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Periodontology

Components of Gingival Crevicular Fluid (GCF) and Matrix Metalloproteinases (MMPs)

Gingival crevicular fluid (GCF) is a serum-like fluid found in the gingival sulcus that plays a significant role in periodontal health and disease. Understanding its composition, particularly glucose and protein content, as well as the role of matrix metalloproteinases (MMPs) in tissue remodeling, is essential for dental professionals.

Composition of Gingival Crevicular Fluid (GCF)

  1. Glucose and Hexosamines:

    • GCF contains compounds such as glucose, hexosamines, and hexuronic acid.
    • Glucose Levels:
      • Blood glucose levels do not correlate with GCF glucose levels; in fact, glucose concentration in GCF is three to four times greater than that in serum.
      • This elevated glucose level is interpreted as a result of the metabolic activity of adjacent tissues and the influence of local microbial flora.
  2. Protein Content:

    • The total protein content of GCF is significantly less than that of serum.
    • This difference in protein concentration reflects the unique environment of the gingival sulcus and the specific functions of GCF in periodontal health.

Matrix Metalloproteinases (MMPs)

  1. Definition and Function:

    • MMPs are a family of proteolytic enzymes that degrade extracellular matrix molecules, including collagen, gelatin, and elastin.
    • They are produced by various cell types, including:
      • Neutrophils
      • Macrophages
      • Fibroblasts
      • Epithelial cells
      • Osteoblasts and osteoclasts
  2. Classification:

    • MMPs are classified based on their substrate specificity, although it is now recognized that many MMPs can degrade multiple substrates. The classification includes:
      • Collagenases: e.g., MMP-1 and MMP-8 (break down collagen)
      • Gelatinases: Type IV collagenases
      • Stromelysins
      • Matrilysins
      • Membrane-type metalloproteinases
      • Others
  3. Activation and Inhibition:

    • MMPs are secreted in an inactive form (latent) and require proteolytic cleavage for activation. This activation is facilitated by proteases such as cathepsin G produced by neutrophils.
    • Inhibitors: MMPs are regulated by proteinase inhibitors, which possess anti-inflammatory properties. Key inhibitors include:
      • Serum Inhibitors:
        • α1-antitrypsin
        • α2-macroglobulin (produced by the liver, inactivates various proteinases)
      • Tissue Inhibitors:
        • Tissue inhibitors of metalloproteinases (TIMPs), with TIMP-1 being particularly important in periodontal disease.
    • Antibiotic Inhibition: MMPs can also be inhibited by tetracycline antibiotics, leading to the development of sub-antimicrobial formulations of doxycycline as a systemic adjunctive treatment for periodontitis, exploiting its anti-MMP properties.

Merkel Cells

  1. Location and Function:
    • Merkel cells are located in the deeper layers of the epithelium and are associated with nerve endings.
    • They are connected to adjacent cells by desmosomes and are identified as tactile receptors.
    • These cells play a role in the sensation of touch and pressure, contributing to the sensory functions of the oral mucosa.

Clinical Implications

  1. GCF Analysis:

    • The composition of GCF, including glucose and protein levels, can provide insights into the inflammatory status of the periodontal tissues and the presence of periodontal disease.
  2. Role of MMPs in Periodontal Disease:

    • MMPs are involved in the remodeling of periodontal tissues during inflammation and disease progression. Understanding their regulation and activity is crucial for developing therapeutic strategies.
  3. Therapeutic Applications:

    • The use of sub-antimicrobial doxycycline as an adjunctive treatment for periodontitis highlights the importance of MMP inhibition in managing periodontal disease.
  4. Sensory Function:

    • The presence of Merkel cells in the gingival epithelium underscores the importance of sensory feedback in maintaining oral health and function.

Bone Graft Materials

Bone grafting is a critical procedure in periodontal and dental surgery, aimed at restoring lost bone and supporting the regeneration of periodontal tissues. Various materials can be used for bone grafting, each with unique properties and applications.

A. Osseous Coagulum

  • Composition: Osseous coagulum is a mixture of bone dust and blood. It is created using small particles ground from cortical bone.
  • Sources: Bone dust can be obtained from various anatomical sites, including:
    • Lingual ridge of the mandible
    • Exostoses
    • Edentulous ridges
    • Bone distal to terminal teeth
  • Application: This material is used in periodontal surgery to promote healing and regeneration of bone in areas affected by periodontal disease.

