutrients and fermentation products ØGradients result in a mosaic of microenvironments ØEstablishment of a mature biofilm with a stable composition Definitions Stages Microorganisms Interactions Hypothesis Tooth surface Koch’s Postulates Clinical Assessments Stage 5 – Detachment • Bacteria ‘sense’ changes to their environment • If conditions deteriorate, some species (A. actinomyctemcomitans) respond by upregulating enzymes to cleave their adhesins to detach and colonize elsewhere Definitions Stages Microorganisms Interactions Tooth surface Hypothesis Koch’s Postulates Clinical Assessments Structural traits of Bacteria • Two parts of describe structural bacteria • Arrangement • Shape Definitions Stages Microorganisms Interactions Hypothesis Koch’s Postulates Clinical Assessments Structural traits of Bacteria • Arrangements • Paired: Diplo• Grapelike cluster: Staphylo• Chains: Strepto- • Examples: • Shapes • Round: Coccus • Rod: Bacillus • Spiral: Spirillum Definitions Stages Microorganisms • Streptococcus: Chains of spheres • Staphylospirillum: Grapelike clusters of spirals • Streptobacillus: Chains of rods Interactions Hypothesis Koch’s Postulates Clinical Assessments Physiological traits of Bacteria • Bacteria can exist in a wide variety of environments, including environments that lack oxygen. • Oxygen can be toxic to some bacteria due to formation of Superoxides (O2-) and Hydrogen Peroxides (H2O2) • Oxygen is harmful to Bacteria if: 1. No enzyme system to eliminate it 2. Oxygen concentration is very high in environment Definitions Stages Microorganisms Interactions Hypothesis Koch’s Postulates Clinical Assessments Physiological traits of Bacteria • Toxic forms of O2 need to be neutralized by Enzyme systems: • Superoxide dismutase • Catalase • Peroxidase • If microbe does not produce these enzymes, they must live in anaerobic conditions • Bacteria that live in O2 containing environments have above enzymes to convert toxic Superoxides (O2-) and Hydrogen Peroxides (H2O2) into Oxygen (O2) and Water (H2O) Definitions Stages Microorganisms Interactions Hypothesis Koch’s Postulates Clinical Assessments Physiological traits of Bacteria Bacteria can be classified based on O2 requirements into 5 main classifications 1. Obligate aerobes 2. 3. 4. 5. Definitions • Require O2 to live Obligate anaerobes • Growth occurs only when there is no O2 • They lack enzymes to neutralize so they die in presence of O2 Facultative anaerobes • Facilitates O2 and aerobic respiration whenever possible • Can use anaerobic respiration to survive without O2 Microaerophiles • Growth occurs under reduced O2 (<0.2 atm) and increased level of CO2 Aerotolerant anaerobes • O2 has no effect • They possess enzymes to neutralize O2 Stages Microorganisms Interactions Hypothesis Koch’s Postulates Clinical Assessments Biochemical traits of Bacteria Definitions Gram Positive Gram Negative Thick Peptidoglycan Cell Wall Layer Thin Peptidoglycan Cell Wall Layer Teichoic Acid Present making Cell Wall Acidic Teichoic Acid Absent making Cell Wall Less Acidic No Outer Lipopolysaccharide Membrane Outer Lipopolysaccharide Membrane Stains Blue-Purple Stains Red Stages Microorganisms Interactions Hypothesis Koch’s Postulates Clinical Assessments Biofilms Associated with Oral Cavity • Challenges to characterize Biofilm in Oral Cavity Ø Over 700 species detected in which half which never been cultivated ØDiversity in microflora between individual and same sites of same individual ØAs humans age, the composition of oral microbiome changes Ø Shift in composition with poor OH and change in diet Definitions Stages Microorganisms Interactions Hypothesis Koch’s Postulates Clinical Assessments Biofilm Associated with Oral Health • A positive association has been observed Oral Health and following bacterial species (Gram +ve cocci and rods) ØCapnocytophaga ochracea Ø Gemella haemolysans Ø Granulicatella adiacens Ø Streptococcus mitis Ø Veillonella • Commensal microbiota • Promote oral health by resistance to colonization by allowing few opportunities for integration by exogenous pathogens Definitions Stages Microorganisms Interactions Hypothesis Koch’s Postulates Clinical Assessments