Advertisement Upgrade to remove ads

Why is it necessary to study the science of dental materials

Help us to explain The properties and performance of material, examine the internal structures of the dental materials, atomic makeup of matter allows us to predict the properties

States of matter

Solid, liquid,gas,colliod

Atomic bonds

Are cohesive forces, are the bindings forces that holds atoms together, are the results of electromagnetic forces

Solids

Are rigid and dence, have low vapor pressure, have low energy state, resist external forces, has the strongest atomic bond, is characterized by a space lattice

Space lattice

Most common form is a cubic, in the shape of all solids

interatomical distance

Atoms in a space lattice maintaining their position relative to 1 another

Normal interatomic distance

The distance at which the force of attraction between atoms equals the force needed to repel them

Cubic shape of space lattice can be either _____ _____ _____ or they can be in ____ range _____

Short range order, long, order

2 types of solids

Chrystalline and amorphous

Short range order

Consistent range only 5 to 10 neighbors apart

Long range order

3 d spatial relationships of repeated atoms and molecules are millions of thousands of neighbors apart but the distance is consistent

Liquids

Have short range order, energy level is high, has a stronger attraction between molecules than gases but not as strong as solids, are unable to carry a load or maintain a shape without support

Molecular relationship of water

Molecules are 5 to 10 neighbors apart

Gases

Atomic bonds are week, has no molecular organization, and will take on any 3 d shape of any container, if thermal energy is removed by cooling it will condense into liquid, has no given volume, has highest energy level

Colloid

Is a mixture of gases, liquid, and solids

Types of bonds

Primary bonds, secondary bond

Primary bonds

Are strong bonds between atoms that involve the transfer or sharing of electrons between atoms

Valence electrons

Electrons involved in chemical reactions and atomic bonds

Ionic bond

Occurs when 1 atom donates its electrons to another, And both become stable through linkage

Ionic bond occurs when there is ___________ between a _______ and ________ charge

Interaction, positive, negative

Ionic bonds are not as strong as _________ _____

Covalent bonds

Examples of ionic bonds

Sodium chloride, table salt, porcelain

Covalent bond

Are strong and stable, is the result of sharing of electrons between 2 atoms, is very directional

Crytallines

Has sharp and definite melting or freezing points, Are both long and short range order, Resist forces, Most used in dentistry are the cubic type space lattice

Examples of christallines

Salt, diamonds, hydroxyapatite of teeth, gold, silver alloy

Amorphous

Is without form, has no definite space lattice, has short range order, molecules tend to be distributed random, does not have a definite melting or freezing point, has closer 3 d relationship

Few materials are bonded only by ________ _____, usually a combination of ________ and _________ _____

Covalent bonds, covalent and hydrogen bonds

Metallic bonds

Occurs when many atoms share all of their outer valence electronics with their neighbors, arrangement is very strong and stable, makeup is dense and heavy

Secondary bonds

Are partial charges the result from an uneven distribution of electrons around an atom or molecule, are weaker and less stable

Metallic bonds are ____ __________ of ____ and ___________

Good conductors, Heat, electricity

_________ charges of secondary bonds can be _________ or _________, ____ or ______

Partial, temporary, permanent, weak, strong

________ _____ are responsible for the limited strength in polymers, and has ________ ________ _____ of ______ and individual ______ of ________ _____

Secondary bonds, Internal covalent bonds, carbon, chains of hydrogen bonds

Hydrogen bonds

Are special type of permanent dipole, contains only 1 electron although weak, is the strongest all secondary bonds

Hydrogen bonds are important in ______ ________ and in ___ and ________

Dental Polymers, dna, protein

Atomic bonds as they relate to dental materials

Metals, ceramics, polymers, composite

Why is colloid not a true solution?

Because 1 material will not disolve into another

Examples of colloid

Fluoride foam, alginate, reversible hydrocolloid

An _____ _________occurs between a _____ ________ and a cement and a _____ structure

Ionic interaction, glass ionomer, tooth

Examples of covalent bonds

Carbon-carbon bond that holds the polymer chain of dental composites and dentures, Protein, DNA

All metals in dentistry consist of _________ _____

Metallic bonds

Metals are:

Opaque in nature, have luster, and electrical conductivity

Ceramics are:

Bonded with ionic bonds, are strong when compressed

Polymers

Consent of repeating units of long chains of covalent bonds, and weaker individual hydrogen bonds, has high molecular weight compound, are poor conductors of heat

Variety of bonds between the polymer chain that help to determine its strength

Cross linking, linear polymers, and permanent dipole

Polymers with permanent dipoles

Have a side group with an uneven distribution of elect,,ron

With permanent dipoles, as the ______ and intensity of the charges _________ so does the _______ and _________

Number, increases, strength, stiffness

Example of polymer with permanent dipoles

PFI and yellow tip probe

Linear polymers

Contains a fluctuating dipoles, which is a weak bond that is broken easily as the chains slide by one another at room temperature, are processed by heat, has a secondary bond

Examples of linear polymer

Plastic bags, bleaching trays, bite guards

Cross linking polymers

Are linked by covalently bonded atoms, preventing them from sliding past on another

Cross-linking results in a _____ somewhat ________ _______ that can sometimes be ________, according to the amount of ____ _____ that exist

Stiff, stronger material, stretched, cross links

Please allow access to your computer’s microphone to use Voice Recording.

Having trouble? Click here for help.

We can’t access your microphone!

Click the icon above to update your browser permissions above and try again

Example:

Reload the page to try again!

Reload

Press Cmd-0 to reset your zoom

Press Ctrl-0 to reset your zoom

It looks like your browser might be zoomed in or out. Your browser needs to be zoomed to a normal size to record audio.

Please upgrade Flash or install Chrome
to use Voice Recording.

For more help, see our troubleshooting page.

Your microphone is muted

For help fixing this issue, see this FAQ.

Star this term

You can study starred terms together

NEW! Voice Recording

Create Set