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VIVA-STYLE ANSWERS - Oral Medicine & Radiology

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SECTION B - LONG ANSWER QUESTIONS

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Q1. Describe components of X-Ray Machine and discuss factors controlling X-Ray Beam.

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1. The X-ray tube head - contains the actual X-ray tube sealed in oil (for cooling and insulation), a metal housing, and a position-indicating device (PID/cone). The tube itself contains:
   • A cathode (tungsten filament - source of electrons)
   • An anode (tungsten target embedded in copper stem - where X-rays are produced)
   • Evacuated glass envelope
   • Focusing cup (molybdenum)
2. The extension arm - connects the tube head to the wall and allows positioning; contains high-voltage and low-voltage cables.
3. The control unit (panel) - the operator console with controls for kVp (kilovoltage peak), mA (milliamperage), and exposure time.

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Q2. Describe predisposing factors, clinical features, differential diagnosis, investigations, and management of Speckled Leukoplakia.

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• Tobacco (most important) - smoking, chewing, reverse smoking. Carcinogens (polycyclic aromatic hydrocarbons, nitrosamines) cause DNA damage.
• Alcohol - acts as a solvent enhancing carcinogen penetration; acetalaldehyde is mutagenic.
• Betel nut chewing (areca nut) - arecoline stimulates fibroblasts and is directly mutagenic.
• Candida albicans - especially in speckled leukoplakia; Candida produces nitrosamines that promote dysplasia.
• Human Papillomavirus (HPV) - particularly HPV 16 and 18.
• UV radiation - for lip leukoplakia.
• Syphilis - syphilitic glossitis predisposes to leukoplakia.
• Nutritional deficiencies - iron, folate, vitamins A, C, E.
• Chronic trauma/irritation - ill-fitting dentures, sharp teeth.

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• Site: Most common on buccal mucosa, floor of mouth, lateral tongue, retromolar area. Floor of mouth and ventral tongue are highest-risk sites.
• Appearance: Irregular white patches (cannot be wiped off) with interspersed red zones - giving a "speckled" or "salt and pepper" appearance.
• Surface: May be rough, nodular, or verrucous.
• Symptoms: Usually asymptomatic; red areas may cause mild burning or pain.
• Size: Variable - from a few mm to several cm.
• Borders: Irregular, not sharply defined.

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1. Homogeneous leukoplakia
2. Erythroplakia (purely red - even higher malignant potential)
3. Oral lichen planus (erosive type)
4. Oral candidiasis (pseudomembranous - can be wiped off)
5. White sponge nevus (familial, bilateral, benign)
6. Leukoedema (disappears on stretching)
7. Chemical burn (history of aspirin/caustic exposure)
8. Discoid lupus erythematosus

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1. Exfoliative cytology - screening tool; brush biopsy (OralCDx) to assess dysplasia
2. Incisional biopsy (gold standard) - essential for any suspected dysplastic lesion; taken from the most suspicious area (red zone)
3. Toluidine blue staining - vital dye that stains dysplastic/malignant cells dark blue; positive staining indicates biopsy site
4. Chemiluminescence (ViziLite) - dysplastic cells appear white under blue-white light
5. Autofluorescence (VELscope) - normal tissue fluoresces green; dysplastic tissue appears dark
6. PAS staining - demonstrates Candida hyphae in tissue sections
7. Candida culture - for Candida identification

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• Mild dysplasia - changes limited to lower 1/3 of epithelium
• Moderate dysplasia - changes in lower 2/3 of epithelium
• Severe dysplasia - changes in all layers; if basement membrane intact = severe dysplasia; if breached = carcinoma in situ
• Carcinoma in situ - full thickness cytological atypia without invasion

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• Complete cessation of tobacco and alcohol
• Antifungal therapy if Candida is present (Fluconazole 150 mg once weekly × 4 weeks or Nystatin oral rinse)

• Vitamin A (retinol) or retinoids (isotretinoin 1 mg/kg/day) - promote normal epithelial differentiation
• Beta-carotene and lycopene - antioxidants
• Vitamin C and E supplementation

• Surgical excision - for small lesions; ensure clear margins
• CO₂ laser ablation - minimal scarring, good hemostasis; preferred for large/multifocal lesions
• Cryosurgery - for accessible lesions
• Photodynamic therapy (PDT) - emerging modality; photosensitizer + light

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SECTION C - SHORT ANSWER QUESTIONS

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Q1. Radiation Caries

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1. Salivary gland damage: Radiation causes irreversible damage to acinar cells of salivary glands - threshold is around 25-30 Gy; permanent xerostomia occurs above 40 Gy.
2. Reduced saliva causes: loss of buffering capacity (normally bicarbonates neutralize acids), reduced mechanical cleansing, loss of antimicrobial proteins (lactoferrin, lysozyme, IgA).
3. Shift in oral flora: Xerostomia promotes colonization by Streptococcus mutans, Lactobacillus - highly cariogenic organisms.
4. Direct radiation effect: Radiation may directly alter enamel crystal structure and reduce its resistance.
5. Result: Rapid, widespread dental destruction.

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• Onset: Within weeks to months of completing radiation
• Pattern: Begins at the cervical region of teeth (distinct from common caries which starts on occlusal/proximal surfaces)
• Spreads circumferentially around the neck of the tooth
• Multiple teeth affected simultaneously
• Brown/black discoloration of cervical enamel
• Progresses to amputation of the entire clinical crown
• Associated with xerostomia, mucositis, trismus

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• Pre-radiation dental assessment - extract all non-restorable teeth before radiation (at least 2 weeks prior)
• Daily fluoride gel application in custom trays (0.4% stannous fluoride or 1% NaF) - lifelong use
• Saliva substitutes and sialogogues (pilocarpine 5 mg TID)
• Dietary modifications - reduce fermentable carbohydrates
• Scrupulous oral hygiene
• Chlorhexidine mouth rinses

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Q2. Radiographic Features and Differential Diagnosis of Chronic Osteomyelitis

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• Mixed radiolucent-radiopaque pattern (hallmark)
• Sequestrum: Dense, sclerotic fragment of avascular necrotic bone surrounded by a radiolucent halo (sequestration zone/involucrum)
• Involucrum: Shell of new periosteal bone forming around the sequestrum
• Cloaca: Channels through the involucrum allowing drainage of pus
• Ill-defined, irregular margins of the lesion
• Mottled "moth-eaten" appearance of bone
• Loss of trabecular pattern
• Periosteal new bone formation (Codman's triangle possible - mimics malignancy)
• In Garré's osteomyelitis: "onion peel" periosteal laminations

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1. Osteoradionecrosis - history of radiation therapy; similar sequestrum formation
2. Osteosarcoma - sunburst pattern, Codman's triangle; no sequestrum
3. Ewing's sarcoma - onion peel periosteal reaction in young patients
4. Florid cemento-osseous dysplasia - lobular opacities, no acute features
5. Paget's disease - "cotton wool" opacities, expansion, elevated ALP
6. Metastatic carcinoma - clinical history; punched-out radiolucencies
7. Multiple myeloma - "punched out" lytic lesions, no sclerosis
8. Bisphosphonate-related osteonecrosis (BRONJ) - similar to ORN; drug history

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• CT scan - superior to plain film; shows sequestrum, periosteal reaction, soft tissue involvement
• MRI - best for soft tissue extent and marrow involvement (T1 low signal, T2 high signal)
• Tc-99m bone scan - increased uptake (hot scan) confirms activity
• Biopsy and culture - essential; tissue for H&E (confirm osteomyelitis) and aerobic/anaerobic culture + sensitivity

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Q3. Collimation and Filtration

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1. Lead diaphragm collimator - flat lead sheet with a central opening; simplest type; limits beam to a circle or rectangle
2. Cylinder collimator (position-indicating device/PID) - open-ended cylinder (cone) that defines beam diameter; round PID = circular beam
3. Rectangular collimator - most effective; limits beam to just slightly larger than the film/sensor; reduces patient exposure by up to 60% compared to round PID

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1. Inherent filtration: Comes from components of the tube head itself - glass envelope of the tube, insulating oil, aluminum tube port window. Equivalent to approximately 0.5-1.0 mm Al.
2. Added filtration: External aluminum (or rare earth) sheets placed at the tube port. Typically 1.0-1.5 mm Al.
3. Total filtration = Inherent + Added. NCRP requirements: minimum 1.5 mm Al equivalent for machines operating below 70 kVp; 2.5 mm Al equivalent for machines at or above 70 kVp.

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Q4. Forms of Oral Lichen Planus

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1. Reticular - most common (>50%); interlacing white lines called Wickham's striae; bilateral symmetrical on buccal mucosa; usually asymptomatic.
2. Papular - small discrete white dots or papules; often seen early or at the periphery of other forms; less common.
3. Plaque-like - homogeneous white patch resembling leukoplakia; dorsum of tongue most common; may be difficult to distinguish from leukoplakia.
4. Erosive/Ulcerative - most symptomatic; central ulceration (pseudomembrane covered) surrounded by peripheral striae; burning pain; common on gingiva and buccal mucosa.
5. Atrophic - diffuse erythema; thinned, atrophic epithelium; often appears as desquamative gingivitis; painful and burning.
6. Bullous - rarest form; fluid-filled vesicles/bullae that quickly rupture leaving erosions; often combined with erosive OLP.

