NEET MDS Lessons
Periodontology
Transforming Growth Factor-Beta (TGF-β)
Transforming Growth Factor-Beta (TGF-β) is a multifunctional cytokine that plays a critical role in various biological processes, including development, tissue repair, immune regulation, and inflammation. Understanding its functions and mechanisms is essential for appreciating its significance in health and disease.
Overview of TGF-β
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Half-Life:
- Active TGF-β has a very short half-life of approximately 2 minutes. This rapid turnover is crucial for its role in dynamic biological processes.
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Functions:
- TGF-β is involved in several key physiological and pathological
processes:
- Development: Plays a vital role in embryonic development and organogenesis.
- Tissue Repair: Promotes wound healing and tissue regeneration by stimulating the proliferation and differentiation of various cell types.
- Immune Defense: Modulates immune responses, influencing the activity of immune cells.
- Inflammation: Regulates inflammatory processes, contributing to both pro-inflammatory and anti-inflammatory responses.
- Tumorigenesis: Involved in cancer progression, where it can have both tumor-suppressive and tumor-promoting effects depending on the context.
- TGF-β is involved in several key physiological and pathological
processes:
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Cellular Effects:
- Stimulates:
- Osteoblasts: Promotes the differentiation and activity of osteoblasts, which are responsible for bone formation.
- Fibroblasts: Enhances the proliferation and activity of fibroblasts, contributing to extracellular matrix production and tissue repair.
- Inhibits:
- Osteoclasts: Suppresses the activity of osteoclasts, which are responsible for bone resorption.
- Epithelial Cells: Inhibits the proliferation of epithelial cells, affecting tissue homeostasis.
- Most Immune Cells: Generally inhibits the activation and proliferation of various immune cells, contributing to its immunosuppressive effects.
- Stimulates:
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Production and Activation:
- TGF-β is produced as an inactive propeptide (latent form) and requires activation to become biologically active.
- Activation Conditions: The activation of TGF-β typically requires acidic conditions, which can occur in various physiological and pathological contexts, such as during inflammation or tissue injury.
Clinical Implications
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Wound Healing:
- TGF-β is crucial for effective wound healing and tissue repair, making it a target for therapeutic interventions in regenerative medicine.
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Bone Health:
- Its role in stimulating osteoblasts makes TGF-β important in bone health and diseases such as osteoporosis.
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Cancer:
- The dual role of TGF-β in tumorigenesis highlights its complexity; it can act as a tumor suppressor in early stages but may promote tumor progression in later stages.
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Autoimmune Diseases:
- Due to its immunosuppressive properties, TGF-β is being studied for its potential in treating autoimmune diseases and in transplant medicine to prevent rejection.
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
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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.
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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:
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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.
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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.
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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.
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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.
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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
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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.
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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.
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Monitoring: Regular assessment of furcation involvement using Naber’s probe can help monitor disease progression and the effectiveness of periodontal therapy.
Changes in Plaque pH After Sucrose Rinse
The pH of dental plaque is a critical factor in the development of dental caries and periodontal disease. Key findings from various studies that investigated the changes in plaque pH following carbohydrate rinses, particularly focusing on sucrose and glucose.
Key Findings from Studies
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Monitoring Plaque pH Changes:
- A study reported that changes in plaque pH after a sucrose rinse were monitored using plaque sampling, antimony and glass electrodes, and telemetry.
- Results:
- The minimum pH at approximal sites (areas between teeth) was approximately 0.7 pH units lower than that on buccal surfaces (outer surfaces of the teeth).
- The pH at the approximal site remained below resting levels for over 120 minutes.
- The area under the pH response curves from approximal sites was five times greater than that from buccal surfaces, indicating a more significant and prolonged acidogenic response in interproximal areas.
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Stephan's Early Studies (1935):
- Method: Colorimetric measurement of plaque pH suspended in water.
- Findings:
- The pH of 211 plaque samples ranged from 4.6 to 7.0.
- The mean pH value was found to be 5.9, indicating a generally acidic environment in dental plaque.