Biofilm Associated with Oral Disease • Transition to oral disease is evident by inflammatory changes accompanied first by appearance of Gram –ve rods and filaments followed by spirochetal and motile microorganisms Definitions Stages Microorganisms Interactions Hypothesis Koch’s Postulates Clinical Assessments Biofilm Associated with Oral Health/Disease Health Gingivitis Aerobic Gram +ve Few Motile Rods Definitions Aerobic Gram -ve Increasing heterogenicity of species Cocci Gram +ve Rods Streptococcus species Actinomyces species Stages Microorganisms Periodontitis Interactions Hypothesis Many Motile Rods Gram -ve Rods Porphyromonas gingivalis Aggregatibacter actinomycetemcomitans Tannerella forsythia Treponema denticola Koch’s Postulates Clinical Assessments Biofilm Associated with Oral Health/Disease Acquired Pellicle Enamel Primary Colonizer Definitions Secondary Colonizer Aerobic Gram +ve Few Motile Rods Aerobic Gram -ve Increasing heterogenicity of species Cocci Gram +ve Rods Streptococcus species Actinomyces species Stages Microorganisms Interactions Hypothesis Many Motile Rods Gram -ve Rods Porphyromonas gingivalis Aggregatibacter actinomycetemcomitans Tannerella forsythia Treponema denticola Koch’s Postulates Clinical Assessments Microbial Complexes • Specific microbial complexes relate to their habitat in terms of: Ø Periodontal health/disease Ø Local clinical characteristics Ø Systemic background of host Definitions Stages Microorganisms Interactions Hypothesis Koch’s Postulates Clinical Assessments Microbial Complexes • Six closely associated groups of bacterial species were determined Definitions Stages Microorganisms Interactions Hypothesis Koch’s Postulates Clinical Assessments Microbial Complexes • Initial colonization involve Actinomyces species, yellow, green, and purple complexes. • Early colonizers of tooth surface • Orange and red complexes become more dominant as disease progresses • Particular species are observed together more frequently in presence of another • Red complex species are difficult to find without presence of orange complex species • Members of Actinomyces species, yellow, green, and purple complexes are often observed without members of orange and red complexes • Absence of a beneficial organism in a biofilm is as important as presence of pathogen in disease • Hypothesis found linking certain disease to a shift in membership of local microbiota Ø MICROBIAL SHIFT HYPOTHESIS Definitions Stages Microorganisms Interactions Hypothesis Koch’s Postulates Clinical Assessments Microbial Interactions in Biofilm • Physiological heterogeneity is found in biofilm • Particular cells of same microbial species can exhibit different physiological state in a biofilm with a small distance of one another Definitions Stages Microorganisms Interactions Hypothesis Koch’s Postulates Clinical Assessments Microbial Interactions in Biofilm • Microorganisms are in close physical proximity to one another and interact in biofilm • Metabolic interactions occur including nutritional co-operation, environmental modification through O2 detoxification, and small molecule signaling mediated gene regulation Definitions Stages Microorganisms Interactions Hypothesis Koch’s Postulates Clinical Assessments Microbial Interactions in Biofilm • Synergistic and antagonistic metabolic interactions occur among bacteria • Bacteria collaborate to catabolize complex host molecules including proteins and glycoproteins • Obligatory anaerobic bacteria (P. gingivalis) can survive in aerobic environment if they co-aggregate to oxygen consuming species (Neisseria) • Antagonistic interactions involve production of inhibitory compounds (Bacteriocin, H2O2, and acids) to inhibit growth of neighboring cells Definitions Stages Microorganisms Interactions Hypothesis Koch’s Postulates Clinical Assessments Quorum Sensing • Bacteria secrete a signaling molecule (autoinducers) that accumulates and triggers change in gene expression once critical concentration threshold is reached Low Cell Density High Cell Density • This threshold is reached at high cell density, reaching a critical mass (quorum) • Quorum sensing can occur within a single