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1. Hyperparakeratosis or orthokeratosis of epithelium with saw-tooth rete ridges
2. Band-like (lichenoid) lymphocytic infiltrate in the superficial lamina propria - predominantly T-lymphocytes (CD8+)
3. Civatte bodies (hyaline bodies) - eosinophilic globules representing apoptotic keratinocytes (liquefaction degeneration of basal cell layer/Max Joseph spaces)

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Q5. Treatment of Oral Submucous Fibrosis (OSMF)

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• Stage 1: Stomatitis; interincisal opening (IO) >35 mm; burning sensation only
• Stage 2: IO 26-35 mm; palpable fibrous bands
• Stage 3a: IO 15-25 mm; moderately restricted opening
• Stage 3b: IO 15-25 mm + precancerous changes
• Stage 4: IO <15 mm + severe fibrosis ± malignancy

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1. Fibrotomy and release of fibrous bands with bilateral coronoidectomy if needed
2. Nasolabial flap - most commonly used local flap for reconstruction
3. Buccal fat pad graft - for coverage after fibrotomy
4. Split thickness skin graft
5. Radial forearm free flap - for large defects

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Q6. Position Distance Rule

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1. Lead apron (0.25 mm Pb equivalent) - covers the trunk, gonads, and chest
2. Thyroid collar (0.25 mm Pb equivalent) - especially important in children and women of child-bearing age
3. Rectangular collimation to minimize beam field
4. Fast film speed or digital sensors (reduce exposure)
5. Proper exposure settings (no retakes due to positioning errors)

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Q7. Differential Diagnosis of Ameloblastoma

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• Multilocular radiolucency - "soap bubble" or "honeycomb" appearance (most characteristic)
• May be unilocular (especially unicystic type)
• Well-defined scalloped margins
• Root resorption of adjacent teeth
• Tooth displacement
• Expansion and thinning of cortical plates
• No calcification within the lesion

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1. Odontogenic keratocyst (OKC/KCOT) - scalloped, multilocular; but tends to grow along medullary cavity without expansion; tooth displacement without resorption; high recurrence
2. Central giant cell granuloma - "wispy" septa; younger patients; anterior mandible
3. Aneurysmal bone cyst - honeycomb, expansile; in young patients
4. Ameloblastic fibroma - young patients; associated with unerupted tooth
5. Vascular malformation (hemangioma) - pulsatile, bleeds on aspiration

1. Dentigerous (follicular) cyst - most common; associated with crown of unerupted tooth; smooth margins; no aggressive features
2. Odontogenic keratocyst - smooth or scalloped; may be unilocular; high recurrence
3. Simple bone cyst (traumatic) - empty cavity; scallops between roots; no expansion
4. Periapical cyst/granuloma - at apex of non-vital tooth; smaller

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• Incisional biopsy + histopathology - gold standard
• Histology shows: follicular pattern (most common) - islands of odontogenic epithelium with peripheral tall columnar cells (ameloblast-like) showing reverse polarity, stellate reticulum-like cells in center; or plexiform, acanthomatous, granular cell, or desmoplastic patterns
• CT/CBCT for extent and surgical planning

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• Radical resection with 1-1.5 cm bony margins is standard - segmental resection for large lesions
• Marginal resection for peripheral/intraosseous small lesions
• Curettage alone has 50-90% recurrence rate - not recommended
• Unicystic type has lower recurrence and may be treated more conservatively
• Reconstruction with bone graft or free fibula flap after resection

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Q8. Properties of X-Ray

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1. Travel in straight lines at the speed of light (3×10⁸ m/s)
2. Electrically neutral - not deflected by electric or magnetic fields
3. Invisible (cannot be seen by naked eye)
4. No mass, no charge
5. Short wavelength (0.01-10 nm for diagnostic X-rays)
6. High frequency and high energy (E = hf)
7. Can penetrate matter - degree depends on tissue density (bone > soft tissue > air)

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Q9. Radiographic Features of Osteosarcoma

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1. "Sunburst" or "sunray" pattern - most characteristic; spicules of tumor bone radiating from center perpendicular to cortex; due to periosteal new bone laid along Sharpey's fibers
2. Codman's triangle - periosteal elevation at margins of tumor creating a triangular opacity; represents reactive bone at the periphery
3. Widening of periodontal ligament space (PDL space) - uniform widening around one or more teeth; highly suggestive (unlike other tumors which cause root resorption); caused by tumor infiltrating PDL space
4. Mixed radiolucent-radiopaque pattern (most common overall appearance) - sclerotic areas (tumor bone) mixed with lytic areas (bone destruction)
5. Ill-defined, irregular margins
6. Cortical destruction and soft tissue extension
7. Root displacement or resorption (less common than PDL widening)

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1. Chondrosarcoma - may have calcified rings/arcs; no sunburst
2. Ewing's sarcoma - "onion peel" periosteal reaction; younger age
3. Metastatic carcinoma - history; lytic or blastic depending on primary
4. Chronic osteomyelitis - sequestrum, history of infection; no sunburst
5. Paget's disease - cotton-wool appearance; older patients; elevated ALP
6. Fibrous dysplasia - "ground glass" density; young patients; benign

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• Jaw osteosarcoma is treated differently from long bone - surgery is the primary modality (wide resection with 2-3 cm margins)
• Pre-operative chemotherapy (neoadjuvant) followed by surgery, then adjuvant chemotherapy
• Standard regimen: MAP (Methotrexate, Adriamycin/doxorubicin, Cisplatin)
• Radiation is used only for unresectable cases (osteosarcoma is relatively radioresistant)
• 5-year survival for jaw osteosarcoma is better than long bones (~70-80%) due to earlier detection

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Q10. Globulomaxillary Cyst

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• Inverted pear-shaped or teardrop-shaped radiolucency (pathognomonic radiographic shape)
• Located between the roots of the maxillary lateral incisor and canine
• Divergence of adjacent tooth roots - the roots are pushed apart
• Well-defined, corticated margins
• The adjacent teeth are vital (unless a radicular cyst from a non-vital tooth)
• Unilocular, smooth outline

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1. Periapical/radicular cyst - most important DD; teeth vital in true globulomaxillary lesion
2. Lateral periodontal cyst - at the side of root; small; botryoid variant
3. Odontogenic keratocyst - high recurrence; keratinized lining
4. Nasopalatine duct cyst - midline, between central incisors
5. Lateral nasal cyst (Nasolabial cyst) - soft tissue cyst; may displace upper lip

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• Enucleation and curettage is the treatment of choice
• Pre-operative vitality testing of adjacent lateral incisor and canine is mandatory - if teeth are non-vital, treat endodontically (this changes it to a radicular cyst)
• Histopathological examination is essential - the lining may reveal the true nature (squamous epithelium in most; parakeratinized in OKC)
• Prognosis after enucleation is excellent

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VIVA-STYLE ANSWERS - Community Dentistry / Dental Public Health

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SECTION B - LONG ANSWER QUESTIONS

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Q1. Define Planning. Describe in detail the steps of the Planning Cycle.

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STEP 1: Community Diagnosis / Situation Analysis

• Assessment of the health problem in the target population
• Identifying needs (felt needs vs. normative needs) vs. demands
• Data collection: epidemiological surveys, existing records, demographic data
• Identifying resources available (manpower, finances, infrastructure)
• Identifying constraints and barriers
• Output: A clear picture of "where we are now"

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STEP 2: Setting Goals and Objectives

• Goal: A broad, long-term desired outcome (e.g., "reduce dental caries in children by 50% in 10 years")
• Objective: Specific, measurable, time-bound statements of what needs to be achieved (SMART - Specific, Measurable, Achievable, Relevant, Time-bound)
• Prioritization of problems using criteria: magnitude, severity, manageability, community concern
• Output: Clear direction for the program

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STEP 3: Assessment of Resources

• Human resources: dentists, auxiliaries, health workers
• Financial resources: budget allocation
• Physical resources: equipment, facilities
• Time constraints
• Matching resources to objectives - if mismatch exists, either modify objectives or seek additional resources

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STEP 4: Developing Alternative Strategies / Formulation of Program

• Identifying multiple possible approaches to achieve objectives
• Comparing alternatives on basis of efficacy, cost, feasibility, acceptability
• Selecting the most appropriate strategy
• Examples: community water fluoridation vs. school fluoride rinse programs vs. dental health education

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STEP 5: Selection and Implementation

• Choosing the best strategy
• Developing a detailed action plan (who, what, when, where, how)
• Training personnel
• Obtaining necessary approvals and resources
• Pilot testing on a small scale before full implementation
• Full-scale implementation

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STEP 6: Monitoring and Evaluation

• Monitoring = continuous, ongoing assessment during program execution to check if activities are proceeding as planned
• Evaluation = periodic, systematic assessment of program performance against objectives
• Types of evaluation:
  • Process evaluation: Was the program implemented correctly?
  • Outcome evaluation: Were objectives achieved?
  • Impact evaluation: Long-term effect on health status?
  • Efficiency evaluation: Cost-effectiveness?

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STEP 7: Reassessment / Feedback

• Results of evaluation feed back into the cycle
• Program is modified, expanded, or terminated based on findings
• The cycle is continuous and dynamic - not a linear, one-time process
• This is what makes it a "cycle" - evaluation leads back to situation analysis

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• Felt need (Perceived need): What the community thinks they need - based on their own perception. Example: A community wants dentures even though tooth extraction was preventable.
• Normative need (Professional need): What experts/professionals define as needed based on objective criteria. Example: The dentist identifies that 80% of children have untreated caries.
• Demand: What people actually seek and ask for. Demand = felt need + motivation + ability to pay.
• The best programs align normative need with felt need to ensure community participation and compliance.

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Q2. Define Index. Explain in detail the recording of OHI Index.

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• Introduced the concept of quantifying oral health status
• Allows comparison across populations, geographic regions, and time periods

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1. Validity - measures what it claims to measure
2. Reliability/Reproducibility - same results when used by same or different examiners under same conditions
3. Sensitivity - detects small changes in the condition
4. Clarity and simplicity - easy to understand and apply
5. Objectivity - not influenced by examiner's judgment
6. Acceptability - acceptable to both examiner and subject
7. Quantifiability - expressed numerically
8. Amenability to statistical analysis - can be analyzed statistically
9. Economy of time and effort - quick to use in field conditions
10. Reversibility - can measure improvement as well as worsening (for reversible conditions)

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1. Only 6 teeth examined - may not represent entire mouth
2. Cannot be used in children under 5 (index teeth may not be erupted)
3. Does not differentiate types of deposits (plaque vs. food debris)
4. Scoring is somewhat subjective
5. Does not measure gingival inflammation directly
6. The 1/3 division of tooth surface is not always easy to determine precisely

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1. Plaque Index (PI) by Silness and Loe (1964) - scores plaque thickness at gingival margin; 0-3 on 4 surfaces of all teeth; better for clinical research
2. Simplified Plaque Index by Ramfjord (1959) - uses 6 Ramfjord teeth
3. Patient Hygiene Performance (PHP) by Podshadley and Haley (1968) - divides tooth surface into 5 sections
4. Turesky-Gillmore-Glickman modification of Q-H Index - uses disclosing solution
5. Quigley-Hein Index (1962) - uses disclosed plaque on labial surfaces

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SECTION C - SHORT ANSWER QUESTIONS

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Q1. Types of Pit and Fissure Sealants

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• Unfilled resins - lower viscosity, better penetration into fissures; less wear resistant
• Filled resins - contain filler particles (glass/quartz); more wear resistant but less penetrating
• Fluoride-releasing resin sealants - contain fluoride compounds for additional caries prevention

• Advantage: chemical bonding to tooth, fluoride release, moisture tolerance
• Disadvantage: lower retention rate than resin sealants (but provide caries protection even after partial loss due to fluoride release)
• Used in: newly erupted teeth (difficult to isolate), special needs patients, ART technique

