Periodontal Health and Biofilm Factors LEC 4 dh308

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Questions and Answers

Which of the following factors can affect periodontal health? (Select all that apply)

Regular dental check-ups

Food impaction areas (correct)

Orthodontic bands and brackets (correct)

Over-contoured dental restorations (correct)

What is the average total measurement of Supracrestal Attached Tissue?

2.04 mm

Bone loss occurs with subgingival placement of fixed restorations.

True

The loss of the first molars in children can lead to increased ________ pressure on remaining teeth.

occlusal Signup and view all the answers

Which conditions can affect periodontal health? (Select all that apply)

Malocclusion Signup and view all the answers

What should be done to temporary crowns to minimize roughness?

Polished Signup and view all the answers

Mouth breathing is associated with decreased plaque accumulation.

False Signup and view all the answers

What is the effect of tobacco use on periodontal disease?

It increases the risk and severity of periodontal disease. Signup and view all the answers

What happens to gingival tissue when there is excessive tobacco use? (Select all that apply)

Increased keratinization Signup and view all the answers

What type of dental cleaning is recommended for partial denture wearers?

Daily cleaning with denture cleaner Signup and view all the answers

What do gram-negative organisms stimulate the release of?

Prostaglandin E2, interleukin-1β, and C-reactive protein Signup and view all the answers

What is the first line of defense in the inflammatory response?

Polymorphonuclear neutrophils (PMNs) Signup and view all the answers

What types of enzymes leak during phagocytosis?

Collagenase, beta-glucuronidase, alkaline phosphatase Signup and view all the answers

What is the second line of defense in the inflammatory response?

Macrophages Signup and view all the answers

Which of the following are bacterial enzymes that can break down periodontal protein structures? (Select all that apply)

Hyaluronidase Signup and view all the answers

What are cytokines?

Soluble proteins produced by stimulated immune cells Signup and view all the answers

What lipids are derived from arachidonic acid?

Prostaglandins Signup and view all the answers

What is the function of Matrix Metalloproteinases (MMPs)?

Degrade collagen, gelatin, and elastin Signup and view all the answers

Which of the following is the most studied cytokine for periodontal pathogenesis?

IL-1β Signup and view all the answers

The presence of dental plaque is essential to the initiation and progression of gingivitis and periodontitis.

True Signup and view all the answers

What are dental plaque biofilms?

Accumulations of microbes on the surface of teeth or other solid oral structures. Signup and view all the answers

What is the role of glycocalyx in biofilms?

It contains a network of channels and canals for nutrient exchange and waste removal. Signup and view all the answers

Which of the following is a gram-positive organism that is fermentative?

Streptococcus mutans Signup and view all the answers

The five major ecosystems in the oral cavity are the tongue, buccal mucosa, saliva, , and .

supragingival tooth surfaces, subgingival tooth surfaces Signup and view all the answers

Saliva contains antimicrobial proteins that help regulate microbe attachment.

True Signup and view all the answers

What is the function of the pellicle in biofilm formation?

It provides a sticky surface for bacteria to attach to and colonize teeth. Signup and view all the answers

Chronic periodontitis is characterized by higher proportions of gram-positive bacteria.

False Signup and view all the answers

What is a characteristic feature of necrotizing ulcerative gingivitis (NUG)?

Severe pain Signup and view all the answers

Which bacteria are primarily responsible for chronic periodontitis?

Porphyromonas gingivalis, Tannerella forsythia, Treponema denticola. Signup and view all the answers

What characterizes bacterial coaggregation in plaque biofilm?

Certain bacteria adhere to previously attached cells. Signup and view all the answers

Periodontal pathogens must be in close proximity to the __________ to exert their effects.

periodontal tissue Signup and view all the answers

What is the primary component that Porphyromonas gingivalis releases to evade host defenses?