bacterial species as well as b/w diverse species Definitions Stages Microorganisms Interactions Hypothesis Individual Behavior Koch’s Postulates Group Behavior Clinical Assessments Quorum Sensing • Therefore, potential to Influence bacterial community structure by encouraging growth of bacterial species in biofilm and discourage growth of competitors • Therefore, quorum sensing play diverse roles: • Modulating the expression of genes for antibiotic resistance • Encouraging the growth of beneficial bacterial species to the biofilm • Discourage growth of competitors Definitions Stages Microorganisms Interactions Hypothesis Koch’s Postulates Clinical Assessments Non-specific Plaque Hypothesis • Non-specific Plaque Hypothesis was initially proposed by Miller (1890) • In mid 1900’s periodontal disease was believed to be a result from accumulation of plaque over time in conjunction with a diminished host response and increased host susceptibility with age • Elaboration of noxious products by entire plaque flora • Control of periodontal disease depends on control of the amount of plaque accumulation • This hypothesis was abandoned after development of techniques to isolate and identify bacteria in mid-20th century Definitions Stages Microorganisms Interactions Hypothesis Koch’s Postulates Clinical Assessments Specific Plaque Hypothesis • Specific plaque hypothesis states that only certain plaque is pathogenic in which pathogenicity depends on presence of specific microorganisms (Loesche, 1976) • Development of culture-based technique and anaerobic hood allowed cultivation of strict anaerobic species proposing periodontal inflammations caused by Gram –ve and anaerobic rods • Plaque harboring specific bacterial pathogens results in specific periodontal disease • Ex. A. actinomycetemcomitans as a pathogen in localized aggressive periodontitis • However, this hypothesis does not support with environmental factors around microorganisms Definitions Stages Microorganisms Interactions Hypothesis Koch’s Postulates Clinical Assessments Ecological Plaque Hypothesis • A change in a key environmental factor(s) will trigger shift in balance of resident plaque microflora which can predispose a site to a disease state (Marsh, 1994) Definitions Stages Microorganisms Interactions Hypothesis Koch’s Postulates Clinical Assessments Ecological Plaque Hypothesis • Dynamic relationship between environmental cause and ecological shifts within the biofilm • Disease can be prevented not only by inhibiting putative pathogens, but also interfering with environmental factors driving the selection and growth of selected bacteria • However, this hypothesis did not address the important role of genetic factors of the host to susceptibility to periodontal diseases Definitions Stages Microorganisms Interactions Hypothesis Koch’s Postulates Clinical Assessments Keystone Plaque Hypothesis • Low abundance microbial pathogens can orchestrate inflammatory disease by remodeling a normally benign microbiota into a dysbiotic one (Hajishengallis, 2012) • The role of the host immune system is critical in susceptibility to inflammatory disease • Certain keystone species (Red complex such as P. gingivalis) have an effect on their environment by triggering inflammation when they are present in low number in contrast to dominant species that can influence inflammation • When disease develops and advanced stage are reached, the keystone pathogen are detected in higher numbers Definitions Stages Microorganisms Interactions Hypothesis Koch’s Postulates Clinical Assessments Keystone Plaque Hypothesis Hajishengalis, 2012 Definitions Stages Microorganisms Interactions Hypothesis Koch’s Postulates Clinical Assessments Koch’s Postulates • Criteria for Identification of Pathogens 1. Pathogens must be routinely isolated from the diseased individuals 2. Must be grown in pure culture in the laboratory 3. Must produce a similar disease when inoculated into susceptible lab animals 4. Must be recovered from lesions in a diseased lab animals Definitions Stages Microorganisms Interactions Hypothesis Koch’s Postulates Clinical Assessments Koch’s Postulates Definitions Stages Microorganisms Interactions Hypothesis Koch’s Postulates Clinical Assessments Exceptions to Koch’s Postulates • Koch’s Postulates do not apply in every situations. Some exceptions include: 1. Microorganisms that are unable to be cultured on artificial media (Viruses, T. pallidum) 2. 