• Combine properties of composite resin and GIC
• Fluoride releasing with better mechanical properties than GIC

• Chemically/auto-cured (self-cure): Two-paste system; cures on mixing; limited working time
• Light-cured (photo-polymerized): Cured with blue light (480 nm); controlled working time; currently the standard

• Clear/translucent - harder to see, patient compliance better
• White/opaque - easy to see for monitoring
• Tinted (pink/amber) - visible during placement, fade with time

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Q2. Operating Auxiliaries

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• Receptionist, dental secretary, office manager, dental technician (works in laboratory, not on patients)

1. Dental Hygienist - performs scaling, root planing, oral prophylaxis, radiographs, fluoride application, sealants, oral health education; works under general supervision
2. Dental Assistant / Chairside assistant - assists dentist chairside; four-handed dentistry; instrument transfer, suction, mixing materials
3. Dental Therapist - performs extractions of primary teeth, simple fillings, denture impressions; widely used in UK, New Zealand, and in India under AYUSH/NHP
4. Community Dental Officer - provides basic dental care in community settings
5. School Dental Nurse - works in school health programs; examinations, treatments

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Q3. Indian Dental Association (IDA)

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1. Promote dental health and oral hygiene of the Indian public
2. Advance the science and art of dentistry
3. Represent the interests of dental professionals
4. Maintain ethical standards in dental practice
5. Continuing dental education (CDE) for members
6. Liaison with government bodies on dental health policy
7. Publish scientific journals - Journal of Indian Dental Association (JIDA) and Indian Journal of Dental Research (IJDR)

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1. Mouth Cancer Awareness Program - annual campaign for early detection
2. Oral Health Month - celebrated every September; public awareness camps
3. Give a Smile Program - free dental treatment for economically weaker sections
4. Tobacco Cessation Programs
5. IDA Welfare Fund - for members in financial distress
6. CDE Programs - postgraduate courses, workshops, symposia
7. IDA House of Delegates - annual legislative body meeting

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• National IDA - apex body, Mumbai headquarters
• State IDA branches - in each state
• City/District branches - local level
• Governed by a President, Secretary General, Treasurer at national level
• House of Delegates meets annually to frame policies

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Q4. Mobile Dental Clinic

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• Dental chair (hydraulic/portable) - 1-2 chairs
• Dental unit with air and water supply
• Compressor and water storage tanks
• Suction/aspiration unit
• X-ray unit (portable dental X-ray)
• Autoclave/sterilization unit
• Dental instruments (extraction forceps, scaling instruments, restorative kit)
• Generator for independent power supply
• Laboratory area (small)
• Waiting area
• Storage for materials and medicines
• Waste disposal facility - biomedical waste

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• Reaches rural, tribal, remote, and underserved areas
• Reduces barriers of distance, cost, and transport
• Used for school dental health programs efficiently
• Cost-effective compared to building fixed facilities in remote areas
• Useful for emergency/disaster response
• Screening and preventive programs (fluoride, sealants)

• High initial capital cost
• Limited space - restricted range of procedures
• Cannot perform complex procedures (implants, surgery)
• Maintenance of vehicle and equipment is challenging
• Dependent on road access - truly remote areas still unreachable
• No emergency facility if complications arise
• Difficult to maintain strict infection control

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• School dental health programs - visiting schools
• Tribal areas under National Health Mission (NHM)
• Military dental services
• Dental college outreach programs
• Industrial camps for workers
• Disaster relief camps (floods, earthquakes)

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Q5. Ideal Requisites of Index

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1. Validity (Accuracy): Measures what it purports to measure. A caries index should truly reflect caries experience.
2. Reliability (Reproducibility/Consistency): Produces the same results on repeated measurements under same conditions; low intraexaminer and interexaminer variability. Measured by kappa statistics.
3. Sensitivity: Ability to detect small differences and changes in the condition being measured; important for detecting early disease.
4. Specificity: Measures only the condition it is designed to measure, not other conditions.
5. Clarity and Simplicity: Criteria must be clear, simple, and easy to learn so examiners can be trained quickly.
6. Objectivity: Based on objective, observable criteria, not subjective judgment. Reduces examiner bias.
7. Quantifiability: Must be expressible as a number or score that allows statistical manipulation.
8. Amenability to statistical analysis: Scores must be analyzable by standard statistical methods (mean, median, standard deviation).
9. Economy in time and effort: Must be practical for large-scale field use; quick to apply without complex equipment.
10. Acceptability: Must be acceptable to both the examiner and the subject being examined; non-invasive whenever possible.
11. Reversibility: For reversible conditions, the index must be able to measure both deterioration and improvement (e.g., gingival inflammation can resolve - a good index measures this). Irreversible conditions (caries) use cumulative indices.

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• Validity: Are you measuring the right thing? (Accuracy) - A scale that consistently shows 5 kg less than actual weight is reliable but NOT valid.
• Reliability: Are you measuring it consistently? (Precision) - A scale that shows different readings each time is neither reliable nor valid.
• You can have reliability without validity, but you cannot have validity without reliability.
• In epidemiology, kappa statistics measure inter-examiner reliability (k >0.8 = excellent agreement).

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Q6. Sampling Techniques

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• Examining an entire population is impractical, expensive, and time-consuming
• A well-chosen sample gives results that can be generalized to the whole population
• Reduces cost, time, and manpower requirements

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1. Simple Random Sampling (SRS): Each individual has an equal chance of being selected. Done by lottery method or random number tables. Example: selecting 100 students from 1000 by random number table. Advantage: simple, unbiased. Disadvantage: requires complete sampling frame; may miss subgroups.
2. Systematic Sampling: Every nth individual is selected after a random start. Example: from 1000 students, select every 10th student after randomly selecting a starting point between 1-10. Advantage: simple, evenly spread. Disadvantage: periodicity bias if list has cyclic pattern.
3. Stratified Random Sampling: Population is divided into homogeneous subgroups (strata) such as age, sex, socioeconomic status; random sampling within each stratum. Advantage: ensures representation of all subgroups; reduces sampling error. Disadvantage: requires knowledge of strata.
4. Cluster Sampling: Population is divided into clusters (e.g., villages, schools); some clusters are randomly selected and all individuals within selected clusters are examined. Advantage: practical when population is widespread; no need for complete list. Disadvantage: higher sampling error than SRS (design effect).
5. Multistage Sampling: Combination of sampling methods applied in stages. Example: WHO's oral health survey uses multistage sampling - first select districts, then select schools, then select students. Most practical for national surveys.

1. Convenience Sampling: Subjects most easily available. Quick but highly biased.
2. Purposive/Judgmental Sampling: Researcher deliberately selects subjects based on judgment.
3. Quota Sampling: Select predetermined numbers from specific subgroups without randomization.
4. Snowball Sampling: Existing subjects recruit future subjects; used for hard-to-reach populations.

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• Sampling error: Difference between sample estimate and true population value, arising purely from chance variation in sample selection. Can be reduced by increasing sample size or using stratified sampling.
• Non-sampling error: Systematic errors from examiner bias, measurement errors, non-response, recording errors. Not reduced by increasing sample size. More dangerous because it is not random.

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Q7. DCI (Dental Council of India)

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1. Prescribing standards for dental education - curriculum, duration, infrastructure, and faculty requirements for BDS and MDS courses
2. Inspection and recognition of dental colleges - inspects colleges before granting recognition; can withdraw recognition from substandard institutions
3. Maintaining Central Register - Central Dental Register; all registered dentists listed
4. Approving colleges for starting new dental institutions
5. Establishing equivalence of foreign dental degrees
6. Prescribing standards for examination - university examinations must conform to DCI norms
7. Advising the Central Government on matters related to dental education and practice
8. Disciplinary powers - can deregister dentists for professional misconduct

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• President (elected from among members)
• Vice-President
• Members include:
  • Representatives elected by State Dental Councils
  • Representatives from universities with dental faculties
  • Nominees of Central Government (Ministry of Health)
  • Director General of Health Services (ex-officio or nominee)
  • Nominees of Medical Council of India (now NMC)
• Secretary (appointed by Central Government)

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• Defines "dentistry" and regulates who may practice it
• Establishes the DCI and State Dental Councils
• Provides for registration of dentists
• Prescribes penalties for illegal practice of dentistry
• Has been amended several times (1964, 1976, 1993) to keep pace with changes

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Q8. DMFT Index

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• D = Decayed teeth (present caries)
• M = Missing teeth (due to caries - extracted because of caries)
• F = Filled teeth (treated caries)
• T = Teeth (unit of measurement)

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• Examination of all 32 permanent teeth (28 if wisdom teeth excluded)
• Each tooth is scored as D, M, or F (one score per tooth)
• A tooth can only be counted once; hierarchy: if a tooth is both decayed and filled, it is counted as D
• Individual DMFT = sum of D + M + F for that individual
• Mean DMFT for a group = Total DMFT of all individuals / Number of individuals examined

• Decayed: Cavity present (carious lesion into dentine; no early/white spot lesions unless WHO ICDAS criteria used)
• Missing: Tooth absent due to caries (in adults >30 years, teeth may be assumed caries-related if no other obvious reason)
• Filled: Restoration present AND no caries

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• d = decayed primary teeth
• e = indicated for extraction (due to caries - equivalent of M in permanent)
• f = filled primary teeth
• t = teeth

• Lowercase letters for primary teeth; uppercase for permanent
• No "m" (missing) as such in the original deft - instead "e" (extracted due to caries); some versions use "dmft" (d-m-f-t) for deciduous with "m" = missing
• Normal exfoliation of primary teeth makes "missing" unreliable
• Score ranges 0-20 (20 primary teeth)

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• 5 years - primary dentition (deft)
• 12 years - permanent dentition benchmark; global monitoring age; all first permanent molars erupted
• 15 years - permanent dentition in adolescents
• 35-44 years - adults; middle age
• 65-74 years - elderly

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• Mean DMFT ≤ 1 at age 12 years
• 80% of 6-year-olds caries-free
• 50% of 5-6 year-olds caries-free in primary dentition
• 85% of persons retaining all teeth at 18 years

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Q9. Steps in ART (Atraumatic Restorative Treatment)

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1. Removing soft, carious tooth tissue using hand instruments only (no rotary instruments)
2. Restoring the cavity with an adhesive restorative material (Glass Ionomer Cement)

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Step-by-Step ART Procedure:

• Patient in comfortable position (may be floor/chair if no dental unit)
• Good light source (headlamp, flashlight, daylight)
• Explain procedure; local anesthesia usually NOT required
• Cotton roll isolation

