Abrasives and Dental Amalgam

A comprehensive set of vocabulary flashcards on abrasives and dental amalgam based on lecture notes.

Abrasive

A sharp, hard substance used for grinding, finishing, or polishing a softer surface.

Abrasive Action

The process in which a harder material comes into contact with a softer substrate, generating stresses that break atomic bonds.

Cutting

The use of a bladed instrument to create notches and grooves in a substrate.

Grinding

The removal of small particles from a substrate using bonded or coated abrasive instruments.

Polishing

The action on an extremely thin region of the substrate to produce a fine finish.

Desirable Characteristics of an Abrasive

Irregular shape, harder than the surface it's working on, tendency to fracture instead of dulling.

Factors Affecting Abrasion - Hardness

Durability of an abrasive determined by its ability to resist indentation.

Factors Affecting Abrasion - Shape

Sharp, irregular particles produce deeper abrasions than round particles.

Factors Affecting Abrasion - Pressure

Increased pressure leads to deeper cutting and removal of material.

Lubrication in Abrasives

Minimizes heat build-up and facilitates debris removal.

Abrasive Grits

Particles sized through a series of mesh screens, classified as course, medium course, medium fine, fine, and super fine.

Bonded Abrasive

Abrasive particles held together by a binder to form grinding tools.

Truing

A process to ensure an abrasive instrument rotates without eccentricity.

Dressing

A method to shape and clean an abrasive instrument to restore efficiency.

Coated Abrasive Discs

Flexible materials with abrasive particles secured to their surface.

Nonbonded Abrasive

Materials like polishing pastes used with non-abrasive devices.

Natural Abrasives

Examples include diamond, garnet, and pumice.

Manufactured Abrasives

Include silicon carbide and aluminum oxide.

Natural Diamond

The hardest known substance, composed of carbon.

Synthetic Diamond Abrasives

Consistent size and shape diamonds at a lower cost.

Emery

A grayish-black corundum used in coated abrasive discs.

Pumice

A light-gray abrasive material used for polishing.

Tin Oxide

An extremely fine abrasive used for polishing teeth.

Abrasive Pastes

Commonly contain aluminum oxide or diamond particles.

Process of Shaping Teeth

Includes bulk reduction, contouring, finishing, and polishing.

Benefits of Finishing

Leads to better gingival health, chewing efficiency, patient comfort, and esthetics.

Silicosis

A major illness caused by inhalation of silica-based particles.

Amalgam

An alloy that contains mercury.

Amalgamation

The process of mixing mercury with metal alloys to create amalgam.

Trituration

Mixing amalgam alloy particles with mercury.

Types of Trituration

Includes hand methods with mortar and pestle and mechanical methods using an amalgamator.

Dental Amalgam Alloys - Conventional

Irregularly shaped particles produced by milling.

Dental Amalgam Alloys - Spherical

Spherical particles created by auto mixing in an inert gas chamber.

High Copper Alloy

Contains 6-30% copper, more resistant to gamma-2 phase.

Amalgamation Phases

Include Gamma, Gamma 1, Gamma 2, Epsilon, and Eta phase.

Clinical Manipulation of Amalgam

Involves proper ratios of mercury to alloy for restoration.

Condensation

The process of compacting alloy in a cavity to achieve density.

Carving and Finishing Objective

To simulate tooth anatomy rather than replicate fine details.

Dimensional Changes of Amalgam

Include initial contraction, expansion, and delayed contraction.

Mercury Hygiene

Safe practices for handling mercury in dental offices.

Allergy Symptoms to Amalgam

Itching, rashes, and difficulty breathing.

Toxicity of Mercury

The potential harm to biological tissues from exposure.

Safety of Amalgam Fillings

Includes allergy and toxicity precautions for patients.

Creep in Amalgam

Plastic deformation of amalgam under stress over time.

Tarnish and Corrosion

Amalgam may corrode in oral environments leading to aesthetics issues.

Smooth Surface Minimization

Achieving a smooth and homogeneous surface reduces tarnish.

Clinical Considerations

Factors influencing the effectiveness of dental restorations.

Strength of Amalgam

Amalgam is strong in compression but weak in tension.

Moisture Contamination

Can cause delayed expansion in zinc-containing amalgams.

Hygiene Maintenance in Dental Offices

Practices to ensure safety and minimize exposure to mercury.