1.Dent 6540 Fall 2025 Materials Concepts

A series of flashcards covering the key concepts from the Dent 6540 lecture notes, including materials classification, properties, polymerization processes, and optical characteristics.

What are the three main types of materials discussed in dental materials?

Metals, polymers, and ceramics.

How are metals typically described?

Hard, ductile, and strong.

What are ceramics typically described as?

Hard, brittle, and strong.

What are the three stages of dental materials?

Uncured material, curing reaction, and cured material.

What does a curing reaction do to a material?

Transitions it from a flowable state to a solid or hardened state.

What are the major classes of dental materials?

Direct cure and indirect cure.

What is one advantage of indirect placement in dental materials?

Longevity.

What are some disadvantages of indirect placement?

Multiple visits and expense.

What is a good description of bonding in metals?

A sea of electrons.

What are the results of metallic bonding?

High thermal and electrical conductivity and ductility.

How are metals formed?

From a molten state undergoing crystallization to form grains.

What is an alloy?

A mixture of two or more metals that improves mechanical properties.

What do alloys inhibit at the molecular level?

Inhibit the movement of atoms and defects.

What are the two main types of bonding in ceramics?

Covalent and ionic.

What do most common ceramics in dentistry contain?

Metallic oxides such as SiO2, Al2O3, and K2O.

What are the three microstructures of ceramics?

Amorphous, semi-crystalline, and crystalline.

What does the amorphous structure of dental porcelain provide?

Good esthetics but relatively poor mechanical properties compared to other ceramics.

What is the structure of polymers compared to?

Entangled long chains like cooked spaghetti.

What are the four steps of chain reaction polymerization?

Activation, initiation, propagation, and termination.

What is a polymer made of?

Many monomers bonded together.

What does the light activation step of polymerization generate?

Free-radicals.

What are two consequences of the propagation step in polymerization?

Chain growth and volume decrease or shrinkage.

What is produced by a monomethacrylate in polymerization?

A linear type of polymer.

What type of polymer does a dimethacrylate produce?

A thermoset type of polymer.

What does light-curing a resin allow for?

A direct type of restoration.

What are physical mixtures of metals, ceramics, and polymers known as?

Composites.

What is the effect of increasing filler in a composite resin?

The composite behaves more like the filler or the ceramic phase.

What is the thermal expansion coefficient?

The dimensional change in a material in response to temperature.

Why is it important for restorative material to match the thermal expansion coefficient of teeth?

To ensure compatibility and prevent damage.

Which materials have high thermal conductivity?

Metals.

Which materials have low thermal conductivity?

Ceramics and polymers.

What is a clinical significance of the conductivity of metals?

Corrosion of metals and galvanic reactions.

What are the main components of optical properties?

Color, translucency, gloss, and surface texture.

What are the three main components of color perception?

The light source, the object, and the eye or individual.

What are the three dimensions of color?

Hue, value, and chroma.

What is metamerism?

Two objects that appear the same color under one light source and different under another.