• If the cavity opening is too small for instrument entry, use a sharp enamel hatchet or dental hatchet to widen the entrance
• No drilling needed - hand instruments only

• Use a sharp spoon excavator (the primary ART instrument) to scoop out soft, infected carious dentine
• Work from the periphery toward the center
• Remove all soft dentine (infected, irreversibly damaged)
• Leave hard, discolored dentine if it is hard to the probe (this is affected dentine - can remineralize)
• Clean all undercuts and lateral walls

• Clean cavity with a small moist cotton pellet
• Dry with a dry cotton pellet
• Do NOT use air-water syringe

• Apply GIC conditioner (polyacrylic acid, 10-20%) or cavity cleanser to cavity walls for 10-15 seconds
• This removes the smear layer and improves GIC bonding to tooth
• Rinse gently with moist cotton pellet; do NOT over-dry

• Mix encapsulated or hand-mixed GIC to a thick, creamy consistency (high powder:liquid ratio - 3:1 for ART)
• Working time is approximately 1.5-2 minutes

• Insert GIC into cavity using a spatula or Applecap
• Press firmly to adapt GIC to cavity walls
• Build up slightly over the occlusal surface

• Apply a thin coat of petroleum jelly (Vaseline) on the gloved index finger
• Press the gloved finger firmly on the GIC for approximately 30 seconds to condense material and reduce porosity
• This is the hallmark of ART - no matrix or condensing instruments needed

• Ask patient to close gently
• Remove excess GIC with a carver before it sets completely
• Adjust occlusion using articulating paper or patient's bite
• Re-apply petroleum jelly on the restoration surface to protect during initial setting

• Advise patient not to eat or drink for 1 hour after ART
• Fluoride varnish application recommended
• Review after 6 months

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1. Chemical bonding to tooth (no need for acid etching/bonding agents)
2. Fluoride release - inhibits secondary caries; remineralizes adjacent tooth structure
3. Biocompatibility - well tolerated by pulp and soft tissues
4. Moisture tolerant - sets even in slightly moist conditions (important in field)
5. Coefficient of thermal expansion similar to tooth structure

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• No electricity or piped water needed
• No rotary instruments - less fear/anxiety, less pain
• Affordable - low cost
• Can be performed by trained auxiliaries
• Suitable for remote/rural areas, schools, camps
• GIC releases fluoride - additional caries prevention
• Minimal tooth tissue removal

• Cannot be used for large, multi-surface cavities
• Not suitable for pulpally involved teeth
• GIC has lower wear resistance than composite
• Long-term survival rates lower than conventional restorations
• Difficult for deep cavities close to pulp
• Operator fatigue with multiple patients

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Q10. Define Epidemiology. Tools of Measurement in Epidemiology.

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• Distribution: Who gets the disease? (person, place, time)
• Determinants: Why do they get it? (risk factors, causes)
• Health-related states: Disease, disability, death, but also positive health
• Specified populations: Defined groups, not individuals
• Application to control: Epidemiology must translate into public health action

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1. Describe the distribution of disease in populations (descriptive epidemiology)
2. Identify risk factors and causes of disease (analytical epidemiology)
3. Plan and evaluate health services and interventions
4. Provide evidence for public health policy
5. Study natural history of disease
6. Assess community health needs
7. Monitor trends in disease over time

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A. Rates and Ratios

1. Incidence Rate: Number of NEW cases of a disease occurring in a defined population during a specified period / Population at risk × 1000 (or 100,000). Measures disease onset; longitudinal.
2. Prevalence Rate: Number of EXISTING cases (new + old) at a point in time / Total population at that time × 100. Point prevalence measures burden of disease; cross-sectional.
3. Attack Rate: Number of persons developing disease after exposure / Total number exposed × 100. Used in outbreak investigations.
4. Case Fatality Rate (CFR): Deaths due to disease / Total cases of disease × 100. Measures severity/lethality.
5. Mortality Rate: Deaths from all causes / Total population × 1000 per year.
6. Morbidity Rate: General term for incidence/prevalence of non-fatal disease.

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B. Indices (Dental Specific)

• DMFT/DMFS - caries experience in permanent teeth
• deft/defs - caries experience in primary teeth
• OHI-S - oral hygiene status
• CPI (Community Periodontal Index) - periodontal status
• DAI (Dental Aesthetic Index) - malocclusion
• Dean's Fluorosis Index - dental fluorosis
• Gingival Index (GI, Loe and Silness) - gingival inflammation
• Plaque Index (PI) - plaque accumulation

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C. Surveys and Study Designs

1. Cross-sectional survey - prevalence; examines population at one point in time; quick, cheap but cannot establish cause
2. Cohort study (prospective/retrospective) - follows exposed and unexposed groups over time; gives incidence and relative risk
3. Case-control study - compares people with and without disease retrospectively; calculates odds ratio; efficient for rare diseases
4. Randomized Controlled Trial (RCT) - gold standard for interventions; evaluates efficacy of treatment/prevention
5. Ecological study - uses group-level (not individual) data; quick but ecological fallacy possible

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D. Measures of Association

1. Relative Risk (RR): Incidence in exposed / Incidence in unexposed. Used in cohort studies. RR >1 = risk factor; RR <1 = protective factor.
2. Odds Ratio (OR): Used in case-control studies. Approximates RR for rare diseases.
3. Attributable Risk: Excess risk due to exposure = Incidence in exposed - Incidence in unexposed.
4. Confidence Interval (CI): Range within which the true value lies with stated probability (usually 95%). If CI of RR or OR includes 1, the association is not statistically significant.
5. p-value: Probability that observed result occurred by chance; p <0.05 = statistically significant.

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E. Screening Tests

• Sensitivity: Ability to correctly identify true positives (TP/TP+FN × 100). Important when missing disease is dangerous.
• Specificity: Ability to correctly identify true negatives (TN/TN+FP × 100). Important to avoid false diagnoses.
• Positive Predictive Value (PPV): Probability that a positive test truly has the disease.
• Negative Predictive Value (NPV): Probability that a negative test truly does not have disease.

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Radiographic Features of Jaw Cysts

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Classification of Jaw Cysts

• Inflammatory: Radicular (periapical), Residual, Lateral periodontal (inflammatory)
• Developmental: Dentigerous, Eruption, Lateral periodontal (developmental), OKC (Keratocystic), Glandular odontogenic, Calcifying odontogenic (Gorlin)

• Nasopalatine duct (Incisive canal) cyst, Nasolabial cyst

• Traumatic (Simple) bone cyst, Aneurysmal bone cyst

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General Radiographic Principles for Any Jaw Cyst

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A. ODONTOGENIC CYSTS - INFLAMMATORY

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1. Radicular Cyst (Periapical/Dental Cyst)

Most common cyst of the jaws (~60% of all jaw cysts). Arises from cell rests of Malassez at the apex of a non-vital tooth, stimulated by pulpal inflammation.

• Well-defined, round/oval radiolucency at the apex of a non-vital tooth
• Corticated (white line) border - smooth, continuous cortex distinguishes it from periapical granuloma
• Loss of lamina dura at the root apex
• Continuous with the periodontal ligament space (PDL space) at the apex
• Size: typically >1 cm (larger than periapical granuloma which is usually <1 cm - though overlap exists; biopsy is definitive)
• May cause root resorption or displacement of adjacent teeth when large
• May expand cortical plates if large

• Lateral radicular cyst - at lateral root canal opening (lateral aspect of root, tooth non-vital)
• Residual cyst - radiolucency persists at extraction site after tooth removal; smooth, well-corticated

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2. Residual Cyst

• Radiolucency in the edentulous area of a previous extraction site
• Well-defined, corticated, unilocular
• No associated tooth
• Gradually increases in size
• May displace or resorb adjacent teeth

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B. ODONTOGENIC CYSTS - DEVELOPMENTAL

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3. Dentigerous (Follicular) Cyst

Second most common odontogenic cyst (after radicular cyst). Associated with crown of unerupted tooth. Most common 10-30 years. (K.J. Lee's Essential Otolaryngology, p. 3702)

• Unilocular radiolucency attached to and surrounding the crown of an unerupted tooth at the cemento-enamel junction (CEJ)
• Well-defined, scalloped corticated border
• Three radiographic types based on relationship to crown:
  • Central type (most common) - crown projects into cyst symmetrically
  • Lateral type - cyst grows to one side of crown
  • Circumferential type - entire tooth (crown + part of root) enclosed
• Displacement of unerupted tooth to a distant position (e.g., mandibular third molar displaced to lower border; maxillary canine displaced to orbital floor level)
• Root resorption of adjacent erupted teeth - more common than other non-neoplastic cysts
• Can reach up to 5 cm in radiographic diameter
• Expansion and thinning of cortical plates when large

Larger lesions must be differentiated from OKC and unicystic ameloblastoma - both can present in a dentigerous relationship. (Scott-Brown's Otorhinolaryngology, p. 8041-8053)

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4. Eruption Cyst

• Clinically diagnosed (bluish fluctuant swelling overlying an erupting tooth in a child <10 years)
• Radiographically: Not typically necessary; if taken, shows erupting tooth with soft tissue swelling; no bony changes
• Usually resolves spontaneously when tooth erupts

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5. Odontogenic Keratocyst (OKC) / Keratocystic Odontogenic Tumour (KCOT)

Reclassified back to "cyst" by WHO 2017 (was called KCOT/tumor in 2005 classification). Most aggressive odontogenic cyst with high recurrence (up to 60%).

