7 Operative Dentistry I: Amalgam Restoration

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Questions and Answers

What is the minimum thickness required for amalgam restoration preparations?

3.0 mm

1.5 mm (correct)

2.5 mm

1.0 mm

Which form is designed to prevent dislodgment of the restoration along the path of insertion?

Outline form

Resistance form

Retention form (correct)

Convenience form

What is the purpose of the resistance form in cavity preparation?

To ensure aesthetic appeal

To increase dislodgement risk

To prepare the tooth surface for bonding

To prevent dislodgment under applied forces (correct)

Which of the following features is NOT an auxiliary means for retention form?

Molds Signup and view all the answers

What does the convenience form in amalgam cavity preparation refer to?

Clearance from the adjacent tooth Signup and view all the answers

What is the role of the outline form in amalgam cavity preparation?

To establish the preparation's shape Signup and view all the answers

Which margin angle is essential to establish in dental amalgam preparations?

90º cavosurface margin Signup and view all the answers

What must be included in cavity preparations to enhance retention?

Undercuts Signup and view all the answers

What is the correct ratio of Alloy to Mercury for achieving a homogenous amalgam mixture?

1:1 Signup and view all the answers

What is the purpose of condensing the amalgam mix?

To increase adaptation and final strength Signup and view all the answers

Under-trituration leads to which of the following outcomes?

Incomplete coating of particles Signup and view all the answers

Why is it necessary to burnish an amalgam restoration?

To remove excess mercury from the surface Signup and view all the answers

What does over-trituration result in?

High early strength and shiny appearance Signup and view all the answers

What is one reason for overfilling an amalgam restoration by 1 mm?

To improve marginal adaptation Signup and view all the answers

During the carving of an amalgam restoration, the technique is aimed at which of the following?

Restoring normal anatomy and contour Signup and view all the answers

Which of the following correctly describes a flash margin?

Explorer tip catches from tooth to amalgam Signup and view all the answers

Study Notes

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

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Description

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.