Introduction to Dental Materials

What is the overriding goal of dentistry?

Which of the following materials were historically used for tooth and root replacement?

When did modern dentistry begin?

Which four groups of materials are used in dentistry today?

What are the three main classifications of dental materials?

Which type of material is used to prevent leakage in teeth?

What are the restorative materials used to replace or repair lost tooth structure?

What differentiates direct from indirect restorative materials?

What are auxiliary dental materials used for?

Dental materials must be poisonous or harmful to the body.

Dental materials should be aesthetically pleasing.

Dental materials should be easy to form and place in the mouth.

Dental materials should not function despite limited access, wet conditions, and poor visibility.

What kind of properties are based on the laws of mechanics, acoustics, optics, thermodynamics, electricity, magnetism, radiation, atomic structure, and nuclear phenomena?

What are three optical properties that relate to color and perception?

What are the laws of thermodynamics used to understand?

What two physical properties are particularly important for dental ceramics?

What are the essential properties of impression materials?

What property of a material is related to the clinical performance of amalgam?

What are the electrochemical properties that significantly affect metals and their alloys?

What is the study of deformation and flow characteristics of matter regardless of its state?

What is the resistance of a fluid to flow?

Dental professionals should strive to manipulate dental materials in a fluid state for successful clinical outcomes.

The success or failure of a material relies solely on its performance properties in the solid state.

Most dental materials are initially in a solid state to allow for ease of placement and shaping.

What transformation do cements and impression materials undergo in the mouth?

What kind of products are transformed from fluid slurries to solids?

What type of materials appear solid but are actually supercooled liquids?

What is the term used to describe the irreversible flow of a supercooled liquid under sustained pressure?

What property is a measure of the consistency of a fluid and its resistance to flow?

A highly viscous fluid flows rapidly.

Dental materials have uniform viscosities regardless of their intended application.

What is the space between two flat surfaces where viscosity is observed?

What phenomenon is the time-dependent plastic strain of a material under a static load or constant stress?

What is the percentage range of mercury by weight found in dental amalgams?

Dental amalgams melt at temperatures far above room temperature.

Dental amalgams cannot undergo creep due to their high melting point.

Creep is a major concern for restorative materials used in the mouth because it can cause permanent deformation of restorations.

What term is more commonly used than creep in dentistry to describe the rheology of amorphous materials?

Creep is always desirable in dental materials to allow for flexibility in the mouth.

What important goal of dentistry is related to the color and appearance of natural dentition?

The development of a general-purpose, technique-insensitive, direct-filling, tooth-colored, color-stable restorative material has been readily achieved.

What type of radiation is detected by the human eye and is responsible for color perception?

What is the range of wavelengths visible to the human eye?

For an object to be visible, it must absorb all wavelengths of light.

What is a mixture of various wavelengths of light commonly known as?

The interaction of light with restorative materials is irrelevant for achieving good esthetics.

What factor determines how an object appears under different types of light?

Electromagnetic radiation in the visible spectrum interacts with objects only through absorption, not reflection or transmission.

What properties of a material are determined by the way it interacts with light?

What happens to light when it strikes a rough surface?

Light from a perfectly smooth surface scatters in many directions.

What type of reflectance is associated with a flat, dull appearance like chalk?

Verbal descriptions of color are precise enough to describe the appearance of teeth.

What are the three objective variables used to describe color perception?

What is the dominant color of an object?

What is the vertical axis of the color solid image?

What is the degree of saturation of a particular hue?

Objects that appear color-matched under one type of light will always appear the same under different types of light.

Color matching should ideally be performed under as many different light sources as possible.

Laboratory shade matching procedures should be performed under varying lighting conditions to improve accuracy.

What is the most common method used for color matching in dental practice?

What are the individual tabs on a shade guide arranged by?

The traditional arrangement of shade guide tabs prioritizes hue before value.

The newer trend in shade guides prioritizes arrangement according to value.

When restorative materials are placed in deep cavities, it is desirable for them to transmit heat readily to the vital dental pulp.

The transmission of thermal energy to the mucosa is undesirable in denture bases.

What properties govern the thermal behavior of restorative materials?

What is another category of thermal behavior besides thermal conductivity and diffusivity?

What is the physical property that governs heat transfer through a material by conductive flow?

What is the transfer of thermal energy in a solid?

How is thermal conductivity defined?

Thermal conductivity is only measured under non-steady-state conditions.

Thermal conductivities increase in the following order: metals < ceramics < polymers.

What are materials with high thermal conductivity called?

What does a high thermal conductivity indicate about a substance?

What property measures the speed of temperature change throughout an object?

A high density and high specific heat always lead to high thermal diffusivity.

Low heat capacity and high thermal conductivity lead to low thermal diffusivity.

What is the coefficient of thermal expansion related to?

The coefficient of thermal expansion is unimportant for dental applications.

The coefficient of thermal expansion can influence the procedures used for creating restorations.

A tooth restoration always expands and contracts at the same rate as the surrounding tooth structure.

What is tarnish?

What can cause tarnish in a dental restoration?

What kind of films can contribute to tarnish?

Tarnish is always a cause for concern and should be treated immediately.

What is corrosion?

Corrosion is always caused by chemical reactions, not electrochemical reactions.

Corrosion can only cause minor surface changes and has no impact on the mechanical integrity of metal restorations.

Corrosion is a significant issue solely in the oral environment.

Corrosion is always a rapid and dramatic process.

What is the first step in both chemical and electrochemical corrosion?

What type of corrosion involves a direct combination of metallic and nonmetallic elements?

Why is chemical corrosion also called dry corrosion?

What type of corrosion requires the presence of water or a fluid electrolyte?

Electrochemical corrosion is solely responsible for corrosion in dental materials.

What are the mechanical properties of dental materials defined by?

What does the study of mechanics involve?

Knowing the mechanical properties of dental materials is unimportant in identifying the potential causes of clinical failures.

The stressing rate has little influence on the strength of brittle materials.

What are three types of deformation?

The type of stress applied to dental materials has little impact on their response.

What is the strength of a material?

The strength of a material is independent of factors like stressing rate and shape of the specimen.

A surface finish that has many flaws has a positive impact on the strength of a material.

Stresses that are below the proportional limit cause permanent deformation.

Brittle materials can plastically deform before fracturing.

The clinical strength of brittle materials like ceramics is not affected by the presence of flaws.

What type of strain is reversible?

What type of strain is permanent?

Visoelastic materials exhibit both viscous and elastic characteristics.

What is the elastic modulus?

Enamel is more flexible and tougher than dentin.

What is strength in relation to dental materials?

Strength values reported by manufacturers are always accurate representations of the actual strength of a material.

What is the proportional limit?

What is the elastic limit?

What is yield strength or proof stress?

What are the four types of ultimate strength?

Toughness is a measure of a material's resistance to scratching.

Fracture toughness is a measure of the energy needed to propagate flaws in a material.

What describes the inability of a material to sustain plastic deformation before fracture?

Brittle materials are typically resistant to fracture.

What is the ability of a material to sustain a large permanent deformation under a tensile load before fracture?

What is the ability of a material to sustain considerable permanent deformation under compression without fracture?

Gold is known for its low ductility and malleability.

What does hardness measure?

Hardness alone is a comprehensive measure of wear resistance for all types of dental materials.

Biting force, chewing frequency, and the abrasiveness of the diet have no impact on wear resistance.