• Unilocular OR multilocular radiolucency with smooth, well-defined, scalloped borders
• Hallmark: Tends to grow along the medullary cavity of the mandible (antero-posterior growth) with minimal bone expansion - unlike other cysts which expand the jaw early
• Posterior mandible (body + ramus region) - most common site (~70%)
• May be associated with an unerupted tooth (dentigerous relationship)
• Root resorption is less common than dentigerous cyst (despite aggressive behavior)
• Tooth displacement rather than resorption
• On aspiration: white/yellow cheese-like keratinous material (distinctive)
• When multiple OKCs are present → screen for Gorlin-Goltz syndrome (Nevoid Basal Cell Carcinoma Syndrome) - autosomal dominant; also has multiple BCCs, calcified falx cerebri, palmar/plantar pits, rib anomalies (K.J. Lee's Essential Otolaryngology, p. 3800-3820)

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6. Lateral Periodontal Cyst (Developmental)

• Unilocular, well-defined, small radiolucency (<1 cm typically) on the lateral aspect of the root of a vital tooth
• Located between the roots (not at apex, not at crown)
• ~80% in mandibular premolar-canine-lateral incisor area
• Adjacent teeth are vital (key differentiator from lateral radicular cyst)
• Well-corticated borders; no root resorption (K.J. Lee's Essential Otolaryngology, p. 3754)

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7. Glandular Odontogenic Cyst (Sialo-odontogenic Cyst)

• Unilocular or multilocular radiolucency
• Well-defined borders
• ~80% in anterior mandible
• Middle-aged adults
• Can be locally aggressive; recurrence >30%
• Must be differentiated from central mucoepidermoid carcinoma (histologically) (K.J. Lee's Essential Otolaryngology, p. 3775)

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8. Calcifying Odontogenic Cyst (Gorlin Cyst)

• Unilocular or multilocular well-defined radiolucency
• Irregular calcifications (radiopaque flecks) within the lesion - pathognomonic when present
• May be associated with odontoma within or adjacent to the lesion (~20%)
• Variable location - anterior jaws more common
• Variable presentation (cystic to solid/neoplastic spectrum) (K.J. Lee's Essential Otolaryngology, p. 3793)

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C. NON-ODONTOGENIC CYSTS

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9. Nasopalatine Duct Cyst (Incisive Canal Cyst)

Most common non-odontogenic cyst of the jaws (5-10% of all jaw cysts). Arises from epithelial remnants of nasopalatine (Jacobson's organ) canal. Most common in 30-60 years; male predominance. (Scott-Brown's Otorhinolaryngology, p. 8260)

• Heart-shaped (inverted pear-shaped) radiolucency in the midline of the anterior maxilla, above the roots of the central incisors - this shape is pathognomonic
• The "heart shape" is caused by the anterior nasal spine superimposed on the lesion
• Well-defined, corticated borders
• Unilocular
• Adjacent central incisors are vital
• Divergence of central incisor roots in large lesions
• Size: usually <6 mm is considered normal (incisive canal); >6 mm raises suspicion for cyst (K.J. Lee's Essential Otolaryngology, p. 3853)

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10. Nasolabial Cyst

• Soft tissue cyst - no bony changes on radiograph in most cases
• Occurs between ala and lip (soft tissue only)
• Occasionally may cause saucerization (shallow erosion) of the anterior maxilla
• Best demonstrated on CT or MRI rather than plain radiographs (K.J. Lee's Essential Otolaryngology, p. 3871)

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D. PSEUDOCYSTS

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11. Traumatic Bone Cyst (Simple/Idiopathic Bone Cyst)

No epithelial lining - hence a pseudocyst. Does not always have a traumatic history. Most common 10-20 years; male predominance; mandible >> maxilla.

• Unilocular radiolucency with characteristically scalloped margins that extend up between the roots of adjacent teeth (scalloping between roots = highly characteristic)
• Well-defined but non-corticated (no white line) border
• Adjacent teeth are vital and roots are NOT resorbed
• Empty on aspiration (nothing or scant blood - distinguishes from dentigerous cyst which yields straw-colored fluid)
• No expansion of cortical plates (K.J. Lee's Essential Otolaryngology, p. 3900)

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12. Aneurysmal Bone Cyst (ABC)

• Multilocular "soap bubble" or "honeycomb" radiolucency
• Marked expansion and ballooning of cortical plates - more expansion than other lesions ("blow-out" appearance)
• Blood-filled spaces on aspiration (frank blood - distinguishes from other cysts)
• Young patients
• May occur in mandible; cervical vertebrae also common

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Summary Comparison Table

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Important Differentiating Features at a Glance

• Tooth vitality: Non-vital → radicular/lateral radicular cyst. Vital → dentigerous, OKC, lateral periodontal, traumatic bone cyst
• Midline maxilla: Nasopalatine duct cyst (heart shape)
• Calcification within lesion: Calcifying odontogenic cyst (Gorlin cyst)
• Grows without expansion: OKC
• Scallops between roots: Traumatic bone cyst
• Ballooned expansion + multilocular: Aneurysmal bone cyst
• Multiple cysts in young patient: Screen for Gorlin-Goltz syndrome (OKC)
• Cheese-like aspirate: OKC; Straw-colored: Dentigerous; Blood: ABC; Nothing: Traumatic bone cyst

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Osteoradionecrosis (ORN)

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Definition

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Why the Mandible?

1. It lies directly in the radiation field during treatment of oral, oropharyngeal, and nasopharyngeal cancers
2. Mandible has a unilateral (end-artery) blood supply via the inferior alveolar artery - easily compromised by radiation
3. Maxilla has a bilateral, collateral blood supply (palatine, infraorbital, facial arteries) - hence ORN of the maxilla is rare, usually only in nasopharyngeal cancer irradiation
4. The mandible is a compact, dense bone with less collateral vasculature

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Incidence

• ORN occurs in 5-10% of patients treated with conventional external beam radiotherapy (EBRT) for head and neck cancers
• Severe ORN requiring surgery: ~2%
• Higher with hyperfractionated regimens (23% vs 9% with conventional fractionation in one study)
• Risk is higher with post-irradiation tooth extraction vs. pre-irradiation extraction (Cummings Otolaryngology, p. 1143)

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Pathogenesis

Classical Theory - "3H" Theory (Marx, 1983):

1. Hypoxia: Radiation damages the microvasculature (endarteritis obliterans) → reduced oxygen delivery to bone
2. Hypovascularity: Progressive obliterative endarteritis, thrombosis, and fibrosis of blood vessels → reduced blood flow
3. Hypocellularity: Death of osteocytes, osteoblasts, and fibroblasts → inability to repair bone

Modern Theory - Fibroatrophic Mechanism (Delanian & Lefaix, 2004):

• Radiation induces free radical generation → oxidative stress
• Activates TGF-β1 → fibroblast dysregulation → myofibroblast activation
• Progressive fibroatrophy: loss of cellular elements, obliterative fibrosis, bone remodeling failure
• This theory questioned the "hypoxic" basis and led to new medical treatments (PENTOCLO protocol)

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Risk Factors

Radiation-Related:

Patient/Local Factors:

• Post-irradiation tooth extraction (most important precipitating factor)
• Poor pre-radiation dental status (caries, periodontal disease, periapical pathology)
• Trauma to the irradiated area (denture pressure sores, biopsy)
• Alcohol and tobacco use
• Malnutrition / poor nutritional status
• Compromised systemic immunity (diabetes, steroids, chemotherapy)
• Posterior mandible location (posterior body, angle, ramus are most affected - highest radiation dose zone)

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Clinical Features

• Exposed necrotic bone in the oral cavity - often following tooth extraction or trauma (may be spontaneous)
• Pain - may be severe, constant, or absent (variable)
• Bad breath (halitosis) and dysgeusia
• Dysesthesia or anesthesia of lower lip/chin (inferior alveolar nerve involvement) - Vincent's sign
• Trismus - due to fibrosis of masticatory muscles
• Fistula formation - orocutaneous or oronasal fistula
• Pathological fracture of mandible in advanced cases
• Dysphagia and speech difficulty in extensive cases

• Yellow/gray necrotic bone exposed through oral mucosa or skin
• Overlying mucosa inflamed, erythematous, or ulcerated
• Surrounding tissues indurated and fibrosed
• Regional lymphadenopathy (reactive)
• May have purulent discharge

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Radiographic Features

• Ill-defined, irregular, "moth-eaten" radiolucency in the affected region
• Sequestrum: Dense, sclerotic fragment of avascular necrotic bone with surrounding radiolucent halo - pathognomonic
• Loss of normal trabecular pattern - disrupted, moth-eaten trabeculation
• Poorly defined, non-corticated margins (unlike cysts which have a clear white cortex)
• Cortical destruction - loss of inferior cortex of mandible in advanced cases
• Pathological fracture line may be visible
• No periosteal reaction (unlike osteomyelitis which may have periosteal new bone)
• Mixed radiolucent-radiopaque pattern in chronic stages
• Widening of PDL space of adjacent teeth

• Better delineation of extent of necrosis
• Sequestrum clearly visible as hyperdense fragment within hypodense necrotic zone
• Soft tissue extension (fistula, abscess) visible
• Cortical destruction, pathological fracture

• Best for assessing marrow involvement and soft tissue extent
• T1: Low signal marrow (fat replaced by necrotic/inflammatory tissue)
• T2: High signal (edema/inflammation)
• Important to exclude recurrent tumor (tumor shows enhancement on contrast MRI; ORN typically does not enhance centrally)

• Increased uptake ("hot scan") in active ORN
• Used to assess extent and activity

"Radiographical features: radiolucent, single, poorly defined margins" - K.J. Lee's Essential Otolaryngology, p. 4578

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Staging

Marx Classification (1983) - Based on Response to HBO:

Notani Classification (2003) - Radiological:

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Differential Diagnosis

1. Recurrent/residual tumor - most important (biopsy is mandatory to exclude); tumor enhances on contrast MRI
2. Chronic osteomyelitis - history of infection; sequestrum + involucrum; periosteal new bone
3. MRONJ (Medication-Related Osteonecrosis of the Jaw) - no radiation history; bisphosphonate/denosumab/anti-angiogenic drug history; similar exposed bone appearance
4. Noma (Cancrum oris) - in malnourished children; gangrenous tissue
5. Actinomycosis - sulfur granules; responds to penicillin

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Prevention

Pre-Radiation (Most Important Stage):

1. Comprehensive dental assessment at least 2-3 weeks before radiation begins
2. Extract all non-restorable, grossly carious, periodontally compromised, and partially erupted teeth in the planned radiation field - allow at least 14-21 days for socket healing before RT
3. Restore restorable teeth
4. Professional oral prophylaxis (scaling and root planing)
5. Fabrication of custom fluoride trays - daily fluoride gel (0.4% SnF₂) use for life after radiation
6. Patient education: oral hygiene instruction, dietary counseling

During and After Radiation:

1. Maintain excellent oral hygiene
2. Avoid post-radiation tooth extractions whenever possible - treat conservatively
3. If extraction is unavoidable post-radiation: use minimum trauma technique, antibiotic prophylaxis (amoxicillin-clavulanate), primary wound closure, avoid sutures in irradiated tissue
4. Saliva substitutes / sialogogues (pilocarpine) for xerostomia management
5. Chlorhexidine mouth rinses
6. Regular dental follow-up
7. Avoid smoking, alcohol, ill-fitting dentures

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Treatment

Conservative (Mild/Early ORN - Stage I):