2 or more organism work in synergy to cause a disease - Mixed Infection 3. Some pathogens cause several different diseases (S. pyogenes cause pharyngitis, scarlet fever, skin infection) 4. Certain pathogens cause disease in humans only (HIV) Definitions Stages Microorganisms Interactions Hypothesis Koch’s Postulates Clinical Assessments Modified Koch’s Postulates • Modification of Koch’s postulates were necessary to Molecular Level 1. Nucleic acid sequence of pathogen should be found in association with disease or diseased organ 2. Nucleic acid sequence should be absent from healthy individual 3. Resolution of disease should result in decrease in pathogen associated nucleic acid sequences 4. Presence of pathogenic nucleic acid in a healthy individual should predict development of disease 5. Nature of microorganism inferred from nucleotide sequence should be consistent with biological characteristics of organism 6. Sequence based findings should be reproducible Definitions Stages Microorganisms Interactions Hypothesis Koch’s Postulates Clinical Assessments Reasons for Failure of Koch’s Postulates in Periodontal Microbiology • In case of periodontitis, three primary problems are: 1. The inability to culture all organisms that have been associated with disease 2. The difficulties inherent in defining and culturing sites of active disease 3. The lack of a good animal model system for the study of periodontitis Definitions Stages Microorganisms Interactions Hypothesis Koch’s Postulates Clinical Assessments Socransky’s Postulates • Proposed criteria by which periodontal microorganisms may be judged to be potential pathogens 1. Must be associated with disease, as evident by increase in the number of organisms at diseased site 2. Must be eliminated or decreased in sites that demonstrate clinical resolution of disease with treatment 3. Must be demonstrate a host response, in the form of an alteration in the host cellular or humoral immune response 4. Must be capable of causing disease in experimental animal model 5. Must demonstrate virulence factors responsible for enable the microorganisms to cause destruction of periodontal tissue Definitions Stages Microorganisms Interactions Hypothesis Koch’s Postulates Clinical Assessments Types of Dental Plaque • Based on relationship to the gingival margin, plaque is differentiated into Two Categories • Supragingival plaque • Subgingival Plaque Definitions Stages Microorganisms Interactions Hypothesis Koch’s Postulates Clinical Assessments Supragingival vs Subgingival Plaque Supragingival Plaque Subgingival Plaque Found at or above gingival margin. Found below gingival margin. (b/w tooth surface and epithelial attachment) Stratified organization of a multilayered accumulation of bacteria. Composition depends on pocket depth. Gram +ve cocci and short rods predominate on tooth surface. Differs in composition composition primarily by anaerobic environment and availability of blood products. Gram –ve rods, filaments, and spirochetes predominate in outer surface of the mature plaque. Definitions Stages Microorganisms Interactions Apical part is predominated by Gram-ve spirochetes, rods while coronal parts are predominated by filaments. Hypothesis Koch’s Postulates Clinical Assessments Supragingival vs Subgingival Plaque Definitions Characteristics Supragingival Plaque Subgingival Plaque Color White-creamy-yellow Or Black due to pigmentation from tobacco/food Dark brown/genuine black Shape Bulky, and gross deposits form between adjacent teeth and extend over gingival margin, shape of calculus is determined by anatomy of teeth. Flattened by pressure from pocket wall Consistency Hard Brittle Attachment Easily detached from tooth Firmly attached to the tooth Visibility Visible in the oral cavity Not visible on clinical exam Source Salivary secretion Gingival exudate Distribution More on lingual surface of mandibular anterior teeth