NEET MDS Lessons
Periodontology
Gingival crevicular fluid is an inflammatory exudate found in the gingival sulcus. It plays a significant role in periodontal health and disease.
A. Characteristics of GCF
- Glucose Concentration: The glucose concentration in GCF is 3-4 times greater than that in serum, indicating increased metabolic activity in inflamed tissues.
- Protein Content: The total protein content of GCF is much less than that of serum, reflecting its role as an inflammatory exudate.
- Inflammatory Nature: GCF is present in clinically normal sulci due to the constant low-grade inflammation of the gingiva.
B. Drugs Excreted Through GCF
- Tetracyclines and Metronidazole: These antibiotics are known to be excreted through GCF, making them effective for localized periodontal therapy.
C. Collection Methods for GCF
GCF can be collected using various techniques, including:
- Absorbing Paper Strips/Blotter/Periopaper: These strips absorb fluid from the sulcus and are commonly used for GCF collection.
- Twisted Threads: Placing twisted threads around and into the sulcus can help collect GCF.
- Micropipettes: These can be used for precise collection of GCF in research settings.
- Intra-Crevicular Washings: Flushing the sulcus with a saline solution can help collect GCF for analysis.
Dimensions of Toothbrushes
Toothbrushes play a crucial role in maintaining oral hygiene, and their design can significantly impact their effectiveness. The American Dental Association (ADA) has established guidelines for the dimensions and characteristics of acceptable toothbrushes. This lecture will outline these specifications and discuss their implications for dental health.
Acceptable Dimensions of Toothbrushes
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Brushing Surface Dimensions:
- Length:
- Acceptable brushing surfaces should measure between 1 to 1.25 inches (25.4 to 31.8 mm) long.
- Width:
- The width of the brushing surface should range from 5/16 to 3/8 inch (7.9 to 9.5 mm).
- Rows of Bristles:
- Toothbrushes should have 2 to 4 rows of bristles to effectively clean the teeth and gums.
- Tufts per Row:
- Each row should contain 5 to 12 tufts of bristles, allowing for adequate coverage and cleaning ability.
- Length:
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Filament Diameter:
- The diameter of the bristles can vary, affecting the stiffness and
cleaning effectiveness:
- Soft Filaments:
- Diameter of 0.2 mm (0.007 inches). Ideal for sensitive gums and children.
- Medium Filaments:
- Diameter of 0.3 mm (0.012 inches). Suitable for most adults.
- Hard Filaments:
- Diameter of 0.4 mm (0.014 inches). Generally not recommended for daily use as they can be abrasive to the gums and enamel.
- Soft Filaments:
- The diameter of the bristles can vary, affecting the stiffness and
cleaning effectiveness:
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Filament Stiffness:
- The stiffness of the bristles is determined by the diameter relative to the length of the filament. Thicker filaments tend to be stiffer, which can affect the brushing technique and comfort.
Special Considerations for Children's Toothbrushes
- Size:
- Children's toothbrushes are designed to be smaller to accommodate their smaller mouths and teeth.
- Bristle Thickness:
- The bristles are thinner, measuring 0.005 inches (0.1 mm) in diameter, making them gentler on sensitive gums.
- Bristle Length:
- The bristles are shorter, typically around 0.344 inches (8.7 mm), to ensure effective cleaning without causing discomfort.
Clinical Implications
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Choosing the Right Toothbrush:
- Dental professionals should guide patients in selecting toothbrushes that meet ADA specifications to ensure effective plaque removal and gum protection.
- Emphasizing the importance of using soft or medium bristles can help prevent gum recession and enamel wear.
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Education on Brushing Technique:
- Proper brushing technique is as important as the toothbrush itself. Patients should be educated on how to use their toothbrush effectively, regardless of the type they choose.
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Regular Replacement:
- Patients should be advised to replace their toothbrush every 3 to 4 months or sooner if the bristles become frayed. This ensures optimal cleaning effectiveness.
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Special Considerations for Children:
- Parents should be encouraged to choose appropriately sized toothbrushes for their children and to supervise brushing to ensure proper technique and effectiveness.
Keratinized Gingiva and Attached Gingiva
The gingiva is an essential component of the periodontal tissues, providing support and protection for the teeth. Understanding the characteristics of keratinized gingiva, particularly attached gingiva, is crucial for assessing periodontal health.
Keratinized Gingiva
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Definition:
- Keratinized gingiva refers to the gingival tissue that is covered by a layer of keratinized epithelium, providing a protective barrier against mechanical and microbial insults.
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Areas of Keratinized Gingiva:
- Attached Gingiva:
- Extends from the gingival groove to the mucogingival junction.
- Marginal Gingiva:
- The free gingival margin that surrounds the teeth.
- Hard Palate:
- The roof of the mouth, which is also covered by keratinized tissue.
- Attached Gingiva:
Attached Gingiva
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Location:
- The attached gingiva is the portion of the gingiva that is firmly bound to the underlying alveolar bone.