1. Meticulous oral hygiene - chlorhexidine rinses, gentle debridement
2. Antibiotics - broad-spectrum (amoxicillin-clavulanate; metronidazole for anaerobes); based on wound culture
3. Local debridement / sequestrectomy - removal of loose sequestra; leave firmly attached bone
4. Analgesics - pain management
5. Nutritional support - high-protein diet; nutritional supplements

Hyperbaric Oxygen (HBO):

• Marx protocol: 30 pre-operative + 10 post-operative sessions at 2.4 atmospheres, 90 minutes/session
• Rationale (Marx): HBO increases tissue oxygen tension → stimulates neovascularization, fibroblast proliferation, and collagen synthesis
• Current controversy: A randomized multicenter trial (Annane et al., 2004 - HEADSTONE trial) showed no benefit of HBO over placebo (healing rate 19% HBO vs 32% placebo; p=0.23); results call into question HBO efficacy
• HBO still used in some centers but not universally recommended (Cummings Otolaryngology, p. 1151-1152)

Medical - PENTOCLO Protocol (Delanian, based on fibroatrophic theory):

• Pentoxifylline (800 mg/day) + Tocopherol/Vitamin E (1000 IU/day) + Clodronate (bisphosphonate - 1600 mg/day)
• Pentoxifylline inhibits TGF-β1 and free radical formation; anti-fibrotic
• Tocopherol is a free radical scavenger
• Clodronate reduces osteoclastic bone resorption
• Shown promising results in Stage I and II ORN; some Stage III regression reported
• Treatment duration: months to years

Surgical (Severe/Stage II-III):

1. Sequestrectomy and saucerization - for limited disease
2. Segmental resection of the mandible - for Stage II/III; removes all necrotic bone with margins
3. Immediate vascularized reconstruction:
   • Free fibula flap (gold standard for mandibular reconstruction) - provides cortical bone + soft tissue
   • Free radial forearm flap (soft tissue only)
   • Pectoralis major pedicled flap (soft tissue coverage)
4. Tracheostomy if airway compromise
5. Gastrostomy tube for nutritional support during treatment

"When bone and soft tissue necrosis are extensive, radical resection of the mandible with immediate microvascular reconstruction may provide better results. Persistence of ORN despite aggressive treatment should raise the suspicion of recurrent cancer." (Cummings Otolaryngology, p. 1149)

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ORN vs. MRONJ - Key Differences

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Summary of Key Points

• ORN = exposed non-healing bone in irradiated field > 3 months, no tumor
• Mandible most affected (unilateral blood supply + high radiation dose)
• Pathogenesis: 3H theory (Marx) OR fibroatrophic theory (Delanian)
• Most common precipitating event: post-irradiation tooth extraction
• Radiograph: ill-defined moth-eaten radiolucency, sequestrum, cortical destruction, no periosteal reaction
• Prevention is far superior to treatment - pre-radiation dental clearance is mandatory
• Treatment: conservative → PENTOCLO → HBO (controversial) → surgical resection + free flap reconstruction
• Always biopsy to exclude recurrent tumor before diagnosing ORN

1. LA composition, theories, max dosage
2. Anatomical landmarks of all nerve blocks + technique/needle insertion
3. Medicine prescription (Antibiotic, NSAIDs, Antacid) Plus: Landmark palpation, Case history, Theory (Balan - 0-3mm cut)

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VIVA-STYLE Q&A: Monheim's Local Anesthesia (OS Practical)

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TOPIC 1: LA COMPOSITION, THEORIES & MAXIMUM DOSAGE

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PART A - COMPOSITION / STRUCTURE OF LOCAL ANESTHETICS

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[Aromatic/Lipophilic End] — [Intermediate Chain] — [Amine/Hydrophilic End]

1. Lipophilic aromatic ring (hydrophobic end):
   • Usually a benzene ring (most LAs)
   • Articaine exception: contains a thiophene ring instead of benzene
   • Responsible for lipid solubility and ability to penetrate nerve membrane
   • Determines potency
2. Intermediate linking chain:
   • Either an ESTER linkage (-CO-O-) or AMIDE linkage (-NH-CO-)
   • This is the basis of classification into ester-type and amide-type LAs
3. Hydrophilic amine group (hydrophilic end):
   • Usually a tertiary amine
   • Determines water solubility
   • Carries a positive charge at physiological pH (weak base)

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1. Stabilizes epinephrine (prevents oxidation)
2. Maintains the LA in its ionized (BH⁺) form which is water-soluble and shelf-stable

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1. pKa (acid dissociation constant):
   • Most LAs have pKa between 7.9-9.1
   • At physiological pH (7.4), the proportion of un-ionized base form is determined by Henderson-Hasselbalch equation
   • Lower pKa = faster onset (more un-ionized form at pH 7.4)
   • Mepivacaine (pKa 7.9) has faster onset than lidocaine (pKa 8.2)
2. Lipid solubility:
   • Higher lipid solubility = higher potency and longer duration
   • Bupivacaine > lidocaine in potency (lipid solubility 8 vs 1)
3. Protein binding:
   • Higher protein binding = longer duration of action
   • Bupivacaine: 96% protein bound → longest duration
   • Prilocaine: 53% protein bound → shorter duration
4. Vasodilatory activity:
   • Most LAs are vasodilators (except cocaine which is a vasoconstrictor)
   • Greater vasodilation → faster absorption → shorter duration → need for vasoconstrictor

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PART B - THEORIES OF LA ACTION

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1. LA is injected → diffuses through connective tissue as un-ionized base (B) (lipid soluble)
2. Crosses the lipid nerve membrane
3. Inside the axoplasm, re-ionizes to cationic form (BH⁺)
4. BH⁺ binds to a specific receptor on the intracellular side of the voltage-gated Na⁺ channel (S6 segment of domain IV)
5. Blocks Na⁺ channel in the inactivated (closed) state
6. Na⁺ cannot flow into the cell → membrane fails to depolarize → no action potential → nerve conduction blocked

"Local anesthetics block nerve conduction of sensory impulses via sodium channel inhibition" - Lippincott Pharmacology

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1. Vasodilation (autonomic block)
2. Loss of pain and temperature
3. Loss of touch and pressure
4. Loss of motor function (last)

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PART C - MAXIMUM DOSAGE

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• MRD (mg) = MRD per kg × body weight (kg)
• Lidocaine: 4.4 mg/kg (without VC); 7 mg/kg (with epi)
• Articaine: 7 mg/kg
• Bupivacaine: 1.3 mg/kg

• 1 dental cartridge = 1.8 mL
• 2% lidocaine = 20 mg/mL × 1.8 mL = 36 mg/cartridge
• MRD 500 mg ÷ 36 mg = ~13.8 cartridges maximum (practical maximum = 8 cartridges)

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• MRD for lidocaine with epi = 7 mg/kg
• For 20 kg child: 7 × 20 = 140 mg
• Per cartridge: 36 mg
• Max cartridges: 140 ÷ 36 = 3.9 cartridges (~4 cartridges maximum)

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• Healthy patient: 0.2 mg (200 µg) epinephrine per appointment
• Cardiac patients: 0.04 mg (40 µg) - use with caution
• 1:100,000 epinephrine = 0.018 mg/cartridge
• For cardiac patient: 0.04 ÷ 0.018 = 2.2 cartridges maximum

• Uncontrolled hypertension
• Severe cardiovascular disease
• Hyperthyroidism
• Pheochromocytoma
• Patients on non-selective beta-blockers (risk of hypertensive crisis)
• Patients on tricyclic antidepressants

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TOPIC 2: ANATOMICAL LANDMARKS OF ALL NERVE BLOCKS - TECHNIQUE & NEEDLE INSERTION

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INFERIOR ALVEOLAR NERVE BLOCK (IANB) - Most Important

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• Inferior alveolar nerve (IAN)
• Lingual nerve
• Long buccal nerve (sometimes)

1. Pterygomandibular raphe - white fibrous band running vertically just medial to the last molar; the needle is inserted just LATERAL to this raphe
2. Coronoid notch (greatest concavity of anterior border of ramus) - palpated with index finger inside the mouth; needle directed toward this point
3. Pterygomandibular triangle - triangular space bounded by:
   • Medially: medial pterygoid muscle
   • Laterally: ramus of mandible
   • Target: mandibular foramen (located on the medial surface of the ramus)
4. Occlusal plane of mandibular teeth - barrel of syringe parallels this plane
5. Retromolar triangle - landmark for palpation

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• Used when patient cannot open mouth (trismus)
• Needle inserted at mucogingival junction of upper 3rd molar, parallel to occlusal plane, alongside the ramus
• Advanced 25 mm medially
• Anesthetizes: IAN, lingual, mylohyoid nerves
• No bone contact is made - blind technique
• Aspiration must be performed

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POSTERIOR SUPERIOR ALVEOLAR (PSA) NERVE BLOCK

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1. Maxillary tuberosity - posterolateral convexity of maxilla behind the last molar
2. Mucobuccal fold - height of vestibule distal to the upper 2nd molar
3. Zygomatic process of maxilla - superior landmark

• Mouth slightly open; cheek retracted
• Penetration: height of mucobuccal fold just distal and buccal to the maxillary tuberosity
• Needle directed: UP (superiorly) 45°, IN (medially) 45°, BACK (posteriorly) 45° - "up, in, back" at 45° in each plane
• Depth: 16 mm (short 25-gauge needle)
• Aspiration mandatory (pterygopalatine plexus is nearby)
• Deposit: 1.8 mL slowly

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MIDDLE SUPERIOR ALVEOLAR (MSA) NERVE BLOCK

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• Present in only ~28% of patients (often absent; territory covered by ASA and PSA)
• When present: innervates upper premolars and mesiobuccal root of 1st molar
• Landmark: Mucobuccal fold at the apex of upper 2nd premolar (midway between ASA and PSA injection sites)
• Depth: 5-6 mm supraperiosteal

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ANTERIOR SUPERIOR ALVEOLAR (ASA) / INFRAORBITAL NERVE BLOCK

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1. Infraorbital foramen - located 1 cm below the infraorbital rim on the midpupillary line (along a vertical line through the pupil, 2nd premolar, and mental foramen)
2. Mucobuccal fold above the upper lateral incisor (intraoral approach)

• Penetration: mucobuccal fold above the upper lateral incisor (NOT at the canine)
• Advance needle UPWARD, OUTWARD, BACKWARD toward infraorbital foramen
• Depth: ~16 mm
• Palpate the foramen extraorally with finger to direct the needle
• Do NOT enter the foramen (risk of orbital hematoma)
• Deposit 0.9-1.2 mL just BELOW the foramen while maintaining digital pressure

