NEET MDS Lessons
Periodontology
Microbes in Periodontics
Bacteria Associated with Periodontal Health
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Primary Species:
- Gram-Positive Facultative Bacteria:
- Streptococcus:
- S. sanguis
- S. mitis
- A. viscosus
- A. naeslundii
- Actinomyces:
- Beneficial for maintaining periodontal health.
- Streptococcus:
- Gram-Positive Facultative Bacteria:
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Protective or Beneficial Bacteria:
- Key Species:
- S. sanguis
- Veillonella parvula
- Corynebacterium ochracea
- Characteristics:
- Found in higher numbers at inactive periodontal sites (no attachment loss).
- Low numbers at sites with active periodontal destruction.
- Prevent colonization of pathogenic microorganisms (e.g., S. sanguis produces peroxide).
- Key Species:
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Clinical Relevance:
- High levels of C. ochracea and S. sanguis are associated with greater attachment gain post-therapy.
Microbiology of Chronic Plaque-Induced Gingivitis
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Composition:
- Roughly equal proportions of:
- Gram-Positive: 56%
- Gram-Negative: 44%
- Facultative: 59%
- Anaerobic: 41%
- Roughly equal proportions of:
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Predominant Gram-Positive Species:
- S. sanguis
- S. mitis
- S. intermedius
- S. oralis
- A. viscosus
- A. naeslundii
- Peptostreptococcus micros
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Predominant Gram-Negative Species:
- Fusobacterium nucleatum
- Porphyromonas intermedia
- Veillonella parvula
- Haemophilus spp.
- Capnocytophaga spp.
- Campylobacter spp.
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Pregnancy-Associated Gingivitis:
- Increased levels of steroid hormones and P. intermedia.
Chronic Periodontitis
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Key Microbial Species:
- High levels of:
- Porphyromonas gingivalis
- Bacteroides forsythus
- Porphyromonas intermedia
- Campylobacter rectus
- Eikenella corrodens
- Fusobacterium nucleatum
- Actinobacillus actinomycetemcomitans
- Peptostreptococcus micros
- Treponema spp.
- Eubacterium spp.
- High levels of:
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Pathogenic Mechanisms:
- P. gingivalis and A. actinomycetemcomitans can invade host tissue cells.
- Viruses such as Epstein-Barr Virus-1 (EBV-1) and human cytomegalovirus (HCMV) may contribute to bone loss.
Localized Aggressive Periodontitis
- Microbiota Characteristics:
- Predominantly gram-negative, capnophilic, and anaerobic rods.
- Almost all localized juvenile periodontitis (LJP) sites harbor A. actinomycetemcomitans, which can comprise up to 90% of the total cultivable microbiota.
Smoking
- Pack years = Packs/day × Years of smoking
Diabetes
- Causes collagen cross – linking via AGEs formation
AIDS
- Most common oral lesion: Candidiasis
- Most common oral malignancy: Kaposi sarcoma
🟡 Jaundice & Liver Disorders
| Condition | Key Features |
|---|---|
| Unconjugated hyperbilirubinemia | No urine bilirubin; seen in hemolysis |
| Conjugated hyperbilirubinemia | Present in Dubin – Johnson syndrome |
| Crigler – Najjar Type II | Autosomal recessive |
| BSP test | Diagnoses Dubin – Johnson |
| ↑ 5’-Nucleotidase | Cholestasis marker |
| ↓ Alk Phosphatase | Seen in hypothyroidism |
🦠 Viral Hepatitis
- Hepatitis E: Feco-oral; dangerous in pregnancy
- Councilman bodies: Acute viral hepatitis
- Most chronic virus: Hepatitis C
- HBV infectivity: HBsAg + HBeAg
- Window period: ↓ HBsAg, ↑ anti-HBs
- Perinatal HBV transmission: 90% risk
- First marker in acute HBV: HBsAg
- HBV P gene: Codes reverse transcriptase
- Hepatitis A prophylaxis: Human Ig
- Most epidemic-prone hepatitis in India: Hepatitis E
⚡️ Acute & Chronic Features
- Acute RHF: Pulmonary embolism
- High-output failure causes: Anaemia
- EF Normal range: 60 – 75%
- Pulmonary edema Rx: Sublingual nitroglycerin
💊 Drugs & Interventions
- Nesiritide: BNP analogue
- Levosimendan: Inotropic for CHF
- Coenzyme Q: Used in CHF treatment
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)
Periodontal Medications and Their Uses
Periodontal medications play a crucial role in the management of periodontal diseases, aiding in the treatment of infections, inflammation, and tissue regeneration. Understanding the various types of medications and their specific uses is essential for effective periodontal therapy.
Types of Periodontal Medications
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Antibiotics:
- Uses:
- Used to treat bacterial infections associated with periodontal disease.
- Commonly prescribed antibiotics include amoxicillin, metronidazole, and doxycycline.
- Mechanism:
- They help reduce the bacterial load in periodontal pockets, promoting healing and reducing inflammation.