due to salivary glands Related to pocket depth and heaviest on proximal surfaces Stages Microorganisms Interactions Hypothesis Koch’s Postulates Clinical Assessments Factors that Affect Plaque Formation • Natural Factors • Iatrogenic Factors • Local Dietary Factors Definitions Stages Microorganisms Interactions Hypothesis Koch’s Postulates Clinical Assessments Natural Factors that Affect Plaque Formation • Supra- and subgingival calculus • Cementoenamel junctions and enamel projections • Furcation entrances and irregularities • Tooth fissure and grooves • Cervical and root surface caries • Crowding of teeth Definitions Stages Microorganisms Interactions Hypothesis Koch’s Postulates Clinical Assessments Natural Factors that Affect Plaque Formation Supragingival Calculus Definitions Stages Subgingival Calculus Microorganisms Interactions Furcation Hypothesis Crowding of Teeth Koch’s Postulates Clinical Assessments Iatrogenic Factors that Affect Plaque Formation • Subgingival Restorative Margins • Overhang Restorative Margins • Open Restorative Margins Definitions Stages Microorganisms Interactions Hypothesis Koch’s Postulates Clinical Assessments Iatrogenic Factors that Affect Plaque Formation Defective Amalgam Margin Definitions Stages Overhang Amalgam Margin Microorganisms Interactions Hypothesis Open Margin of Crown Koch’s Postulates Clinical Assessments Local Dietary Factors that Affect Plaque Formation 1. Intake of fermentable carbohydrates (sucrose) 2. Acidogenicity (Acid Production) of bacteria of plaque lower pH to <5.5 3. Inhibit growth of beneficial bacteria 4. Further lower the pH, promote aciduric (acid tolerant) bacteria 5. Allows carious/pathogenic bacteria in plaque to thrive under acidic condition while other beneficial bacteria are inhibited Definitions Stages Microorganisms Interactions Hypothesis Koch’s Postulates Clinical Assessments Detection of Plaque 1. Direct Vision • Thin plaque: Film of plaque that is translucent and not visible with naked eye • Thick plaque: Moderate accumulation of plaque visible with naked eye 2. Use of Periodontal Explorer • Useful to detect plaque by adhering to explorer tip 3. Use of Disclosing Tablet • Dye that react with plaque • Used to identify plaque deposit for oral hygiene instruction and evaluation Definitions Stages Microorganisms Interactions Hypothesis Koch’s Postulates Clinical Assessments Plaque Index (Loe, 1967) Grade 0: No Plaque Grade 1: Film of Plaque Grade 2: Moderate accumulation of plaque within gingival pocket or on the tooth and gingival margin that can be seen with the naked eye Grade 3: Abundance of plaque within gingival pocket or on the tooth and gingival margin Definitions Stages Microorganisms Interactions Hypothesis Koch’s Postulates Clinical Assessments Variations in Dentition of Plaque • Plaque formation occurs faster on... • • • • Definitions Lower Dentition > Upper Dentition Posterior Dentition > Anterior Dentition Buccal Surface > Palatal Surface Interdental Areas > Buccal/Palatal Surface Stages Microorganisms Interactions Hypothesis Koch’s Postulates Clinical Assessments Components of Gingival Inflammation Gingival inflammation has 2 components 1. Acute inflammation • Vasodilation • Edema • Polymorphonuclear infiltration 2. Chronic Inflammation • B and T Lymphocyte • Capillary proliferation forming a granulomatous response Definitions Stages Microorganisms Interactions Hypothesis Koch’s Postulates Clinical Assessments Definition of Dental Plaque Induced Gingivitis Defined at the site level as • Inflammatory lesion resulting from interactions between dental plaque biofilm and host’s immune inflammatory response • Contained within gingiva and does not extend periodontal attachment (cementum, pdl, alveolar bone) • Reversible by reducing levels of dental plaque at and apical to the gingival margin Definitions Stages Microorganisms Interactions Hypothesis Koch’s Postulates Clinical Assessments Clinical Features of Dental Plaque Induced Gingivitis • Redness of gingival tissue • Bleeding on probing • Changes in contour • Presence of calculus or plaque with no radiographic evidence of bone loss * Reversibility of the inflammation by removing or