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GREATER PALATINE (ANTERIOR PALATINE) NERVE BLOCK

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• Patient: head tilted back, mouth wide open
• Needle inserted at 45° to the palate directly into the foramen (or just anterior to it)
• Depth: 4-6 mm (just into the canal)
• Deposit: 0.5 mL slowly (palate is tightly bound - painful; use slow injection)
• Blanching of palatal mucosa confirms correct placement

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NASOPALATINE (INCISIVE) NERVE BLOCK

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• Needle inserted at the lateral border of the incisive papilla (NOT directly into the papilla - very painful)
• Direction: perpendicular to the palate, slightly posteriorly
• Depth: 5 mm
• Deposit: 0.3-0.5 mL (small volume; very sensitive area)

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MENTAL / INCISIVE NERVE BLOCK

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• Penetration: mucobuccal fold anterior to the mental foramen (at 1st premolar area)
• Advance needle posteriorly at 45° to contact near the foramen
• Deposit: 0.6 mL for mental nerve block
• For incisive block: apply firm digital pressure over foramen for 2 min after injection to force LA through foramen

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LONG BUCCAL (BUCCINATOR) NERVE BLOCK

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TOPIC 3: MEDICINE PRESCRIPTION

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Standard Prescription Format:

Name: ___________________    Date: ___________
Age/Sex: _______________     Rx No.: __________

Rx

1. Tab. Amoxicillin 500 mg
   Cap. No. XXI (21 capsules)
   Sig: 1 capsule TID × 7 days (after food)

2. Tab. Ibuprofen 400 mg + Paracetamol 325 mg (Combiflam/Brufen)
   Tab. No. XXI (21 tablets)
   Sig: 1 tablet TID × 7 days (after food)

3. Tab. Pantoprazole 40 mg (Pantocid/Pan)
   Tab. No. XIV (14 tablets)
   Sig: 1 tablet BD × 7 days (30 min before food - empty stomach)

Advice:
- Complete the full course of antibiotics
- Cold/ice packs for 24 hours post-extraction
- Soft diet; avoid hot fluids for 24 hours
- Do not spit or use straw (dislodges clot)
- Bite on gauze for 30 minutes
- Return if bleeding, swelling, or fever

Signature: _______________
Registration No.: __________

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• 1st choice: Azithromycin 500 mg OD × 3-5 days (macrolide)
• Alternative: Clindamycin 300 mg TID × 7 days (most effective for orofacial/dental infections - excellent bone penetration)
• Alternative: Metronidazole 400 mg TID × 5 days (especially for anaerobic infections; add to erythromycin)

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• 1st line: Amoxicillin 500 mg TID × 5-7 days
• If no response in 48 hours / anaerobic component suspected: Amoxicillin 500 mg + Metronidazole 400 mg (combination)
• Severe/spreading infection: Amoxicillin-Clavulanate (Augmentin) 625 mg TID (covers beta-lactamase producing organisms)

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• Avoid ibuprofen/diclofenac (non-selective COX inhibitors)
• Use selective COX-2 inhibitor: Celecoxib 200 mg BD or Etoricoxib 60 mg OD
• COX-2 inhibitors spare gastric COX-1 → less GI toxicity
• However, increased cardiovascular risk with long-term use

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TOPIC 4: CASE HISTORY (Relevant to OS Viva)

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Structure (HOPI + PMH + Drug History):

• Nature of dental problem
• Duration, severity, any treatment so far

• Beta-blockers (propranolol) + epinephrine → hypertensive crisis (block β2 → unopposed α1 vasoconstriction)
• Tricyclic antidepressants (amitriptyline) → enhanced pressor effect of epinephrine (3-4× increase in BP)
• MAO inhibitors → profound hypertension with vasoconstrictors
• Anticoagulants → aspiration and injection site hematoma risk

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TOPIC 5: LANDMARK PALPATION

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1. Coronoid notch: Using the thumb of the operator's left hand (for right-side injection), palpate inside the mouth along the anterior border of the ramus → the greatest concavity felt is the coronoid notch. This orients the direction of needle insertion.
2. Pterygomandibular raphe: Visually identified as a white ridge running vertically from the upper to lower jaw when the mouth is wide open, just medial to the last upper and lower molars. Needle enters just LATERAL to this.
3. Retromolar triangle: Palpate the retromolar pad area to confirm position of ramus.
4. External oblique ridge: Felt on the buccal surface as a ridge running from the ramus diagonally forward.

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TOPIC 6: THEORY - BALAN (Depth of Incision 0-3 mm)

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• A surgical scalpel incision must be firm, decisive, and continuous - 0-3 mm refers to the planned depth of initial incision through mucosa and periosteum to reach bone
• 0 mm: Surface (mucosa only) - for mucosal lesion biopsy
• 1-2 mm: Through mucosa + submucosa - for soft tissue flaps
• 3 mm: Full thickness mucoperiosteal incision - through mucosa, submucosa, and periosteum to bone (used for surgical extractions, periapical surgery)

• 0 mm depth probe - no resistance to pressure = superficial anesthesia
• 1-2 mm = partial anesthesia
• 3 mm = deep anesthesia adequate for surgery

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QUICK REVISION TABLE: LA Drugs at a Glance

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COMPLETE GUIDE: EXTRACTION & LOCAL ANESTHESIA

(Monheim's LA + Oral Surgery - All Important Topics)

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PART 1: LOCAL ANESTHESIA

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1A. COMPOSITION OF LOCAL ANESTHETIC

Chemical Structure - Three Parts:

[AROMATIC RING] ——— [INTERMEDIATE CHAIN] ——— [AMINE GROUP]
  Lipophilic/                Ester (-CO-O-)          Hydrophilic/
  Hydrophobic             or Amide (-CO-NH-)          Tertiary amine

• Usually a benzene ring → responsible for lipid solubility and membrane penetration
• Articaine exception: has a thiophene ring (4-membered ring with sulfur) instead of benzene - gives superior bone diffusion
• Determines potency

• ESTER linkage (-CO-O-): procaine, cocaine, benzocaine, tetracaine
• AMIDE linkage (-NH-CO-): lidocaine, mepivacaine, bupivacaine, prilocaine, articaine
• Memory trick: Amides have TWO "i"s in their name (lidocaine, bupivacaine, articaine)

• Tertiary amine → determines water solubility
• Exists as ionized (BH⁺) or un-ionized (B) form depending on pH

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Dental Cartridge Composition (1.8 mL carpule):

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Ester vs. Amide Comparison:

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1B. MECHANISM OF ACTION (THEORIES)

Currently Accepted: Specific Receptor / Na⁺ Channel Theory

1. LA injected (acidic solution, ionized form BH⁺) → tissue buffers raise pH
2. Un-ionized base (B) form is lipid soluble → diffuses across nerve lipid membrane
3. Inside axoplasm, re-ionizes to BH⁺ (cationic form)
4. BH⁺ binds to intracellular receptor on S6 segment of voltage-gated Na⁺ channel (domain IV)
5. Na⁺ channel locked in inactivated/closed state → Na⁺ cannot flow in
6. Membrane fails to depolarize → no action potential → nerve conduction blocked

"Local anesthetics reversibly block lipid membrane sodium channels, preventing influx of sodium ions into the axon, blocking depolarization and the nerve action potential" - Rosen's Emergency Medicine

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All Theories (For Viva):

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Why LAs Fail in Infected Tissue:

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1C. PHYSICOCHEMICAL PROPERTIES

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1D. MAXIMUM RECOMMENDED DOSES (MRD)

• 1.8 mL cartridge × concentration = mg/cartridge
• 2% lidocaine = 20 mg/mL × 1.8 = 36 mg/cartridge
• 4% articaine = 40 mg/mL × 1.8 = 72 mg/cartridge

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1E. DIFFERENTIAL NERVE BLOCK (Order of Blockade)

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PART 2: NERVE BLOCKS - LANDMARKS, TECHNIQUE & NEEDLE INSERTION

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Maxillary (Upper Jaw) Nerve Supply:

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MAXILLARY NERVE BLOCKS

1. SUPRAPERIOSTEAL INFILTRATION (For maxillary teeth)

• Why it works in maxilla: Thin, porous cortical bone → LA diffuses through bone to root apex
• Landmark: Height of mucobuccal fold (mucoginigval junction) above the apex of the tooth
• Technique: Needle at 45° to bone; advance to root apex level; do NOT contact periosteum; deposit 0.9-1.2 mL slowly
• Anesthetizes: Single tooth (pulp + buccal periosteum + gingiva)
• Limitation: Fails for lower maxillary molars (thick zygomatic buttress blocks diffusion) → need PSA block

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2. POSTERIOR SUPERIOR ALVEOLAR (PSA) NERVE BLOCK

• Maxillary tuberosity (posterolateral bulge behind last molar)
• Height of mucobuccal fold distal to upper 2nd molar
• Zygomatic process of maxilla (superior boundary)

• Mouth slightly open, cheek retracted
• Needle enters at mucobuccal fold, distal and buccal to maxillary tuberosity
• Direction: Up 45° + In (medially) 45° + Back 45° = classic "Up, In, Back"
• Gauge/length: 25-gauge SHORT needle
• Depth: 16 mm
• ASPIRATE - pterygoid plexus of veins is here → hematoma is most common complication
• Deposit: 1.5-1.8 mL

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3. MIDDLE SUPERIOR ALVEOLAR (MSA) NERVE BLOCK

• Present in only ~28% of population
• Anesthetizes: Upper premolars + mesiobuccal root of 1st molar
• Landmark: Mucobuccal fold at apex of 2nd premolar (midway between ASA and PSA sites)
• Depth: 5-6 mm (supraperiosteal)
• Deposit: 0.9-1.2 mL

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4. ANTERIOR SUPERIOR ALVEOLAR (ASA) / INFRAORBITAL NERVE BLOCK

• Infraorbital foramen - 1 cm below infraorbital rim, on midpupillary line (vertical line through pupil, 2nd premolar, mental foramen)
• Palpate externally with index finger to locate foramen

• Penetration: mucobuccal fold above upper lateral incisor (NOT at canine)
• Direction: upward, outward, backward toward infraorbital foramen
• Advance toward foramen (do NOT enter it - risk of orbital hematoma)
• Keep external finger over foramen throughout injection
• Depth: 16 mm
• Deposit: 0.9-1.2 mL directly below foramen with digital pressure to push LA into foramen

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5. GREATER PALATINE (ANTERIOR PALATINE) NERVE BLOCK

• Greater palatine foramen - located at the junction of the horizontal plate of palatine bone and the maxillary alveolar process, approximately 1 cm medial to the gingival margin of the upper 2nd or 3rd molar
• Appears as a depression in the palate in this region