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Width of Attached Gingiva:
- The width of attached gingiva varies based on location and can increase with age and in cases of supraerupted teeth.
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Measurements:
- Greatest Width:
- Found in the incisor region:
- Maxilla: 3.5 mm - 4.5 mm
- Mandible: 3.3 mm - 3.9 mm
- Found in the incisor region:
- Narrowest Width:
- Found in the posterior region:
- Maxillary First Premolar: 1.9 mm
- Mandibular First Premolar: 1.8 mm
- Found in the posterior region:
- Greatest Width:
Clinical Significance
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Importance of Attached Gingiva:
- The width of attached gingiva is important for periodontal health, as it provides a buffer zone against mechanical forces and helps maintain the integrity of the periodontal attachment.
- Insufficient attached gingiva may lead to increased susceptibility to periodontal disease and gingival recession.
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Assessment:
- Regular assessment of the width of attached gingiva is essential during periodontal examinations to identify potential areas of concern and to plan appropriate treatment strategies.
Periodontics: Dental specialty deals with the supporting and surrounding tissues of the teeth.
1. Periodontium: tissues that invest and support teeth Includes Gingiva, Alveolar mucosa Cementum, Periodontal ligament, Alveolar bone, Support bone
2. Periodontal disease: changes to periodontium beyond normal range of variation
a. Specific plaque hypothesis: specific microorganisms cause periodontal disease; mostly anaerobes. Three implicated: Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, and Bacteriodes forsythus
b. Contributing factors: often a combination of factors
i. Local: calculus (tarter, home for bacteria, with age), traumatic occlusal forces, caries (root caries), overhangs and over-contoured restorations, open contacts with food impaction, missing/malaligned teeth
Invasion of biological width: from free gingival margin -> attached gingiva need ~ 3 mm. If enter this area -> problems (e.g., resorption)
ii. Host factors: exacerbate periodontal problems; e.g., smoking/tobacco use, pregnancy and puberty (hormonal changes, blood vessel permeability), stress, poor diet
iii.Medications: often -> tissue overgrowth; e.g., oral contraceptives, antidepressants, heart medicines, transplant anti-rejection drugs
iv.Systemic diseases: e.g., diabetes, immunosuppression
B. Gingivitis: inflammation of gingiva; with age; generally reversible
C. Periodontitis: inflammation of supporting tissues of teeth, characterized by loss of attachment (PDL) and bone; generally irreversible
D. Periodontal disease as risk factor for systemic diseases:
1. Causes difficulty for diabetics to control blood sugar
2. Pregnant women with periodontal disease ~ 7 times more likely to have premature and/or underweight baby
3. Periodontal diseased patients may be at risk for heart disease
Periodontal Medicaments
Periodontal diseases often require adjunctive therapies to traditional mechanical treatments such as scaling and root planing. Various medicaments have been developed to enhance the healing process and control infection in periodontal tissues. This lecture will discuss several periodontal medicaments, their compositions, and their clinical applications.
1. Elyzol
- Composition:
- Elyzol is an oil-based gel containing 25% metronidazole. It is formulated with glyceryl mono-oleate and sesame oil.
- Clinical Use:
- Elyzol has been found to be equivalent to scaling and root planing in terms of effectiveness for treating periodontal disease.
- However, no adjunctive effects beyond those achieved with mechanical debridement have been demonstrated.
2. Actisite
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Composition:
- Actisite consists of tetracycline-containing fibers.
- Each fiber has a diameter of 0.5 mm and contains 12.7 mg of tetracycline per 9 inches of fiber.
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Clinical Use:
- The fibers are placed directly into periodontal pockets, where they release tetracycline over time, helping to reduce bacterial load and promote healing.
3. Arestin
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Composition:
- Arestin contains minocycline, which is delivered as a biodegradable powder in a syringe.
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Clinical Use:
- Arestin is indicated for the treatment of periodontal disease and is applied directly into periodontal pockets, where it provides localized antibiotic therapy.
4. Atridox
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Composition:
- Atridox contains 10% doxycycline in a syringeable gel system that is biodegradable.
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Clinical Use:
- The gel is injected into periodontal pockets, where it solidifies and releases doxycycline over time, aiding in the management of periodontal disease.
5. Dentamycin and Periocline
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Composition:
- Both Dentamycin and Periocline contain 2% minocycline hydrochloride.
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Clinical Use:
- These products are used similarly to other local delivery systems, providing localized antibiotic therapy to reduce bacterial infection in periodontal pockets.
6. Periochip
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Composition:
- Periochip is a biodegradable chip that contains chlorhexidine.
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Clinical Use:
- The chip is placed in the gingival crevice, where it releases chlorhexidine over time, providing antimicrobial action and helping to control periodontal disease.
Acquired Pellicle in the Oral Cavity
The acquired pellicle is a crucial component of oral health, serving as the first line of defense in the oral cavity and playing a significant role in the initial stages of biofilm formation on tooth surfaces. Understanding the composition, formation, and function of the acquired pellicle is essential for dental professionals in managing oral health.