B. Bioactive Glass

  • Composition: Bioactive glass consists of sodium and calcium salts, phosphates, and silicon dioxide.
  • Function: It promotes bone regeneration by forming a bond with surrounding bone and stimulating cellular activity.

C. HTR Polymer

  • Composition: HTR Polymer is a non-resorbable, microporous, biocompatible composite made from polymethyl methacrylate (PMMA) and polyhydroxymethacrylate.
  • Application: This material is used in various dental and periodontal applications due to its biocompatibility and structural properties.

D. Other Bone Graft Materials

  • Sclera: Used as a graft material due to its collagen content and biocompatibility.
  • Cartilage: Can be used in certain grafting procedures, particularly in reconstructive surgery.
  • Plaster of Paris: Occasionally used in bone grafting, though less common due to its non-biological nature.
  • Calcium Phosphate Biomaterials: These materials are osteoconductive and promote bone healing.
  • Coral-Derived Materials: Natural coral can be processed to create a scaffold for bone regeneration.

Influence of Host Response on Periodontal Disease

The host response plays a critical role in the progression and management of periodontal disease. Various host factors influence bacterial colonization, invasion, tissue destruction, and healing processes. Understanding these interactions is essential for developing effective treatment strategies.

Aspects of Periodontal Disease and Host Factors

  1. Bacterial Colonization:

    • Host Factor: Antibody C in crevicular fluid.
    • Mechanism:
      • Antibody C inhibits the adherence and coaggregation of bacteria in the subgingival environment.
      • This action potentially reduces bacterial numbers by promoting lysis (destruction of bacterial cells).
    • Implication: A robust antibody response can help control the initial colonization of pathogenic bacteria, thereby influencing the onset of periodontal disease.
  2. Bacterial Invasion:

    • Host Factor: Antibody C-mediated lysis and neutrophil activity.
    • Mechanism:
      • Antibody C-mediated lysis reduces bacterial counts in the periodontal tissues.
      • Neutrophils, through processes such as chemotaxis (movement towards chemical signals), phagocytosis (engulfing and digesting bacteria), and lysis, further reduce bacterial counts.
    • Implication: An effective neutrophil response is crucial for controlling bacterial invasion and preventing the progression of periodontal disease.
  3. Tissue Destruction:

    • Host Factors: Antibody-mediated hypersensitivity and cell-mediated immune responses.
    • Mechanism:
      • Activation of tissue factors, such as collagenase, leads to the breakdown of connective tissue and periodontal structures.
      • The immune response can inadvertently contribute to tissue destruction, as inflammatory mediators can damage host tissues.
    • Implication: While the immune response is essential for fighting infection, it can also lead to collateral damage in periodontal tissues, exacerbating disease progression.
  4. Healing and Fibrosis:

    • Host Factors: Lymphocytes and macrophage-produced chemotactic factors.
    • Mechanism:
      • Lymphocytes and macrophages release chemotactic factors that attract fibroblasts to the site of injury.
      • Fibroblasts are activated by specific factors, promoting tissue repair and fibrosis (the formation of excess connective tissue).
    • Implication: A balanced immune response is necessary for effective healing and regeneration of periodontal tissues following inflammation.

Anatomy and Histology of the Periodontium

Gingiva (normal clinical appearance): no muscles, no glands; keratinized

  • Color: coral pink but does vary with individuals and races due to cutaneous pigmentation
  • Papillary contour: pyramidal shape with one F and one L papilla and the col filling interproximal space to the contact area (col the starting place gingivitis)
  • Marginal contour: knife-edged and scalloped
  • Texture: stippled (orange-peel texture); blow air to dry out and see where stippling ends to see end of gingiva
  • Consistency: firm and resilient (push against it and won’t move); bound to underlying bone
  • Sulcus depth: 0-3mm
  • Exudate: no exudates (blood, pus, water)

  Anatomic and histological structures

Gingival unit: includes periodontium above alveolar crest of bone

a. Alveolar mucosa: histology- non-keratinized, stratified, squamous epithelium, submucosa with glands, loose connective tissue with collagen and elastin, muscles.  No epithelial ridges, no stratum granulosum (flattened cells below keratin layer)

b. Mucogingival junction: clinical demarcation between alveolar mucosa and attached gingiva

c. Attached gingiva: histology- keratinized, stratified, squamous epithelium with epithelial ridges (basal cell layer, prickle cell layer, granular cell layer (stratum granulosum), keratin layer); no submucosa

