NEET MDS Lessons
Periodontology
Erythema Multiforme
- Characteristics: Erythema multiforme presents with
"target" or "bull's eye" lesions, often associated with:
- Etiologic Factors:
- Herpes simplex infection.
- Mycoplasma infection.
- Drug reactions (e.g., sulfonamides, penicillins, phenylbutazone, phenytoin).
- Etiologic Factors:
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.
Dental Calculus
Dental calculus, also known as tartar, is a hard deposit that forms on teeth due to the mineralization of dental plaque. Understanding the composition and crystal forms of calculus is essential for dental professionals in diagnosing and managing periodontal disease.
Crystal Forms in Dental Calculus
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Common Crystal Forms:
- Dental calculus typically contains two or more crystal forms. The
most frequently detected forms include:
- Hydroxyapatite:
- This is the primary mineral component of both enamel and calculus, constituting a significant portion of the calculus sample.
- Hydroxyapatite is a crystalline structure that provides strength and stability to the calculus.
- Octacalcium Phosphate:
- Detected in a high percentage of supragingival calculus samples (97% to 100%).
- This form is also a significant contributor to the bulk of calculus.
- Hydroxyapatite:
- Dental calculus typically contains two or more crystal forms. The
most frequently detected forms include:
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Other Crystal Forms:
- Brushite:
- More commonly found in the mandibular anterior region of the mouth.
- Brushite is a less stable form of calcium phosphate and may indicate a younger calculus deposit.
- Magnesium Whitlockite:
- Typically found in the posterior areas of the mouth.
- This form may be associated with older calculus deposits and can indicate changes in the mineral composition over time.
- Brushite:
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Variation with Age:
- The incidence and types of crystal forms present in calculus can vary with the age of the deposit.
- Younger calculus deposits may have a higher proportion of brushite, while older deposits may show a predominance of hydroxyapatite and magnesium whitlockite.
Clinical Significance
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Understanding Calculus Formation:
- Knowledge of the crystal forms in calculus can help dental professionals understand the mineralization process and the conditions under which calculus forms.
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Implications for Treatment:
- The composition of calculus can influence treatment strategies. For example, older calculus deposits may be more difficult to remove due to their hardness and mineral content.
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Assessment of Periodontal Health:
- The presence and type of calculus can provide insights into a patient’s oral hygiene practices and periodontal health. Regular monitoring and removal of calculus are essential for preventing periodontal disease.
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Research and Development:
- Understanding the mineral composition of calculus can aid in the development of new dental materials and treatments aimed at preventing calculus formation and promoting oral health.
Flossing Technique
Flossing is an essential part of oral hygiene that helps remove plaque and food particles from between the teeth and along the gumline, areas that toothbrushes may not effectively clean. Proper flossing technique is crucial for maintaining gum health and preventing cavities.
Flossing Technique
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Preparation:
- Length of Floss: Take 12 to 18 inches of dental floss. This length allows for adequate maneuverability and ensures that you can use a clean section of floss for each tooth.
- Grasping the Floss: Hold the floss taut between your hands, leaving a couple of inches of floss between your fingers. This tension helps control the floss as you maneuver it between your teeth.
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Inserting the Floss:
- Slip Between Teeth: Gently slide the floss between your teeth. Be careful not to snap the floss, as this can cause trauma to the gums.
- Positioning: Insert the floss into the area between your teeth and gums as far as it will comfortably go, ensuring that you reach the gumline.
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Flossing Motion:
- Vertical Strokes: Use 8 to 10 vertical strokes with the floss to dislodge food particles and plaque. Move the floss up and down against the sides of each tooth, making sure to clean both the front and back surfaces.
- C-Shaped Motion: For optimal cleaning, wrap the floss around the tooth in a C-shape and gently slide it beneath the gumline.
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Frequency:
- Daily Flossing: Aim to floss at least once a day. Consistency is key to maintaining good oral hygiene.
- Best Time to Floss: The most important time to floss is before going to bed, as this helps remove debris and plaque that can accumulate throughout the day.
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Flossing and Brushing:
- Order of Operations: Flossing can be done either before or after brushing your teeth. Both methods are effective, so choose the one that fits best into your routine.
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)
Aggressive Periodontitis (formerly Juvenile Periodontitis)
- Historical Names: Previously referred to as periodontosis, deep cementopathia, diseases of eruption, Gottleib’s diseases, and periodontitis marginalis progressive.
- Risk Factors:
- High frequency of Actinobacillus actinomycetemcomitans.
- Immune defects (functional defects of PMNs and monocytes).
- Autoimmunity and genetic factors.
- Environmental factors, including smoking.
- Clinical Features:
- Vertical loss of alveolar bone around the first molars and incisors, typically beginning around puberty.
- Bone loss patterns often described as "target" or "bull" shaped lesions.
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.