Enzymes (proteases) Signup and view all the answers

Study Notes

Biofilm Retentive Factors and Periodontal Health

Over-contoured or worn restorations, food impaction areas, and orthodontic appliances can negatively affect periodontal health.

Supracrestal Attached Tissue (SAT)

SAT comprises connective tissue attachment (average 1.07 mm above alveolar bone crest) and junctional epithelium attachment (average 0.97 mm above connective tissue attachment).
Total average SAT is approximately 2.04 mm, ranging from 0.75 mm to 4.3 mm.
Previously termed "Biologic Width".

Violation of Supracrestal Attached Tissue

Restorative margins placed too far below the gingival crest can cause unpredictable bone loss with gingival recession or gingival inflammation without bone level change.

Crown Contours and Margins

Over-contoured restorations are linked to gingival inflammation and periodontal disease.
Subgingival margins increase plaque biofilm formation due to surface roughness, margin fit, and restoration contour.

Dental Hygiene Considerations for Crown Margins

A healthy gingival sulcus is needed before restorative treatment to determine gingiva height relative to the restoration margin.
Margins should be kept away from the gingiva.
Thin cement lines on crown margins allow biofilm adhesion.
Temporary crowns should have well-fitting, polished margins to minimize roughness.
Restorations must preserve embrasure spaces and be contoured for easy oral hygiene, especially in furcation areas.
Customized oral hygiene instructions are essential.

Amalgam Overhangs

Contribute to gingival inflammation.
Removal is a legally permitted task for dental hygienists in many states.

Removable Partial Dentures

Collect supragingival calculus.
Daily cleaning with appropriate tools is crucial.

Removable Partial Dentures and Natural Teeth

Can lead to deep periodontal pockets, increased caries susceptibility, requiring thorough oral hygiene instruction.

Conditions Affecting Periodontal Health

Orthodontic appliances, malocclusion, mouth breathing, first molar loss, tobacco, and alcohol use all impact periodontal health.

Orthodontics and Periodontal Health

Increases plaque, gingivitis, and caries risk.
In adults, uncontrolled periodontal disease during orthodontic treatment can cause bone loss.
Excessive orthodontic force increases apical root resorption risk.

Trauma and Periodontal Health

Toothbrush and flossing trauma, self-inflicted injuries, oral jewelry (especially tongue piercing), chemical irritation (allergies, burns), food impaction, smokeless tobacco, radiation therapy (mucositis), and occlusal trauma can harm periodontal tissues. Note that occlusal trauma itself doesn't initiate pocket formation.

Malocclusion and Periodontal Health

Poorly aligned teeth alter embrasure spaces, complicating oral hygiene.

Unreplaced Missing Teeth

Increased occlusal pressure on remaining teeth causing migration, typically mesially (mesial drift), except premolars which may drift distally.

First Molar Loss

Leads to mesial drift of second and third molars, distal drift of mandibular premolars, and loss of vertical dimension, often resulting in gingival inflammation and pocket formation.

Mouth Breathing

Causes localized labial gingival inflammation in maxillary anterior teeth, characterized by redness, swelling, shininess, and bleeding.
Associated with increased plaque, gingivitis, and poor response to therapy. Palliative care may include petroleum jelly or saliva substitutes.

Anatomic Anomalies

Variations in tooth anatomy necessitate careful instrumentation.

Tobacco and Alcohol Use

Both increase periodontal disease severity, with combined use significantly elevating the risk of oral and other cancers.

Tobacco Use and Periodontal Disease

All forms of tobacco (cigarettes, cigars, smokeless) are strong risk factors, increasing calculus, stains, and aggressive periodontal disease.
Causes increased keratinization, vasoconstriction, reduced phagocytosis, and impaired inflammatory response. Tissue destruction is observed where smokeless tobacco is placed. Smoking negatively affects healing after periodontal therapy.

Alcohol Use and Periodontal Disease

Contributes to periodontal disease severity, with higher consumption correlating with increased pocket depths, gingival bleeding, and attachment loss. It also increases biofilm accumulation due to reduced salivary flow.