Composition of the Acquired Pellicle
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Definition:
- The acquired pellicle is a thin, organic layer that coats all surfaces in the oral cavity, including both hard (tooth enamel) and soft tissues (gingiva, mucosa).
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Components:
- The pellicle consists of more than 180 peptides, proteins,
and glycoproteins, which include:
- Keratins: Structural proteins that provide strength.
- Mucins: Glycoproteins that contribute to the viscosity and protective properties of saliva.
- Proline-rich proteins: Involved in the binding of calcium and phosphate.
- Phosphoproteins: Such as statherin, which helps in maintaining calcium levels and preventing mineral loss.
- Histidine-rich proteins: May play a role in buffering and mineralization.
- These components function as adhesion sites (receptors) for bacteria, facilitating the initial colonization of tooth surfaces.
- The pellicle consists of more than 180 peptides, proteins,
and glycoproteins, which include:
Formation and Maturation of the Acquired Pellicle
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Rapid Formation:
- The salivary pellicle can be detected on clean enamel surfaces within 1 minute after exposure to saliva. This rapid formation is crucial for protecting the enamel and providing a substrate for bacterial adhesion.
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Equilibrium State:
- By 2 hours, the pellicle reaches a state of equilibrium between adsorption (the process of molecules adhering to the surface) and detachment. This dynamic balance allows for the continuous exchange of molecules within the pellicle.
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Maturation:
- Although the initial pellicle formation occurs quickly, further maturation can be observed over several hours. This maturation process involves the incorporation of additional salivary components and the establishment of a more complex structure.
Interaction with Bacteria
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Bacterial Adhesion:
- Bacteria that adhere to tooth surfaces do not contact the enamel directly; instead, they interact with the acquired enamel pellicle. This interaction is critical for the formation of dental biofilms (plaque).
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Active Role of the Pellicle:
- The acquired pellicle is not merely a passive adhesion matrix. Many
proteins within the pellicle retain enzymatic activity when
incorporated. Some of these enzymes include:
- Peroxidases: Enzymes that can break down hydrogen peroxide and may have antimicrobial properties.
- Lysozyme: An enzyme that can lyse bacterial cell walls, contributing to the antibacterial defense.
- α-Amylase: An enzyme that breaks down starches and may influence the metabolism of adhering bacteria.
- The acquired pellicle is not merely a passive adhesion matrix. Many
proteins within the pellicle retain enzymatic activity when
incorporated. Some of these enzymes include:
Clinical Significance
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Role in Oral Health:
- The acquired pellicle plays a protective role by providing a barrier against acids and bacteria, helping to maintain the integrity of tooth enamel and soft tissues.
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Biofilm Formation:
- Understanding the role of the pellicle in bacterial adhesion is essential for managing plaque-related diseases, such as dental caries and periodontal disease.
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Preventive Strategies:
- Dental professionals can use knowledge of the acquired pellicle to develop preventive strategies, such as promoting saliva flow and maintaining good oral hygiene practices to minimize plaque accumulation.
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Therapeutic Applications:
- The enzymatic activities of pellicle proteins can be targeted in the development of therapeutic agents aimed at enhancing oral health and preventing bacterial colonization.
Pathogens Implicated in Periodontal Diseases
Periodontal diseases are associated with a variety of pathogenic microorganisms. Below is a list of key pathogens implicated in different forms of periodontal disease, along with their associations:
General Pathogens Associated with Periodontal Diseases
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Actinobacillus actinomycetemcomitans:
- Strongly associated with destructive periodontal disease.
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Porphyromonas gingivalis:
- A member of the "black pigmented Bacteroides group" and a significant contributor to periodontal disease.
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Bacteroides forsythus:
- Associated with chronic periodontitis.
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Spirochetes (Treponema denticola):
- Implicated in various periodontal conditions.
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Prevotella intermedia/nigrescens:
- Also belongs to the "black pigmented Bacteroides group" and is associated with several forms of periodontal disease.
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Fusobacterium nucleatum:
- Plays a role in the progression of periodontal disease.
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Campylobacter rectus:
- These organisms include members of the new genus Wolinella and are associated with periodontal disease.
Principal Bacteria Associated with Specific Periodontal Diseases
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Adult Periodontitis:
- Porphyromonas gingivalis
- Prevotella intermedia
- Bacteroides forsythus
- Campylobacter rectus
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Refractory Periodontitis:
- Bacteroides forsythus
- Porphyromonas gingivalis
- Campylobacter rectus
- Prevotella intermedia
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Localized Juvenile Periodontitis (LJP):
- Actinobacillus actinomycetemcomitans
- Capnocytophaga
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Periodontitis in Juvenile Diabetes:
- Capnocytophaga
- Actinobacillus actinomycetemcomitans
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Pregnancy Gingivitis:
- Prevotella intermedia
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Acute Necrotizing Ulcerative Gingivitis (ANUG):
- Prevotella intermedia
- Intermediate-sized spirochetes