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Stephan's Follow-Up Studies (1940):
- Method: Use of an antimony electrode to measure in situ plaque pH after rinsing with sugar solutions.
- Findings:
- A 10% solution of glucose or sucrose caused a rapid drop in plaque pH by about 2 units within 2 to 5 minutes, reaching values between 4.5 and 5.0.
- A 1% lactose solution lowered the pH by 0.3 units, while a 1% glucose solution caused a drop of 1.5 units.
- A 1% boiled starch solution resulted in a reduction of 1.5 pH units over 51 minutes.
- In all cases, the pH tended to return to initial values within approximately 2 hours.
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Investigation of Proximal Cavities:
- Studies of actual proximal cavities opened mechanically showed that the lowest pH values ranged from 4.6 to 4.1.
- After rinsing with a 10% glucose or sucrose solution, the pH in the plaque dropped to between 4.5 and 5.0 within 2 to 5 minutes and gradually returned to baseline levels within 1 to 2 hours.
Implications
- The studies highlight the significant impact of carbohydrate exposure, particularly sucrose and glucose, on the pH of dental plaque.
- The rapid drop in pH following carbohydrate rinses indicates an acidogenic response from plaque microorganisms, which can contribute to enamel demineralization and caries development.
- The prolonged acidic environment in approximal sites suggests that these areas may be more susceptible to caries due to the slower recovery of pH levels.
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
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
Automated Probing Systems
Automated probing systems have become increasingly important in periodontal assessments, providing enhanced accuracy and efficiency in measuring pocket depths and clinical attachment levels. This lecture will focus on the Florida Probe System, the Foster-Miller Probe, and the Toronto Automated Probe, discussing their features, advantages, and limitations.
1. Florida Probe System
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Overview: The Florida Probe System is an automated probing system designed to facilitate accurate periodontal assessments. It consists of several components:
- Probe Handpiece: The instrument used to measure pocket depths.
- Digital Readout: Displays measurements in real-time.
- Foot Switch: Allows for hands-free operation.
- Computer Interface: Connects the probe to a computer for data management.
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Specifications:
- Probe Diameter: The end of the probe is 0.4 mm in diameter, allowing for precise measurements in periodontal pockets.
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Advantages:
- Constant Probing Force: The system applies a consistent force during probing, reducing variability in measurements.
- Precise Electronic Measurement: Provides accurate and reproducible measurements of pocket depths.
- Computer Storage of Data: Enables easy storage, retrieval, and analysis of patient data, facilitating better record-keeping and tracking of periodontal health over time.
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Disadvantages:
- Lack of Tactile Sensitivity: The automated nature of the probe means that clinicians do not receive tactile feedback, which can be important for assessing tissue health.
- Fixed Force Setting: The use of a fixed force setting throughout the mouth may not account for variations in tissue condition, potentially leading to inaccurate measurements or patient discomfort.
2. Foster-Miller Probe
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Overview: The Foster-Miller Probe is another automated probing system that offers unique features for periodontal assessment.
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Capabilities:
- Pocket Depth Measurement: This probe can measure pocket depths effectively.
- Detection of the Cemento-Enamel Junction (CEJ): It is capable of coupling pocket depth measurements with the detection of the CEJ, providing valuable information about clinical attachment levels.
3. Toronto Automated Probe
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Overview: The Toronto Automated Probe is designed to enhance the accuracy of probing in periodontal assessments.
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Specifications:
- Probing Mechanism: The sulcus is probed with a 0.5 mm nickel titanium wire that is extended under air pressure, allowing for gentle probing.
- Angular Control: The system controls angular discrepancies using a mercury tilt sensor, which limits angulation within ±30 degrees. This feature helps maintain consistent probing angles.
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Limitations:
- Reproducible Positioning: The probe requires reproducible positioning of the patient’s head, which can be challenging in some clinical settings.
- Limited Access: The design may not easily accommodate measurements of second or third molars, potentially limiting its use in comprehensive periodontal assessments.
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.