Plaque Formation and Composition

Dental plaque biofilms are microbial accumulations on teeth, resisting removal by rinsing; unlike material alba, easily removed by rinsing.
Biofilms are encased in a glycocalyx matrix, facilitating nutrient exchange and waste removal, and protecting against external threats.
Biofilms are not random bacterial mixes but structured arrangements based on bacterial characteristics.
Gram-positive bacteria (e.g., Streptococcus mutans) are fermentative, deriving energy from sugars; producing lactic acid as a byproduct.

Oral Microbial Ecosystems and Saliva

The oral cavity hosts diverse microbial ecosystems: tongue, buccal mucosa, saliva, supragingival, and subgingival tooth surfaces.
Saliva is protective, containing shed cells and plaque, mediating biofilm removal via fluid movement and antimicrobial proteins (e.g., lysozyme).
Supragingival plaque initially appears as a thin, hard-to-detect film, becoming visible as a white-yellow mass with accumulation.

Biofilm Development

Pellicle formation (step 1): salivary glycoproteins adhere to teeth, forming a tenacious pellicle; not removable by brushing, only polishing. This influences subsequent bacterial colonization.
Initial bacterial colonization (step 2): bacteria adhere to the pellicle via specific receptors; S. mutans, S. sanguinis colonize supragingival plaque; S. salivarius is abundant on the tongue and in saliva. Initial biofilm is primarily gram-positive cocci, mainly streptococci.
Growth and maturation (step 3): plaque increases in mass and thickness; different bacteria adhere to each other, forming a complex intermicrobial matrix including salivary material, gingival exudate, microbial substances (polysaccharides).
Extracellular polysaccharides: produced by bacteria (e.g., S. mutans) from sucrose; serve as energy and structural support. Low levels of lipids and LPS (endotoxin) are present; inorganic components (calcium, phosphate) increase as plaque develops into calculus
Bacterial coaggregation: specific bacteria attach to previously attached cells creating complex aggregations (e.g., "corn cob" structure). Early colonizers (streptococci, Actinomyces) followed by late colonizers (Fusobacteria).
Microbial succession: biofilm composition changes over time; initial colonizers alter the environment enabling new species. Cocci decrease as filamentous bacteria increase, making the biofilm more anaerobic; spirochetes and gram-negative rods appear. This can lead to subgingival invasion and gingival disease

Subgingival Biofilm

Subgingival biofilm differs from supragingival biofilm; more anaerobic, gram-negative, motile, and asaccharolytic.
The subgingival environment is anaerobic with gingival crevicular fluid (GCF) increasing with inflammation, providing nutrients for bacteria.
Tooth-associated subgingival plaque is initially gram-positive filamentous bacteria. The apical portion is dominated by gram-negative rods.
Tissue-associated subgingival plaque is rich in motile bacteria and spirochetes, loosely adherent and activating host responses.

Periodontal Disease and Microbial Hypotheses

Early theories linked inflammation severity to plaque quantity, assuming homogeneity.
The specific plaque hypothesis focuses on specific species causing periodontitis.

Specific Periodontitis

Healthy subgingival areas have early biofilm organisms: gram-positive and facultative anaerobic species (cocci, rods, Actinomyces).
Gingivitis can be caused by numerous species in high numbers due to poor hygiene, distinct from specific periodontitis infections involving limited bacteria.
Periodontitis involves periodontal ligament, cementum, and alveolar bone loss; early stages resemble gingivitis but becomes more complex with anaerobes, gram-negative bacteria, and spirochetes dominating. Porphyromonas gingivalis is a key pathogen.
The "red complex" (P. gingivalis, Tannerella forsythia, Treponema denticola) is highly pathogenic. The "orange complex" is considered less virulent. Other complexes (yellow, green, purple) are earlier colonizers, less associated with disease.

