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Operative Dentistry Techniques

Principles and Procedures for Tooth Restoration

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Course Objectives

By the end of this module, you will understand:

  • Cavity classification systems
  • Tooth preparation principles
  • Restorative material selection
  • Direct restoration techniques
  • Matrix systems and wedges
  • Adhesion protocols
  • Finishing and polishing
  • Troubleshooting common issues
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Cavity Classification Systems

Black's Classification

  • Class I: Pits/fissures
  • Class II: Proximal posterior
  • Class III: Proximal anterior (no incisal)
  • Class IV: Proximal anterior (incisal)
  • Class V: Gingival 1/3 facial/lingual
  • Class VI: Cusp tips/incisal edges
Black's Classification

Other Systems

  • Mount & Hume:
    • Site 1-3 (pit/fissure, contact, cervical)
    • Size 1-4 (increasing size)
  • ICDAS:
    • 0-6 scale (intact to distinct cavity)
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Tooth Preparation Principles

Mechanical Considerations

  • Outline form:
    • Extension for prevention
    • Include all defects
  • Resistance form:
    • Flat floors
    • Box shape
    • 90° cavosurface
  • Retention form:
    • Undercuts
    • Dovetails
    • Grooves
Tooth Preparation

Biological Considerations

  • Conservation:
    • Minimize removal
    • Preserve cusps
  • Pulp protection:
    • Liners/bases
    • Indirect pulp cap
  • Margins:
    • Clear of gingiva
    • Definable finish
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Amalgam Preparations

Class I

  • 1.5mm occlusal depth
  • 90° cavosurface
  • Dovetail if extending
  • Rounded internal angles

Class II

  • 0.5mm into dentin proximal
  • Gingival floor 0.5mm into CEJ
  • Isthmus width ≥1.5mm
  • Converging walls (2-5°)
Amalgam Prep

Modifications

  • Slot preparation:
    • Minimal proximal extension
  • Tunnel prep:
    • Access proximal from occlusal
    • Preserve marginal ridge
  • Bonded amalgam:
    • Less mechanical retention
    • More conservative
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Composite Preparations

Principles

  • Bevel enamel margins (45°)
  • 0.5mm into dentin
  • Round internal angles
  • No undercuts needed
  • Conservative extension

Class III

  • Lingual access when possible
  • 0.5mm clearance from adjacent
  • Gingival margin on enamel
Composite Prep

Class IV

  • Bevel incisal edge (2-3mm)
  • Chamfer lingual margin
  • Consider pulpal proximity

Class V

  • Round outline
  • No retention grooves
  • Extend to sound margins
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Restorative Materials

Amalgam

  • Composition:
    • 50% Hg, 35% Ag, 15% Sn/Cu/Zn
  • Advantages:
    • Durable
    • Self-sealing
    • Less technique sensitive
  • Disadvantages:
    • Non-esthetic
    • Requires bulk
    • Thermal conductivity
Dental Materials

Composite Resin

  • Composition:
    • Resin matrix + filler particles
  • Advantages:
    • Esthetic
    • Bonded to tooth
    • Conservative prep
  • Disadvantages:
    • Polymerization shrinkage
    • Technique sensitive
    • Wear over time
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Adhesion Protocols

Etch-and-Rinse (4th Gen)

  1. 37% phosphoric acid etch (15 sec)
  2. Rinse thoroughly
  3. Apply primer (hydrophilic)
  4. Apply adhesive (hydrophobic)
  5. Light cure

Self-etch (7th/8th Gen)

  1. Apply self-etch adhesive
  2. Agitate 20 sec
  3. Air thin
  4. Light cure
Dental Etching

Factors Affecting Bonding

  • Smear layer:
    • Remove for etch-and-rinse
    • Incorporate for self-etch
  • Moisture control:
    • Dentinal wetness (etch-and-rinse)
    • Dry field (self-etch)
  • C-factor:
    • Higher = more stress
    • Incremental layering
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Matrix Systems