- Uses:
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Antimicrobial Agents:
- Chlorhexidine:
- Uses: A topical antiseptic used as a mouth rinse to reduce plaque and gingivitis.
- Mechanism: It disrupts bacterial cell membranes and inhibits bacterial growth.
- Tetracycline:
- Uses: Can be used topically in periodontal pockets to reduce bacteria.
- Mechanism: Inhibits protein synthesis in bacteria, reducing their ability to cause infection.
- Chlorhexidine:
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Anti-Inflammatory Medications:
- Non-Steroidal Anti-Inflammatory Drugs (NSAIDs):
- Uses: Used to manage pain and inflammation associated with periodontal disease.
- Examples: Ibuprofen and naproxen.
- Corticosteroids:
- Uses: May be used in severe cases to reduce inflammation.
- Mechanism: Suppress the immune response and reduce inflammation.
- Non-Steroidal Anti-Inflammatory Drugs (NSAIDs):
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Local Delivery Systems:
- Doxycycline Gel (Atridox):
- Uses: A biodegradable gel that releases doxycycline directly into periodontal pockets.
- Mechanism: Provides localized antibiotic therapy to reduce bacteria and inflammation.
- Minocycline Microspheres (Arestin):
- Uses: A localized antibiotic treatment that is placed directly into periodontal pockets.
- Mechanism: Releases minocycline over time to combat infection.
- Doxycycline Gel (Atridox):
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Regenerative Agents:
- Bone Grafts and Guided Tissue Regeneration (GTR) Materials:
- Uses: Used in surgical procedures to promote the regeneration of lost periodontal tissues.
- Mechanism: Provide a scaffold for new tissue growth and prevent the ingrowth of epithelium into the defect.
- Bone Grafts and Guided Tissue Regeneration (GTR) Materials:
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Desensitizing Agents:
- Fluoride Varnishes:
- Uses: Applied to sensitive areas to reduce sensitivity and promote remineralization.
- Mechanism: Strengthens enamel and reduces sensitivity by occluding dentinal tubules.
- Fluoride Varnishes:
Clinical Significance of Periodontal Medications
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Management of Periodontal Disease:
- Medications are essential in controlling infections and inflammation, which are critical for the successful treatment of periodontal diseases.
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Adjunct to Non-Surgical Therapy:
- Periodontal medications can enhance the effectiveness of non-surgical treatments, such as scaling and root planing, by reducing bacterial load and inflammation.
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Surgical Interventions:
- In surgical procedures, medications can aid in healing and regeneration, improving outcomes for patients undergoing periodontal surgery.
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Patient Compliance:
- Educating patients about the importance of medications in their treatment plan can improve compliance and overall treatment success.
Localized Aggressive Periodontitis and Necrotizing Ulcerative Gingivitis
Localized Aggressive Periodontitis (LAP)
Localized aggressive periodontitis, previously known as localized juvenile periodontitis, is characterized by specific microbial profiles and clinical features.
- Microbiota Composition:
- The microbiota associated with LAP is predominantly composed of:
- Gram-Negative, Capnophilic, and Anaerobic Rods.
- Key Organisms:
- Actinobacillus actinomycetemcomitans: The main organism involved in LAP.
- Other significant organisms include:
- Porphyromonas gingivalis
- Eikenella corrodens
- Campylobacter rectus
- Bacteroides capillus
- Spirochetes (various species).
- Viral Associations:
- Herpes viruses, including Epstein-Barr Virus-1 (EBV-1) and Human Cytomegalovirus (HCMV), have also been associated with LAP.
- The microbiota associated with LAP is predominantly composed of:
Necrotizing Ulcerative Gingivitis (NUG)
- Microbial Profile:
- NUG is characterized by high levels of:
- Prevotella intermedia
- Spirochetes (various species).
- NUG is characterized by high levels of:
- Clinical Features:
- NUG presents with necrosis of the gingival tissue, pain, and ulceration, often accompanied by systemic symptoms.
Microbial Shifts in Periodontal Disease
When comparing the microbiota across different states of periodontal health, a distinct microbial shift can be identified as the disease progresses from health to gingivitis to periodontitis:
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From Gram-Positive to Gram-Negative:
- Healthy gingival sites are predominantly colonized by gram-positive bacteria, while diseased sites show an increase in gram-negative bacteria.
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From Cocci to Rods (and Later to Spirochetes):
- In health, cocci (spherical bacteria) are prevalent. As the disease progresses, there is a shift towards rod-shaped bacteria, and in advanced stages, spirochetes become more prominent.
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From Non-Motile to Motile Organisms:
- Healthy sites are often dominated by non-motile bacteria, while motile organisms increase in number as periodontal disease develops.
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From Facultative Anaerobes to Obligate Anaerobes:
- In health, facultative anaerobes (which can survive with or without oxygen) are common. In contrast, obligate anaerobes (which thrive in the absence of oxygen) become more prevalent in periodontal disease.
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From Fermenting to Proteolytic Species:
- The microbial community shifts from fermentative bacteria, which primarily metabolize carbohydrates, to proteolytic species that break down proteins, contributing to tissue destruction and inflammation.