  • Dense connective tissue: predominantly collagen, bound to periosteum of bone by Sharpey fibers
  • Reticular fibers between collagen fibers and are continuous with reticulin in blood vessels

d. Free gingival groove: demarcation between attached and free gingiva; denotes base of gingival sulcus in normal gingiva; not always seen

e. Free gingival margin: area from free gingival groove to epithelial attachment (up and over ® inside)

  • Oral surface: stratified, squamous epithelium with epithelial ridges
  • Tooth side surface (sulcular epithelium): non-keratinized, stratified, squamous epithelium with no epithelial ridges (basal cell and prickle cell layers)

f. Gingival sulcus: space bounded by tooth surface, sulcular epithelium, and junctional epithelium; 0-3mm depth; space between epithelium and tooth

g. Dento-gingival junction: combination of epithelial and fibrous attachment

  • Junctional epithelium (epithelial attachment): attachment of epithelial cells by hemi-desmosomes and sticky substances (basal lamina- 800-1200 A, DAS-acid mucopolysaccharides, hyaluronic acid, chondroitin sulfate A, C, and B), to enamel, enamel and cementum, or cementum depending on stage of passive eruption.  Length ranges from 0.25-1.35mm.
  • Fibrous attachment: attachment of collagen fibers (Sharpey’s fibers) into cementum just beneath epithelial attachment; ~ 1mm thick

h. Nerve fibers: myelinated and non-myelinated (for pain) in connective tissue.  Both free and specialized endings for pain, touch pressure, and temperature -> proprioception.  If dentures, rely on TMJ.

i.Mesh of terminal argyophilic fibers (stain silver), some extending into epithelium

ii  Meissner-type corpuscles: pressure sensitive sensory nerve encased in CT

iii.Krause-type corpuscles: temperature receptors

iv. Encapsulated spindles

i. Gingival fibers:

i.  Gingivodental group:

  • Group I (A): from cementum to free gingival margin
  • Group II (B): from cementum to attached gingiva
  • Group III (C): from cementum over alveolar crest to periosteum on buccal and lingual plates

ii.  Circular (ligamentum circularis): encircles tooth in free gingiva

iii. Transeptal fibers: connects cementum of adjacent teeth, runs over interdental septum of alveolar bone.  Separates gingival unit from attachment apparatus.

Transeptal and Group III fibers the major defense against stuff getting into bone and ligament.

 

2.  Attachment apparatus: periodontium below alveolar crest of bone

Periodontal ligament: Sharpey’s fibers (collagen) connecting cementum to bone (bundle bone).  Few elastic and oxytalan fibers associated with blood vessels and embedded in cementum in cervical third of tooth.  Components divided as follows:

i. Alveolar crest fibers: from cementum just below CEJ apical to alveolar crest of bone

ii.Horizontal fibers: just apical to alveolar crest group, run at right angles to long axis of tooth from cementum horizontally to alveolar bone proper

iii.Oblique fibers: most numerous, from cementum run coronally to alveolar bone proper

iv. Apical fibers: radiate from cementum around apex of root apically to alveolar bone proper, form socket base

v. Interradicular fibers: found only between roots of multi-rooted teeth from cementum to alveolar bone proper

vi. Intermediate plexus: fibers which splice Sharpey’s fibers from bone and cementum

vii. Epithelial Rests of Malassez: cluster and individual epithelial cells close to cementum which are remnants of Hertwig’s epithelial root sheath; potential source of periodontal cysts.

viii. Nerve fibers: myelinated and non-myelinated; abundant supply of sensory free nerve endings capable of transmitting tactile pressure and pain sensation by trigeminal pathway and elongated spindle-like nerve fiber for proprioceptive impulses

Cementum: 45-50% inorganic; 50-55% organic (enamel is 97% inorganic; dentin 70% inorganic)

i.  Acellular cementum: no cementocytes; covers dentin (older) in coronal ½ to 2/3 of root, 16-60 mm thick

ii. Cellular cementum: cementocytes; covers dentin in apical ½ to 1/3 of root; also may cover acellular cementum areas in repair areas, 15-200 mm thick

iii. Precementum (cementoid): meshwork of irregularly arranged collagen in surface of cementum where formation starts

iv. Cemento-enamel junction (CEJ): 60-65% of time cementum overlaps enamel; 30% meet end-to-end; 5-10% space between

v. Cementum slower healing than bone or PDL.  If expose dentinotubules ® root sensitivity.

