NEET MDS Lessons
Periodontology
Full Mouth Debridement (Quirynen)
- Scaling in 2 appointments within 24 hours
- Tongue brushing with 1% chlorhexidine gel
- 0.2% chlorhexidine rinse
- 1% chlorhexidine pocket irrigation
Oral Hygiene Tools
Toothbrush Bristle Diameter:
- Soft: 0.007" (0.2 mm)
- Medium: 0.012" (0.3 mm)
- Hard: 0.014" (0.4 mm)
Brushing Techniques:
- Roll: Modified Stillman
- Circular: Fones
- Vertical: Leonard
- Horizontal: Scrub
Scaling Instruments
- Gracey curettes: Only outer cutting edge
- Universal curettes: Both edges cutting
- Langer curettes: Gracey shank + Universal blade
- Best grasp: Modified pen grasp (tripod effect)
- Scaling angle: 45 – 90°
Ultrasonic Scaling
- Vibration frequency: 18,000 – 50,000 cycles/sec
Stroke Types
- Exploratory: Light feeling (with probes)
- Scaling: Short powerful pull
- Root planing: Moderate to light pull
Gingival Crevicular Fluid (GCF) is a serum-like exudate found in the gingival sulcus. Initially considered a transudate in healthy gingiva, it transitions to an inflammatory exudate during disease states. GCF serves as a valuable diagnostic medium due to its dynamic composition, reflective of periodontal status.
Composition of GCF
GCF contains a variety of biochemical and cellular components that mirror periodontal health:
| Component | Characteristics & Clinical Importance |
|---|---|
| Glucose | 3–4 times higher than serum levels, indicating microbial metabolism and inflammation |
| Proteins | Albumin, IgG, enzymes like elastase, collagenase, myeloperoxidase |
| Electrolytes | Sodium, potassium, calcium — influence osmotic balance and tissue response |
| Cytokines | IL-1β, TNF-α, IL-6 — markers of inflammation and bone resorption |
| Prostaglandins | PGE2 — associated with tissue destruction and inflammation |
| Lymphocytes | T:B ratio is reversed (1:3) compared to serum (3:1), reflecting immune modulation |
| Microbial Products | Lipopolysaccharides, enzymes from plaque — triggers host response |
| Metabolic Products | Lactate, pyruvate — indicators of anaerobic bacterial activity |
Sharpening Stones
- Natural: India, Arkansas
- Artificial: Ruby, Carborundum, Ceramic
Surgical Equipment
- Dental loupes: 1.5 – 6× magnification
- Coe – pak working time: 15 – 20 minutes
Preventive Measures
- Calculus control toothpastes: Contain pyrophosphates
- Antibiotic prophylaxis: Amoxicillin 2.0g, 30 – 60 min before procedure
Abrasion Rates
- Dentin: 25× faster than enamel
- Cementum: 35× faster than enamel
Critical Measurements
- PMN threshold: 60% in junctional epithelium → tissue detachment
- Clinical significance: Level 1 provides tangible benefit of large size
Important Ratios & Numbers
- GCF glucose: 3 – 4× serum levels
- Aggressive vs chronic periodontitis: 3 – 4× faster bone loss
- Mineralization timeline: 50% (2 days), 60 – 90% (12 days)
🧬 Risk Factors
- Increased homocysteine levels
- Raised lipoprotein(a)
- Nephrotic syndrome increases CAD risk
- Unsaturated fatty acid intake: Protective
- Best probability predictor in elderly: LDL/HDL ratio
⚕️ Diagnosis & Presentation
| Condition | Diagnostic Best Practice |
|---|---|
| Angina pectoris | History |
| Stable angina | Cardiac markers unchanged |
| Acute MI | Tall T wave (earliest ECG sign) |
| MI ≥12 hrs post-onset | Test of choice: Cardiac troponin |
| Prinzmetal’s angina | First-line agent: Nitrates |
| Intraoperative MI | Transesophageal echocardiography |
| Best biomarker of MI | Troponin T |
| WHO MI criteria | Echo not part of official criteria |
🧪 Enzymes & Drugs
- Enzyme ↑ at 4 – 6 hrs, ↓ in 3 – 4 days: CPK
- Stress ECHO agent: Dobutamine
- Intervention of choice: Streptokinase + Heparin
- Thrombolytics window: Within 12 hrs of MI
🚨 Prognosis & Complications
- Day 1: Maximum MI mortality
- Post-MI valvular lesion: Mitral regurgitation
- Best predictor of morbidity: LVEF
- Fatal thrombolysis complication: Intracranial hemorrhage
- LAD artery nicknamed: Widow’s artery
- Attached Gingiva Width:
- Maxillary incisors: 3.5 – 4.5 mm
- Mandibular incisors: 3.3 – 3.9 mm
- Least in premolars (~1.8 – 1.9 mm)
- Cementum:
- Thickest in apical third and furcation (150 – 200 µm)
- Acellular cementum: cervical third
- Cellular cementum: forms after occlusal contact
- PDL Fibres:
- Principal: Type I collagen
- Reticular: Type III collagen
- Oblique fibres: Largest group, resist vertical forces
- Transseptal fibres: Reconstructed post bone loss
- Alveolar crest fibres: Prevent extrusion
- Gingival Conditions:
- Pregnancy gingivitis: Bleeding.
- Desquamative gingivitis: Fiery red, painful sloughing.
- Gingival hyperplasia: Most commonly caused by phenytoin.
- Gingival enlargement covering 3/4 of tooth: Grade III.
- ANUG:
- Organism: Spirochetes.
- Seen in: Young adults.
- First-day management: Avoid deep scaling.
- Stages: Superficial zone = bacterial contamination.
- Granulomatous Lesion: Pyogenic granuloma.
- Gingival Recession: Most commonly due to traumatic brushing.