Types

  • Tofflemire:
    • Universal matrix
    • Rigid band
    • Buccal/lingual placement
  • Sectional matrices:
    • Bi-directional rings
    • Better contacts
    • Less gingival excess
  • Custom matrices:
    • Celluloid strips
    • Class III/V restorations
Matrix System

Wedges

  • Functions:
    • Separate teeth
    • Seal matrix
    • Contour restoration
  • Types:
    • Wooden (absorb moisture)
    • Plastic (transparent)
    • Anatomical
  • Placement:
    • Gingival to contact
    • Firm seating
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Amalgam Restoration Technique

Condensation

  1. Incremental placement (1-2mm)
  2. Firm pressure with condenser
  3. Overfill preparation

Carving

  1. Remove excess with explorer
  2. Carve anatomical contours
  3. Check occlusion

Finishing

  1. 24-hour delay
  2. Brown/green/pink cups
  3. Final polish
Amalgam Condensation

Common Errors

  • Inadequate condensation:
    • Voids
    • Weak restoration
  • Overcarving:
    • Low marginal ridge
    • Open contacts
  • Premature polishing:
    • Marginal breakdown
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Composite Layering Techniques

Incremental Placement

  • Horizontal:
    • Simple cavities
    • 2mm increments
  • Vertical:
    • Deep cavities
    • Reduces C-factor
  • Oblique:
    • Class IV restorations
    • Better esthetics
Composite Layering

Three-Layer Technique

  1. Dentin replacement:
    • Opaque shade
    • Placed first
  2. Body shade:
    • Main bulk
  3. Enamel shade:
    • Surface layer
    • Translucent
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Finishing and Polishing

Objectives

  • Remove excess material
  • Establish anatomy
  • Create smooth surfaces
  • Minimize plaque retention

Sequence

  1. Gross reduction (flame burs)
  2. Contouring (finishing burs)
  3. Pre-polish (rubber points)
  4. High polish (paste/brush)
Polishing

Instruments

  • Burs:
    • 12-fluted carbide
    • Diamond finishing
  • Strips:
    • Proximal surfaces
  • Rubber points/cups:
    • Various grits
  • Polishing pastes
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Troubleshooting Common Issues

Postoperative Sensitivity

  • Causes:
    • Inadequate bonding
    • Over-drying dentin
    • High spots
  • Solutions:
    • Re-bond
    • Adjust occlusion
    • Desensitizing agents

Marginal Discrepancies

  • Causes:
    • Inadequate condensation
    • Polymerization shrinkage
    • Improper carving
  • Solutions:
    • Re-restore if significant
    • Flowable composite repair
Restoration Issues

Fractured Restorations

  • Causes:
    • Inadequate thickness
    • Occlusal overload
    • Material fatigue
  • Solutions:
    • Full replacement
    • Consider stronger material

Recurrent Caries

  • Causes:
    • Marginal gaps
    • Poor oral hygiene
  • Solutions:
    • Complete caries removal
    • Improved preventive care
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Emerging Technologies

Bulk-Fill Composites

  • 4-5mm increments
  • Reduced polymerization stress
  • Modified photoinitiators
  • Flowable and sculptable types

Bioactive Materials

  • Calcium silicate cements
  • Glass ionomer hybrids
  • Remineralizing composites
  • Antimicrobial properties
Bulk Fill Composite

Digital Workflows

  • CAD/CAM restorations:
    • In-office milling
    • Same-day dentistry
  • 3D printing:
    • Temporary restorations
    • Models
  • Digital impressions:
    • Improved accuracy
    • Patient comfort
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Key Takeaways

  • Proper preparation is foundation for success
  • Material selection should match clinical needs
  • Adhesion protocols vary by system
  • Matrix systems enable proper contacts
  • Incremental technique reduces stress
  • Finishing/polishing improves longevity
  • New materials expand treatment options

Questions and Discussion

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