Aggressive Periodontitis (Grade C: Rapid Rate)

Characterized by rapid attachment loss; affecting young adults, often with minimal plaque and inflammation.
Linked to genetic susceptibility and defective polymorphonuclear neutrophils (PMNs).
Gram-negative rods dominate (e.g., A. naeslundii, F. nucleatum, C. rectus; Aggregatibacter actinomycetemcomitans in some populations).

Necrotizing Ulcerative Gingivitis/Periodontitis (NUG/NUP)

Aggressive periodontitis with necrotic lesions, pain, rapid tissue loss, and halitosis.
Histopathology shows a necrotic zone with spirochetes and gram-negative rods; infiltrated connective tissue.
Abundant spirochetes, Prevotella intermedia, and gram-negative rods. High levels of Fusobacterium and Selenomonad species.

Virulence Factors of Periodontal Pathogens

Virulence depends upon proximity to tissue, evasion of host defenses, and ability to destroy tissue.
Proximity is mediated by cell surface features (fimbriae, polysaccharides) and bacterial interactions.
Evasion involves enzymes (proteases) degrading host proteins; leukotoxins killing PMNs; and factors interfering with PMN movement (P. gingivalis, T. forsythia, T. denticola, A. actinomycetemcomitans).
Tissue destruction is partly due to host inflammatory response to bacterial products (red and orange complexes); some bacterial products directly damage tissue.

Direct and Indirect Tissue Damage

Enzymes (e.g., collagenase from P. gingivalis) directly damage tissues.
Toxins (e.g., LPS; toxins from P. gingivalis, P. intermedia, A. actinomycetemcomitans, Capnocytophaga) induce inflammation, bone resorption, and affect collagen synthesis. Volatile sulfides also inhibit collagen synthesis.
Indirect effects involve inflammatory reactions from bacterial products (e.g., LPS stimulating prostaglandin, interleukin-1β, and C-reactive protein release).

Inflammatory and Enzymatic Responses

PMNs are the first line of defense, phagocytosing bacteria and releasing enzymes (collagenase, etc.).
Macrophages are a second line of defense, contributing to prostaglandin and cytokine release.
Bacterial enzymes and noxious products (ammonia, hydrogen sulfide, acids, proteases, collagenase, hyaluronidase, elastases) damage periodontal tissues. Hyaluronidase increases tissue permeability.

Cytokines

Cytokines are soluble proteins from immune cells (neutrophils, macrophages, lymphocytes).

Cell Communication Signals

Cytokines act as communication signals between cells.
Cytokine signaling is complex, involving many proteins.
Examples of cytokines include interleukins (IL), tumor necrosis factors (TNF), and interferons (IFN).
In periodontal disease, IL-1β and TNF-α are the most studied cytokines.
Lymphotoxin is a cytokine found in high amounts in response to plaque bacteria antigens in periodontal disease; it stimulates bone resorption.

Prostaglandins

Prostaglandins are lipid compounds derived from arachidonic acid (ARA).
ARA is found in cell membrane phospholipids.
Cyclooxygenases (COX-1/COX-2) are involved in prostaglandin synthesis.
Prostaglandin E2 (PGE2) induces the production of matrix metalloproteinases (MMPs).
PGE2 contributes to osteoclastic bone resorption and tissue damage in periodontitis.

Matrix Metalloproteinases (MMPs)

MMPs are pro-inflammatory, proteolytic enzymes.
They degrade collagen, gelatin, and elastin.
MMPs are produced by various cells, including neutrophils, macrophages, fibroblasts, epithelial cells, osteoblasts, and osteoclasts.
Examples of MMPs include gelatinase A (MMP-2) and collagenase 1 (MMP-1).

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Description

This quiz focuses on the impact of dental restorations and the importance of supracrestal attached tissue in maintaining periodontal health. It covers factors that can lead to periodontal disease and the consequences of improper restoration margins. Test your understanding of how these elements affect gum health and inflammation.