disrupting the biofilm Definitions Stages Microorganisms Interactions Hypothesis Koch’s Postulates Clinical Assessments Experimental Gingivitis (Loe et al, 1965) • Loe et al (1965) conducted a study to produce experimental gingivitis in patients with healthy gingiva by withdrawing all oral hygiene • Clinically health gingiva resulted gross accumulation of plaque and developed marginal gingivitis in all subjects • Time to develop gingivitis occurred from 10 to 21 days • Once adequate oral hygiene was resumed, gingival inflammation subsided within a week Definitions Stages Microorganisms Interactions Hypothesis Koch’s Postulates Clinical Assessments Gingival Index (Loe, 1967) Grade 0: Normal gingiva Grade 1: Mild inflammation, slight color change, slight edema, no BOP Grade 2: Moderate inflammation, redness, edema, glazing, and BOP Grade 3: Severe inflammation, marked redness, edema, ulceration, spontaneous bleeding Definitions Stages Microorganisms Interactions Hypothesis Koch’s Postulates Clinical Assessments Mechanical Removal of Microorganisms • Biofilms in the oral cavity can be eliminated by physical removal • Mechanical removal of supra- and subgingival plaque • Prophylaxis • Scaling and Root planing (SRP) • Pocket Reduction Surgery (Ex. Open Flap Debridement, Osseous Surgery) Definitions Stages Microorganisms Interactions Hypothesis Koch’s Postulates Clinical Assessments Calculus Removal and Prevention • Calculus harbors oral biofilms associated with periodontal diseases due to its rough surface • So, removal of supra- and subgingival calculus are important to prevent and treat periodontal diseases • Hand instruments, ultrasonic scalers, and ER:YAG lasers are often used for removal of supra- and subgingival calculus Definitions Stages Microorganisms Interactions Hypothesis Koch’s Postulates Clinical Assessments Systematic Antibiotics • Prime candidates who exhibit continuing loss of periodontal attachment despite conventional mechanical therapy • SRP in addition to systemic use of amoxicillin and metronidazole treatment was effective therapy in patients with aggressive periodontitis (AAP Position Paper, 2004) • SRP in addition to metronidazole is effective to treat necrotizing ulcerative gingivitis (AAP Position Paper, 2004) • Used as adjunct to SRP and should not be used alone to remove biofilm Definitions Stages Microorganisms Interactions Hypothesis Koch’s Postulates Clinical Assessments Locally Delivered Antibiotics • Placed in periodontal pocket with a delivery system and released a minimum inhibitory concentration for 7 days after SRP is performed • Compared to SRP alone, locally delivered antibiotics allowed significant reduction of PD, BOP, and improvement in CAL (Hanes, 2003) Actisite • Tetracycline fiber • No longer available Definitions Stages Atridox • Doxycycline gel 10% • Bioabsorbable mixture in a syringe • Placed below the gingival margin Microorganisms Interactions PerioChip Arestin • Chlorhexidine chip, 2.5mg Hypothesis • Minocycline microsphere, 1mg • Bioabsorbable powder Koch’s Postulates Clinical Assessments Host Modulation Therapy • Goal is to adjust the host response to a microbial challenge by suppressing inflammatory response • Matrix metalloproteinases mediate tissue destruction by contributing to the tissue destruction and alveolar bone loss • Subantimicrobial Dose Doxycycline (SDD) has no antibacterial activity but its low concentration blocks matrix metalloproteinase involved in tissue destruction • Significant benefit to manage chronic periodontitis (Preshaw, 2008) Definitions Stages Microorganisms Interactions Hypothesis Koch’s Postulates Clinical Assessments Assessment of Efficacy of Treatment • Two categories are used to assess efficacy of treatment • Biological and Clinical • Biological: Determine whether treatment altered the content of the microflora and helped to resolve the host inflammatory response • Clinical: Measurement of PD reduction, CAL gain, BOP reduction, prevention of tooth loss, and patient compliance Definitions Stages Microorganisms Interactions Hypothesis Koch’s Postulates Clinical Assessments Questions? Dr. Chiho Ahn, DMD, DMSc, CAGS, FACD [email protected]