Alveolar bone: 65% inorganic, 35% organic

i. Alveolar bone proper (cribriform plate): lamina dura on x-ray; bundle bone receive Sharpey fibers from PDL

ii. Supporting bone: cancellous, trabecular (vascularized) and F and L plates of compact bone

Blood supply to periodontium

i. Alveolar blood vessels (inferior and superior)

A) Interalveolar: actually runs through bone then exits, main supply to alveolar bone and PDL

B) Supraperiosteal: just outside bone, to gingiva and alveolar bone

C) Dental (pulpal): to pulp and periapical area

D) Terminal vessels (supracrestal): anastomose of A and B above beneath the sulcular epithelium

E) PDL gets blood from: most from branches of interalveolar blood vessels from alveolar bone marrow spaces, supraperiosteal vessels when interalveolar vessels not present, pulpal (apical) vessels, supracrestal gingival vessels

ii. Lymphatic drainage: accompany blood vessels to regional lymph nodes (esp. submaxillary group)

PERIOTEST Device in Periodontal Assessment

The PERIOTEST device is a valuable tool used in dentistry to assess the mobility of teeth and the reaction of the periodontium to applied forces. This lecture covers the principles of the PERIOTEST device, its measurement scale, and its clinical significance in evaluating periodontal health.

Function: The PERIOTEST device measures the reaction of the periodontium to a defined percussion force applied to the tooth. This is done using a tapping instrument that delivers a controlled force to the tooth.

Contact Time: The contact time between the tapping head and the tooth varies between 0.3 and 2 milliseconds. This duration is typically shorter for stable teeth compared to mobile teeth, allowing for a quick assessment of tooth stability.

PERIOTEST Scale

The PERIOTEST scale ranges from -8 to +50, with specific ranges indicating different levels of tooth mobility:

Readings Inference
-8 to 9 Clinically firm teeth
10 to 19 First distinguishable sign of movement
20 to 29 Crown deviates within 1 mm of its normal position
30 to 50 Mobility is readily observed

Clinical Significance

Assessment of Tooth Mobility:
The PERIOTEST device provides a quantitative measure of tooth mobility, which is essential for diagnosing periodontal disease and assessing the stability of teeth.

Correlation with Other Measurements:
The PERIOTEST values correlate well with:

  • Tooth Mobility Assessed with a Metric System: This allows for a standardized approach to measuring mobility, enhancing the reliability of assessments.

  • Degree of Periodontal Disease and Alveolar Bone Loss: Higher mobility readings often indicate more severe periodontal disease and greater loss of supporting bone, making the PERIOTEST a useful tool in monitoring disease progression.

Treatment Planning:
Understanding the mobility of teeth can aid in treatment planning, including decisions regarding periodontal therapy, splinting of mobile teeth, or extraction in cases of severe mobility.

Significant Immune Findings in Periodontal Diseases

Periodontal diseases are associated with various immune responses that can influence disease progression and severity. Understanding these immune findings is crucial for diagnosing and managing different forms of periodontal disease.

Immune Findings in Specific Periodontal Diseases

  1. Acute Necrotizing Ulcerative Gingivitis (ANUG):

    • Findings:
      • PMN (Polymorphonuclear neutrophil) chemotactic defect: This defect impairs the ability of neutrophils to migrate to the site of infection, compromising the immune response.
      • Elevated antibody titres to Prevotella intermedia and intermediate-sized spirochetes: Indicates an immune response to specific pathogens associated with the disease.
  2. Pregnancy Gingivitis:

    • Findings:
      • No significant immune findings reported: While pregnancy gingivitis is common, it does not show distinct immune abnormalities compared to other forms of periodontal disease.
  3. Adult Periodontitis:

    • Findings:
      • Elevated antibody titres to Porphyromonas gingivalis and other periodontopathogens: Suggests a heightened immune response to these specific bacteria.
      • Occurrence of immune complexes in tissues: Indicates an immune reaction that may contribute to tissue damage.
      • Immediate hypersensitivity to gingival bacteria: Reflects an exaggerated immune response to bacterial antigens.
      • Cell-mediated immunity to gingival bacteria: Suggests involvement of T-cells in the immune response against periodontal pathogens.
  4. Juvenile Periodontitis:

    • Localized Juvenile Periodontitis (LJP):
      • Findings:
        • PMN chemotactic defect and depressed phagocytosis: Impairs the ability of neutrophils to respond effectively to bacterial invasion.
        • Elevated antibody titres to Actinobacillus actinomycetemcomitans: Indicates an immune response to this specific pathogen.
    • Generalized Juvenile Periodontitis (GJP):
      • Findings:
        • PMN chemotactic defect and depressed phagocytosis: Similar to LJP, indicating a compromised immune response.
        • Elevated antibody titres to Porphyromonas gingivalis: Suggests an immune response to this pathogen.
  5. Prepubertal Periodontitis:

    • Findings:
      • PMN chemotactic defect and depressed phagocytosis: Indicates impaired neutrophil function.
      • Elevated antibody titres to Actinobacillus actinomycetemcomitans: Suggests an immune response to this pathogen.
  6. Rapid Periodontitis:

    • Findings:
      • Suppressed or enhanced PMN or monocyte chemotaxis: Indicates variability in immune response among individuals.
      • Elevated antibody titres to several gram-negative bacteria: Reflects an immune response to multiple pathogens.
  7. Refractory Periodontitis:

    • Findings:
      • Reduced PMN chemotaxis: Indicates impaired neutrophil migration, which may contribute to disease persistence despite treatment.
  8. Desquamative Gingivitis:

    • Findings:
      • Diagnostic or characteristic immunopathology in two-thirds of cases: Suggests an underlying immune mechanism.
      • Autoimmune etiology in cases resulting from pemphigus and pemphigoid: Indicates that some cases may be due to autoimmune processes affecting the gingival tissue.

 Naber’s Probe and Furcation Involvement

Furcation involvement is a critical aspect of periodontal disease that affects the prognosis of teeth with multiple roots. Naber’s probe is a specialized instrument designed to assess furcation areas, allowing clinicians to determine the extent of periodontal attachment loss and the condition of the furcation. This lecture will cover the use of Naber’s probe, the classification of furcation involvement, and the clinical significance of these classifications.

Naber’s Probe

  • Description: Naber’s probe is a curved, blunt-ended instrument specifically designed for probing furcation areas. Its unique shape allows for horizontal probing, which is essential for accurately assessing the anatomy of multi-rooted teeth.

  • Usage: The probe is inserted horizontally into the furcation area to evaluate the extent of periodontal involvement. The clinician can feel the anatomical fluting between the roots, which aids in determining the classification of furcation involvement.

Classification of Furcation Involvement

Furcation involvement is classified into four main classes using Naber’s probe:

  1. Class I:

    • Description: The furcation can be probed to a depth of 3 mm.
    • Clinical Findings: The probe can feel the anatomical fluting between the roots, but it cannot engage the roof of the furcation.
    • Significance: Indicates early furcation involvement with minimal attachment loss.
  2. Class II:

    • Description: The furcation can be probed to a depth greater than 3 mm, but not through and through.
    • Clinical Findings: This class represents a range between Class I and Class III, where there is partial loss of attachment but not complete penetration through the furcation.
    • Significance: Indicates moderate furcation involvement that may require intervention.
  3. Class III:

    • Description: The furcation can be completely probed through and through.
    • Clinical Findings: The probe passes from one furcation to the other, indicating significant loss of periodontal support.
    • Significance: Represents advanced furcation involvement, often associated with a poor prognosis for the affected tooth.
  4. Class III+:

    • Description: The probe can go halfway across the tooth.
    • Clinical Findings: Similar to Class III, but with partial obstruction or remaining tissue.
    • Significance: Indicates severe furcation involvement with a significant loss of attachment.
  5. Class IV:

    • Description: Clinically, the examiner can see through the furcation.
    • Clinical Findings: There is complete loss of tissue covering the furcation, making it visible upon examination.
    • Significance: Indicates the most severe form of furcation involvement, often leading to tooth mobility and extraction.

Measurement Technique

  • Measurement Reference: Measurements are taken from an imaginary tangent connecting the prominences of the root surfaces of both roots. This provides a consistent reference point for assessing the depth of furcation involvement.

Clinical Significance

  • Prognosis: The classification of furcation involvement is crucial for determining the prognosis of multi-rooted teeth. Higher classes of furcation involvement generally indicate a poorer prognosis and may necessitate more aggressive treatment strategies.

  • Treatment Planning: Understanding the extent of furcation involvement helps clinicians develop appropriate treatment plans, which may include scaling and root planing, surgical intervention, or extraction.

  • Monitoring: Regular assessment of furcation involvement using Naber’s probe can help monitor disease progression and the effectiveness of periodontal therapy.

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