• Patient: head tilted back, mouth wide open
• Needle inserted at 45° to the palate, just anterior to or directly into the greater palatine foramen
• Depth: 4-6 mm (into the canal entrance)
• Deposit: 0.5 mL (slow - extremely tight mucosa)
• Blanching of palatal tissue confirms correct placement

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6. NASOPALATINE (INCISIVE CANAL) NERVE BLOCK

• Incisive papilla (small soft tissue bump in midline palate, just posterior to upper central incisors)
• Incisive foramen lies beneath it

• Insert needle at the lateral border of the incisive papilla (NOT centrally - very painful)
• Direction: slightly posterior, perpendicular to palate
• Depth: 5 mm
• Deposit: 0.3-0.5 mL (very small volume; highly sensitive area)
• Most painful injection in dentistry - use topical anesthesia, slow injection, distraction

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MANDIBULAR NERVE BLOCKS

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7. INFERIOR ALVEOLAR NERVE BLOCK (IANB) - Halsted Technique

1. Coronoid notch - greatest concavity of anterior border of ramus (palpated internally with thumb)
2. Pterygomandibular raphe - white, fibrous band running vertically from upper to lower jaw just medial to last molars; visible when mouth is wide open
3. Pterygomandibular triangle/space - bounded medially by medial pterygoid, laterally by ramus; contains the IAN
4. Lingula (mandibular spine) - bony projection just anterior to mandibular foramen; sphenomandibular ligament attaches here
5. Mandibular foramen - on medial surface of ramus; target of injection
6. Occlusal plane of mandibular teeth

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8. GOW-GATES TECHNIQUE (Alternative IANB)

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9. VAZIRANI-AKINOSI (CLOSED MOUTH) TECHNIQUE

• Used when patient has trismus (cannot open mouth)
• Needle inserted at the mucogingival junction of upper 3rd molar, parallel to maxillary occlusal plane
• Advanced 25 mm alongside ramus (no bone contact)
• Blind technique - aspiration mandatory
• Anesthetizes: IAN, lingual, mylohyoid

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10. MENTAL / INCISIVE NERVE BLOCK

• Mental foramen - lateral surface of mandible, at apex of mandibular 2nd premolar (or between premolars), mid-height of mandibular body
• On same vertical midpupillary line as infraorbital foramen (above) and mental foramen (below)

• Penetration: mucobuccal fold anterior to mental foramen (at 1st premolar area)
• Needle directed posteriorly at 45°
• Depth: 5-6 mm near foramen (do NOT enter foramen)
• Deposit: 0.6 mL for mental nerve
• For incisive block: Apply firm digital pressure over foramen for 2 min after injection → forces LA into foramen → anesthetizes incisive nerve → pulps of premolars, canine, incisors

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11. LONG BUCCAL (BUCCINATOR) NERVE BLOCK

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WHICH BLOCK FOR WHICH TOOTH? (Quick Reference)

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PART 3: TOOTH EXTRACTION

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3A. INSTRUMENTS FOR EXTRACTION

1. Elevators:

1. Lever principle: Fulcrum on alveolar bone crest; force applied to crown
2. Wedge principle: Blade driven between root and socket wall → expands PDL
3. Wheel and axle: Rotation of elevator handle → rotational force at tip

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2. Extraction Forceps:

1. Expansion of socket (buccal-lingual pressure)
2. Luxation (loosening from PDL)
3. Rotation (for single-rooted teeth)
4. Traction/Delivery (removal)

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3B. STEPS OF EXTRACTION (Standard Technique)

1. History & examination - medical, dental, allergy history
2. Radiograph - periapical X-ray (assess root morphology, bone level, proximity to IAN)
3. Informed consent
4. Appropriate LA (correct nerve block for region)
5. Wait for LA onset (3-5 min; confirm by probing)

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3C. POST-EXTRACTION INSTRUCTIONS

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3D. POST-EXTRACTION COMPLICATIONS

IMMEDIATE (during procedure):

EARLY (within hours):

LATE (days to weeks):

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3E. DRY SOCKET (ALVEOLAR OSTEITIS)

• General: 2-4% of all extractions
• Mandibular molars: 10-30%
• After impacted 3rd molar removal: up to 30%

• Smoking (most important modifiable risk) - nicotine impairs healing; negative pressure from sucking
• Trauma during extraction - excessive bone removal
• Oral contraceptives - estrogen increases fibrinolytic activity
• Osteomyelitis / pre-existing infection
• Poor oral hygiene
• Irrigation with vasoconstrictor (excess epinephrine → vasoconstriction → ischemia)
• Dense bone (mandibular molar region has least blood supply)

• Onset: 3rd-5th post-extraction day (pain returns and worsens after initial relief)
• Severe, constant, radiating pain (to ear, eye, temple - classic)
• Empty socket with grey/brown necrotic walls - no blood clot visible
• Bone exposed and painful to touch
• Fetid odor (putrefactive bacteria)
• No fever (distinguishes from surgical infection)
• Regional lymphadenopathy may be present

1. Gentle irrigation of socket with warm saline/chlorhexidine (0.2%)
2. Place Alvogyl (Eugenol-based) dressing or Zinc oxide eugenol (ZOE) into socket - replaces every 2-3 days
3. Systemic antibiotics (if signs of spreading infection)
4. Analgesics (NSAIDs or paracetamol + codeine)
5. Patient reassurance - heals in 1-3 weeks by secondary intention
6. DO NOT curettage the socket (destroys new granulation tissue)

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PART 4: COMPLICATIONS OF LA INJECTION

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PART 5: CONTRAINDICATIONS TO EXTRACTION

Absolute (temporary - defer until managed):

Local Contraindications:

• Malignancy of jaw (biopsy first to rule out)
• Vascular lesions (hemangioma) - risk of uncontrolled hemorrhage

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PART 6: PRESCRIPTION AFTER EXTRACTION

Rx

1. Tab. Amoxicillin 500 mg
   [OR if allergic: Tab. Azithromycin 500 mg OD]
   Cap. No. XXI (21)
   Sig: 1 capsule TID × 7 days after food

2. Tab. Ibuprofen 400 mg + Paracetamol 325 mg
   Tab. No. XXI (21)
   Sig: 1 tablet TID × 7 days after food
   [For peptic ulcer patients: Tab. Celecoxib 200 mg OD]

3. Tab. Pantoprazole 40 mg
   Tab. No. XIV (14)
   Sig: 1 tablet BD × 7 days (30 min before food)

4. Tab. Vitamin C 500 mg [Optional - promotes healing]
   Tab. No. XIV
   Sig: 1 tablet BD × 7 days

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QUICK SUMMARY TABLES

LA Drug Quick Reference:

Nerve Block Summary:

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Radiographic Diagnosis & Dental Treatment Plan

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What Is This?

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Radiographic Findings

1. Teeth Identified

• Two mandibular incisors (lower central incisors - most likely #31 and #41)
• Narrow, slender roots typical of lower anteriors
• Crowns appear relatively intact with no obvious gross caries

2. PRIMARY FINDING: Severe Vertical (Angular) Bone Loss

3. Endodontic Status

• Root canals appear patent with no previous RCT visible
• Severe bone loss extending to apices → strong suspicion of combined Endo-Perio lesion (pulpal pathology secondary to deep periodontal pocketing via lateral canals / apical foramen)
• Periapical pathology cannot be fully excluded due to image artifact

4. Periodontal Ligament Space

• Widened PDL space likely present (obscured by artifact)
• Clinical probing depths would be expected to be >7-10 mm in the interproximal area

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Diagnosis

Primary Diagnosis:

Localized Stage IV, Grade C Periodontitis (Severe, with complexity factors) affecting mandibular central incisors - with a hopeless to guarded prognosis

Possible Secondary Diagnosis:

Combined Endo-Perio Lesion (Class III - true combined lesion) if pulps are non-vital on testing

Using AAP/EFP 2017 Classification:

• Stage IV: Complexity factor - severe bone loss (apical third), likely tooth mobility Grade III, bite collapse potential
• Grade C: Rapid progression rate; vertical pattern; affecting younger individuals disproportionately

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Prognosis Assessment

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Complete Dental Treatment Plan

Phase 1: Diagnosis & Emergency (Immediate)

1. Vitality testing - EPT (Electric Pulp Test) and cold test on both teeth
   • If non-vital → confirms endo-perio lesion; RCT will NOT save the teeth at this stage
   • If vital → periodontal origin only
2. Periodontal probing - full-mouth periodontal chart; probe all 6 points per tooth; measure pocket depths, attachment loss, bleeding on probing, mobility score
3. Radiographic full assessment - retake proper periapical X-ray (not photographed from screen); consider CBCT for 3D bone defect assessment
4. Medical history - rule out systemic causes: uncontrolled diabetes (accelerates bone loss), immunosuppression, medications (bisphosphonates affect bone)

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Phase 2: Cause-Related Therapy (Non-Surgical Periodontal)

1. Oral hygiene instruction (OHI) - modified Bass technique; interdental brushes/floss
2. Supragingival scaling - remove supragingival calculus and deposits
3. Subgingival scaling and root planing (SRP) - full-mouth debridement under LA
4. Systemic antibiotics (if generalized aggressive periodontitis) - Amoxicillin 500 mg + Metronidazole 400 mg TID × 7 days
5. Chlorhexidine mouthwash (0.2%) BD × 2 weeks

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Phase 3: Re-evaluation (4-6 weeks post-SRP)

• Reassess pocket depths, mobility, radiographic bone levels
• Assess patient compliance
• At this stage, for teeth with bone loss to the apical third → extraction is the indicated treatment

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Phase 4: Extraction of Hopeless Teeth (Most Likely Definitive Treatment)

• Amoxicillin 500 mg TID × 5-7 days
• Ibuprofen 400 mg + Paracetamol TID × 5 days
• Pantoprazole 40 mg BD × 5 days
• Chlorhexidine rinse 0.2% BD × 1 week (after 24 hours)

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Phase 5: Prosthodontic Rehabilitation (Tooth Replacement)

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Phase 6: Maintenance (Supportive Periodontal Therapy)

• Full-mouth periodontal reassessment every 3 months for the first year
• Then every 6 months
• Reinforce OHI at every visit
• Address any residual pockets at other sites

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Summary

Bottom line: This radiograph shows advanced/severe localized periodontitis with hopeless prognosis for the two mandibular incisors. The primary treatment is extraction followed by implant-supported rehabilitation, preceded by cause-related periodontal therapy and management of contributing systemic factors.