Synopsis

• Least risk site: Atrial septal defect
• IV drug user: Tricuspid valve affected
• Common organism: Staph aureus
• Late prosthetic valve endocarditis: CoNS
• Signs:
  • Osler’s nodes – Palms & soles
  • Roth spots – Retinal hemorrhage
• Best test: Echocardiography
• Criteria: Duke’s
• Dental prophylaxis: Amoxicillin

• Primary site of LA action: Amygdala (limbic system).
• pKa of lignocaine: 7.8.
• Pregnancy supine hypotension: Due to IVC compression.
• Pregnant patient position: Left lateral decubitus.
• Corticosteroids in pregnancy: FDA Category C.
• Ketamine action site: Thalamocortical junction.
• Atracurium & cisatracurium metabolism: Hoffman elimination.
• Neuralgia treatment: Carbamazepine arrests Na⁺ channels in inactive state.

• Stevens-Johnson Syndrome (SJS):

  • Characterized by ulcers with hemorrhagic crusts.

  • Typically has an acute onset following drug exposure (mainly sulfa group drugs).

• Biopsy for Vesiculobullous Pathology: Should be taken from the margin of the vesicle/bulla, including a significant amount of normal-appearing mucosa, to capture the pathological changes and adjacent healthy tissue for comparison.

• Linea Alba: A white, bilateral line on the buccal mucosa associated with pressure, frictional irritation, or sucking trauma from the facial surface of teeth.

• Morsicatio Buccarum: Chronic irritation seen on the buccal mucosa as a result of suction and glassblowers (chewing habits).

• Riga-Fede Disease: Sublingual ulcerations in infants resulting from chronic mucosal trauma from adjacent primary teeth (often natal/neonatal teeth).

 Biomechanical Principles

Crown-Root Ratio

• Ideal ratio: 1:2 (crown:root)
• Clinical significance: Optimal load distribution and retention
• Failure correlation: Unfavorable ratios increase mobility risk

Length-Deflection Relationship

• Critical formula: FPD length increases 3× → deflection increases 27×
• Mathematical basis: Deflection ∝ length³ (cubic relationship)
• Clinical implication: Longer spans have exponentially higher failure risk

Preparation Design Parameters

Optimal Taper

• Range: 10–15°
• Clinical balance: Retention vs. resistance form
• Excessive taper: Reduces retention
• Insufficient taper: Insertion difficulty

Resistance Form Enhancement

• Method: Add vertical groove to tapered preparation
• Purpose: Prevents rotation and improves retention
• Application: Especially important for shorter clinical crowns

Pivoting Prevention

• Solution: Smaller diameter preparation
• Mechanism: Reduces rotational tendency
• Clinical correlation: Improves long-term stability

Abutment Classifications

Pier Abutment

• Definition: Edentulous space on both sides
• Clinical challenge: Higher stress concentration
• Design consideration: Requires careful evaluation

Restoration Types & Advantages

Retention Hierarchy

• Maximum retention: Complete crown
• Reason: 360° circumferential preparation
• Clinical application: Preferred for compromised abutments

Connector Systems

• Non-rigid connector type: Tenon mortise
• Function: Allows independent movement of abutment segments
• Indication: Different mobility patterns of abutments

 Specialized Techniques

Virginia Bridge

• Technique: Lost salt crystal method
• Historical significance: Early adhesive bridge technique
• Clinical correlation: Minimal preparation approach

Anatomy

• Course: Mandibular foramen → mental foramen
• Branches: Dental branches, mental nerve, incisive nerve
• Function: Sensation to mandibular teeth, chin, lower lip
• Clinical significance: Most commonly injured nerve in oral surgery

Common Injury Scenarios

• Third molar extraction: Most frequent cause
• Implant placement: Especially posterior mandible
• Orthognathic surgery: Bilateral sagittal split osteotomy
• Mandible fractures: Direct trauma or surgical treatment
• Local anesthesia: Rare but reported

Repair Considerations

• Timing: Early repair (within 3-6 months) preferred
• Surgical approach: Intraoral vs extraoral
• Magnification: Operating microscope or loupes essential
• Patient factors: Age, overall health, functional expectations

Surgical Technique for IAN Repair

Preoperative Planning

• Imaging: CT or MRI to assess defect size
• Function testing: Baseline sensory evaluation
• Patient counseling: Realistic expectations

Surgical Steps

1. Exposure: Careful dissection to identify nerve ends
2. Debridement: Remove scar tissue and neuromas
3. Assessment: Determine gap size and repair options
4. Repair: Direct suture vs grafting based on gap
5. Closure: Tension-free, layered closure

Postoperative Care

• Protection: Avoid trauma to surgical site
• Monitoring: Regular sensory function assessment
• Rehabilitation: Sensory re-education if appropriate
• Timeline: Monitor recovery for 18-24 months

• Junctional Epithelium: Attached to enamel via hemidesmosomes; to connective tissue via external basal lamina.
• Corneocyte Formation: Keratinohyalin granules disappear, forming filaggrin.
• Langerhans Cells: Suprabasal level; antigen-presenting with Birbeck granules.
• Keratinization: Oral epithelium is 0.2 – 0.3 mm thick; may be keratinized or parakeratinized.