7 Operative Dentistry I: Amalgam Restoration

Operative Dentistry I: Amalgam Restoration and Manipulation II

• Course offered by Batterjee Medical College
• Presented by Dr. Luluah K. Alhagas, Assistant Professor in Operative Dentistry
• Year: 2024

Lecture Objectives

• Identify amalgam cavity preparations
• Identify amalgam manipulations
• Recognize amalgam safety precautions

Dental Amalgam Cavity Preparation

• Pre-operative assessment of the case is crucial

  • Includes medical/dental history
  • Taking radiographs (OPG, BW)
  • Dental screening
  • Chief complaint of the patient

• Local anesthesia is required

• Isolation is necessary for the procedure

• Cavity Preparation: General Requirements

  • Remove defects (caries, defective restorations)
  • Extend preparation on sound enamel
  • Establish a 90° cavosurface margin
  • Maintain a minimum thickness of 1.5-2 mm
  • Prepare undercut form
  • Incorporate additional preparation features (grooves, slots, pins, cove)

Cavity Principles

• Initial tooth preparation depth (pulpal floor depth)
• Outline form
• Cavosurface margin
• Primary retention form
• Primary resistance form
• Convenience form

1- Initial Tooth Preparation Depth: Pulpal Floor Depth

• Central groove depth is measured
• DEJ depth is also measured

1- Initial Tooth Preparation Depth: Axial Wall Depth

• Measurements for axial wall depth are taken
  • DEJ location
  • Pulpal floor is also measured

2- Outline Form/ Cavosurface Margin

• Cavosurface margin should be 90 degrees and have appropriate clearance

3- Retention Form

• Prevents dislodging of restoration along the insertion path

3- Retention form (Secondary)

• Auxiliary features support retention:
  • Locks
  • Coves
  • Pins
  • Slots

4- Resistance Form

• Prevents dislodgment if applied at the apical or oblique direction

4- Resistance Form (Secondary)

• Auxiliary features support resistance:
  • Locks
  • Coves
  • Pins
  • Slots

5- Convenience Form

• Making the procedure easier or more accessible
• Extending outline form for caries removal
• Matrix placement
• Amalgam insertion
• Providing clearance from adjacent tooth

Dental Amalgam Manipulation

• Alloy selection
• Alloy proportion
• Trituration proportion
• Condensation of amalgam mix
  • Increasing adaptation
  • Allow mercury to surface
  • Increase amalgam density
  • Increase final strength

Alloy Selection

• Depends on the case
  • Particle shape
  • Copper content
  • Zinc content

Alloy Proportion

• Ratio of alloy to mercury is typically 1:1
• Less mercury leads to a dry/friable mix, less strength, and more creep
• More mercury leads to high early strength and fast setting but less strength

Trituration Proportion

• Mixing mercury and alloy to produce a coherent, plastic, and homogenous amalgam mass ready for condensation

Under-Trituration/Over- Trituration

• Under-trituration yields a dull, friable amalgam mixture.
• Over-trituration results in a shiny, hard amalgam mix

Amalgam Carrier

• The instrument used to carry and place the amalgam

Burnishing of Amalgam Restoration

• Removing excess mercury from the surface to improve adaptation
• Guidelines for carving are necessary
• Ensuring increased adaptation at restoration margin

Carving of Amalgam Restoration

• Restoring normal tooth anatomy and contour
• Enhancing adaptation at restoration margins

Checking Occlusion

• Articulating paper is used to ensure proper occlusal contacts.

Checking Margin

• Using an explorer to evaluate the amalgam's margin's adaptation

Finishing/Polishing of Amalgam Restoration

• Reducing plaque retention
• Minimizing tarnish and corrosion

Dental Amalgam Manipulation: Finishing/Polishing- Coolant

• Is it necessary to use coolant with handpiece during finishing?
• Yes, amalgam is a conducive material.

Dental Amalgam Safety Precautions

• Proper procedures for scrap disposal, mercury containment and aerosols are essential to minimize environmental and occupational risks.
  • Amalgam removal and replacement
  • Scrap on bracket table
  • Amalgamator aerosol
  • Amalgam scrap container
  • Amalgam waste on cotton rolls
  • Amalgam and mercury in plumbing traps
  • Mercury trapped in tiles and carpeting

Dental Amalgam Recommendations (High Risk Populations)

• Children under six, pregnant women, nursing mothers, individuals with neurological impairment or kidney dysfunction must be careful
• Avoid dental amalgam fillings but if already present, don't remove unnecessarily

References

• Sturdevant's Art and Science of Operative Dentistry
• Chapter 13: Introduction to Amalgam Restorations
• Chapter 18: Biomaterials

Explore key concepts in Operative Dentistry I focused on amalgam restoration and manipulation. This quiz covers cavity preparations, manipulations, and essential safety precautions. Enhance your understanding of dental amalgam procedures and protocols.